SUPPORT / THE LANGUAGE OF EXPLORATION

Every term.
A little clearer.

The Mandelbrot Metal glossary. From your first bookmark to the math inside a GPU thread, find the words behind the image.

Find a term

501 definitionsAbout the sources

One reference, several kinds of knowledge.

Definitions cover current Version 3 behavior, general mathematics, historical engineering language, and future roadmap concepts. Older articles remain useful background; where descriptions differ, app-specific definitions follow the current technical materials and Revision 19 of the white paper. Planned features are identified as planned.

4K / 6K / 8K capture

Navigation & controls

Also found as 3840 · 5760 · 7680

App presets with nominal longest edges of 3,840, 5,760, and 7,680 pixels, preserving the canvas proportions. They are still-image options, not claims of current video export.

Read more: GPU Pipeline · User Guide

ABI

GPU & rendering

Also found as application binary interface

The binary layout contract between compiled components. For shared Swift–Metal uniforms, field order, sizes, alignment, and padding must match.

Read more: Technical white paper · Revision 19

Absorption

Precision & deep zoom

Also found as lost increment · precision wall

When a tiny increment rounds away on addition to a much larger value. The increment may be representable separately even though the resulting sum is unchanged.

Read more: Beyond Complex Numbers · Inside the Infinity Engine

Adaptive quality

GPU & rendering

Also found as interactive quality · idle quality

Adjusting work according to interaction and rendering conditions. Preview responsiveness and completed-image fidelity are separate goals.

Read more: Technical white paper · Revision 19

Aggregate speedup

Engineering & roadmap

A ratio comparing total or aggregate elapsed times for a corpus. It is not necessarily the arithmetic average of individual scene speedup ratios.

Read more: Inside the Infinity Engine

Aliasing

GPU & rendering

Also found as jaggies · stair-stepping

Visible errors when fine spatial detail is sampled too sparsely, including jagged edges or misleading patterns. Extra samples can reduce it but cannot repair lost coordinates.

Read more: GPU Pipeline

Alignment

GPU & rendering

Also found as padding · field offset

Rules governing where data sits in memory. Padding can place fields at required boundaries; mismatched offsets make GPU code read the wrong values.

Read more: Technical white paper · Revision 19

All-QS control

Engineering & roadmap

Also found as control image

An image computed with every relevant sample using the quad-single path, for comparison with adaptive routing. Agreement checks a related implementation, not an independent mathematical truth.

Read more: Inside the Infinity Engine

Alpha

Color & lighting

Also found as opacity · alpha channel

A channel describing opacity or coverage. BGRA and RGBA color formats include alpha in addition to three color channels.

Read more: Technical white paper · Revision 19

Ambient light

Color & lighting

Also found as ambient fill

A baseline illumination term that keeps shaded regions visible. It is distinct from directional diffuse and specular contributions.

Read more: GPU Pipeline · Roadmap

Analytic function

Fractals & mathematics

Also found as holomorphic · complex differentiable

A function complex-differentiable throughout a neighborhood, where it has a convergent power-series expansion. This structure supports local derivative and Taylor analysis.

Read more: Beyond Complex Numbers · Perturbation Rendering

Apply

Navigation & controls

Accepting the previewed values in a tool. In Gradient Import, Apply saves the resulting palette after you choose its name.

Read more: User Guide

Approximate equality

Fractals & mathematics

Also found as ≈

A symbol indicating approximation rather than exact equality. The full quadratic perturbation identity is exact algebraically, while a first-order truncation is approximate.

Read more: Perturbation Rendering

AppTransaction

Engineering & roadmap

Also found as original app ownership

StoreKit's signed app-ownership information, including original acquisition details. The app uses verified ownership evidence in its Legacy Pro policy.

Read more: Technical white paper · Revision 19

Arbitrary precision

Precision & deep zoom

Also found as multiprecision · variable precision

Arithmetic whose precision can be selected or expanded beyond a fixed hardware format, within resource limits. It is a research direction for references, not a description of the current public Infinity path.

Read more: Inside the Infinity Engine · Roadmap

Aspect ratio

Navigation & controls

Image width divided by height. Coordinate fitting and capture presets preserve proportions rather than assuming every image has the same rectangular shape.

Read more: User Guide · GPU Pipeline

Asynchronous work

Engineering & roadmap

Also found as callback · completion handler

Work whose result arrives later. Generation and lifecycle checks prevent delayed results from updating a view or ownership request that is no longer current.

Read more: Technical white paper · Revision 19

Auto Iterations

Navigation & controls

Also found as Auto Iteration · Auto Iter · Auto

Automatic iteration policy responding to scale and renderer state. Its displayed proposal and the effective renderer count are distinct; deep-path policy can constrain or disable adaptation.

Read more: Technical white paper · Revision 19 · User Guide

Backup

Files & sharing

Also found as Export All backup

A separate saved copy used to recover files or move them between devices. Purchase restoration and a website download history are not substitutes for backing up personal work.

Read more: User Guide

Bailout radius

Fractals & mathematics

Also found as escape radius · bailout threshold

A magnitude threshold beyond which escape is established for the applicable map and parameter. Radius 2 is sufficient for Mandelbrot's critical orbit; arbitrary Julia constants need a suitable bound.

Read more: Technical white paper · Revision 19 · Perturbation Rendering

Banding

Color & lighting

Also found as color bands · quantization bands

Visible steps in a gradient. Source stops, LUT width, quantization, escape values, contrast, and display behavior can all contribute.

Read more: Palette System

Baseline scale

Navigation & controls

Also found as relative magnification

A stored reference scale used to interpret magnification and restore navigation consistently. It is separate from the current scale.

Read more: Technical white paper · Revision 19

Basin of attraction

Fractals & mathematics

Also found as basin of infinity

The starting points whose iterates approach a specified attracting behavior. For a polynomial, escaping points form the basin of infinity.

Read more: What Are Fractals?

Batch

GPU & rendering

Also found as bounded batch

A group of work units submitted together. Smaller batches can create opportunities for cancellation and feedback, while every batch still has scheduling overhead.

Read more: Inside the Infinity Engine

Batch export

Engineering & roadmap

Also found as export queue

Rendering several saved scenes through a managed queue. The roadmap treats it separately from the current single-image capture workflow.

Read more: Roadmap

BGRA8Unorm

GPU & rendering

Also found as BGRA8 · normalized eight-bit color

A four-channel format storing blue, green, red, and alpha in eight bits each, interpreted as normalized values. The app's active color output uses this format.

Read more: Technical white paper · Revision 19

Bifurcation

Fractals & mathematics

A qualitative change in a dynamical system as a parameter varies, such as a change in the stability or period of an attracting cycle.

Read more: Beyond Complex Numbers

Big O

Engineering & roadmap

Also found as algorithmic complexity · O(width × height × maxIt)

Notation for how a workload grows. A worst-case pixel-iteration estimate explains scale, but real work also depends on early escape, sampling, recovery, and hardware.

Read more: Archived code review · October 2025

BLA

Precision & deep zoom

Also found as block-linear approximation

An acceleration approach that replaces a validated block of iterations with a local linear approximation. The roadmap treats it as research requiring validity checks and recovery.

Read more: Roadmap · Inside the Infinity Engine

Blinn–Phong

Color & lighting

Also found as Blinn Phong shading

A lighting model using a halfway direction to shape specular highlights alongside diffuse and ambient terms. It is discussed in the historical lighting review.

Read more: Archived code review · October 2025

Blit

GPU & rendering

Also found as copy pass

A GPU copy or transfer operation that moves existing buffer or image data. It does not recalculate fractal orbits.

Read more: Technical white paper · Revision 19

Bookmark schema 7

Files & sharing

Also found as bookmark JSON v7

The portable bookmark version adding canonical Infinity center strings alongside numeric coordinates and optional residuals. Supported older versions retain compatible defaults.

Read more: Technical white paper · Revision 19

Boundary

Fractals & mathematics

The frontier where every neighborhood meets both a set and its complement. Fine Mandelbrot detail concentrates near this mathematically intricate interface.

Read more: Beyond Complex Numbers · What Are Fractals?

Bounded orbit

Fractals & mathematics

Also found as non-escaping orbit

An orbit that stays within some finite distance of the origin for all iterations. Surviving a finite iteration budget alone does not establish boundedness.

Read more: Technical white paper · Revision 19

Bounds check

GPU & rendering

Also found as out-of-bounds access

A test that rejects positions outside a valid image or resource range. It is essential when rounded-up dispatch sizes exceed the actual data dimensions.

Read more: Technical white paper · Revision 19

Branch divergence

GPU & rendering

Also found as divergent execution

When threads in one execution group follow different branches or need different iteration counts. This can reduce parallel efficiency even though the calculations remain independent.

Read more: Inside the GPU Engine of Mandelbrot Metal

Buffer

GPU & rendering

Also found as MTLBuffer

A contiguous GPU-accessible data resource. The reference orbit uses a buffer, while image-like color and height resources use textures.

Read more: Technical white paper · Revision 19

Burning Ship

Engineering & roadmap

A fractal family formed by taking absolute values of real and imaginary components before a quadratic update. It is a proposed additional family, not a current Mandelbrot mode label.

Read more: Roadmap

Cache

Engineering & roadmap

Also found as cache invalidation

Stored work reused to avoid recalculation, with rules for discarding it when inputs change. Orbit-free palette editing is planned work, not a current persistent escape cache.

Read more: GPU Pipeline · Roadmap

Canonical string

Precision & deep zoom

Also found as exact center string · hexadecimal center

A standardized text encoding of a stored coordinate. It avoids discarding low-order state during serialization; the renderer still projects it into its working arithmetic.

Read more: Technical white paper · Revision 19

Cantor set

Fractals & mathematics

Also found as Cantor dust · disconnected dust

A compact, perfect, totally disconnected set. Escaping parameters in the quadratic family produce Julia sets of this kind, often appearing as dust at finite resolution.

Read more: What Are Fractals? · Beyond Complex Numbers

Canvas

Navigation & controls

The visible drawing area containing your fractal composition. Its display dimensions determine the Canvas capture size, but capture still performs a separate render.

Read more: User Guide · GPU Pipeline

Canvas Size

Navigation & controls

Also found as Canvas capture

A capture using the drawable's current pixel dimensions. It still performs a dedicated complete render rather than saving a partially refined screen texture.

Read more: GPU Pipeline · User Guide

Capture

Navigation & controls

The command for rendering a complete PNG at a chosen output size. It snapshots the composition and renders separately from the live preview.

Read more: User Guide · GPU Pipeline

Capture Now

Navigation & controls

Starting the capture after choosing an output size. The app reports progress and opens the share sheet when the complete image is ready.

Read more: User Guide

Cartesian form

Fractals & mathematics

Also found as rectangular form · x + iy

Writing a complex number using perpendicular coordinates, z = x + iy. Polar form describes the same number using magnitude and angle.

Read more: Beyond Complex Numbers

Cauchy–Riemann equations

Fractals & mathematics

Also found as Cauchy Riemann

Relations between the partial derivatives of a complex function's real and imaginary parts. With suitable regularity, they characterize complex differentiability.

Read more: Beyond Complex Numbers

Center

Navigation & controls

Also found as center coordinates · x and y

The complex-plane position at the middle of the view. The HUD displays a rounded summary while saved state can retain more precise components.

Read more: Technical white paper · Revision 19 · User Guide

Center-out scheduling

GPU & rendering

Also found as bounded scheduling

Ordering small regions from the image center outward and limiting work submitted together. It improves the order of feedback without guaranteeing a fixed completion time.

Read more: Inside the Infinity Engine

Central difference

Color & lighting

Also found as finite difference · gradient estimate

Estimating a derivative from values on opposite sides of a point. The relief pass uses neighboring heights to estimate slopes.

Read more: GPU Pipeline

Circuit breaker

GPU & rendering

Also found as runtime failure circuit

A policy that avoids an unusable rendering route after failure. The current design keeps valid slow frames; exceeding the 250 ms diagnostic target alone is not a failure.

Read more: Technical white paper · Revision 19

Clear All

Navigation & controls

Removing a whole managed library after confirmation. This is distinct from clearing a website search or selection.

Read more: User Guide

Clear selection

Navigation & controls

Also found as Download selected

Community Portal actions that reset the selected rows or package them into a ZIP. The ZIP contains bookmark JSON files, not rendered images.

Read more: Community Portal

CLI

Files & sharing

Also found as command-line interface

A text-command interface used to run tools such as Photo2Palette. It supports repeatable scripted or batch workflows outside the app's graphical interface.

Read more: Introducing Photo2Palette: A Command-Line Tool

CMYK

Color & lighting

Also found as cyan magenta yellow black

A subtractive printing color model. The app exports RGB PNGs; a printer or managed print workflow handles conversion to an appropriate print profile.

Read more: From Screen to Print: Your First Fractal Artwork

Collection

Navigation & controls

Also found as bookmark set

A named group of shared files on the Community Portal. Choosing a collection narrows the visible catalog without importing anything into the app.

Read more: Community Portal

Color gamut

Color & lighting

Also found as wide gamut · wide color

The range of colors a space or device can represent. A wider gamut can include more saturated colors; it does not inherently reduce banding.

Read more: Palette System

Color management

Color & lighting

Also found as color conversion

Interpreting and converting color values between defined spaces and devices. Check a finished PNG in its intended viewer because the app does not claim a validated ICC round trip.

Read more: Palette System

Color space

Color & lighting

Also found as colour space

A specification relating numeric channels to colors, including primaries and an encoding. Choosing a wider gamut is separate from choosing more precision or higher brightness range.

Read more: Palette System

Color stop

Color & lighting

Also found as source stop · design stop · anchor

A position and color in a palette definition. The renderer constructs its lookup texture from these source values.

Read more: Palette System

Commit

Navigation & controls

Also found as committed viewport · committed state

Accepting an interaction's resulting view as a rendering and history state. This is distinct from the transient image transform displayed during a gesture.

Read more: Technical white paper · Revision 19

Commutativity

Fractals & mathematics

Also found as commutative

The property ab = ba. Complex multiplication is commutative; quaternion multiplication generally is not.

Read more: Beyond Complex Numbers

Compensated center

Precision & deep zoom

Also found as high-low center · split center

A viewport center stored with leading components and small residuals. This helps navigation retain displacements that one ordinary number would round away.

Read more: Technical white paper · Revision 19

Complex multiplication

Fractals & mathematics

Multiplying two complex numbers multiplies their magnitudes and adds their angles. This gives the quadratic map both a growth and a rotation interpretation.

Read more: Beyond Complex Numbers

Complex number

Fractals & mathematics

Also found as ℂ · a + bi · complex numbers

A number with real and imaginary parts, written a + bi, where i² = −1. Mandelbrot Metal maps each sample to a point in this two-dimensional number system.

Read more: Beyond Complex Numbers

Complex plane

Fractals & mathematics

Also found as Argand plane · parameter map

A plane whose horizontal axis is the real part and vertical axis is the imaginary part. Points represent complex numbers.

Read more: Beyond Complex Numbers

Compute kernel

GPU & rendering

Also found as kernel · compute shader

A GPU function invoked across a grid of threads. The primary app kernel performs coordinate mapping, orbit work, coloring, and optional height output.

Read more: GPU Pipeline

Compute pass

GPU & rendering

A stage of GPU work described by a compute command encoder. The primary orbit-and-color pass and optional relief pass have different input and output responsibilities.

Read more: GPU Pipeline

Conditioning

Precision & deep zoom

Also found as well-conditioned · ill-conditioned

How sensitive the mathematical result is to small changes in the input. A well-implemented algorithm still has difficulty when the underlying problem is strongly sensitive.

Read more: Perturbation Rendering · Inside the Infinity Engine

Conformal

Fractals & mathematics

Also found as conformality · angle preserving

Locally preserving angles. A holomorphic map is conformal where its derivative is nonzero; the quadratic map's critical point is an exception.

Read more: Beyond Complex Numbers

Connectedness locus

Fractals & mathematics

The set of parameters whose corresponding Julia sets are connected. For the quadratic family z² + c, this locus is the Mandelbrot set.

Read more: What Are Fractals?

Constant folding

GPU & rendering

Also found as compile-time evaluation

Evaluating expressions known at compilation or specialization time. A value shared by all threads is not automatically known to the compiler as a constant.

Read more: Archived code review · October 2025

Contrast

Color & lighting

Also found as contrast exponent · contrast slider

A nonlinear remapping of the computed value before color lookup. It redistributes visible tones and colors without changing the underlying fractal equation.

Read more: Palette System · User Guide

Contrast stretch

Color & lighting

Also found as value stretch · stretch factor

Expanding sampled value differences around a midpoint. In photo import, it adjusts the resulting palette rather than adding geometric detail to the fractal.

Read more: Palette System

Convergence

Fractals & mathematics

Approaching a limiting value or function as a sequence or series progresses. A useful approximation needs convergence or an appropriate error bound over the region used.

Read more: Perturbation Rendering

Coordinate Jump

Navigation & controls

Also found as Go to Rect · Go to Rectangle

Entering a complex-plane rectangle and fitting it to the canvas. Decimal input is finite precision; a bookmark is preferable for transporting an already saved deep coordinate.

Read more: User Guide · Technical white paper · Revision 19

CPU

GPU & rendering

Also found as central processing unit

The general-purpose processor that manages application state and rendering policy, builds the accurate reference orbit, and provides the deep fallback renderer.

Read more: GPU Pipeline

Creative Guide

Navigation & controls

Also found as Creating Art

The longer workflow guide to composition, iterations, palette selection, lighting, and finished capture.

Read more: Creating Art

Critical point

Fractals & mathematics

A point where a complex function's derivative is zero. For f_c(z) = z² + c, the finite critical point is z = 0.

Read more: Beyond Complex Numbers

CSV

Files & sharing

Also found as comma-separated values

A plain-text table format useful for exported measurements or benchmarks. It is not the app's bookmark-sharing schema.

Read more: Inside the Infinity Engine

Custom capture

Navigation & controls

Also found as custom dimensions

A capture with explicitly chosen width and height. Larger dimensions increase output storage and work; the practical limit depends on the device and scene.

Read more: User Guide · GPU Pipeline

Custom palette

Color & lighting

Also found as [C] · Custom

A palette created or imported by the user, usually marked [C]. Its definition must be available separately when a bookmark refers to it by name.

Read more: Palette System · User Guide

Debouncing

Engineering & roadmap

Also found as anchor-based debounce

Waiting for a meaningful or settled change before repeating an action. In rendering policy, it can reduce excessive switching or redundant requests.

Read more: Archived code review · October 2025

Deep zoom

Precision & deep zoom

Also found as ultra-deep zoom · extreme magnification

Viewing a very small complex-plane region at high scale. Useful detail depends on accurate coordinates, orbit evaluation, iteration budget, and output resolution.

Read more: Technical white paper · Revision 19 · User Guide

Delete

Navigation & controls

Removing an individual saved item. Keeping an exported backup is useful when you may want the bookmark or custom palette again.

Read more: User Guide

Delta c

Precision & deep zoom

Also found as δc · Δc · parameter offset

The difference c − c₀ between a sample's parameter and the reference parameter. Keeping this small displacement separate avoids an early absolute-coordinate rounding loss.

Read more: Perturbation Rendering

Delta z

Precision & deep zoom

Also found as δz · δₙ · orbit offset

The difference zₙ − Zₙ between a sample orbit and its reference orbit at an iteration. The perturbation recurrence advances this difference.

Read more: Perturbation Rendering

Derivative

Fractals & mathematics

Also found as f′ · f prime · local sensitivity

The local rate of change of a function. For f(z) = z² + c, the derivative with respect to z is 2z; parameter sensitivity follows its own recurrence.

Read more: Perturbation Rendering · Beyond Complex Numbers

Deterministic test

Engineering & roadmap

Also found as repeatability

A test with controlled inputs and conditions. Repeatability within that setup does not promise identical exported pixels across devices, builds, and color conversions.

Read more: Technical white paper · Revision 19

DeviceRGB

Color & lighting

A device-dependent Core Graphics color space. Its appearance relies on the drawing context and device interpretation rather than a universal, explicit RGB definition.

Read more: Technical white paper · Revision 19

DF64

Precision & deep zoom

An emulated extended-precision label used by a comparison app. The label alone does not establish native IEEE binary64 support or the same arithmetic as Mandelbrot Metal's CPU DD.

Read more: Compare Apps

Dielectric breakdown

Fractals & mathematics

Electrical breakdown through an insulating medium. Related growth models can produce branching, fractal-like structures such as discharge patterns.

Read more: What Are Fractals?

Diffuse light

Color & lighting

Also found as diffuse shading

A lighting contribution based on how the surface faces the light, producing broad shape cues rather than narrow highlights.

Read more: GPU Pipeline

Display-P3

Color & lighting

Also found as Display P3 · P3 · Wide Color (P3)

A wide-gamut RGB space used in Apple color workflows. The app's P3 choice participates in palette construction and conversion; it is not an HDR switch.

Read more: Palette System

Dithering

Color & lighting

Small variations introduced to make quantization steps less conspicuous. Older blogs discuss it; it should not be taken as a promise of a distinct current user control or HDR output.

Read more: Inside the GPU Engine of Mandelbrot Metal

Double

Precision & deep zoom

Also found as FP64 · binary64 · double precision

A 64-bit floating-point format with 53 bits of significand precision, roughly 15–17 significant decimal digits depending on the conversion or accuracy requirement.

Read more: Technical white paper · Revision 19

Double-single

Precision & deep zoom

Also found as DS · two-Float expansion

A compensated value represented as a high and low Float. It retains more significant information than one Float but is not a native 64-bit Double.

Read more: Technical white paper · Revision 19

Double-tap

Navigation & controls

Also found as 2× zoom

A navigation gesture that zooms in around a selected location. It is distinct from the single tap used for the Mandelbrot–Julia transition.

Read more: User Guide

Dynamical plane

Fractals & mathematics

Also found as z-plane · dynamical space

The plane of starting values z for one fixed function. A Julia image explores this plane, while a Mandelbrot image explores parameters.

Read more: Beyond Complex Numbers

Easing

Engineering & roadmap

Also found as temporal interpolation

Changing how a parameter progresses over time, such as starting or stopping gently. It controls motion timing rather than the fractal recurrence.

Read more: Roadmap

Effective iterations

Navigation & controls

Also found as effective iteration budget · Nmax · Nₘₐₓ

The finite budget actually used for the rendering request. It can differ from an earlier UI proposal or the configurable manual-control ceiling.

Read more: Technical white paper · Revision 19

Eligibility

GPU & rendering

Also found as render-path qualification

Checks that a request and its resources are suitable for a rendering route. Export re-evaluates eligibility because its dimensions and pixel steps can differ from the live view.

Read more: GPU Pipeline · Technical white paper · Revision 19

Entitlement

Engineering & roadmap

Also found as hasProAccess

A verified access state granting a product tier or feature set. The app derives a shared Pro-access decision from current ownership evidence.

Read more: Technical white paper · Revision 19

Error bound

Precision & deep zoom

Also found as error control

A quantitative limit on numerical error under stated assumptions. Runtime growth checks are useful safeguards, but should not be presented as certified error bounds.

Read more: Perturbation Rendering

Error tolerance

Engineering & roadmap

Also found as pixel difference · image comparison

A stated allowance when comparing numeric or image outputs. Its meaning depends on the metric and reference; a visual match alone is narrower evidence.

Read more: Technical white paper · Revision 19

Error-free transform

Precision & deep zoom

Also found as EFT

An arithmetic building block that returns a rounded result and its exact residual under required rounding and range assumptions. It does not make the entire renderer error-free.

Read more: Technical white paper · Revision 19

Escape

Fractals & mathematics

Also found as divergence · escaped sample

Growth of an orbit toward infinity. For Mandelbrot's critical orbit, crossing radius 2 proves escape in exact arithmetic; a fixed Julia parameter needs an appropriate escape bound.

Read more: Technical white paper · Revision 19

Exact LUT

Color & lighting

A table-construction mode that selects the nearest source stop for each texel. Metal still linearly filters that texture; Exact LUT does not promise zero shader interpolation.

Read more: Palette System

Exponent

Precision & deep zoom

Also found as exponent range

The power-of-two scale in a binary floating-point number. It determines range separately from the significand's ability to distinguish nearby values.

Read more: Technical white paper · Revision 19

Export

Navigation & controls

Writing an image or structured record for saving or sharing. PNG artwork, bookmark JSON, and palette JSON have different purposes.

Read more: User Guide

Export All

Navigation & controls

Exporting a managed collection, such as custom palettes or bookmarks. Built-in palettes are not exported as a user's custom library.

Read more: User Guide · Palette System

Fast math

Precision & deep zoom

Also found as reassociation · contraction

Compiler choices that permit changes to floating-point evaluation for speed. They can affect rounding-sensitive expansion identities and require deliberate qualification.

Read more: Inside the Infinity Engine

Fast tier

Precision & deep zoom

Also found as Float fast path

The inexpensive Float perturbation attempt used for suitable Infinity samples. Rejected samples restart in a wider representation rather than making every pixel pay that cost.

Read more: Technical white paper · Revision 19

Fatou set

Fractals & mathematics

Also found as stable dynamics

The region where the family of iterates is normal, a precise complex-analytic notion of locally controlled behavior. Its complement is the Julia set.

Read more: What Are Fractals?

Favorites

Navigation & controls

Also found as favorite star · favourite

Palettes marked with a star for easier access. Favorites are identified by palette name and shown ahead of other choices.

Read more: Palette System

Filament

Fractals & mathematics

Also found as tendril

A thin connecting or branching feature seen in fractal images. Its apparent thickness depends on resolution, sampling, iterations, and numerical precision.

Read more: What Are Fractals? · Creating Art

Fixed-point coordinates

Precision & deep zoom

Also found as InfinityFixed · canonical center

Coordinates stored at a fixed binary scale. The app's canonical center format has 1,152 fractional bits for transport and persistence, not 1,152-bit arithmetic throughout rendering.

Read more: Technical white paper · Revision 19

Float

Precision & deep zoom

Also found as FP32 · binary32 · single precision

A 32-bit floating-point format with 24 bits of significand precision for normal values. Metal uses Float for the inexpensive Infinity tier and for expansion components.

Read more: Technical white paper · Revision 19

FMA

Precision & deep zoom

Also found as fused multiply-add · fma(a,b,c)

Computing a × b + c with one final rounding. It is useful for recovering product residuals and building expansion arithmetic.

Read more: Technical white paper · Revision 19

Focal point

Navigation & controls

Also found as pinch anchor

The canvas position around which a zoom gesture is applied. Preserving its coordinate helps the selected feature stay under your fingers.

Read more: Technical white paper · Revision 19

FPS

GPU & rendering

Also found as frames per second · refresh rate

A rate describing displayed or rendered frames. A smoothly transformed preview can update rapidly while a newly computed deep frame takes much longer.

Read more: GPU Pipeline · Inside the Infinity Engine

Fractal

Fractals & mathematics

A mathematical object or pattern with structure across scales, often described through scaling laws or a nontrivial dimension. Natural fractal-like patterns span a limited range of scales.

Read more: What Are Fractals? · Fractals in Nature

Fractal selector

Navigation & controls

Also found as Fractal Type · Mandelbrot Set · Julia Set

The control choosing the fractal family. Switching between Mandelbrot and Julia changes which parameter or initial value is varied across the canvas.

Read more: User Guide

Frame

GPU & rendering

Also found as full frame

The output image for one viewport and appearance request. A partially refined preview is not yet the completed requested frame.

Read more: GPU Pipeline

Free

Navigation & controls

The access tier with the core renderer, built-in palettes, Canvas capture, and a limited personal bookmark allowance. Starter bookmarks are separate from those personal slots.

Read more: Technical white paper · Revision 19

Full-frame progress

Navigation & controls

Also found as progress percentage · rendering overlay

The fraction of the current requested image completed. The overlay ends after full current-frame presentation, not merely after the first tile or a reference orbit is ready.

Read more: Technical white paper · Revision 19

Gamma

Color & lighting

Also found as gamma adjustment

A nonlinear power-law adjustment. In photo import it modifies sampled HSV value; this creative control is distinct from an entire display's color-management behavior.

Read more: Palette System

Geometric measure theory

Fractals & mathematics

The study of size, dimension, and geometry for sets that may be irregular. It supplies tools for analyzing fractal boundaries beyond smooth curves and surfaces.

Read more: What Are Fractals?

Glitch detection

Precision & deep zoom

Also found as glitch indicator · cancellation check

Checks for numerical symptoms such as excessive delta growth, cancellation, ambiguous escape, or non-finite values. They route difficult work to recovery.

Read more: Technical white paper · Revision 19

Go

Navigation & controls

Also found as open bookmark

The action that loads a saved bookmark's composition into the renderer. Loading state can still require a new render to complete.

Read more: User Guide

GPU

GPU & rendering

Also found as graphics processing unit

A processor suited to large parallel workloads. Mandelbrot Metal uses it for many independent sample calculations, palette evaluation, relief shading, and presentation work.

Read more: GPU Pipeline

GPU stall

GPU & rendering

A pause while the GPU waits for resources, data, or synchronization. Buffering and scheduling can reduce some stalls but do not eliminate numerical workload.

Read more: Archived code review · October 2025

GPU-first

GPU & rendering

Also found as Metal-first

An architecture that assigns the large parallel pixel workload to the GPU while retaining CPU preparation and fallback. It does not mean all work executes on the GPU.

Read more: Inside the Infinity Engine

Gradient

Color & lighting

Also found as color ramp · colour ramp

A progression of colors along a normalized position. Gradients may be smooth or intentionally stepped.

Read more: Palette System

Grid

GPU & rendering

Also found as dispatch grid

The full collection of thread positions launched for a compute operation. Its dimensions are commonly derived from the output image or tile.

Read more: Apple: threadgroup and grid sizes

Grid-stride loop

GPU & rendering

A loop that lets each GPU thread process several data positions separated by the dispatch grid's stride. It is a workload pattern discussed in the archived review, not the definition of a tile.

Read more: Archived code review · October 2025

Guard bits

Precision & deep zoom

Also found as stability margin

Extra working precision beyond a basic coordinate estimate, reserved for rounding and sensitivity. A rough bit-count formula is not a scene-independent correctness guarantee.

Read more: Inside the Infinity Engine

Halo

GPU & rendering

Also found as tile border · one-pixel halo

Extra neighboring samples around a tile used for operations such as relief gradients. Consistent full-image coordinates prevent seams between independently rendered tiles.

Read more: GPU Pipeline

HEIC

Files & sharing

Also found as High Efficiency Image Container

An image-container format commonly used for Apple photos. A photo must be available locally and decodable before gradient import can sample it.

Read more: User Guide

Height field

Color & lighting

Also found as heightmap · escape field

A scalar value over the image used to infer local shape for lighting. It is a visualization resource, not a geometric mesh or a proof of physical depth.

Read more: GPU Pipeline

Hi-res LUT

Color & lighting

Also found as high-resolution LUT · high res LUT

The color option selecting a 1,024-texel lookup row instead of 256. It controls table density, not output image dimensions or numerical orbit precision.

Read more: Palette System · User Guide

Higher-order term

Fractals & mathematics

Also found as quadratic term · δz²

A term involving a second or higher power of a small change. Infinity retains δz² in its perturbation recurrence instead of dropping it through first-order truncation.

Read more: Perturbation Rendering

Home

Navigation & controls

Also found as house icon · Full Mandelbrot Set · Reset

Returning to the full Mandelbrot overview. The current paper specifies that Home preserves palette and 3D Look, resets contrast, enables Auto, and records a reversible history transition.

Read more: Technical white paper · Revision 19

HSV

Color & lighting

Also found as hue saturation value

A color model separating hue, saturation, and value. The photo-to-palette processing adjusts saturation and value before returning to RGB.

Read more: Palette System

Hysteresis

GPU & rendering

Using different thresholds for entering and leaving a state to avoid rapid oscillation. It helps keep precision or quality choices stable around a boundary.

Read more: Technical white paper · Revision 19

iCloud sync

Engineering & roadmap

Also found as library synchronization

A proposed way to keep scenes and palettes available across devices. Current portable-file sharing and Community Portal downloads do not provide automatic library synchronization.

Read more: Roadmap · Technical white paper · Revision 19

IEEE 754

Precision & deep zoom

The standard defining common floating-point formats and operations. Its binary32 and binary64 formats underlie Float and Double; software expansions add their own implementation assumptions.

Read more: Technical white paper · Revision 19

IFS

Fractals & mathematics

Also found as iterated function system

A collection of repeatedly applied transformations that can generate a fractal attractor. It is another fractal construction, separate from iterating the single quadratic map.

Read more: Fractals in Nature

Image resolution

Files & sharing

Also found as output dimensions

The number of pixels across and down an image. Increasing it changes sampling and storage costs; it is separate from zoom scale and arithmetic precision.

Read more: GPU Pipeline

Imaginary part

Fractals & mathematics

Also found as Im(z) · imaginary component

The real coefficient b in a + bi. It is the vertical coordinate on the complex plane; b itself is not an imaginary number.

Read more: Beyond Complex Numbers

Imaginary unit

Fractals & mathematics

Also found as i · square root of minus one

The number i satisfies i² = −1. Multiplication by i rotates a complex number by a quarter turn.

Read more: Beyond Complex Numbers

Import Gradient

Navigation & controls

Also found as photo import

The Pro tool that samples colors from an image's center line, applies palette adjustments, and saves a custom palette. It does not turn the photo into a fractal.

Read more: Palette System · User Guide

Initial value

Fractals & mathematics

Also found as initial condition · z₀ · z-zero

The value from which an orbit starts. Mandelbrot membership uses z₀ = 0; Julia rendering varies the initial value across the image.

Read more: Technical white paper · Revision 19

Iteration

Fractals & mathematics

Also found as iterate · recurrence step

One application of the update rule. An iteration count tells how many updates were evaluated; the iteration budget limits how many may be attempted.

Read more: Technical white paper · Revision 19 · User Guide

Iteration Cap

Navigation & controls

Also found as Set Max Iterations · maximum iteration cap

The selectable upper end of manual iteration control. It is separate from the current value and the renderer's effective policy; changing it does not itself add numerical precision.

Read more: User Guide · Technical white paper · Revision 19

Iterations control

Navigation & controls

Also found as manual iterations · iteration slider

The control setting how much orbit work to allow when Auto is off. More iterations can reveal later escape but cannot recover coordinate information already lost.

Read more: User Guide

Journey

Engineering & roadmap

Also found as camera path · saved-view path

A planned route between saved compositions, with timing and appearance choices. This is roadmap terminology rather than a current video-capture feature.

Read more: Roadmap

JPEG

Files & sharing

Also found as JPG · .jpeg · .jpg

A widely supported image format commonly using lossy compression. It is useful for photographs and previews but differs from the app's lossless PNG captures.

Read more: User Guide

JSON

Files & sharing

Also found as JavaScript Object Notation · .json

A structured text format for objects, arrays, numbers, strings, and other simple values. The app uses it for portable bookmark and palette records.

Read more: Technical white paper · Revision 19

Julia set

Fractals & mathematics

Also found as Julia

For a fixed parameter c, the boundary of the filled Julia set: the starting points with bounded orbits under z² + c. The displayed colors also describe surrounding escaping points.

Read more: Beyond Complex Numbers · User Guide

Keyframe

Engineering & roadmap

Also found as animation keyframe

A saved value at a chosen time, with values between keyframes computed by interpolation. The roadmap proposes this for camera and appearance changes.

Read more: Roadmap

L-system

Fractals & mathematics

Also found as Lindenmayer system

A rewriting system often used to model branching forms and plant-like patterns. It illustrates fractal-like growth outside Mandelbrot and Julia dynamics.

Read more: Fractals in Nature

Lambertian shading

Color & lighting

Also found as Lambert · N dot L

A diffuse lighting model proportional to the nonnegative dot product of the surface normal and light direction. It produces broad surface-facing brightness cues.

Read more: Archived code review · October 2025

Latency

GPU & rendering

Also found as input response · first-refinement latency

Elapsed time until a specified event. Input feedback, first completed region, and the final frame measure different parts of the experience.

Read more: Inside the Infinity Engine

Leading / trailing edge

Navigation & controls

Also found as swipe actions

Direction-aware interface edges. Swipe actions are described this way so Export and Delete guidance can adapt to left-to-right and right-to-left layouts.

Read more: User Guide

Legacy dd2

Precision & deep zoom

Also found as GPU dd2 · historical deep label

A historical nested-Float GPU representation in the app. Its name should not be interpreted as two IEEE Doubles or as a promise of native FP64 computation.

Read more: Technical white paper · Revision 19

Lifecycle

Engineering & roadmap

Also found as backgrounding · foreground

The active, inactive, and teardown stages of an interface or app scene. Long work and callbacks must respect those transitions.

Read more: Technical white paper · Revision 19

Light direction

Color & lighting

Also found as light elevation

The orientation from which illumination is evaluated. The roadmap discusses expanded direction and elevation controls separately from current 3D Look behavior.

Read more: Roadmap · GPU Pipeline

Limb

Precision & deep zoom

Also found as high limb · low limb · component

One part of a multi-component representation. Expansion limbs carry successively smaller contributions; fixed-point limbs instead hold chunks of an integer representation.

Read more: Technical white paper · Revision 19

Linear filtering

Color & lighting

Also found as linear interpolation

Blending neighboring texel values according to the sample position. It smooths between LUT texels but does not imply scene-linear light values.

Read more: Palette System

Localization

Navigation & controls

Also found as locale · translated interface

Adapting text, formatting, and layout to a language and region. Number grouping and percentages may differ even when the stored numerical state is identical.

Read more: Technical white paper · Revision 19

Loop unrolling

GPU & rendering

Also found as pragma unroll

Replacing a loop with repeated operations to reduce control overhead or expose optimization opportunities. It can increase code size and does not automatically improve every workload.

Read more: Archived code review · October 2025

LUT

Color & lighting

Also found as lookup table · look-up table · 1D LUT

A sampled table mapping an input value to an output. The app's color LUT is a one-row texture sampled using a normalized escape coordinate.

Read more: Palette System

LUT width

Color & lighting

Also found as LUT resolution · 256 · 1024 · 1,024

The number of texels in the rendering lookup table. The current setting selects 256 or 1,024; more texels do not add more bits to each channel.

Read more: Palette System

Magnitude

Fractals & mathematics

Also found as modulus · absolute value · norm · ∣z∣

The distance of a complex number from zero: for z = x + iy, its magnitude is √(x² + y²). Escape tests use this size.

Read more: Beyond Complex Numbers · Perturbation Rendering

Manage Palettes

Navigation & controls

The custom-palette library for importing, exporting, renaming where supported, and deleting user-created color definitions. Built-in palettes are protected.

Read more: Palette System · User Guide

Mandelbulb

Fractals & mathematics

A three-dimensional fractal construction based on a spherical-coordinate power mapping. It is distinct from the complex Mandelbrot set and from relief shading.

Read more: Beyond Complex Numbers

Max norm

Precision & deep zoom

Also found as infinity norm · ∥x∥∞

The largest absolute component of a vector. It is a different size measure from the Euclidean norm and appears in historical numerical cutoff discussions.

Read more: Archived code review · October 2025

MetalKit

Engineering & roadmap

Apple's support framework for integrating Metal drawing into apps, including MTKView. It handles part of the bridge between a GPU renderer and a platform view.

Read more: Technical white paper · Revision 19

MiB / KiB

Files & sharing

Also found as mebibyte · kibibyte · binary memory units

Binary units: 1 KiB = 1,024 bytes and 1 MiB = 1,048,576 bytes. They differ from decimal kB and MB when reporting texture or image storage.

Read more: GPU Pipeline · Inside the Infinity Engine

minX / minY / maxX / maxY

Navigation & controls

Also found as rectangle bounds

The minimum and maximum coordinates defining the rectangle supplied to Coordinate Jump. The app derives its center and an aspect-preserving scale.

Read more: User Guide

More Options

Navigation & controls

Also found as More · ellipsis · …

The menu providing management, settings, and help actions. Available placement can differ between iPhone and iPad.

Read more: User Guide

MPFR

Precision & deep zoom

Also found as GNU MPFR

A multiple-precision floating-point library with specified rounding behavior. The technical discussion considers such tools for higher-precision reference work; current public Infinity uses CPU double-double.

Read more: Inside the Infinity Engine

MSL

GPU & rendering

Also found as Metal Shading Language

The language used to write Metal shader and compute functions. The app's orbit and relief kernels are implemented in Metal source.

Read more: Technical white paper · Revision 19

MTKView

GPU & rendering

Also found as MetalKit view

An Apple view that manages a Metal-backed drawing surface. The app embeds this canvas inside its SwiftUI interface.

Read more: Technical white paper · Revision 19

Multibrot

Engineering & roadmap

The family zₙ₊₁ = zₙᵈ + c for integer powers beyond the quadratic case. The roadmap proposes evaluating additional families with their own rendering limits.

Read more: Roadmap

Multiplier

Fractals & mathematics

Also found as λ · lambda

The derivative of a full return around a periodic cycle. Magnitude below 1 means attracting, above 1 repelling, and equal to 1 requires further analysis.

Read more: Beyond Complex Numbers

NaN

Precision & deep zoom

Also found as not a number · non-finite

NaN represents an invalid numerical result; infinity is also non-finite. These values are checked rather than accepted as trustworthy orbit state.

Read more: Technical white paper · Revision 19

Native Mac workspace

Engineering & roadmap

A possible future interface designed for Mac displays, keyboard, pointer, and longer sessions. It is a candidate direction rather than an existing mobile-app capability.

Read more: Roadmap

Nearest-neighbor sampling

Color & lighting

Also found as nearest source stop

Choosing one nearest stored value rather than blending. Exact LUT uses nearest source stops while building texels; the later Metal sampler still uses linear filtering.

Read more: Palette System

Neutral cycle

Fractals & mathematics

Also found as indifferent cycle

A periodic orbit with multiplier magnitude 1. Linear information alone does not determine all nearby behavior.

Read more: Beyond Complex Numbers

Nonlinear oscillator

Fractals & mathematics

A system with repeating or oscillatory behavior governed by nonlinear equations. It is one example connecting dynamics, bifurcations, and complex behavior beyond fractal rendering.

Read more: What Are Fractals?

Nonlinear slider

Navigation & controls

Also found as slider calibration

A control whose position does not increase the value at a constant rate. The app allocates extra travel to useful lower iteration or contrast ranges.

Read more: User Guide

Offline-first

Engineering & roadmap

Also found as offline workflow

A design in which local work remains useful without a network connection, with synchronization handled separately. This is a principle in the library roadmap.

Read more: Roadmap

Offscreen rendering

GPU & rendering

Also found as export render

Rendering to an image resource rather than directly to the live display. Every app capture uses a dedicated complete output render, including Canvas Size.

Read more: GPU Pipeline · User Guide

Open source

Engineering & roadmap

Also found as MIT license

Source code made available under a license specifying reuse conditions. Photo2Palette is the companion tool discussed as open source; this does not describe all app code.

Read more: Introducing Photo2Palette: A Command-Line Tool

Orbit reuse versus recoloring

Engineering & roadmap

Reusing a valid reference orbit and reusing per-pixel escape results are different optimizations. Current reference sharing does not imply instant palette-only recoloring.

Read more: GPU Pipeline · Roadmap

Overflow

Precision & deep zoom

A result too large in magnitude for the working format, potentially producing infinity. Additional significand limbs alone do not guarantee a wider exponent range.

Read more: Technical white paper · Revision 19

Palette

Color & lighting

Also found as color palette · colour palette

An ordered color definition mapped onto computed fractal values. The source definition, its rendering texture, and the final display conversion are separate stages.

Read more: Palette System

Palette filters

Navigation & controls

Also found as All · Standard · Ultra-Wide · Custom

Categories that narrow the palette picker. They describe the palette source and ownership, rather than selecting a different fractal equation.

Read more: Palette System · User Guide

Palette interpolation

Color & lighting

Computing intermediate colors between sampled positions. Both source construction and texture sampling can affect the final transition.

Read more: Palette System

Palette JSON v1

Files & sharing

Also found as portable palette schema

The sharing format carrying a palette name, color-space label, and normalized stops. It has a different version history from local palette storage and bookmarks.

Read more: Palette System

Palette picker

Navigation & controls

Also found as palette button · brush menu

The interface for choosing a palette, inspecting previews, filtering its categories, and accessing related color options.

Read more: User Guide · Palette System

Palette reference

Files & sharing

Also found as builtIn · customByName · embedded

A bookmark's way of identifying colors: a built-in index, a custom name, or embedded stops when supported on import. Current exported named custom palettes should be shared separately.

Read more: Technical white paper · Revision 19

Pan

Navigation & controls

Also found as drag

Moving the visible region without intentionally changing scale. The retained image follows the gesture, then a committed view is rendered.

Read more: User Guide

Parallelism

GPU & rendering

Also found as parallel computation

Doing independent work at the same time. Per-sample orbit evaluation offers extensive parallelism, while a reference orbit advances sequentially along its recurrence.

Read more: GPU Pipeline · Inside the Infinity Engine

Parameter plane

Fractals & mathematics

The complex plane interpreted as choices of c. The Mandelbrot set lies in parameter space; each chosen c specifies a different dynamical system.

Read more: Beyond Complex Numbers

PDF

Files & sharing

Also found as Portable Document Format

A fixed-layout document format used for the technical white paper and downloadable guides. It preserves page layout rather than interactive app state.

Read more: The Tech in the App

Percentile

Engineering & roadmap

Also found as p95 · p99 · latency distribution

A value below which a stated percentage of observations falls. Two timed runs per scene are insufficient to characterize reliable tail-latency percentiles.

Read more: Inside the Infinity Engine

Percolation

Fractals & mathematics

A mathematical model of connectivity through occupied sites or links. Near critical conditions it can generate scaling and fractal structure.

Read more: What Are Fractals?

Period

Fractals & mathematics

Also found as periodic orbit · cycle length

The smallest positive number of updates after which an orbit repeats. A fixed point has period 1; a two-cycle has period 2.

Read more: Beyond Complex Numbers

Perturbation rendering

Precision & deep zoom

Also found as delta orbit · perturbation orbit

Computing nearby orbits relative to a shared reference. For the quadratic family, δzₙ₊₁ = 2Zₙδzₙ + δzₙ² + δc is algebraically exact; finite arithmetic still introduces error.

Read more: Perturbation Rendering

Phase space

Fractals & mathematics

The space of possible states of a dynamical system. In a fixed quadratic Julia problem, the complex z-plane is the phase space.

Read more: What Are Fractals?

Pi

Fractals & mathematics

Also found as π · 𝛑

The ratio of a circle's circumference to its diameter. It appears in angular, cyclic, and trigonometric descriptions of fractals, although z² + c does not require π.

Read more: 𝛑 and Fractals: Is There a Connection?

Pinch

Navigation & controls

Also found as pinch to zoom · spread

A two-finger gesture that changes scale. Spreading zooms in and pinching together zooms out, with the gesture's focal point guiding the mapping.

Read more: User Guide

Pipeline state

GPU & rendering

Also found as compute pipeline state

A prepared Metal object describing the compiled GPU function and execution requirements. It lets commands invoke the intended kernel efficiently.

Read more: Technical white paper · Revision 19

Pixel

GPU & rendering

One output picture element. A pixel can combine several samples; it should not be confused with a source palette stop or a texture texel.

Read more: GPU Pipeline

Pixel format

GPU & rendering

Also found as MTLPixelFormat

The channel arrangement, bit depth, and numerical interpretation of texture elements. Color and relief use different formats because they store different kinds of data.

Read more: Technical white paper · Revision 19

Pixel step

Navigation & controls

Also found as sample spacing

The complex-plane distance between adjacent drawable pixel centers. It depends on scale and the display's pixels-per-point factor.

Read more: GPU Pipeline · Inside the Infinity Engine

PNG

Files & sharing

Also found as Portable Network Graphics · .png

A lossless raster-image format used for finished captures. It stores pixels rather than the editable orbit and palette state of a bookmark.

Read more: User Guide · Technical white paper · Revision 19

Point

Navigation & controls

Also found as UIKit point · logical point

A logical interface distance unit. A display can use multiple physical pixels per point, so gesture coordinates need conversion for the drawable.

Read more: GPU Pipeline

Polar form

Fractals & mathematics

Also found as r exp(iθ) · r eⁱθ

Writing z = r(cos θ + i sin θ), or reⁱθ. Here r is magnitude and θ is angle; squaring squares r and doubles θ.

Read more: Beyond Complex Numbers

Polynomial

Fractals & mathematics

A finite sum of nonnegative integer powers with coefficients. For a fixed c, z² + c is a quadratic polynomial in z.

Read more: Beyond Complex Numbers

Popover

Navigation & controls

Also found as dropdown menu

A compact contextual panel of choices. The website's Support dropdown provides navigation to help pages, including this glossary.

Read more: User Guide

Presentation

GPU & rendering

Also found as presented frame

Making a completed image available to the display. Kernel completion, the first refined tile, and complete-frame presentation are distinct events.

Read more: GPU Pipeline · Inside the Infinity Engine

Print size

Files & sharing

Also found as print-ready artwork

The intended physical dimensions of a print. A high-resolution capture should be inspected at that size, with the destination's color and resolution requirements considered.

Read more: From Screen to Print: Your First Fractal Artwork

Procedural color

Color & lighting

Also found as procedural palette

Generating color with a function rather than only reading a gradient texture. The documented shader includes HSV, Fire, and Ocean branches.

Read more: Palette System

Progressive rendering

GPU & rendering

Also found as progressive refinement

Revealing completed regions while the remaining image is calculated. Infinity replaces an initialized preview with finished tiles before reporting whole-frame completion.

Read more: GPU Pipeline

PSO

GPU & rendering

Also found as pipeline state object

A prepared graphics or compute pipeline object. Creation and compilation costs are separate from the time spent running a kernel.

Read more: Archived code review · October 2025

Quad precision

Precision & deep zoom

Also found as binary128 · IEEE binary128

A distinct IEEE floating-point format with 113 significand bits. Four Float storage slots or a double-double pair do not automatically implement this format.

Read more: Technical white paper · Revision 19

Quad-single

Precision & deep zoom

Also found as QS · four-Float expansion

A software expansion of four Float limbs used for difficult GPU pixels and recovery. Its practical accuracy depends on normalization, operations, range, and reductions.

Read more: Technical white paper · Revision 19

Quaternion

Fractals & mathematics

Also found as ℍ · quaternions

A four-component number a + bi + cj + dk with order-sensitive multiplication. Quaternion fractals and rotations are background mathematics, not the app's 3D Look renderer.

Read more: Beyond Complex Numbers

QuickTwoSum

Precision & deep zoom

Also found as quick-two-sum

A shorter addition transform requiring a magnitude ordering between its operands. Using it without that precondition can invalidate its residual guarantee.

Read more: Technical white paper · Revision 19

R32Float

GPU & rendering

Also found as height texture format

A texture format containing one 32-bit floating-point component per texel. The relief pipeline uses it to store height values rather than display colors.

Read more: GPU Pipeline

Race condition

Engineering & roadmap

Also found as stale callback

An outcome depending on the timing of concurrent or delayed operations. Shared state and completion handlers need ordering and identity checks.

Read more: Technical white paper · Revision 19

Real part

Fractals & mathematics

Also found as Re(z) · real component

The a in a + bi. It is the horizontal coordinate on the complex plane.

Read more: Beyond Complex Numbers

Rebasing

Precision & deep zoom

Also found as rebase · reference-index reset

Changing the current perturbation representation, including resetting its reference index when appropriate. An in-kernel rebase does not mean the CPU rebuilds the shared orbit.

Read more: Perturbation Rendering

Reconstruction

Precision & deep zoom

Also found as reconstructed orbit

Combining the reference and deviation, zₙ = Zₙ + δzₙ, for escape, color, or recovery decisions. Cancellation can make this combination numerically delicate.

Read more: Perturbation Rendering

Reference point

Precision & deep zoom

Also found as reference parameter · c₀ · anchor

The parameter chosen for the accurate shared orbit. Nearby sample parameters are expressed as offsets from this anchor.

Read more: Perturbation Rendering

Reference reuse

Precision & deep zoom

Also found as reference caching

Reusing a compatible accurate orbit rather than rebuilding it for every request. Safe reuse depends on mapping, validity, and state compatibility, not just visual similarity.

Read more: Roadmap · Inside the Infinity Engine

Regression test

Engineering & roadmap

Also found as regression testing

A check intended to catch behavior broken by a change. Passing the asserted cases is evidence about those cases, not a proof covering all possible fractal coordinates.

Read more: Technical white paper · Revision 19

Relief iteration budget

Color & lighting

Also found as height budget · probe pattern

The iteration allowance used to derive a useful height field. A small CPU probe grid helps select it; this heuristic does not exhaustively inspect every output pixel.

Read more: GPU Pipeline

Relief shading

Color & lighting

Also found as bump-like shading · surface relief

Lighting a surface inferred from a scalar height field. In the app, a second compute pass shades colors using completed neighboring height samples.

Read more: GPU Pipeline

Relief strength

Color & lighting

Also found as relief depth · detail scale

Parameters controlling how strongly height variations influence apparent shape. The roadmap proposes broader controls; these change appearance rather than fractal coordinates.

Read more: Roadmap

Render manifest

Engineering & roadmap

Also found as reproduction record

A record of the exact rendering conditions, including state, build, device, arithmetic, LUT data, and output settings. It can capture more than a normal bookmark.

Read more: Technical white paper · Revision 19

Render pipeline

GPU & rendering

Also found as rendering pipeline

The chain from view state through coordinates, arithmetic, orbit evaluation, color, optional lighting, and display or export. Correctness depends on the whole chain.

Read more: GPU Pipeline

Repelling cycle

Fractals & mathematics

A periodic orbit whose multiplier has magnitude greater than 1, so sufficiently small perturbations grow locally.

Read more: Beyond Complex Numbers

Representability

Precision & deep zoom

Also found as representable pixel step

Whether a value can be stored distinctly in a chosen format. A nonzero stored step does not prove it survives addition to a large absolute coordinate.

Read more: Technical white paper · Revision 19

Residual

Precision & deep zoom

Also found as low part · rounding residual

A smaller remainder retained after a rounded leading result. Preserving residuals is central to compensated coordinates and expansion arithmetic.

Read more: Technical white paper · Revision 19

Resource binding

GPU & rendering

Also found as buffer index · texture index

Connecting a buffer or texture to the numbered input or output expected by a kernel. Correct data and compatible access permissions are both required.

Read more: Technical white paper · Revision 19

Retained frame

GPU & rendering

Also found as retained image · gesture preview

The last completed image, temporarily transformed to follow a pan or pinch. It provides immediate feedback without claiming that new deep detail has already been calculated.

Read more: GPU Pipeline

Return snapshot

Navigation & controls

Also found as Mandelbrot return view

The originating Mandelbrot state retained when entering Julia mode. It preserves a useful way back after exploring the linked Julia set.

Read more: Technical white paper · Revision 19

RGB

Color & lighting

Also found as red green blue

An additive color model using red, green, and blue channels. Their numerical values only acquire a precise color meaning with a defined color space and encoding.

Read more: Palette System

RGBA8

GPU & rendering

Also found as RGBA · red green blue alpha

An eight-bit-per-channel arrangement in red, green, blue, alpha order. The photo-import working image uses RGBA8 before producing palette stops.

Read more: Palette System · Technical white paper · Revision 19

Roadmap

Engineering & roadmap

Also found as planned · research dependent · candidate

A sequence of proposed work, distinct from available features. Research milestones require qualification before a new precision or functionality promise is made.

Read more: Roadmap

RTL

Navigation & controls

Also found as right-to-left layout

Interface layout for languages such as Arabic and Hebrew. Leading and trailing directions adapt with reading direction rather than always meaning left and right.

Read more: Technical white paper · Revision 19

Sample grid

GPU & rendering

Also found as SSAA×4 · SSAAx4 · subpixel grid

The pattern of sample locations inside a pixel. Ordinary renderer grids use totals such as 1, 4, 9, 16, or 25; four samples do not mean four times each image dimension.

Read more: GPU Pipeline

Saturation

Color & lighting

The intensity of color relative to gray in a chosen color model. Photo import can increase or decrease it in the sampled palette.

Read more: Palette System · User Guide

Scale

Navigation & controls

Also found as zoom scale · magnification

A measure of how much screen distance represents one complex-plane unit. The technical materials distinguish navigation points per unit from drawable pixels per unit and relative zoom factors.

Read more: Technical white paper · Revision 19 · Inside the Infinity Engine

Scale invariance

Fractals & mathematics

Also found as dilation · scaling law

A property that remains unchanged, exactly or approximately, after rescaling. Statistical resemblance in nature should not be confused with exact mathematical invariance.

Read more: What Are Fractals? · Fractals in Nature

Scene

Files & sharing

Also found as portable scene · self-contained scene

A complete composition description. The roadmap proposes a richer self-contained format including custom colors and full appearance; current bookmarks do not serialize every lighting parameter.

Read more: Technical white paper · Revision 19 · Roadmap

Schema

Files & sharing

Also found as schemaVersion · file version

The agreed structure and version of a record. It tells an importer which fields and compatibility rules to apply.

Read more: Technical white paper · Revision 19

Screen scale

Navigation & controls

Also found as content scale · pixels per point

The ratio between logical points and drawable pixels. Omitting it changes the effective sampling distance and can misstate zoom comparisons.

Read more: GPU Pipeline · Inside the Infinity Engine

Search bookmarks

Navigation & controls

Also found as website search

The Community Portal field that filters bookmark entries by their searchable names and metadata. It operates on the website catalog rather than the app's local library.

Read more: Community Portal

Select visible

Navigation & controls

Also found as bulk selection

Selecting the bookmark rows currently shown by the website's filters. A selection can be downloaded together as a ZIP.

Read more: Community Portal

Serialization

Files & sharing

Also found as deserialization

Encoding structured state into a file or reconstructing it from that file. Careful numerical representation prevents unnecessary loss of deep-coordinate information.

Read more: Technical white paper · Revision 19

Series approximation

Precision & deep zoom

Also found as series acceleration

Approximating orbit differences with a truncated series, potentially skipping repeated work within a validated range. It is separate from Version 3's full per-step quadratic recurrence.

Read more: Perturbation Rendering · Roadmap

Shader

GPU & rendering

A GPU program. In this app, compute shaders calculate fractals and relief; the term does not imply that every shader is a traditional triangle-coloring fragment shader.

Read more: GPU Pipeline

Shader specialization

GPU & rendering

Also found as function constant · shader variant

Preparing a version of a shader for particular constant choices. It can remove unused branches, at a cost in compilation, variants, and resource management.

Read more: Archived code review · October 2025

Sheet

Navigation & controls

Also found as share sheet · management sheet

A presented interface panel for a focused task. The system share sheet offers destinations for exported artwork or files.

Read more: User Guide

SIMD group

GPU & rendering

Also found as simdgroup · SIMD-group

A group of GPU threads executing together. It is an execution unit within a threadgroup; its width is a hardware and pipeline property to query.

Read more: Apple: threads and threadgroups

Simulator

Engineering & roadmap

A development environment that runs an app with simulated platform behavior. Its GPU compatibility paths and timing are not substitutes for physical-device qualification.

Read more: Technical white paper · Revision 19

Slice and projection

Fractals & mathematics

Also found as 4D slice · three-dimensional slice

Ways to inspect a higher-dimensional object: intersect it with a lower-dimensional space, or map it onto one. The selected method changes the visible structure.

Read more: Beyond Complex Numbers

Smooth LUT

Color & lighting

Also found as Smooth

Constructing the lookup texture from a continuous gradient. This differs from the Exact LUT source-stop selection, while both textures use linear shader sampling.

Read more: Palette System

Sort order

Navigation & controls

Also found as Name · Mode · Newest · Oldest · Iterations · Palette · Scale

The ordering used to browse bookmarks. These options compare saved metadata, not necessarily how long each scene will take to render.

Read more: User Guide

Source density

Color & lighting

Also found as stop count · palette length

The number and arrangement of colors in the source definition. It differs from LUT width, per-channel bit depth, and fractal-coordinate precision.

Read more: Palette System

Specular highlight

Color & lighting

Also found as specular · highlight strength

A concentrated lighting reflection that can make a surface appear polished. Its strength and shape affect the perceived material.

Read more: GPU Pipeline · Roadmap

Split view

Navigation & controls

Also found as iPad multitasking

An iPad window arrangement with reduced available width. The app adapts controls so narrow layouts can still access the same actions.

Read more: Technical white paper · Revision 19

Squared magnitude

Fractals & mathematics

Also found as norm squared · ∣z∣²

The value x² + y² for z = x + iy. Comparing it with 4 avoids a square root in a radius-2 escape test.

Read more: GPU Pipeline

sRGB

Color & lighting

A widely used RGB color space and transfer encoding for web and screen imagery. It offers a smaller gamut than Display-P3.

Read more: Palette System

SSAA

GPU & rendering

Also found as supersampling anti-aliasing · super-sampling

Evaluating multiple subpixel samples and averaging their colors to reduce jagged edges. The app selects sampling automatically; public Infinity currently uses one sample per pixel.

Read more: GPU Pipeline · User Guide

Stale work

GPU & rendering

Also found as obsolete completion

A tile or callback belonging to a superseded request. Generation checks and cancellation prevent it from presenting the wrong composition.

Read more: Technical white paper · Revision 19

Standard palette

Color & lighting

Also found as Standard

A built-in palette outside the Ultra-Wide and Custom categories. Standard source definitions have varying stop counts; they are not all 512-step ramps.

Read more: Palette System

Starter bookmark

Files & sharing

Also found as starter collection

A curated scene installed once for exploration. Stable identifiers and matching checks preserve existing work and avoid reinstalling deleted starters after installation completes.

Read more: Technical white paper · Revision 19

Storage precision

Precision & deep zoom

Also found as transport precision

The information retained in saved or transmitted values. It is separate from the arithmetic precision used to generate a reference orbit or evaluate a pixel.

Read more: Technical white paper · Revision 19

StoreKit 2

Engineering & roadmap

Also found as StoreKit

Apple's framework for App Store products, verified purchases, subscriptions, and ownership. It is separate from storage for a user's artwork or bookmarks.

Read more: Technical white paper · Revision 19

String Catalog

Engineering & roadmap

Also found as xcstrings

Apple's structured localization resource for translated strings and variants. It supports the app's interface and guide localization workflow.

Read more: Technical white paper · Revision 19

Subpixel sample

GPU & rendering

A calculation at a position within an output pixel. Each supersample can perform its own orbit and palette lookup before color averaging.

Read more: GPU Pipeline

Subscription

Engineering & roadmap

Also found as monthly · annual

A time-limited purchase that grants Pro while eligible ownership remains current. It differs from a lifetime non-consumable purchase.

Read more: Technical white paper · Revision 19

Surface normal

Color & lighting

Also found as normal vector

A direction perpendicular to the inferred surface. Lighting uses it to decide how strongly a point faces the light.

Read more: GPU Pipeline

Swift

Engineering & roadmap

Apple's programming language used for application state, policy, reference construction, export orchestration, and other CPU-side responsibilities.

Read more: Technical white paper · Revision 19

Sync conflict

Engineering & roadmap

Also found as conflict resolution

A disagreement between independently edited copies of saved data. Planned synchronization needs explicit rules for edits, deletions, and recovery.

Read more: Roadmap

Tap-to-Julia

Navigation & controls

Also found as single-tap · Julia linkage

Selecting a Mandelbrot location as the fixed Julia parameter c. A stored return snapshot lets the interface take you back to the originating Mandelbrot composition.

Read more: User Guide · Technical white paper · Revision 19

Taylor coefficient

Fractals & mathematics

Also found as a₁,n · series coefficient

A multiplier of a power in a Taylor expansion. Orbit coefficients describe how the nth iterate changes when the parameter changes near a reference.

Read more: Perturbation Rendering

Temporal flicker

Engineering & roadmap

Also found as shimmer

Unwanted changes between animation frames, potentially from sampling, numerical routing, or lighting. Future video workflows need to qualify consistency over time.

Read more: Roadmap

TestFlight

Engineering & roadmap

Also found as beta access

Apple's beta-distribution system for trying prerelease app builds. Beta testing and a published App Store release are different stages.

Read more: Beta Tester’s Guide

Texel

GPU & rendering

Also found as texture element · tap

One stored element of a texture. A one-row palette LUT contains 256 or 1,024 texels, which the shader samples to obtain colors.

Read more: Palette System

Texture

GPU & rendering

Also found as MTLTexture

A GPU resource arranged as texels, often an image or lookup table. The app uses textures for color, palette lookup, and temporary relief heights.

Read more: GPU Pipeline

Texture usage

GPU & rendering

Also found as shaderRead · shaderWrite · access permissions

Declared ways a texture may be used. A texture bound to a writable shader parameter needs compatible write usage even when a runtime branch skips writing.

Read more: Technical white paper · Revision 19

Thermal throttling

Engineering & roadmap

Also found as thermal state · sustained heat

A device reducing performance under thermal constraints. Sustained and repeated benchmarks need to consider heat and test order.

Read more: Roadmap · Inside the Infinity Engine

Thread

GPU & rendering

One invocation of a GPU kernel. The main fractal kernel typically assigns an output pixel to a thread, which may evaluate several subpixel samples.

Read more: GPU Pipeline

Thread execution width

GPU & rendering

Also found as threadExecutionWidth

The number of threads in a compute pipeline's SIMD execution group. It informs efficient threadgroup sizing and should be queried rather than assumed universally.

Read more: Apple: threadgroup and grid sizes

Threadgroup

GPU & rendering

A group of compute threads scheduled together, with facilities for cooperation and shared memory. It can contain more than one SIMD group.

Read more: Apple: threads and threadgroups

ThreeSum

Precision & deep zoom

Also found as three-sum · five-term renormalization

Expansion primitives that combine several components and retain smaller residuals before reducing them to an ordered, fixed-length expansion.

Read more: Technical white paper · Revision 19

Throughput

GPU & rendering

The amount of completed work per unit time. High throughput does not automatically imply low latency for one demanding frame.

Read more: Inside the Infinity Engine

Tile

GPU & rendering

Also found as tiled rendering

A bounded rectangular part of an image calculated as a work unit. Shared full-image mapping keeps neighboring tiles aligned.

Read more: GPU Pipeline

TL;DR

Engineering & roadmap

Also found as too long didn't read

A short overview before a longer technical explanation. It helps readers find the main idea without replacing the detailed assumptions and evidence.

Read more: Beyond Complex Numbers

Toolbar

Navigation & controls

Also found as floating toolbar · utility row

A group of nearby controls for navigation or creative work. Phone and tablet layouts arrange them differently while using the same underlying state.

Read more: User Guide · Technical white paper · Revision 19

Topological dimension

Fractals & mathematics

A notion of dimension defined through the structure of open covers rather than metric scaling. It differs from Hausdorff and box-counting dimension.

Read more: What Are Fractals?

Transaction

Engineering & roadmap

Also found as verified transaction

A purchase record checked before granting access. Expired or revoked records should not be treated as current subscriptions.

Read more: Technical white paper · Revision 19

Triple buffering

GPU & rendering

Also found as in-flight buffers

Using multiple resource sets so CPU preparation and GPU work can overlap without overwriting data still in use. It appears in the archived renderer review.

Read more: Archived code review · October 2025

Truncation error

Fractals & mathematics

The error from omitting terms of an infinite series or approximation. It differs from rounding error introduced by finite numerical storage and arithmetic.

Read more: Perturbation Rendering

Turbulence

Fractals & mathematics

Irregular fluid motion with interacting structures at many scales. Fractal-like models can describe aspects of it; a Mandelbrot image is not a fluid simulation.

Read more: What Are Fractals? · Fractals in Nature

TwoProd

Precision & deep zoom

Also found as two-product

A transform returning a rounded product plus its residual. A suitable fused multiply-add can recover that residual when rounding and range conditions hold.

Read more: Technical white paper · Revision 19

TwoSum

Precision & deep zoom

Also found as two-sum

An error-free addition transform that separates a sum into a leading rounded value and a residual under its operating assumptions.

Read more: Technical white paper · Revision 19

UI

Navigation & controls

Also found as user interface

The controls, labels, readouts, and interaction patterns through which you use the app. The same exploration state supports the phone and tablet layouts.

Read more: User Guide · Technical white paper · Revision 19

UIKit

Engineering & roadmap

Also found as gesture bridge

Apple's interface framework supplying platform views and gesture handling. The gesture bridge maps touches into the actual Metal canvas coordinates.

Read more: Technical white paper · Revision 19

ULP

Precision & deep zoom

Also found as unit in the last place

The spacing represented by the least significant position at a given magnitude and format. A pixel offset smaller than that spacing can disappear when added to a center.

Read more: Beyond Complex Numbers · Inside the Infinity Engine

Ultra-Wide

Color & lighting

Also found as [UW] · ultra wide · 768-step

The palette category whose source ramps contain 768 stops. The tag describes the source, not a separate shader, a color gamut, or a forced 768-texel texture.

Read more: Palette System

Underflow

Precision & deep zoom

A result entering the format's smallest-magnitude region, where precision may be reduced or the value may become zero. Deep pixel-step qualification must account for this.

Read more: Technical white paper · Revision 19

Uniforms

GPU & rendering

Also found as uniform buffer · MandelbrotUniforms

Parameters shared across a dispatch, such as mapping, dimensions, iteration limits, palette settings, and lighting. Swift and Metal must interpret their layout identically.

Read more: Technical white paper · Revision 19

UUID

Files & sharing

Also found as universally unique identifier

An identifier used to distinguish records independently of their displayed names. Duplicate names can therefore be renamed without making identity depend only on text.

Read more: Technical white paper · Revision 19

Value

Color & lighting

Also found as HSV value · brightness

The V coordinate in HSV, based on the largest RGB component. It is not a physical measurement of scene luminance.

Read more: Palette System

Volumetric fractal

Engineering & roadmap

Also found as true 3D fractal

A fractal object defined in three-dimensional space or inspected through higher-dimensional construction. It differs from 3D Look's lighting of a two-dimensional field.

Read more: Beyond Complex Numbers · Roadmap

WebKit

Engineering & roadmap

Also found as help viewer

Apple's web-content framework used for the in-app HTML guides. Load and layout callbacks must coordinate correctly with SwiftUI state updates.

Read more: Technical white paper · Revision 19

Working set

GPU & rendering

Also found as peak memory · memory pressure

The resources needed during a computation. Tiling bounds part of the work, but export still needs final-image storage and may need conversion and encoding buffers.

Read more: GPU Pipeline · Technical white paper · Revision 19

ZIP

Files & sharing

Also found as archive · bulk download

A container holding multiple files. Community bookmark ZIPs retain individual JSON filenames and contents for convenient download and extraction.

Read more: Community Portal

KEEP EXPLORING

The reading behind the words.

This reference brings together the website’s technical explanations, app and testing guides, all 32 journal articles, the archived code review, and the 38-page technical white paper, Revision 19 (September 24, 2026). Entries link to their relevant reading; older posts and the archived review retain their original historical scope. Platform and mathematical references clarify selected definitions.

Browse the 32 journal articles

Glossary reviewed September 25, 2026. Looking for steps rather than definitions? Open the User Guide →