Glossary
Quick definitions for terms unique to Paint Forge. Where a term has a dedicated docs page the definition links into it. Most pages cross-link back here from the first place they use an unfamiliar term.
Adjustment Layer
A non-destructive layer that applies a filter (Curves, Hue/Saturation, etc.) to all visible layers below it. Toggle, reorder, or clip to the single layer immediately below.
Alpha Lock
A per-layer toggle that confines paint strokes to existing non-transparent pixels. Useful for re-coloring a shape without painting outside its silhouette.
Anchor (Path)
A control point on a vector path. Bezier handles attach to anchors and define the curvature of the segments around them. Drag in Edit Path tool.
Blend Mode
Determines how a layer or object composites onto the layers below — Multiply, Screen, Overlay, Difference, etc. 24 modes total; six (Subtract, Divide, Vivid Light, Linear Light, Pin Light, Hard Mix) use software blending and are slightly slower.
Brush Stroke (vector)
A BrushStrokeObject — vector centerline with per-vertex width data, drawn by the Smart Brush tool. Editable after creation via double-click → Edit Brush Stroke.
Brush Tip
The stamp shape used by raster brushes (soft, hard, calligraphic, custom image). Each stamp is rendered along the stroke path at a configurable spacing.
Bidi (Bidirectional Text)
Unicode UAX #9 algorithm that lays out text containing both left-to-right (Latin) and right-to-left (Arabic, Hebrew) runs in correct visual order. Paint Forge text honors the base direction set on TextObject and automatically mirrors brackets / quotation marks when they resolve inside an RTL run.
Canvas
The bounded drawing area defined by the document's width × height (in pixels). Distinct from the viewport, which is what you currently see on screen.
Cel Animation
Frame-by-frame animation using a Frame Group layer — children render one at a time at the group's FPS. Onion skin shows ghosts of adjacent frames for registration.
Clipping Mask
A flag on one layer that clips its content to the alpha channel of the layer immediately below it. Stack multiple clipped layers above the same base.
Color Jitter
Per-segment HSL randomization on a brush stroke. A master amount slider sets the overall magnitude; per-axis weight sliders (Hue / Saturation / Luminance) attenuate jitter on each axis independently. Each stroke seeds a deterministic xorshift32 PRNG, so the live drag and the committed stroke share identical visuals.
Composition Guide
View-only overlay (rule of thirds, golden ratio, diagonals, isometric, etc.) that helps compose the canvas. Configurable color and opacity in Canvas Settings.
Document
The full project state — canvas dimensions, all layers, settings, and metadata. What gets saved to a file or to the cloud. Distinct from a single layer.
Dash Pattern
Pixel-length array (e.g. [12, 6, 3, 6]) that splits a stroke centerline into ON / OFF intervals matching SVG stroke-dasharray semantics. Each ON segment is tessellated independently; halo, color stops, and jitter all apply per segment.
Easing
The curve that shapes how a property tween moves between two keyframes — Linear, Ease-In, Ease-Out, cubic Bezier, Step, etc. Edit per-keyframe in the Animation graph editor.
Effect (Object)
Per-object visual effects: Drop Shadow, Inner Shadow, Outer Glow, Stroke Effect, Gaussian Blur. Toggleable via the Effects section of the Properties panel; serialize with the object.
Filter
A pixel-space transformation applied to a raster layer or via an adjustment layer. Includes tonal adjustments, color adjustments, blur, distortion, stylize, and more. See the Filters reference.
Frame Group
A group layer with cel-animation playback enabled — only the active child renders, with FPS, loop mode, and per-frame duration overrides controlled per group.
Halo (Brush Multipass)
Outer ring of softer color drawn around a stroke's ribbon by stacking N alpha-graded passes (multipass > 1 with softness > 0). Halo color can be a flat string or an N-stop gradient sampled per ring (outermost ring at t=1). Used by neon and glow-style brush variants.
Group Layer
A folder containing other layers. Move, reorder, or apply blend modes / opacity at the group level. Convert to a Frame Group for cel animation.
Keyframe
A snapshot of a property's value at a specific time on the animation timeline. Tweens between keyframes are interpolated by the easing curve attached to the segment.
LUT (3D Color Lookup Table)
A pre-computed cube of RGB-in → RGB-out mappings, sampled via trilinear interpolation at render time. Distributable as a .cube file. Paint Forge uses LUTs as an Adjustment Layer for film-emulation and color-grading workflows.
Layer
A hybrid container — every layer has a raster canvas (for pixel tools) AND a vector objects array (for shapes, text, paths). Vector objects render on top of the raster within the same layer.
Layer Comp
A lightweight named snapshot of layer visibility, opacity, and lock state. Cycle through comps to compare design alternatives without duplicating the whole document.
Layer Mask
A grayscale image attached to a layer that controls per-pixel visibility. Paint white to reveal, black to hide; partial gray for semi-transparency. Density and feather are adjustable.
Mask Editing Mode
When toggled on a layer, painting tools draw on the mask canvas instead of the raster. Toggle via Ctrl+\\ or the Mask icon in the Layers panel.
Object (Vector)
A vector primitive on a layer — Rectangle, Ellipse, Line, Arrow, Polygon, Star, Path, Text, Textbox, Brush Stroke, Image, Group, Callout. Editable after creation; supports effects, blend modes, and transforms.
Onion Skin
View-only ghosts of adjacent frames in a Frame Group, drawn around the active frame for registration. Configure 0–3 prev/next frames with independent opacity and tint.
Path
A vector shape defined by an SVG path string (anchors, bezier handles, line segments). Created with Pen tool or Freeform Polygon; editable via Edit Path tool.
Pressure Curve
A 0..1 → 0..1 mapping that remaps raw pen-tablet pressure to effective pressure (which in turn drives stroke width or opacity). Built-in named curves (Linear, Soft, Firm, S-Curve) cover most cases; a per-stroke custom curve editor lets you place arbitrary control points.
Pixel Selection
A per-document mask of which pixels are currently selected. Created by Marquee, Lasso, Magic Wand, etc. Painting tools clip strokes to the selection.
Quick Mask Mode
Toggle (Q) that lets you paint the current pixel selection with brush and eraser tools. White adds, black removes. Active selection renders as a semi-transparent red overlay.
Raster
Pixel-based content — the layer's canvas. Edited by brushes, erasers, fill, blur, etc. Resolution-dependent: scaling up beyond the canvas size loses detail.
Stroke Smoothing (Stabilizer / Streamline)
Two algorithms that smooth shaky cursor input on brush strokes. Stabilizer averages the last N samples in a weighted ring buffer — reactive with subtle softening. Streamline (Phase 80) is a Procreate- style cursor leash where each output blends toward the cursor by a fixed amount — silkier on long strokes but perceptibly laggier. Pick per-tool in the brush options.
Snapshot
A named copy of the entire project state stored separately from undo history. Up to 20 snapshots per cloud project; cloud-synced for signed-in users.
Symmetry Painting
Auto-mirrors brush strokes along vertical, horizontal, both, or radial axes. Configure in Canvas Settings; works with the brush, raster brush, calligraphy, and most painting tools.
Vector
Resolution-independent geometry — paths, shapes, text, brush strokes. Stored as math descriptions, rasterized at render time. Stays sharp at any zoom level.
Width Profile
A piecewise-linear curve in normalized arc-length space (x ∈ [0, 1]) that multiplies per-vertex stroke half-width by 0..2 along the centerline. Useful for tapered, bulged, or dumbbell-shaped strokes. Applied AFTER the variant's built-in taper so the two compose; editable via Width Profile editor in BrushStrokeProperties.
Viewport
The visible portion of the canvas on screen, controlled by zoom and pan. Distinct from the canvas itself, which has fixed pixel dimensions.