Types

The named sets of values used across the API. A value you pass must be one of these.

ColorMode

How a sprite stores pixel colors. Converting between modes is lossy out of rgba.

• "rgba" — Full color with transparency: four bytes per pixel.
• "grayscale" — Shades of gray (with alpha), from each color's Rec. 709 luma, as in Aseprite.
• "indexed" — Each pixel is an index into the sprite's palette.

LayerType

What a layer holds.

• "image" — Pixel art: one image per frame (a cel).
• "tilemap" — Tiles from the layer's own tileset, placed on a grid per frame.
• "reference" — An imported picture to trace over; never exported, never painted on.
• "adjustment" — Holds no pixels, only effects: they change everything composited beneath it in its group (or the whole picture), on every frame, at the layer's opacity. Colour and per-pixel effects only (levels, gradient map, noise, vignette, ...). Clipped, it changes just its base layer.
• "group" — A folder of layers. Holds no pixels; hiding or locking it hides or locks everything inside. At normal blend and full opacity its layers blend straight into what's below (pass-through) unless the group is isolated; an isolated group, or any other blend or opacity, composites its layers together first, then blends them as one image.

BlendMode

How a layer's colors combine with the layers beneath it.

• "normal" — The layer's own colors, source-over.
• "multiply" — Multiplies colors; always darkens.
• "screen" — Inverse of multiply; always lightens.
• "overlay" — Multiply in the shadows, screen in the highlights, by the layer below.
• "darken" — Keeps the darker color of each channel.
• "lighten" — Keeps the lighter color of each channel.
• "color-dodge" — Brightens the layer below to reflect this one.
• "color-burn" — Darkens the layer below to reflect this one.
• "hard-light" — Multiply or screen by this layer's own colors.
• "soft-light" — A gentler hard-light.
• "difference" — Absolute difference of the colors.
• "exclusion" — A lower-contrast difference.
• "hue" — This layer's hue with the saturation and luminosity beneath.
• "saturation" — This layer's saturation with the hue and luminosity beneath.
• "color" — This layer's hue and saturation with the luminosity beneath.
• "luminosity" — This layer's luminosity with the hue and saturation beneath.
• "addition" — Adds the colors.
• "subtract" — Subtracts this layer from the one below.
• "divide" — Divides the layer below by this one.

TagDirection

How a tag's frame span plays.

• "forward" — First frame to last, then repeat.
• "reverse" — Last frame to first, then repeat.
• "pingpong" — First to last, then back again.
• "pingpongReverse" — Last to first, then back again.

UserDataKind

Which kind of thing a user data target names (see app.setUserData).

• "sprite" — The sprite itself.
• "layer" — A layer or group: layerId.
• "cel" — A layer's image on one frame: layerId and frameId.
• "tag" — An animation tag: tagId. Its colour stays Tag.color, so userData.color is not accepted.
• "slice" — A slice: sliceId.
• "tileset" — A tilemap layer's tileset: layerId.

FillMode

Whether a shape is drawn as a border or solid.

• "outline" — Only the 1px border.
• "filled" — Every pixel inside the shape.

BucketFillMode

Which pixels a flood fill or the magic wand reaches.

• "contiguous" — Only the connected region around the starting pixel.
• "global" — Every matching pixel on the canvas, connected or not.

FillPattern

The repeating two-color pattern a flood fill paints, tiled from the canvas's top-left corner so neighbouring fills line up.

• "solid" — Only the fill color (no pattern).
• "checker" — A 1px checkerboard of the two colors.
• "dither25" — A 2x2 ordered dither: one pixel in four is the fill color.
• "dither75" — A 2x2 ordered dither: three pixels in four are the fill color.
• "hstripes" — 1px horizontal stripes, alternating the two colors.
• "vstripes" — 1px vertical stripes, alternating the two colors.
• "diagonal" — Diagonal lines of the fill color, one every 4px.
• "grid" — A grid of fill-color lines on a 4px pitch.
• "dots" — Single fill-color dots on a 4px pitch.
• "bricks" — A brick wall: fill-color mortar, 8x4 bricks offset every other row.

GradientType

The shape of a gradient.

• "linear" — A straight ramp from the first point to the second.
• "radial" — A ramp radiating out from the first point.

GradientDithering

The ordered-dithering pattern applied to a gradient's ramp.

• "none" — A smooth ramp (shows color banding).
• "bayer2" — A 2x2 Bayer matrix: the coarsest checker steps.
• "bayer4" — A 4x4 Bayer matrix.
• "bayer8" — An 8x8 Bayer matrix (finer).
• "dots" — Clustered dots on a 4px grid that grow into each other (halftone).
• "lines-h" — Horizontal lines that thicken along the ramp.
• "lines-v" — Vertical lines that thicken along the ramp.
• "diagonal" — Diagonal lines that thicken along the ramp.
• "noise" — An even, pattern-free scatter (interleaved gradient noise).

GradientSnap

Whether a gradient's colors are free blends or snapped to the palette.

• "free" — Any color: the stops blend smoothly into each other.
• "palette" — Palette colors only: each pixel takes the nearest palette color; with dithering, the ramp steps between neighbouring palette colors.

GradientColors

Where the gradient tool takes its colors from.

• "fg-bg" — From the foreground color to the background color.
• "stops" — Along the gradientStops list (fewer than two stops falls back to foreground to background).

DitherPattern

An ordered pattern the dither brush paints through: a pixel is painted where the pattern's threshold there is below the density. Patterns tile from the sprite's top-left corner, so strokes line up.

• "bayer2" — A 2x2 Bayer matrix: 50% is a checkerboard.
• "bayer4" — A 4x4 Bayer matrix: 16 even steps.
• "bayer8" — An 8x8 Bayer matrix: 64 even steps (the finest).
• "dots" — Clustered dots on a 4px grid that grow into each other (halftone).
• "lines-h" — Horizontal lines that thicken with the density.
• "lines-v" — Vertical lines that thicken with the density.
• "diagonal" — Diagonal lines that thicken with the density.
• "noise" — An even, pattern-free scatter (interleaved gradient noise).

BrushShape

The footprint a brush paints.

• "circle" — A round dot of the brush size.
• "square" — A square of the brush size, rotated by the brush angle.
• "line" — A 1px line of the brush size, tilted by the brush angle (0 = horizontal, 90 = vertical; a calligraphy nib).
• "diamond" — A diamond (a square standing on its corner) of the brush size.
• "cross" — A plus sign of the brush size (2px-wide arms at even sizes).
• "x" — An X: both diagonals of the brush-size square.
• "star" — A five-pointed star, one point up, of the brush size.
• "horizontal" — Alias for a line at angle 0: a flat size x 1 bar that ignores the brush angle.
• "custom" — The context's custom brush mask, at its own size.

SymmetryAxis

A mirror line through the canvas center. Several axes combine (horizontal + vertical = 4-way).

• "horizontal" — A horizontal line: mirrors top to bottom (flips Y).
• "vertical" — A vertical line: mirrors left to right (flips X).
• "diagonal" — The top-left to bottom-right diagonal.
• "antidiagonal" — The top-right to bottom-left diagonal.

TilemapEditMode

How pixel paint treats a tilemap layer.

• "tiles" — Only whole-tile stamping edits the layer; pixel tools are refused.
• "pixels-edit" — Paint edits the tile a cell already uses, in place: every placement of it updates.
• "pixels-auto" — Paint changes only the painted cells, like Aseprite Auto: an identical tile (also flipped/rotated, per the tileset match options) is reused, otherwise a new tile is made (a shared one is copied first), and tiles left unused by the edit are removed.

TilePaintMode

How app.paintTilemapPixels applies pixels to tiles.

• "edit" — Edit the tiles the cells already use, in place (all placements update).
• "auto" — Per painted cell: reuse an identical (or flipped/rotated, per the tileset match options) tile, else copy on write / create one; then remove tiles the edit orphaned.

SelectionCombineMode

How a new selection shape combines with the current selection.

• "replace" — The new shape becomes the selection.
• "add" — Union with the current selection.
• "subtract" — Remove the new shape from the current selection.
• "intersect" — Keep only where both overlap.

SelectionModifyOp

How Select > Modify changes the selection's shape.

• "expand" — Grows the selection outward by the amount.
• "contract" — Shrinks the selection inward by the amount; parts thinner than that vanish.
• "border" — Keeps only the selection's inside edge band, the amount wide; the middle is deselected.

SelectionModifyShape

How distance is measured when growing or shrinking a selection.

• "circle" — Straight-line distance: corners round off (at 1 pixel only the 4 orthogonal neighbours count).
• "square" — Grid distance: corners stay square (all 8 neighbours count at 1 pixel).

EyedropperSource

What the eyedropper samples.

• "composite" — What the canvas shows: every visible layer blended.
• "layer" — Only the active layer's pixels.

Ink

How freehand paint (drawStroke, spray) combines the paint color with the pixels already there.

• "copy" — Replaces the pixel with the paint color, alpha included (a transparent color erases). The default.
• "simple" — Alpha-composites the paint color over the existing pixel: an opaque color replaces it, a translucent one tints it.
• "lock-alpha" — Recolors only pixels that are already visible (alpha above 0), keeping each one's alpha.
• "shading" — Ignores the paint color: a pixel whose color is in the shades list moves one step forward in it (or one step back with shadeReverse); other pixels are untouched. Each pixel shifts at most once per stroke.

EraserRightClick

What the eraser paints with the right mouse button.

• "background" — Paints the background color over every pixel the eraser touches.
• "replace" — Replaces only pixels of the foreground color with the background color (Aseprite's eraser); other pixels are untouched.

FlipAxis

Which way to flip a region.

• "horizontal" — Left to right (mirror across a vertical line).
• "vertical" — Top to bottom (mirror across a horizontal line).

TransformInterpolation

How pixels are resampled when a selection is scaled, rotated or skewed.

• "nearest" — Fast Rotation: each output pixel copies the nearest source pixel. Fast and exact, but diagonals come out jagged.
• "rotsprite" — RotSprite: upscales the source 8x with Scale2X, resamples there, and samples back down. Keeps pixel-art edges clean when rotating; never invents colors.
• "bilinear" — Bilinear: blends the four nearest source pixels (alpha-weighted). Smooth, antialiased results for scaling and rotating painterly or high-res art; invents in-between colors (an indexed sprite snaps them to the palette).

IsoProjection

Which face of an isometric cube a region is projected onto (pixel-exact, never blended).

• "left" — The left face: a vertical shear whose rows run down to the right along the slope.
• "right" — The right face: a vertical shear whose rows run up to the right along the slope.
• "floor" — The top face: the region's x axis runs down-right and its y axis down-left along the slope, so a square becomes a diamond (twice as wide as tall at 2:1).

IsoShape

The solid the Iso Shape tool (drawIsoShape) draws, in pixel-art dimetric projection.

• "box" — A rectangular block: W x D footprint, H tall.
• "ramp" — A wedge whose top slopes from H down to the ground, descending toward direction.
• "stairs" — Steps descending toward direction, about two footprint units deep each.
• "pyramid" — Four triangular faces from the footprint up to an apex H above its center.
• "prism" — A roof: two slopes meeting at a ridge H up. The slopes face direction and its opposite.
• "cylinder" — A round column with pixel-ellipse caps; W is the diameter (D is ignored), H the height.
• "cone" — A round base tapering to an apex H above its center; W is the diameter (D is ignored).
• "sphere" — A ball resting on the footprint's center; W is the diameter (D and H are ignored).
• "dome" — Half a ball on a round base; W is the diameter (D is ignored), H the height of its top.

IsoShapeStyle

Which parts of an iso shape are painted.

• "filled" — The faces (and the inner edges between them), no silhouette outline.
• "outline" — The silhouette outline and inner edges only; the faces stay untouched.
• "filled-outline" — Faces, inner edges and the silhouette outline.

IsoDirection

Which way a ramp or stairs descend, or which way a prism's slopes face, along the iso axes (x runs down-right on screen, y down-left).

• "+x" — Toward +x: down-right, the right face's side.
• "-x" — Toward -x: up-left, away from the viewer.
• "+y" — Toward +y: down-left, the left face's side.
• "-y" — Toward -y: up-right, away from the viewer.

CanvasAnchor

Where existing content sits when the canvas is resized (the 3x3 anchor picker).

• "top-left" — Pinned to the top-left corner.
• "top" — Centered along the top edge.
• "top-right" — Pinned to the top-right corner.
• "left" — Centered along the left edge.
• "center" — Centered.
• "right" — Centered along the right edge.
• "bottom-left" — Pinned to the bottom-left corner.
• "bottom" — Centered along the bottom edge.
• "bottom-right" — Pinned to the bottom-right corner.

OutlinePlace

Which side of the shape's edge the outline is drawn on.

• "outside" — Paints background pixels that touch the shape; the shape grows by the outline.
• "inside" — Repaints the shape's own edge pixels; the shape keeps its size.

OutlineShape

A preset for the 3x3 outline matrix, which says which neighbors count as touching.

• "circle" — The 4 orthogonal neighbors (a plus): diagonal corners stay open, giving rounder outlines.
• "square" — All 8 neighbors: diagonal corners are filled too, giving a thicker, squarer outline.

StrokePosition

Where Stroke Selection's line sits relative to the selection's edge.

• "inside" — Along the inside of the edge: the selection keeps its size.
• "center" — Centered on the edge: half the width outside it, half inside.
• "outside" — Along the outside of the edge: the stroke grows past the selection.

AdjustHueMode

The colour model Hue/Saturation works in.

• "hsv" — Hue, saturation, value (as in Aseprite): the lightness slider moves the brightest channel toward full or zero.
• "hsl" — Hue, saturation, lightness (as in Aseprite): the lightness slider moves toward white or black.
• "oklch" — Perceptual OKLCH: hue turns and chroma scales at constant perceived lightness, so a hue shift doesn't brighten or darken colours; the lightness slider moves toward white or black. Colours pushed outside sRGB lose chroma rather than clip.

AdjustCurveChannel

Which channel a colour curve edits.

• "value" — Red, green and blue alike (applied before the single-channel curves).
• "red" — Only the red channel.
• "green" — Only the green channel.
• "blue" — Only the blue channel.
• "alpha" — Only the alpha channel.

AdjustIndexedMode

How a colour adjustment is applied on an indexed sprite. Ignored in rgba and grayscale.

• "remap" — Recolours the pixels, then snaps each changed pixel to the nearest palette entry. Selection-aware; the palette is untouched.
• "palette" — Edits the palette entries the targeted cels use, so every pixel (in any cel) using those entries changes. The selection is ignored.

GradientMapSpace

The colour space a gradient map blends between its stops in.

• "rgb" — Straight sRGB: the plain per-channel ramp pixel art tools use.
• "oklab" — Perceptual OKLab: even-looking steps, no muddy greys between saturated stops.
• "oklch" — OKLCH: blends hue as an angle, so two stops pass through the colours between them.

FxShape

The footprint of an outline, shadow or glow spread.

• "circle" — A rounded footprint: reach is measured as straight-line distance.
• "square" — A square footprint: reach is the same in every direction, corners included.
• "diamond" — A diamond footprint: reach is measured along the grid (|dx| + |dy|).

ShadowEdge

How a soft shadow's edge is drawn (with softness above 0).

• "dithered" — An ordered dither of fully opaque shadow pixels, denser where the shadow is stronger; keyed to the canvas, so it doesn't shimmer as the art moves.
• "hard" — Each pixel is shadow where the softened shadow is at least half strength, else nothing.
• "smooth" — A real alpha ramp: half-transparent shadow pixels (not pixel-art safe).

ConvolveEdges

What the Convolution Matrix reads beyond the edge of the cel.

• "clamp" — Repeats the nearest edge pixel.
• "tiled" — Wraps around to the opposite edge (for tileable art).

DitherMethod

How colours with no exact palette match are approximated when reducing to a palette (Convert to Indexed, Reduce Colors, GIF export).

• "none" — Each pixel takes its nearest palette colour (flat areas, visible banding).
• "bayer2" — Ordered dithering with a 2x2 Bayer matrix: a coarse, regular checker of the two nearest colours.
• "bayer4" — Ordered dithering with a 4x4 Bayer matrix.
• "bayer8" — Ordered dithering with an 8x8 Bayer matrix (the finest pattern).
• "floydSteinberg" — Floyd-Steinberg error diffusion: each pixel's error spreads to its unprocessed neighbours (smooth, noisy; patterns shift when pixels change, so it can shimmer in animation).
• "atkinson" — Atkinson error diffusion: spreads only 3/4 of the error, so highlights and shadows stay clean (the classic Macintosh look).

ReduceColorsPalette

Where Reduce Colors gets the colours it maps pixels onto.

• "generate" — Generates the best colors colours from the targeted cels (median cut).
• "palette" — Uses the sprite's palette (the transparent entry excluded): dithers the art onto it without converting to indexed.

TweenEaseFamily

The shape of a tween's easing curve (combined with a TweenEaseMode, except linear and hold).

• "linear" — Constant speed.
• "hold" — Keeps the start value until the next keyframe, then jumps.
• "sine" — Gentle ease (a quarter sine wave).
• "quad" — Ease by t^2.
• "cubic" — Ease by t^3.
• "quart" — Ease by t^4.
• "quint" — Ease by t^5.
• "expo" — Sharp ease (exponential).
• "circ" — Ease along a quarter circle.
• "back" — Winds up (in) or overshoots (out) by overshoot before settling.
• "elastic" — Overshoots and wobbles into place (amplitude, period).
• "bounce" — Lands and bounces bounces times before settling.

TweenEaseMode

Which end of the tween an easing family shapes.

• "in" — Starts slow (or winds up) and ends fast.
• "out" — Starts fast and settles slowly (or overshoots) at the end.
• "inOut" — Eased at both ends: the in curve for the first half, the out curve for the second.

TweenPath

The route a tween's position takes between its start and end, as an offset across the straight line.

• "straight" — The straight line.
• "arc" — One hump of height pixels (a jump).
• "wave" — A sine wave of amplitude pixels, cycles full waves long, starting at phase turns.
• "zigzag" — A triangle wave of amplitude pixels, cycles full zigzags long.
• "shake" — Random jitter of up to amplitude pixels each frame, the same every time for one seed.
• "custom" — A drawn route: cubic Bézier points from the start position to the end position, travelled at constant speed (the position easing sets the pace).

TweenSubpixel

How a tween turns fractional positions into whole pixels.

• "round" — Rounds each frame's position to the nearest pixel.
• "floor" — Rounds each frame's position down.
• "monotonic" — Rounds, but never steps back against the direction of travel (no jitter on slow eases). Falls back to round for easings that overshoot.

TweenTiming

What a tween's progress counts.

• "frames" — Frames: every in-between frame advances progress by the same amount.
• "time" — Time: progress follows the frames' durations, so a longer frame covers more of the motion.

TweenPivotSpace

What a tween's pivotX and pivotY are measured in.

• "cel" — Fractions of the start keyframe cel's box (0.5, 0.5 = its centre).
• "sprite" — Sprite pixels: one fixed point on the canvas, so several layers tweened with the same pose move rigidly as a group.

TweenFade

How a tween shows its opacity track (and a crossfade).

• "alpha" — Partial opacity: the cel's opacity follows the track.
• "dither" — An ordered-dither dissolve: whole pixels appear or disappear through a pattern fixed to the canvas, so only existing colours are ever shown.

TweenDither

The pattern a dither fade dissolves through, tiled from the canvas's top-left corner.

• "bayer2" — A 2x2 Bayer matrix: 4 steps, 50% is a checkerboard.
• "bayer4" — A 4x4 Bayer matrix: 16 even steps.
• "bayer8" — An 8x8 Bayer matrix: 64 even steps (the finest).
• "cluster" — Clustered dots on a 4px grid that grow into each other (halftone).

TweenStaggerOrder

Which layer of a stagger starts first.

• "topDown" — The top layer first, then each layer below it.
• "bottomUp" — The bottom layer first, then each layer above it.
• "given" — In the order the layers are listed (the selection order).

TweenStaggerLength

What a stagger does with each later layer's span.

• "keep" — Every span keeps the same end keyframe: later layers wait, then move faster to finish together.
• "extend" — Each later span ends step frames later than the one before, so every layer's motion keeps the same length.

As Markdown: types.md.