Interface and input

The 2D layer

116 symbols, imported from @driftengine/ui2d.

Explained in Sprites and tilemaps.

Interfaces

A11yHost
A11yNode
Camera2D: A 2D camera: where it is, how far in, and which way up.
DirtyTracker
PointerState
RowWindow: Which rows a scroll offset makes visible, so that a list costs a screenful rather than a list.
SheetEntry: One entry of an atlas, in texels, as a packer emits it.
SliceInset
SpriteBatch: One frame's worth of sprites.
SpriteFrame: A UvRect a caller owns and refills, so reading a frame allocates nothing.
SpritePass
SpritePassOptions
SpritePlacement: Where a sprite goes, in whatever space the batch is being drawn in.
SpriteRun: A run of consecutive instances that share a texture.
SpriteSheet: The frames of one texture.
SpriteTextureOptions
TextHost
TextModel: A caret, a selection, and the operations that move them.
TextRun: Overlapping style runs, normalised into disjoint ones that cover every character once.
Theme: Named colours and sizes, so an interface stops repeating its own constants.
Tilemap
UiContentSink: Where a caller draws what a quad cannot be.
UiInput: What the router remembers between calls.
UiNode: A node.
UiNodeOptions
UiRect: A resolved box, in whatever units the tree is laid out in. Written by layoutUiTree.
UvRect: A rectangle of a texture, in the 0..1 the sampler reads. See spriteSheet.ts.
ViewRect: What the view can see, in the same units the map is placed in.

Functions

a11yTree: Fill out with every node worth describing, in tree order. Returns how many.
addUiChild: Put child at the end of parent's children, detaching it from wherever it was.
applyComposition: Fold one composition update into the model.
beginDrag
capturePointer
clampScroll
clearDirty
clipRectFor: The rectangle node may draw into, cut by every clipping ancestor between it and root.
createAffine2D
createDirtyTracker
createNullA11yHost: A host that accepts a tree and does nothing with it. See the header.
createNullTextHost: A host that focuses nothing and whose clipboard is empty.
createPointerState
createSpriteBatch
createSpriteFrame
createSpritePass
createTextModel
createTheme
createTilemap
createUiInput
createUiNode
deleteBackward
deleteForward
deriveTheme: A new theme with overrides applied over base. base is not modified.
diffTree: Compare the tree against last frame and mark what changed.
dirtyBounds: The union of everything marked. Returns false when nothing was.
drawSprite: Push one quad. Allocates nothing.
drawTilemap: Draw the tiles the view can see. Returns how many that was.
drawUiTree: Draw a tree. Returns how many quads it came to.
dropTarget: The node a drop would land on, or null.
endDrag: Finish a drag and report where it landed. Null when no drag was in progress.
frameOf: The index a name has, or -1.
gridSheet: A sheet cut into equal cells, row-major: left to right, then down.
insertText
intersectClip: Write the overlap of two rectangles into out. Never negative; see the header.
layerOrder: Fill out with the tree in draw order and return how many entries were written.
layoutUiTree: Lay a tree out into x, y, w, h.
markDirty: Union rect into what must be redrawn. A zero-area rectangle still counts as a change.
moveCaret
moveToLineEdge
namedSheet: A sheet from an atlas description: whatever rectangles a packer put where.
pointerTarget: Who should receive pointer input at this position.
releasePointer
removeUiChild: Take child out of parent. A child that is not there is left alone.
resetSpriteBatch
resetUiInput: Forget everything, and clear the flags this router set on the tree.
routeScrollWheel: Give a wheel to the innermost container under the pointer that can use it, then outwards.
routeUiKey: Route a key. Returns the node it activated, or null.
routeUiPointer: Route a pointer. Returns the node this call activated, or null.
runsFor: Fill out with disjoint, ordered, gap-free runs covering [0, text.length).
screenToNdc: The affine for CSS pixels with a top-left origin — the convention InsetRect and fillPanel already use, and the one a caller laying out an overlay already has.
scrollBy: Scroll, clamped. Returns whether anything actually moved — see the header for why.
scrollExtent: How far this node's contents extend past its own box, along each axis.
selectAll
selectedText
selectionRange
setTile: Put a frame in a cell. A cell outside the map is ignored rather than wrapping into another row.
setUiFocus: Move focus, clearing whatever had it. null focuses nothing.
sheetFrame: Read a frame into a rectangle the caller owns. Allocates nothing.
sheetFrameHeight: A frame's height in texels, or 0 for an index the sheet does not have.
sheetFrameWidth: A frame's width in texels, or 0 for an index the sheet does not have.
sliceInto
spriteRun: Read a run back. For tests and diagnostics; the pass reads runs directly.
themeColour
themeRgba: themeColour and unpackRgba in one call, which is how a widget uses both.
themeSize
tileAt: The frame in a cell, or TILE_EMPTY — including for a cell outside the map.
uiFocusNext: The next focusable node after current, wrapping.
uiFocusOrder: Every focusable node, in tree order, appended to out.
uiFocusPrevious: The focusable node before current, wrapping.
uiHitTest: The interactive node under a point, or null.
uiNodeNamed: The node named, depth-first from root, or null. For a caller finding its own tree again.
uiRectHolds: Whether a point is inside a node's resolved box.
unpackRgba: A packed 0xRRGGBBAA token as the four floats a node's background and tint are.
visibleRange: Uniform row heights, which is arithmetic.
visibleRangeVariable: Variable row heights, through a prefix-sum table of row tops the caller owns.
worldToNdc: The affine for a 2D world seen through a camera.

Types

Affine2D: Six numbers, laid out the way a 2D graphics API has laid them out for thirty years:
SpriteImage: The three sources both backends take without a conversion.
UiAlign: Where children sit across the parent's main axis. stretch gives them the whole cross extent.
UiJustify: How the leftover along the main axis is spent when no child asked to grow.
UiSize: How big a node asks to be along one axis.

Constants

DEFAULT_SPRITE_CAPACITY: Sprites a frame, if the caller does not say. Four thousand quads is 224 KB of instance data.
DEFAULT_SPRITE_SLOTS: Texture slots, if the caller does not say.
DEFAULT_SPRITE_TEXTURE_OPTIONS
SLICE_STRIDE: Floats per placement: x, y, w, h, u0, v0, u1, v1.
SPRITE_FLOATS: Floats per instance: two edge vectors, a UV rectangle, a tint, and an origin.
TILE_EMPTY: A cell holding nothing. Negative, so it can never be a frame index.