254 lines
10 KiB
JavaScript
254 lines
10 KiB
JavaScript
import { Transform, Util } from "./Util.js";
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import { SceneContext, HitContext } from "./Context.js";
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import { Konva } from "./Global.js";
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/**
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* Canvas Renderer constructor. It is a wrapper around native canvas element.
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* Usually you don't need to use it manually.
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* @constructor
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* @abstract
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* @memberof Konva
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* @param {Object} config
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* @param {Number} config.width
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* @param {Number} config.height
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* @param {Number} config.pixelRatio
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*/
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export class Canvas {
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constructor(config) {
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this.pixelRatio = 1;
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// the bitmap size, in device pixels
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this.width = 0;
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this.height = 0;
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// the size the canvas was given, in CSS pixels; the bitmap truncates it
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this._logicalWidth = 0;
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this._logicalHeight = 0;
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this.isCache = false;
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const conf = config || {};
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// a Konva.pixelRatio reset to undefined or 0 means the device ratio
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const pixelRatio = conf.pixelRatio ||
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Konva.pixelRatio ||
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Konva._global.devicePixelRatio ||
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1;
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this.pixelRatio = pixelRatio;
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this._canvas = Util.createCanvasElement();
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// set inline styles
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this._canvas.style.padding = '0';
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this._canvas.style.margin = '0';
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this._canvas.style.border = '0';
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this._canvas.style.background = 'transparent';
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this._canvas.style.position = 'absolute';
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this._canvas.style.top = '0';
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this._canvas.style.left = '0';
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}
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/**
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* get canvas context
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* @method
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* @name Konva.Canvas#getContext
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* @returns {CanvasContext} context
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*/
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getContext() {
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return this.context;
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}
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/**
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* get pixel ratio
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* @method
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* @name Konva.Canvas#getPixelRatio
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* @returns {Number} pixel ratio
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* @example
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* var pixelRatio = layer.getCanvas().getPixelRatio();
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*/
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getPixelRatio() {
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return this.pixelRatio;
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}
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/**
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* set pixel ratio
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* KonvaJS automatically handles pixel ratio adustments in order to render crisp drawings
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* on all devices. Most desktops, low end tablets, and low end phones, have device pixel ratios
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* of 1. Some high end tablets and phones, like iPhones and iPads have a device pixel ratio
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* of 2. Some Macbook Pros, and iMacs also have a device pixel ratio of 2. Some high end Android devices have pixel
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* ratios of 2 or 3. Some browsers like Firefox allow you to configure the pixel ratio of the viewport. Unless otherwise
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* specificed, the pixel ratio will be defaulted to the actual device pixel ratio. You can override the device pixel
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* ratio for special situations, or, if you don't want the pixel ratio to be taken into account, you can set it to 1.
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* @method
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* @name Konva.Canvas#setPixelRatio
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* @param {Number} pixelRatio
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* @example
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* layer.getCanvas().setPixelRatio(3);
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*/
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setPixelRatio(pixelRatio) {
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this.pixelRatio = pixelRatio;
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this.setSize(this._logicalWidth, this._logicalHeight);
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}
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setWidth(width) {
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this.setSize(width, this._logicalHeight);
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}
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setHeight(height) {
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this.setSize(this._logicalWidth, height);
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}
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getWidth() {
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return this.width;
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}
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getHeight() {
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return this.height;
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}
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// the bitmap holds whole pixels: a fractional pixel ratio truncates, and
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// a size that does not match the bitmap would resample every draw of it
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_bitmapSize(size) {
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return Math.floor((size || 0) * this.pixelRatio);
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}
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setSize(width, height) {
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// a NaN or Infinity size would silently give an empty bitmap
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if (!isFinite(width !== null && width !== void 0 ? width : 0) || !isFinite(height !== null && height !== void 0 ? height : 0)) {
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Util.error(`Canvas size must be finite numbers, got ${width}x${height}. The canvas is left empty.`);
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width = height = 0;
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}
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width = width || 0;
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height = height || 0;
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const pixelRatio = this.pixelRatio;
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const context = this.getContext()._context;
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const imageSmoothingEnabled = context.imageSmoothingEnabled;
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this._logicalWidth = width;
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this._logicalHeight = height;
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// take into account pixel ratio. Assigning a dimension reallocates the
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// bitmap and resets the whole context state, so scale once after both
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this.width = this._canvas.width = this._bitmapSize(width);
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this.height = this._canvas.height = this._bitmapSize(height);
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this._canvas.style.width = width + 'px';
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this._canvas.style.height = height + 'px';
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context.scale(pixelRatio, pixelRatio);
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context.imageSmoothingEnabled = imageSmoothingEnabled;
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}
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// setSize() re-allocates and clears the canvas even for the same size,
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// so lazily sized canvases use this to stay untouched when nothing changed
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setSizeIfChanged(width, height) {
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if (this.width !== this._bitmapSize(width) ||
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this.height !== this._bitmapSize(height)) {
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this.setSize(width, height);
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}
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}
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/**
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* to data url
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* @method
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* @name Konva.Canvas#toDataURL
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* @param {String} mimeType
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* @param {Number} quality between 0 and 1 for jpg mime types
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* @returns {String} data url string
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*/
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toDataURL(mimeType, quality) {
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try {
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// If the requested encoding fails, retry with the default PNG encoding.
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return this._canvas.toDataURL(mimeType, quality);
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}
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catch (e) {
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try {
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return this._canvas.toDataURL();
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}
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catch (err) {
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Util.error('Unable to get data URL. ' +
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err.message +
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' For more info read https://konvajs.org/docs/posts/Tainted_Canvas.html.');
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throw err;
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}
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}
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}
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}
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export class SceneCanvas extends Canvas {
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// A cleared surface over `rect` (in the current drawing space), or over the
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// whole canvas, in this canvas's device pixels. Siblings reuse it; nested
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// groups borrow from the surface itself, so they cannot clear a parent's
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// unfinished image.
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_prepareIsolationCanvas(rect) {
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const { a, b, c, d, e, f } = this.getContext()._context.getTransform();
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const view = this._isolationRect || this;
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let x = 0, y = 0, width = view.width, height = view.height;
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if (rect) {
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const box = new Transform([a, b, c, d, e, f])._getTransformedRect(rect);
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// Round outwards, with a pixel for antialiasing.
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x = Math.max(0, Math.floor(box.x) - 1);
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y = Math.max(0, Math.floor(box.y) - 1);
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width = Math.min(width, Math.ceil(box.x + box.width) + 1) - x;
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height = Math.min(height, Math.ceil(box.y + box.height) + 1) - y;
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}
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if (!(width > 0 && height > 0)) {
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// An empty source must still composite for copy/destination-in/etc.
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x = y = 0;
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width = height = 1;
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}
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const surface = (this._isolationCanvas || (this._isolationCanvas = new SceneCanvas({
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width: 0,
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height: 0,
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pixelRatio: this.pixelRatio,
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})));
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if (surface.width < width || surface.height < height) {
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// Headroom on a short side, so a growing group does not reallocate
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// every frame.
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const ratio = this.pixelRatio;
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const grow = (need, have, max) => Math.min(max, Math.ceil((have < need ? Math.max(need, have * 1.5) : have) / ratio));
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surface.setSize(grow(width, surface.width, this._logicalWidth), grow(height, surface.height, this._logicalHeight));
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}
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surface._isolationRect = { x, y, width, height };
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const peak = surface._isolationPeak;
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peak.width = Math.max(peak.width, width);
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peak.height = Math.max(peak.height, height);
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const context = surface.getContext();
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context.setTransform(1, 0, 0, 1, 0, 0);
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context.clearRect(0, 0, width, height);
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context.setTransform(a, b, c, d, e - x, f - y);
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const parent = this.getContext();
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context.imageSmoothingEnabled = parent.imageSmoothingEnabled;
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context.imageSmoothingQuality = parent.imageSmoothingQuality;
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context.direction = parent.direction;
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return surface;
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}
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// After a frame, free surfaces that ten frames in a row did not use or used
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// a small part of. Content that changes size keeps its surface.
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_trimIsolationCanvas() {
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const surface = this._isolationCanvas;
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if (!surface)
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return;
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const peak = surface._isolationPeak;
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const low = surface.width * surface.height > 4 * peak.width * peak.height;
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surface._isolationLowFrames = low ? surface._isolationLowFrames + 1 : 0;
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if (surface._isolationLowFrames >= 10) {
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this._releaseIsolationCanvas();
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}
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else {
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peak.width = peak.height = 0;
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surface._trimIsolationCanvas();
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}
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}
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_releaseIsolationCanvas() {
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const surface = this._isolationCanvas;
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if (surface) {
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surface._releaseIsolationCanvas();
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Util.releaseCanvas(surface._canvas);
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this._isolationCanvas = undefined;
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}
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}
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setSize(width, height) {
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// A bitmap reset also resets its origin-clean state. A surface from the
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// previous lifetime may be tainted even after clearing its pixels.
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this._releaseIsolationCanvas();
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super.setSize(width, height);
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}
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constructor(config = { width: 0, height: 0, willReadFrequently: false }) {
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super(config);
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// The largest width and height requested since the last trim.
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this._isolationPeak = { width: 0, height: 0 };
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// Consecutive frames that used less than a quarter of the surface.
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this._isolationLowFrames = 0;
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this.context = new SceneContext(this, {
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willReadFrequently: config.willReadFrequently,
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});
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this.setSize(config.width, config.height);
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}
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}
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export class HitCanvas extends Canvas {
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constructor(config = { width: 0, height: 0 }) {
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super(config);
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this.hitCanvas = true;
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this.context = new HitContext(this);
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this.context.imageSmoothingEnabled = false;
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this.setSize(config.width, config.height);
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}
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}
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