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Convert TempImageFactory to a class, using static fields/methods

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Please refer to https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes/Private_class_fields
This commit is contained in:
Jonas Jenwald 2021-10-17 13:42:21 +02:00
parent 89785a23f3
commit 7216511fbf
1 changed files with 32 additions and 38 deletions
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70
web/pdf_thumbnail_view.js
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@ -36,48 +36,42 @@ const THUMBNAIL_WIDTH = 98; // px
* @property {IL10n} l10n - Localization service.
*/
const TempImageFactory = (function TempImageFactoryClosure() {
let tempCanvasCache = null;
class TempImageFactory {
static #tempCanvas = null;
return {
getCanvas(width, height) {
let tempCanvas = tempCanvasCache;
if (!tempCanvas) {
tempCanvas = document.createElement("canvas");
tempCanvasCache = tempCanvas;
}
tempCanvas.width = width;
tempCanvas.height = height;
static getCanvas(width, height) {
const tempCanvas = (this.#tempCanvas ||= document.createElement("canvas"));
tempCanvas.width = width;
tempCanvas.height = height;
// Since this is a temporary canvas, we need to fill it with a white
// background ourselves. `_getPageDrawContext` uses CSS rules for this.
if (
typeof PDFJSDev === "undefined" ||
PDFJSDev.test("MOZCENTRAL || GENERIC")
) {
tempCanvas.mozOpaque = true;
}
// Since this is a temporary canvas, we need to fill it with a white
// background ourselves. `_getPageDrawContext` uses CSS rules for this.
if (
typeof PDFJSDev === "undefined" ||
PDFJSDev.test("MOZCENTRAL || GENERIC")
) {
tempCanvas.mozOpaque = true;
}
const ctx = tempCanvas.getContext("2d", { alpha: false });
ctx.save();
ctx.fillStyle = "rgb(255, 255, 255)";
ctx.fillRect(0, 0, width, height);
ctx.restore();
return [tempCanvas, tempCanvas.getContext("2d")];
},
const ctx = tempCanvas.getContext("2d", { alpha: false });
ctx.save();
ctx.fillStyle = "rgb(255, 255, 255)";
ctx.fillRect(0, 0, width, height);
ctx.restore();
return [tempCanvas, tempCanvas.getContext("2d")];
}
destroyCanvas() {
const tempCanvas = tempCanvasCache;
if (tempCanvas) {
// Zeroing the width and height causes Firefox to release graphics
// resources immediately, which can greatly reduce memory consumption.
tempCanvas.width = 0;
tempCanvas.height = 0;
}
tempCanvasCache = null;
},
};
})();
static destroyCanvas() {
const tempCanvas = this.#tempCanvas;
if (tempCanvas) {
// Zeroing the width and height causes Firefox to release graphics
// resources immediately, which can greatly reduce memory consumption.
tempCanvas.width = 0;
tempCanvas.height = 0;
}
this.#tempCanvas = null;
}
}
/**
* @implements {IRenderableView}