webp-hero
Version:
webp image format polyfill for browsers
297 lines • 14.2 kB
JavaScript
"use strict";
var __extends = (this && this.__extends) || (function () {
var extendStatics = function (d, b) {
extendStatics = Object.setPrototypeOf ||
({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
function (d, b) { for (var p in b) if (Object.prototype.hasOwnProperty.call(b, p)) d[p] = b[p]; };
return extendStatics(d, b);
};
return function (d, b) {
if (typeof b !== "function" && b !== null)
throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
extendStatics(d, b);
function __() { this.constructor = d; }
d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
})();
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
return new (P || (P = Promise))(function (resolve, reject) {
function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
step((generator = generator.apply(thisArg, _arguments || [])).next());
});
};
var __generator = (this && this.__generator) || function (thisArg, body) {
var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
function verb(n) { return function (v) { return step([n, v]); }; }
function step(op) {
if (f) throw new TypeError("Generator is already executing.");
while (_) try {
if (f = 1, y && (t = op[0] & 2 ? y["return"] : op[0] ? y["throw"] || ((t = y["return"]) && t.call(y), 0) : y.next) && !(t = t.call(y, op[1])).done) return t;
if (y = 0, t) op = [op[0] & 2, t.value];
switch (op[0]) {
case 0: case 1: t = op; break;
case 4: _.label++; return { value: op[1], done: false };
case 5: _.label++; y = op[1]; op = [0]; continue;
case 7: op = _.ops.pop(); _.trys.pop(); continue;
default:
if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
if (op[0] === 3 && (!t || (op[1] > t[0] && op[1] < t[3]))) { _.label = op[1]; break; }
if (op[0] === 6 && _.label < t[1]) { _.label = t[1]; t = op; break; }
if (t && _.label < t[2]) { _.label = t[2]; _.ops.push(op); break; }
if (t[2]) _.ops.pop();
_.trys.pop(); continue;
}
op = body.call(thisArg, _);
} catch (e) { op = [6, e]; y = 0; } finally { f = t = 0; }
if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
}
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.WebpMachine = exports.improvedWebpImageDetector = exports.defaultDetectWebpImage = exports.WebpMachineError = void 0;
var webp_js_1 = require("../libwebp/dist/webp.cjs.js");
var load_binary_data_js_1 = require("./load-binary-data.js");
var get_mime_type_js_1 = require("./utils/get-mime-type.js");
var parse_data_url_js_1 = require("./utils/parse-data-url.js");
var detect_webp_support_js_1 = require("./detect-webp-support.js");
var convert_binary_data_js_1 = require("./convert-binary-data.js");
var detect_canvas_reading_support_js_1 = require("./detect-canvas-reading-support.js");
var relax = function () { return new Promise(function (resolve) { return setTimeout(resolve, 0); }); };
var WebpMachineError = /** @class */ (function (_super) {
__extends(WebpMachineError, _super);
function WebpMachineError() {
return _super !== null && _super.apply(this, arguments) || this;
}
return WebpMachineError;
}(Error));
exports.WebpMachineError = WebpMachineError;
/**
* detect a webp image by its extension
* @deprecated please use `improvedWebpImageDetector` instead, but note it returns a promise
*/
var defaultDetectWebpImage = function (image) {
return /\.webp.*$/i.test(image.src);
};
exports.defaultDetectWebpImage = defaultDetectWebpImage;
function improvedWebpImageDetector(image) {
return __awaiter(this, void 0, void 0, function () {
var dataUrl, type, _a;
return __generator(this, function (_b) {
switch (_b.label) {
case 0:
dataUrl = (0, parse_data_url_js_1.parseDataUrl)(image.src);
if (!dataUrl) return [3 /*break*/, 1];
_a = dataUrl.format;
return [3 /*break*/, 3];
case 1: return [4 /*yield*/, (0, get_mime_type_js_1.getMimeType)(image.src)];
case 2:
_a = _b.sent();
_b.label = 3;
case 3:
type = _a;
return [2 /*return*/, type.indexOf("image/webp") !== -1];
}
});
});
}
exports.improvedWebpImageDetector = improvedWebpImageDetector;
/**
* Webp Machine
* - decode and polyfill webp images
* - can only decode images one-at-a-time (otherwise will throw busy error)
*/
var WebpMachine = /** @class */ (function () {
function WebpMachine(_a) {
var _b = _a === void 0 ? {} : _a, _c = _b.webp, webp = _c === void 0 ? new webp_js_1.Webp() : _c, _d = _b.webpSupport, webpSupport = _d === void 0 ? (0, detect_webp_support_js_1.detectWebpSupport)() : _d, _e = _b.useCanvasElements, useCanvasElements = _e === void 0 ? !(0, detect_canvas_reading_support_js_1.detectCanvasReadingSupport)() : _e, _f = _b.detectWebpImage, detectWebpImage = _f === void 0 ? improvedWebpImageDetector : _f;
this.busy = false;
this.cache = {};
this.webp = webp;
this.webpSupport = webpSupport;
this.useCanvasElements = useCanvasElements;
this.detectWebpImage = detectWebpImage;
}
/**
* Replace an <img> element with a <canvas> element
*/
WebpMachine.replaceImageWithCanvas = function (image, canvas) {
canvas.className = image.className;
canvas.style.cssText = window.getComputedStyle(image).cssText;
canvas.style.pointerEvents = canvas.style.pointerEvents || "none";
var imageWidth = image.getAttribute("width");
var imageHeight = image.getAttribute("height");
canvas.style.width = image.style.width
|| (imageWidth
? "".concat(imageWidth, "px")
: "auto");
canvas.style.height = image.style.height
|| (imageHeight
? "".concat(imageHeight, "px")
: "auto");
var parent = image.parentElement;
parent.replaceChild(canvas, image);
};
/**
* Make a copy of a canvas element (useful for caching)
*/
WebpMachine.cloneCanvas = function (oldCanvas) {
var newCanvas = document.createElement("canvas");
newCanvas.className = oldCanvas.className;
newCanvas.width = oldCanvas.width;
newCanvas.height = oldCanvas.height;
newCanvas.style.cssText = window.getComputedStyle(oldCanvas).cssText;
var context = newCanvas.getContext("2d");
context.drawImage(oldCanvas, 0, 0);
return newCanvas;
};
/**
* Paint a webp image onto a canvas element
*/
WebpMachine.prototype.decodeToCanvas = function (canvas, webpData) {
return __awaiter(this, void 0, void 0, function () {
var error_1;
return __generator(this, function (_a) {
switch (_a.label) {
case 0:
if (this.busy)
throw new WebpMachineError("cannot decode when already busy");
this.busy = true;
_a.label = 1;
case 1:
_a.trys.push([1, 3, 4, 5]);
return [4 /*yield*/, relax()];
case 2:
_a.sent();
this.webp.setCanvas(canvas);
this.webp.webpToSdl(webpData, webpData.length);
return [3 /*break*/, 5];
case 3:
error_1 = _a.sent();
error_1.name = WebpMachineError.name;
error_1.message = "failed to decode webp image: ".concat(error_1.message);
throw error_1;
case 4:
this.busy = false;
return [7 /*endfinally*/];
case 5: return [2 /*return*/];
}
});
});
};
/**
* Decode raw webp data into a png data url
*/
WebpMachine.prototype.decode = function (webpData) {
return __awaiter(this, void 0, void 0, function () {
var canvas;
return __generator(this, function (_a) {
switch (_a.label) {
case 0:
canvas = document.createElement("canvas");
return [4 /*yield*/, this.decodeToCanvas(canvas, webpData)];
case 1:
_a.sent();
return [2 /*return*/, canvas.toDataURL()];
}
});
});
};
/**
* Polyfill the webp format on the given <img> element
*/
WebpMachine.prototype.polyfillImage = function (image) {
return __awaiter(this, void 0, void 0, function () {
var src, canvas, webpData, _a, canvas, pngData, error_2;
return __generator(this, function (_b) {
switch (_b.label) {
case 0: return [4 /*yield*/, this.webpSupport];
case 1:
if (_b.sent())
return [2 /*return*/];
src = image.src;
return [4 /*yield*/, this.detectWebpImage(image)];
case 2:
if (!_b.sent()) return [3 /*break*/, 12];
if (!this.cache[src]) return [3 /*break*/, 3];
if (this.useCanvasElements) {
canvas = WebpMachine.cloneCanvas(this.cache[src]);
WebpMachine.replaceImageWithCanvas(image, canvas);
}
else
image.src = this.cache[src];
return [3 /*break*/, 12];
case 3:
_b.trys.push([3, 11, , 12]);
if (!(0, convert_binary_data_js_1.isBase64Url)(src)) return [3 /*break*/, 4];
_a = (0, convert_binary_data_js_1.convertDataURIToBinary)(src);
return [3 /*break*/, 6];
case 4: return [4 /*yield*/, (0, load_binary_data_js_1.loadBinaryData)(src)];
case 5:
_a = _b.sent();
_b.label = 6;
case 6:
webpData = _a;
if (!this.useCanvasElements) return [3 /*break*/, 8];
canvas = document.createElement("canvas");
return [4 /*yield*/, this.decodeToCanvas(canvas, webpData)];
case 7:
_b.sent();
WebpMachine.replaceImageWithCanvas(image, canvas);
this.cache[src] = canvas;
return [3 /*break*/, 10];
case 8: return [4 /*yield*/, this.decode(webpData)];
case 9:
pngData = _b.sent();
image.src = this.cache[src] = pngData;
_b.label = 10;
case 10: return [3 /*break*/, 12];
case 11:
error_2 = _b.sent();
error_2.name = WebpMachineError.name;
error_2.message = "failed to polyfill image \"".concat(src, "\": ").concat(error_2.message);
console.error(error_2);
return [3 /*break*/, 12];
case 12: return [2 /*return*/];
}
});
});
};
/**
* Polyfill webp format on the entire web page
*/
WebpMachine.prototype.polyfillDocument = function (_a) {
var _b = _a === void 0 ? {} : _a, _c = _b.document, document = _c === void 0 ? window.document : _c;
return __awaiter(this, void 0, void 0, function () {
var _i, _d, image;
return __generator(this, function (_e) {
switch (_e.label) {
case 0:
_i = 0, _d = Array.from(document.querySelectorAll("img"));
_e.label = 1;
case 1:
if (!(_i < _d.length)) return [3 /*break*/, 4];
image = _d[_i];
return [4 /*yield*/, this.polyfillImage(image)];
case 2:
_e.sent();
_e.label = 3;
case 3:
_i++;
return [3 /*break*/, 1];
case 4: return [2 /*return*/];
}
});
});
};
/**
* Manually wipe the cache to save memory
*/
WebpMachine.prototype.clearCache = function () {
this.cache = {};
};
return WebpMachine;
}());
exports.WebpMachine = WebpMachine;
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