[api-minor] Generate images in the worker instead of the main thread.

We introduced the use of OffscreenCanvas in #14754 and this patch aims
to use them for all kind of images.
It'll slightly improve performances (and maybe slightly decrease memory use).
Since an image can be rendered in using some transfer maps but because of
OffscreenCanvas we don't have the underlying pixels array the transfer maps
stuff is re-implemented in using the SVG filter feComponentTransfer.

src/core/jpg.js

@@ -14,6 +14,7 @@
  */
 
 import { assert, BaseException, warn } from "../shared/util.js";
+import { grayToRGBA } from "../shared/image_utils.js";
 import { readUint16 } from "./core_utils.js";
 
 class JpegError extends BaseException {
@@ -1217,6 +1218,19 @@ class JpegImage {
     return data;
   }
 
+  _convertYccToRgba(data, out) {
+    for (let i = 0, j = 0, length = data.length; i < length; i += 3, j += 4) {
+      const Y = data[i];
+      const Cb = data[i + 1];
+      const Cr = data[i + 2];
+      out[j] = Y - 179.456 + 1.402 * Cr;
+      out[j + 1] = Y + 135.459 - 0.344 * Cb - 0.714 * Cr;
+      out[j + 2] = Y - 226.816 + 1.772 * Cb;
+      out[j + 3] = 255;
+    }
+    return out;
+  }
+
   _convertYcckToRgb(data) {
     let Y, Cb, Cr, k;
     let offset = 0;
@@ -1287,6 +1301,74 @@ class JpegImage {
     return data.subarray(0, offset);
   }
 
+  _convertYcckToRgba(data) {
+    for (let i = 0, length = data.length; i < length; i += 4) {
+      const Y = data[i];
+      const Cb = data[i + 1];
+      const Cr = data[i + 2];
+      const k = data[i + 3];
+
+      data[i] =
+        -122.67195406894 +
+        Cb *
+          (-6.60635669420364e-5 * Cb +
+            0.000437130475926232 * Cr -
+            5.4080610064599e-5 * Y +
+            0.00048449797120281 * k -
+            0.154362151871126) +
+        Cr *
+          (-0.000957964378445773 * Cr +
+            0.000817076911346625 * Y -
+            0.00477271405408747 * k +
+            1.53380253221734) +
+        Y *
+          (0.000961250184130688 * Y -
+            0.00266257332283933 * k +
+            0.48357088451265) +
+        k * (-0.000336197177618394 * k + 0.484791561490776);
+
+      data[i + 1] =
+        107.268039397724 +
+        Cb *
+          (2.19927104525741e-5 * Cb -
+            0.000640992018297945 * Cr +
+            0.000659397001245577 * Y +
+            0.000426105652938837 * k -
+            0.176491792462875) +
+        Cr *
+          (-0.000778269941513683 * Cr +
+            0.00130872261408275 * Y +
+            0.000770482631801132 * k -
+            0.151051492775562) +
+        Y *
+          (0.00126935368114843 * Y -
+            0.00265090189010898 * k +
+            0.25802910206845) +
+        k * (-0.000318913117588328 * k - 0.213742400323665);
+
+      data[i + 2] =
+        -20.810012546947 +
+        Cb *
+          (-0.000570115196973677 * Cb -
+            2.63409051004589e-5 * Cr +
+            0.0020741088115012 * Y -
+            0.00288260236853442 * k +
+            0.814272968359295) +
+        Cr *
+          (-1.53496057440975e-5 * Cr -
+            0.000132689043961446 * Y +
+            0.000560833691242812 * k -
+            0.195152027534049) +
+        Y *
+          (0.00174418132927582 * Y -
+            0.00255243321439347 * k +
+            0.116935020465145) +
+        k * (-0.000343531996510555 * k + 0.24165260232407);
+      data[i + 3] = 255;
+    }
+    return data;
+  }
+
   _convertYcckToCmyk(data) {
     let Y, Cb, Cr;
     for (let i = 0, length = data.length; i < length; i += 4) {
@@ -1371,7 +1453,81 @@ class JpegImage {
     return data.subarray(0, offset);
   }
 
-  getData({ width, height, forceRGB = false, isSourcePDF = false }) {
+  _convertCmykToRgba(data) {
+    for (let i = 0, length = data.length; i < length; i += 4) {
+      const c = data[i];
+      const m = data[i + 1];
+      const y = data[i + 2];
+      const k = data[i + 3];
+
+      data[i] =
+        255 +
+        c *
+          (-0.00006747147073602441 * c +
+            0.0008379262121013727 * m +
+            0.0002894718188643294 * y +
+            0.003264231057537806 * k -
+            1.1185611867203937) +
+        m *
+          (0.000026374107616089405 * m -
+            0.00008626949158638572 * y -
+            0.0002748769067499491 * k -
+            0.02155688794978967) +
+        y *
+          (-0.00003878099212869363 * y -
+            0.0003267808279485286 * k +
+            0.0686742238595345) -
+        k * (0.0003361971776183937 * k + 0.7430659151342254);
+
+      data[i + 1] =
+        255 +
+        c *
+          (0.00013596372813588848 * c +
+            0.000924537132573585 * m +
+            0.00010567359618683593 * y +
+            0.0004791864687436512 * k -
+            0.3109689587515875) +
+        m *
+          (-0.00023545346108370344 * m +
+            0.0002702845253534714 * y +
+            0.0020200308977307156 * k -
+            0.7488052167015494) +
+        y *
+          (0.00006834815998235662 * y +
+            0.00015168452363460973 * k -
+            0.09751927774728933) -
+        k * (0.0003189131175883281 * k + 0.7364883807733168);
+
+      data[i + 2] =
+        255 +
+        c *
+          (0.000013598650411385307 * c +
+            0.00012423956175490851 * m +
+            0.0004751985097583589 * y -
+            0.0000036729317476630422 * k -
+            0.05562186980264034) +
+        m *
+          (0.00016141380598724676 * m +
+            0.0009692239130725186 * y +
+            0.0007782692450036253 * k -
+            0.44015232367526463) +
+        y *
+          (5.068882914068769e-7 * y +
+            0.0017778369011375071 * k -
+            0.7591454649749609) -
+        k * (0.0003435319965105553 * k + 0.7063770186160144);
+      data[i + 3] = 255;
+    }
+    return data;
+  }
+
+  getData({
+    width,
+    height,
+    forceRGBA = false,
+    forceRGB = false,
+    isSourcePDF = false,
+  }) {
     if (
       typeof PDFJSDev === "undefined" ||
       PDFJSDev.test("!PRODUCTION || TESTING")
@@ -1387,23 +1543,37 @@ class JpegImage {
     // Type of data: Uint8ClampedArray(width * height * numComponents)
     const data = this._getLinearizedBlockData(width, height, isSourcePDF);
 
-    if (this.numComponents === 1 && forceRGB) {
-      const rgbData = new Uint8ClampedArray(data.length * 3);
+    if (this.numComponents === 1 && (forceRGBA || forceRGB)) {
+      const len = data.length * (forceRGBA ? 4 : 3);
+      const rgbaData = new Uint8ClampedArray(len);
       let offset = 0;
-      for (const grayColor of data) {
-        rgbData[offset++] = grayColor;
-        rgbData[offset++] = grayColor;
-        rgbData[offset++] = grayColor;
+      if (forceRGBA) {
+        grayToRGBA(data, new Uint32Array(rgbaData.buffer));
+      } else {
+        for (const grayColor of data) {
+          rgbaData[offset++] = grayColor;
+          rgbaData[offset++] = grayColor;
+          rgbaData[offset++] = grayColor;
+        }
       }
-      return rgbData;
+      return rgbaData;
     } else if (this.numComponents === 3 && this._isColorConversionNeeded) {
+      if (forceRGBA) {
+        const rgbaData = new Uint8ClampedArray((data.length / 3) * 4);
+        return this._convertYccToRgba(data, rgbaData);
+      }
       return this._convertYccToRgb(data);
     } else if (this.numComponents === 4) {
       if (this._isColorConversionNeeded) {
+        if (forceRGBA) {
+          return this._convertYcckToRgba(data);
+        }
         if (forceRGB) {
           return this._convertYcckToRgb(data);
         }
         return this._convertYcckToCmyk(data);
+      } else if (forceRGBA) {
+        return this._convertCmykToRgba(data);
       } else if (forceRGB) {
         return this._convertCmykToRgb(data);
       }