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Use the convertBlackAndWhiteToRGBA helper with grayscale images in putBinaryImageData

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This removes a little bit of code duplication, which only exist since the `src/display/canvas.js` code pre-dates the helper function by many years.

*Note:* Given that `OffscreenCanvas` is enabled by default there's currently not a lot of test coverage for this code-path, hence the added browser-test.
This commit is contained in:
Jonas Jenwald 2026-06-10 18:27:50 +02:00
parent ce08a803c4
commit d1926fb179
2 changed files with 15 additions and 39 deletions
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46
src/display/canvas.js
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@ -349,48 +349,16 @@ function putBinaryImageData(ctx, imgData) {
// imgData.kind tells us which one this is. // imgData.kind tells us which one this is.
if (imgData.kind === ImageKind.GRAYSCALE_1BPP) { if (imgData.kind === ImageKind.GRAYSCALE_1BPP) {
// Grayscale, 1 bit per pixel (i.e. black-and-white). // Grayscale, 1 bit per pixel (i.e. black-and-white).
const srcLength = src.byteLength;
const dest32 = new Uint32Array(dest.buffer, 0, dest.byteLength >> 2);
const dest32DataLength = dest32.length;
const fullSrcDiff = (width + 7) >> 3;
const white = 0xffffffff;
const black = FeatureTest.isLittleEndian ? 0xff000000 : 0x000000ff;
for (i = 0; i < totalChunks; i++) { for (i = 0; i < totalChunks; i++) {
thisChunkHeight = i < fullChunks ? FULL_CHUNK_HEIGHT : partialChunkHeight; thisChunkHeight = i < fullChunks ? FULL_CHUNK_HEIGHT : partialChunkHeight;
destPos = 0;
for (j = 0; j < thisChunkHeight; j++) {
const srcDiff = srcLength - srcPos;
let k = 0;
const kEnd = srcDiff > fullSrcDiff ? width : srcDiff * 8 - 7;
const kEndUnrolled = kEnd & ~7;
let mask = 0;
let srcByte = 0;
for (; k < kEndUnrolled; k += 8) {
srcByte = src[srcPos++];
dest32[destPos++] = srcByte & 128 ? white : black;
dest32[destPos++] = srcByte & 64 ? white : black;
dest32[destPos++] = srcByte & 32 ? white : black;
dest32[destPos++] = srcByte & 16 ? white : black;
dest32[destPos++] = srcByte & 8 ? white : black;
dest32[destPos++] = srcByte & 4 ? white : black;
dest32[destPos++] = srcByte & 2 ? white : black;
dest32[destPos++] = srcByte & 1 ? white : black;
}
for (; k < kEnd; k++) {
if (mask === 0) {
srcByte = src[srcPos++];
mask = 128;
}
dest32[destPos++] = srcByte & mask ? white : black; ({ srcPos } = convertBlackAndWhiteToRGBA({
mask >>= 1; src,
} srcPos,
} dest,
// We ran out of input. Make all remaining pixels transparent. width,
while (destPos < dest32DataLength) { height: thisChunkHeight,
dest32[destPos++] = 0; }));
}
ctx.putImageData(chunkImgData, 0, i * FULL_CHUNK_HEIGHT); ctx.putImageData(chunkImgData, 0, i * FULL_CHUNK_HEIGHT);
} }

8
test/test_manifest.json
View File

@ -5389,6 +5389,14 @@
"rounds": 1, "rounds": 1,
"type": "eq" "type": "eq"
}, },
{
"id": "images_1bit_grayscale-disable-isOffscreenCanvasSupported",
"file": "pdfs/images_1bit_grayscale.pdf",
"md5": "e1c36a19563944891bd30cfc0199d07f",
"rounds": 1,
"type": "eq",
"isOffscreenCanvasSupported": false
},
{ {
"id": "html5checker", "id": "html5checker",
"file": "pdfs/html5checker.pdf", "file": "pdfs/html5checker.pdf",