Faster 1 bpp image drawing #4466

p01 · 2014-03-14T14:36:42Z

Moving up the end condition and using Uint32Array view of the destination array where possible gives about ~36% speed improvement on 33M pixels B&W images ( typical B&W scanned document ), going from ~1180ms down to ~753ms.

timvandermeij · 2014-03-14T20:14:18Z

Travis somewhat complains:

src/display/canvas.js: line 551, col 150, Line is too long.
src/display/canvas.js: line 462, col 12, 'performance' is not defined.
src/display/canvas.js: line 546, col 15, 'performance' is not defined.

p01 · 2014-03-15T09:37:15Z

my bad, looks like my git commit -p included parts of the performance test comparing the different versions. I'll fix this when I get access to a laptop.

p01 · 2014-03-17T15:22:42Z

Done. Travis seems happier now.

yurydelendik · 2014-03-17T15:52:38Z

src/display/canvas.js

-              if (srcPos >= srcLength) {
-                break;
+      var srcLastLine = srcLength - (width >> 3);
+      var nativeTypedArray = 'set' in dest && 'subarray' in src;


We decided to move the support for the IE9 to the compatibility.js (see #4420).

I'm not finding the use of new Uint32Array() and polyfill for that. Let's special-case it in compatibility.js: for Uint32Array constructor with array, and we will create/return an object instead with the numerical index setters that will tweak the array's items. (CanvasPixelArray may be extended to return itself in the buffer getter as well). Let me know I you need help with creating such polyfill.

That sounds much cleaner, however I'm not sure what's the most efficient way to define numerical setters for an array of 33M Uint32s. Defining 33M setters is not gonna cut it, or do you know a way to define arbitrary numerical setters ?

Why 33M? Looks like fullChunkHeight == 16, so I'm expecting amount of setters ~256K. Also, we can try to cache them on the object's prototype.

Actually the setters are on the Uint32Array, so we're rather talking about ~80.000 unique setters. Still a big number.The poor souls on IE9+ will suffer a greater pain.

Is that more or less what you have in mind ?

for (var i = 0; i < this.length; i++) { Object.defineProperty(this, String(i), { set: (function(i) { var index = i * 4; return function(newValue){ // this._Uint8Array refers to the Uint8Array passed in the // constructor of the Uint32Array var dest = this._Uint8view; dest[index++] = newValue & 255; dest[index++] = (newValue >> 8) & 255; dest[index++] = (newValue >> 16) & 255; dest[index++] = (newValue >> 24) & 255; }; })(i) }) }

Also I took the IE11's F12 Developer Tools for a spin to get a profile of how IE fares with a test documents containing 10 600 DPI JBIG2 images. Decoding one of these takes ~1s in Firefox, ~1.2 s in Opera, and ~15s in IE11. This makes me all the more doubtful about creating tens of thousands of unique setters for IE.

Here is my prototype/testing https://gist.github.com/yurydelendik/9624811 . It's expected IE9 be a little bit slower. Decoding on my low end machine of 4000x8000 image takes about 7 sec, not sure what are the expectation here, but carrying code that used by small amount of users is not really acceptable, since we cannot really test or properly maintain it.

yurydelendik · 2014-03-17T15:53:23Z

/botio test

pdfjsbot · 2014-03-17T15:53:24Z

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Live output at: http://107.21.233.14:8877/6f8a3901f1a42be/output.txt

pdfjsbot · 2014-03-17T15:53:24Z

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pdfjsbot · 2014-03-17T16:24:43Z

From: Bot.io (Linux)

Failed

Full output at http://107.21.233.14:8877/6f8a3901f1a42be/output.txt

Total script time: 25.87 mins

Font tests: Passed
Unit tests: Passed
Regression tests: FAILED

Image differences available at: http://107.21.233.14:8877/6f8a3901f1a42be/reftest-analyzer.html#web=eq.log

yurydelendik · 2014-03-17T16:31:37Z

Hmm, loosing some pixels/lines at issue1658-page10

pdfjsbot · 2014-03-17T16:47:32Z

From: Bot.io (Windows)

Failed

Full output at http://107.22.172.223:8877/25bb0c0c5caae8a/output.txt

Total script time: 37.26 mins

Font tests: Passed
Unit tests: Passed
Regression tests: FAILED

Image differences available at: http://107.22.172.223:8877/25bb0c0c5caae8a/reftest-analyzer.html#web=eq.log

yurydelendik · 2014-03-18T04:38:40Z

src/display/canvas.js


-        ctx.putImageData(chunkImgData, 0, i * fullChunkHeight);
+              dest32[destPos++] = (srcByte & mask) ? 0xFFFFFFFF : 0xFF000000;


Looks like there is an assumption the all platforms will be little-endian based. We shall not assume there will no be big-endian Uint32Array.

True.
Where would you rather see the detection of endianness; compatibility.js, util.js, canvas.js ?

About the endianness of dest32, I could force little-endian but this could be significantly slower on big-endian platforms. Better make two local variables: black and white based on the endianness of the platform.

edit: s/smaller/slower

The detection can be added to the util.js.

I like making "black and white based on the endianness of the platform" thing

yurydelendik · 2014-03-20T23:33:42Z

/botio test

pdfjsbot · 2014-03-20T23:33:43Z

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pdfjsbot · 2014-03-20T23:33:43Z

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pdfjsbot · 2014-03-20T23:37:10Z

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Failed

Full output at http://107.21.233.14:8877/9612e6a50988967/output.txt

Total script time: 3.44 mins

Font tests: Passed
Unit tests: FAILED
Regression tests: FAILED

Image differences available at: http://107.21.233.14:8877/9612e6a50988967/reftest-analyzer.html#web=eq.log

yurydelendik · 2014-03-20T23:42:36Z

src/shared/util.js

+
+  function Uint32ArrayView(buffer) {
+    this.buffer = buffer;
+    this.byteLength = buffer.byteLength;


this.byteLength = buffer.length';

pdfjsbot · 2014-03-20T23:43:29Z

From: Bot.io (Windows)

Failed

Full output at http://107.22.172.223:8877/4760ddaa259933d/output.txt

Total script time: 3.95 mins

Font tests: Passed
Unit tests: FAILED
Regression tests: FAILED

Image differences available at: http://107.22.172.223:8877/4760ddaa259933d/reftest-analyzer.html#web=eq.log

yurydelendik · 2014-03-21T12:44:07Z

/botio test

pdfjsbot · 2014-03-21T12:44:08Z

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pdfjsbot · 2014-03-21T12:44:08Z

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pdfjsbot · 2014-03-21T13:09:14Z

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Failed

Full output at http://107.21.233.14:8877/983f252c3470781/output.txt

Total script time: 25.11 mins

Font tests: Passed
Unit tests: Passed
Regression tests: FAILED

Image differences available at: http://107.21.233.14:8877/983f252c3470781/reftest-analyzer.html#web=eq.log

pdfjsbot · 2014-03-21T13:20:14Z

From: Bot.io (Windows)

Failed

Full output at http://107.22.172.223:8877/5e685f388fc9423/output.txt

Total script time: 36.10 mins

Font tests: Passed
Unit tests: Passed
Regression tests: FAILED

Image differences available at: http://107.22.172.223:8877/5e685f388fc9423/reftest-analyzer.html#web=eq.log

yurydelendik · 2014-03-21T14:04:55Z

There are some issues with issue1658-page10.

Could you also squash the commits in one?

yurydelendik · 2014-03-21T17:21:16Z

src/display/canvas.js

-      for (var i = 3; i < destDataLength; i += 4) {
-        dest[i] = 255;
-      }
+      var srcLastLine = srcLength - (width >> 3);


unused variable

p01 · 2014-03-26T12:35:42Z

Done.

Snuffleupagus · 2014-03-26T12:38:48Z

src/shared/util.js

+  canvas.width = canvas.height = 1;
+  var ctx = canvas.getContext('2d');
+  var imageData = ctx.createImageData(1, 1);
+  return (typeof imageData.data.buffer != 'undefined');


Nit: use strict equality.

The following changes make putBinaryImageData 2.2x faster. * Use a Uint32Array to draw whole pixels instead component by component * Unroll the inner most loop * Added lazy PDFJS.hasCanvasTypedArrays, PDFJS.isLittleEndian and compatibility Uint32ArrayView for browsers using the old CanvasPixelArray

yurydelendik · 2014-03-26T14:18:16Z

/botio test

pdfjsbot · 2014-03-26T14:18:17Z

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pdfjsbot · 2014-03-26T14:18:17Z

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pdfjsbot · 2014-03-26T15:04:15Z

From: Bot.io (Linux)

Success

Full output at http://107.21.233.14:8877/300c346bdced9fa/output.txt

Total script time: 25.87 mins

Font tests: Passed
Unit tests: Passed
Regression tests: Passed

pdfjsbot · 2014-03-26T15:25:16Z

From: Bot.io (Windows)

Success

Full output at http://107.22.172.223:8877/dedaaf92938fc97/output.txt

Total script time: 36.17 mins

Font tests: Passed
Unit tests: Passed
Regression tests: Passed

Faster 1 bpp image drawing

yurydelendik · 2014-03-26T15:32:17Z

Nice. Thank you for the patch

yurydelendik reviewed Mar 17, 2014
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yurydelendik reviewed Mar 18, 2014
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yurydelendik reviewed Mar 20, 2014
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yurydelendik reviewed Mar 21, 2014
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Snuffleupagus reviewed Mar 26, 2014
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yurydelendik added a commit that referenced this pull request Mar 26, 2014

Merge pull request #4466 from p01/Faster_1BPP_image_drawing

e80c6a8

Faster 1 bpp image drawing

yurydelendik merged commit e80c6a8 into mozilla:master Mar 26, 2014


		ctx.putImageData(chunkImgData, 0, i * fullChunkHeight);
		dest32[destPos++] = (srcByte & mask) ? 0xFFFFFFFF : 0xFF000000;

Faster 1 bpp image drawing #4466

Faster 1 bpp image drawing #4466

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