Improve performance with image masks (bug 857031)

- it aims to partially fix performance issue reported: https://bugzilla.mozilla.org/show_bug.cgi?id=857031;
- the idea is too avoid to use byte arrays but use ImageBitmap which are a way faster to draw:
  * an ImageBitmap is Transferable which means that it can be built in the worker instead of in the main thread:
    - this is achieved in using an OffscreenCanvas when it's available, there is a bug to enable them
      for pdf.js: https://bugzilla.mozilla.org/show_bug.cgi?id=1763330;
    - or in using createImageBitmap: in Firefox a task is sent to the main thread to build the bitmap so
      it's slightly slower than using an OffscreenCanvas.
  * it's transfered from the worker to the main thread by "reference";
  * the byte buffers used to create the image data have a very short lifetime and ergo the memory used is globally
    less than before.
- Use the localImageCache for the mask;
- Fix the pdf issue4436r.pdf: it was expected to have a binary stream for the image;
- Move the singlePixel trick from operator_list to image: this way we can use this trick even if it isn't in a set
  as defined in operator_list.
This commit is contained in:
Calixte Denizet 2022-04-06 15:34:08 +02:00
parent 2b673a6941
commit 040fcae5ab
11 changed files with 256 additions and 65 deletions

View file

@ -1241,6 +1241,8 @@ class PDFPageProxy {
this.commonObjs = transport.commonObjs;
this.objs = new PDFObjects();
this._bitmaps = new Set();
this.cleanupAfterRender = false;
this.pendingCleanup = false;
this._intentStates = new Map();
@ -1696,6 +1698,10 @@ class PDFPageProxy {
}
}
this.objs.clear();
for (const bitmap of this._bitmaps) {
bitmap.close();
}
this._bitmaps.clear();
this._annotationPromises.clear();
this._jsActionsPromise = null;
this._structTreePromise = null;
@ -1737,6 +1743,10 @@ class PDFPageProxy {
if (resetStats && this._stats) {
this._stats = new StatTimer();
}
for (const bitmap of this._bitmaps) {
bitmap.close();
}
this._bitmaps.clear();
this.pendingCleanup = false;
return true;
}
@ -2778,8 +2788,19 @@ class WorkerTransport {
// Heuristic that will allow us not to store large data.
const MAX_IMAGE_SIZE_TO_STORE = 8000000;
if (imageData?.data?.length > MAX_IMAGE_SIZE_TO_STORE) {
pageProxy.cleanupAfterRender = true;
if (imageData) {
let length;
if (imageData.bitmap) {
const { bitmap, width, height } = imageData;
length = width * height * 4;
pageProxy._bitmaps.add(bitmap);
} else {
length = imageData.data?.length || 0;
}
if (length > MAX_IMAGE_SIZE_TO_STORE) {
pageProxy.cleanupAfterRender = true;
}
}
break;
case "Pattern":