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Allow subpixel anti-aliasing for most of the content.

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This commit is contained in:
Yury Delendik 2015-11-16 10:50:02 -06:00
parent f096e4ab91
commit 1d8800370a
7 changed files with 111 additions and 55 deletions
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91
src/display/canvas.js
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@ -162,13 +162,15 @@ function addContextCurrentTransform(ctx) {
}
var CachedCanvases = (function CachedCanvasesClosure() {
var cache = {};
return {
function CachedCanvases() {
this.cache = Object.create(null);
}
CachedCanvases.prototype = {
getCanvas: function CachedCanvases_getCanvas(id, width, height,
trackTransform) {
var canvasEntry;
if (cache[id] !== undefined) {
canvasEntry = cache[id];
if (this.cache[id] !== undefined) {
canvasEntry = this.cache[id];
canvasEntry.canvas.width = width;
canvasEntry.canvas.height = height;
// reset canvas transform for emulated mozCurrentTransform, if needed
@ -179,21 +181,22 @@ var CachedCanvases = (function CachedCanvasesClosure() {
if (trackTransform) {
addContextCurrentTransform(ctx);
}
cache[id] = canvasEntry = {canvas: canvas, context: ctx};
this.cache[id] = canvasEntry = {canvas: canvas, context: ctx};
}
return canvasEntry;
},
clear: function () {
for (var id in cache) {
var canvasEntry = cache[id];
for (var id in this.cache) {
var canvasEntry = this.cache[id];
// Zeroing the width and height causes Firefox to release graphics
// resources immediately, which can greatly reduce memory consumption.
canvasEntry.canvas.width = 0;
canvasEntry.canvas.height = 0;
delete cache[id];
delete this.cache[id];
}
}
};
return CachedCanvases;
})();
function compileType3Glyph(imgData) {
@ -431,6 +434,7 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
this.smaskStack = [];
this.smaskCounter = 0;
this.tempSMask = null;
this.cachedCanvases = new CachedCanvases();
if (canvasCtx) {
// NOTE: if mozCurrentTransform is polyfilled, then the current state of
// the transformation must already be set in canvasCtx._transformMatrix.
@ -707,28 +711,39 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
CanvasGraphics.prototype = {
beginDrawing: function CanvasGraphics_beginDrawing(viewport, transparency) {
beginDrawing: function CanvasGraphics_beginDrawing(transform, viewport,
transparency) {
// For pdfs that use blend modes we have to clear the canvas else certain
// blend modes can look wrong since we'd be blending with a white
// backdrop. The problem with a transparent backdrop though is we then
// don't get sub pixel anti aliasing on text, so we fill with white if
// we can.
// don't get sub pixel anti aliasing on text, creating temporary
// transparent canvas when we have blend modes.
var width = this.ctx.canvas.width;
var height = this.ctx.canvas.height;
if (transparency) {
this.ctx.clearRect(0, 0, width, height);
} else {
this.ctx.mozOpaque = true;
this.ctx.save();
this.ctx.fillStyle = 'rgb(255, 255, 255)';
this.ctx.fillRect(0, 0, width, height);
this.ctx.restore();
}
var transform = viewport.transform;
this.ctx.save();
this.ctx.transform.apply(this.ctx, transform);
this.ctx.fillStyle = 'rgb(255, 255, 255)';
this.ctx.fillRect(0, 0, width, height);
this.ctx.restore();
if (transparency) {
var transparentCanvas = this.cachedCanvases.getCanvas(
'transparent', width, height, true);
this.compositeCtx = this.ctx;
this.transparentCanvas = transparentCanvas.canvas;
this.ctx = transparentCanvas.context;
this.ctx.save();
// The transform can be applied before rendering, transferring it to
// the new canvas.
this.ctx.transform.apply(this.ctx,
this.compositeCtx.mozCurrentTransform);
}
this.ctx.save();
if (transform) {
this.ctx.transform.apply(this.ctx, transform);
}
this.ctx.transform.apply(this.ctx, viewport.transform);
this.baseTransform = this.ctx.mozCurrentTransform.slice();
@ -810,7 +825,14 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
endDrawing: function CanvasGraphics_endDrawing() {
this.ctx.restore();
CachedCanvases.clear();
if (this.transparentCanvas) {
this.ctx = this.compositeCtx;
this.ctx.drawImage(this.transparentCanvas, 0, 0);
this.transparentCanvas = null;
}
this.cachedCanvases.clear();
WebGLUtils.clear();
if (this.imageLayer) {
@ -924,7 +946,7 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
var drawnWidth = activeSMask.canvas.width;
var drawnHeight = activeSMask.canvas.height;
var cacheId = 'smaskGroupAt' + this.groupLevel;
var scratchCanvas = CachedCanvases.getCanvas(
var scratchCanvas = this.cachedCanvases.getCanvas(
cacheId, drawnWidth, drawnHeight, true);
var currentCtx = this.ctx;
@ -1708,7 +1730,7 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
// Using two cache entries is case if masks are used one after another.
cacheId += '_smask_' + ((this.smaskCounter++) % 2);
}
var scratchCanvas = CachedCanvases.getCanvas(
var scratchCanvas = this.cachedCanvases.getCanvas(
cacheId, drawnWidth, drawnHeight, true);
var groupCtx = scratchCanvas.context;
@ -1849,7 +1871,8 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
return;
}
var maskCanvas = CachedCanvases.getCanvas('maskCanvas', width, height);
var maskCanvas = this.cachedCanvases.getCanvas('maskCanvas',
width, height);
var maskCtx = maskCanvas.context;
maskCtx.save();
@ -1874,7 +1897,8 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
var fillColor = this.current.fillColor;
var isPatternFill = this.current.patternFill;
var maskCanvas = CachedCanvases.getCanvas('maskCanvas', width, height);
var maskCanvas = this.cachedCanvases.getCanvas('maskCanvas',
width, height);
var maskCtx = maskCanvas.context;
maskCtx.save();
@ -1909,7 +1933,8 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
var image = images[i];
var width = image.width, height = image.height;
var maskCanvas = CachedCanvases.getCanvas('maskCanvas', width, height);
var maskCanvas = this.cachedCanvases.getCanvas('maskCanvas',
width, height);
var maskCtx = maskCanvas.context;
maskCtx.save();
@ -1982,7 +2007,8 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
if (imgData instanceof HTMLElement || !imgData.data) {
imgToPaint = imgData;
} else {
tmpCanvas = CachedCanvases.getCanvas('inlineImage', width, height);
tmpCanvas = this.cachedCanvases.getCanvas('inlineImage',
width, height);
var tmpCtx = tmpCanvas.context;
putBinaryImageData(tmpCtx, imgData);
imgToPaint = tmpCanvas.canvas;
@ -2004,7 +2030,8 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
newHeight = Math.ceil(paintHeight / 2);
heightScale /= paintHeight / newHeight;
}
tmpCanvas = CachedCanvases.getCanvas(tmpCanvasId, newWidth, newHeight);
tmpCanvas = this.cachedCanvases.getCanvas(tmpCanvasId,
newWidth, newHeight);
tmpCtx = tmpCanvas.context;
tmpCtx.clearRect(0, 0, newWidth, newHeight);
tmpCtx.drawImage(imgToPaint, 0, 0, paintWidth, paintHeight,
@ -2036,7 +2063,7 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
var w = imgData.width;
var h = imgData.height;
var tmpCanvas = CachedCanvases.getCanvas('inlineImage', w, h);
var tmpCanvas = this.cachedCanvases.getCanvas('inlineImage', w, h);
var tmpCtx = tmpCanvas.context;
putBinaryImageData(tmpCtx, imgData);