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Fixes text clipping

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This commit is contained in:
Yury Delendik 2012-10-12 22:33:56 -05:00
parent 8427e745fc
commit ab058dbe75
3 changed files with 77 additions and 3 deletions
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72
src/canvas.js
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@ -28,7 +28,8 @@ var TextRenderingMode = {
FILL_ADD_TO_PATH: 4,
STROKE_ADD_TO_PATH: 5,
FILL_STROKE_ADD_TO_PATH: 6,
ADD_TO_PATH: 7
ADD_TO_PATH: 7,
ADD_TO_PATH_FLAG: 4
};
// Minimal font size that would be used during canvas fillText operations.
@ -414,6 +415,10 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
this.current = old.clone();
},
restore: function CanvasGraphics_restore() {
if ('textClipLayers' in this) {
this.completeTextClipping();
}
var prev = this.stateStack.pop();
if (prev) {
this.current = prev;
@ -543,6 +548,64 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
this.current.y = this.current.lineY = 0;
},
endText: function CanvasGraphics_endText() {
if ('textClipLayers' in this) {
this.swapImageForTextClipping();
}
},
getCurrentTextClipping: function CanvasGraphics_getCurrentTextClipping() {
var ctx = this.ctx;
var transform = ctx.mozCurrentTransform;
if ('textClipLayers' in this) {
// we need to reset only font and transform
var maskCtx = this.textClipLayers.maskCtx;
maskCtx.setTransform.apply(maskCtx, transform);
maskCtx.font = ctx.font;
return maskCtx;
}
var canvasWidth = ctx.canvas.width;
var canvasHeight = ctx.canvas.height;
// keeping track of the text clipping of the separate canvas
var maskCanvas = createScratchCanvas(canvasWidth, canvasHeight);
var maskCtx = maskCanvas.getContext('2d');
maskCtx.setTransform.apply(maskCtx, transform);
maskCtx.font = ctx.font;
var textClipLayers = {
maskCanvas: maskCanvas,
maskCtx: maskCtx
};
this.textClipLayers = textClipLayers;
return maskCtx;
},
swapImageForTextClipping:
function CanvasGraphics_swapImageForTextClipping() {
var ctx = this.ctx;
var canvasWidth = ctx.canvas.width;
var canvasHeight = ctx.canvas.height;
// saving current image content and clearing whole canvas
ctx.save();
ctx.setTransform(1, 0, 0, 1, 0, 0);
var data = ctx.getImageData(0, 0, canvasWidth, canvasHeight);
this.textClipLayers.imageData = data;
ctx.clearRect(0, 0, canvasWidth, canvasHeight);
ctx.restore();
},
completeTextClipping: function CanvasGraphics_completeTextClipping() {
var ctx = this.ctx;
// applying mask to the image (result is saved in maskCanvas)
var maskCtx = this.textClipLayers.maskCtx;
maskCtx.setTransform(1, 0, 0, 1, 0, 0);
maskCtx.globalCompositeOperation = 'source-in';
maskCtx.drawImage(ctx.canvas, 0, 0);
// restoring image data and applying the result of masked drawing
ctx.save();
ctx.setTransform(1, 0, 0, 1, 0, 0);
ctx.putImageData(this.textClipLayers.imageData, 0, 0);
ctx.drawImage(this.textClipLayers.maskCanvas, 0, 0);
ctx.restore();
delete this.textClipLayers;
},
setCharSpacing: function CanvasGraphics_setCharSpacing(spacing) {
this.current.charSpacing = spacing;
@ -610,8 +673,6 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
this.ctx.font = rule;
},
setTextRenderingMode: function CanvasGraphics_setTextRenderingMode(mode) {
if (mode >= TextRenderingMode.FILL_ADD_TO_PATH)
TODO('unsupported text rendering mode: ' + mode);
this.current.textRenderingMode = mode;
},
setTextRise: function CanvasGraphics_setTextRise(rise) {
@ -777,8 +838,13 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
ctx.strokeText(character, scaledX, 0);
break;
case TextRenderingMode.INVISIBLE:
case TextRenderingMode.ADD_TO_PATH:
break;
}
if (textRenderingMode & TextRenderingMode.ADD_TO_PATH_FLAG) {
var clipCtx = this.getCurrentTextClipping();
clipCtx.fillText(character, scaledX, 0);
}
}
x += charWidth;