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Refactor TilingPattern

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- Deduplicate size/scale calculation, by introducing `getSizeAndScale`.
- Eliminate unnecessary calculations / variables.
This commit is contained in:
Rob Wu 2015-10-03 14:40:59 +02:00
parent 9b5a937f78
commit 60d4685c10
1 changed files with 19 additions and 34 deletions
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53
src/display/pattern_helper.js
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@ -332,13 +332,6 @@ var TilingPattern = (function TilingPatternClosure() {
var x0 = bbox[0], y0 = bbox[1], x1 = bbox[2], y1 = bbox[3]; var x0 = bbox[0], y0 = bbox[1], x1 = bbox[2], y1 = bbox[3];
var topLeft = [x0, y0];
// we want the canvas to be as large as the step size
var botRight = [x0 + xstep, y0 + ystep];
var width = botRight[0] - topLeft[0];
var height = botRight[1] - topLeft[1];
// Obtain scale from matrix and current transformation matrix. // Obtain scale from matrix and current transformation matrix.
var matrixScale = Util.singularValueDecompose2dScale(this.matrix); var matrixScale = Util.singularValueDecompose2dScale(this.matrix);
var curMatrixScale = Util.singularValueDecompose2dScale( var curMatrixScale = Util.singularValueDecompose2dScale(
@ -346,50 +339,42 @@ var TilingPattern = (function TilingPatternClosure() {
var combinedScale = [matrixScale[0] * curMatrixScale[0], var combinedScale = [matrixScale[0] * curMatrixScale[0],
matrixScale[1] * curMatrixScale[1]]; matrixScale[1] * curMatrixScale[1]];
// MAX_PATTERN_SIZE is used to avoid OOM situation.
// Use width and height values that are as close as possible to the end // Use width and height values that are as close as possible to the end
// result when the pattern is used. Too low value makes the pattern look // result when the pattern is used. Too low value makes the pattern look
// blurry. Too large value makes it look too crispy. // blurry. Too large value makes it look too crispy.
width = Math.min(Math.ceil(Math.abs(width * combinedScale[0])), var dimx = this.getSizeAndScale(xstep, combinedScale[0]);
MAX_PATTERN_SIZE); var dimy = this.getSizeAndScale(ystep, combinedScale[1]);
height = Math.min(Math.ceil(Math.abs(height * combinedScale[1])),
MAX_PATTERN_SIZE);
var tmpCanvas = owner.cachedCanvases.getCanvas('pattern', var tmpCanvas = owner.cachedCanvases.getCanvas('pattern',
width, height, true); dimx.size, dimy.size, true);
var tmpCtx = tmpCanvas.context; var tmpCtx = tmpCanvas.context;
var graphics = canvasGraphicsFactory.createCanvasGraphics(tmpCtx); var graphics = canvasGraphicsFactory.createCanvasGraphics(tmpCtx);
graphics.groupLevel = owner.groupLevel; graphics.groupLevel = owner.groupLevel;
this.setFillAndStrokeStyleToContext(graphics, paintType, color); this.setFillAndStrokeStyleToContext(graphics, paintType, color);
this.setScale(width, height, xstep, ystep); graphics.transform(dimx.scale, 0, 0, dimy.scale, 0, 0);
this.transformToScale(graphics);
// transform coordinates to pattern space // transform coordinates to pattern space
var tmpTranslate = [1, 0, 0, 1, -topLeft[0], -topLeft[1]]; graphics.transform(1, 0, 0, 1, -x0, -y0);
graphics.transform.apply(graphics, tmpTranslate);
this.clipBbox(graphics, bbox, x0, y0, x1, y1); this.clipBbox(graphics, bbox, x0, y0, x1, y1);
graphics.executeOperatorList(operatorList); graphics.executeOperatorList(operatorList);
// Rescale canvas so that the ctx.createPattern call generates a pattern
// with the desired size.
this.ctx.scale(1 / dimx.scale, 1 / dimy.scale);
return tmpCanvas.canvas; return tmpCanvas.canvas;
}, },
setScale: function TilingPattern_setScale(width, height, xstep, ystep) { getSizeAndScale: function TilingPattern_getSizeAndScale(step, scale) {
this.scale = [width / xstep, height / ystep]; // xstep / ystep may be negative -- normalize.
}, step = Math.abs(step);
// MAX_PATTERN_SIZE is used to avoid OOM situation.
transformToScale: function TilingPattern_transformToScale(graphics) { var size = Math.min(Math.ceil(step * scale), MAX_PATTERN_SIZE);
var scale = this.scale; scale = size / step;
var tmpScale = [scale[0], 0, 0, scale[1], 0, 0]; return { scale, size, };
graphics.transform.apply(graphics, tmpScale);
},
scaleToContext: function TilingPattern_scaleToContext() {
var scale = this.scale;
this.ctx.scale(1 / scale[0], 1 / scale[1]);
}, },
clipBbox: function clipBbox(graphics, bbox, x0, y0, x1, y1) { clipBbox: function clipBbox(graphics, bbox, x0, y0, x1, y1) {
@ -427,12 +412,12 @@ var TilingPattern = (function TilingPatternClosure() {
}, },
getPattern: function TilingPattern_getPattern(ctx, owner) { getPattern: function TilingPattern_getPattern(ctx, owner) {
var temporaryPatternCanvas = this.createPatternCanvas(owner);
ctx = this.ctx; ctx = this.ctx;
// PDF spec 8.7.2 NOTE 1: pattern's matrix is relative to initial matrix.
ctx.setTransform.apply(ctx, this.baseTransform); ctx.setTransform.apply(ctx, this.baseTransform);
ctx.transform.apply(ctx, this.matrix); ctx.transform.apply(ctx, this.matrix);
this.scaleToContext();
var temporaryPatternCanvas = this.createPatternCanvas(owner);
return ctx.createPattern(temporaryPatternCanvas, 'repeat'); return ctx.createPattern(temporaryPatternCanvas, 'repeat');
}, },