pdf.js/src/pattern.js
2012-05-01 20:48:07 +03:00

304 lines
8.4 KiB
JavaScript

/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
'use strict';
var PatternType = {
AXIAL: 2,
RADIAL: 3
};
var Pattern = (function PatternClosure() {
// Constructor should define this.getPattern
function Pattern() {
error('should not call Pattern constructor');
}
Pattern.prototype = {
// Input: current Canvas context
// Output: the appropriate fillStyle or strokeStyle
getPattern: function Pattern_getPattern(ctx) {
error('Should not call Pattern.getStyle: ' + ctx);
}
};
Pattern.shadingFromIR = function Pattern_shadingFromIR(raw) {
return Shadings[raw[0]].fromIR(raw);
};
Pattern.parseShading = function Pattern_parseShading(shading, matrix, xref,
res) {
var dict = isStream(shading) ? shading.dict : shading;
var type = dict.get('ShadingType');
switch (type) {
case PatternType.AXIAL:
case PatternType.RADIAL:
// Both radial and axial shadings are handled by RadialAxial shading.
return new Shadings.RadialAxial(dict, matrix, xref, res);
default:
return new Shadings.Dummy();
}
};
return Pattern;
})();
var Shadings = {};
// Radial and axial shading have very similar implementations
// If needed, the implementations can be broken into two classes
Shadings.RadialAxial = (function RadialAxialClosure() {
function RadialAxial(dict, matrix, xref, res, ctx) {
this.matrix = matrix;
this.coordsArr = dict.get('Coords');
this.shadingType = dict.get('ShadingType');
this.type = 'Pattern';
this.ctx = ctx;
var cs = dict.get('ColorSpace', 'CS');
cs = ColorSpace.parse(cs, xref, res);
this.cs = cs;
var t0 = 0.0, t1 = 1.0;
if (dict.has('Domain')) {
var domainArr = dict.get('Domain');
t0 = domainArr[0];
t1 = domainArr[1];
}
var extendStart = false, extendEnd = false;
if (dict.has('Extend')) {
var extendArr = dict.get('Extend');
extendStart = extendArr[0];
extendEnd = extendArr[1];
TODO('Support extend');
}
this.extendStart = extendStart;
this.extendEnd = extendEnd;
var fnObj = dict.get('Function');
if (isArray(fnObj))
error('No support for array of functions');
if (!isPDFFunction(fnObj))
error('Invalid function');
var fn = PDFFunction.parse(xref, fnObj);
// 10 samples seems good enough for now, but probably won't work
// if there are sharp color changes. Ideally, we would implement
// the spec faithfully and add lossless optimizations.
var step = (t1 - t0) / 10;
var diff = t1 - t0;
var colorStops = [];
for (var i = t0; i <= t1; i += step) {
var rgbColor = cs.getRgb(fn([i]));
var cssColor = Util.makeCssRgb(rgbColor[0], rgbColor[1], rgbColor[2]);
colorStops.push([(i - t0) / diff, cssColor]);
}
this.colorStops = colorStops;
}
RadialAxial.fromIR = function RadialAxial_fromIR(raw) {
var type = raw[1];
var colorStops = raw[2];
var p0 = raw[3];
var p1 = raw[4];
var r0 = raw[5];
var r1 = raw[6];
return {
type: 'Pattern',
getPattern: function RadialAxial_getPattern(ctx) {
var curMatrix = ctx.mozCurrentTransform;
if (curMatrix) {
var userMatrix = ctx.mozCurrentTransformInverse;
p0 = Util.applyTransform(p0, curMatrix);
p0 = Util.applyTransform(p0, userMatrix);
p1 = Util.applyTransform(p1, curMatrix);
p1 = Util.applyTransform(p1, userMatrix);
}
var grad;
if (type == PatternType.AXIAL)
grad = ctx.createLinearGradient(p0[0], p0[1], p1[0], p1[1]);
else if (type == PatternType.RADIAL)
grad = ctx.createRadialGradient(p0[0], p0[1], r0, p1[0], p1[1], r1);
for (var i = 0, ii = colorStops.length; i < ii; ++i) {
var c = colorStops[i];
grad.addColorStop(c[0], c[1]);
}
return grad;
}
};
};
RadialAxial.prototype = {
getIR: function RadialAxial_getIR() {
var coordsArr = this.coordsArr;
var type = this.shadingType;
if (type == PatternType.AXIAL) {
var p0 = [coordsArr[0], coordsArr[1]];
var p1 = [coordsArr[2], coordsArr[3]];
var r0 = null;
var r1 = null;
} else if (type == PatternType.RADIAL) {
var p0 = [coordsArr[0], coordsArr[1]];
var p1 = [coordsArr[3], coordsArr[4]];
var r0 = coordsArr[2];
var r1 = coordsArr[5];
} else {
error('getPattern type unknown: ' + type);
}
var matrix = this.matrix;
if (matrix) {
p0 = Util.applyTransform(p0, matrix);
p1 = Util.applyTransform(p1, matrix);
}
return ['RadialAxial', type, this.colorStops, p0, p1, r0, r1];
}
};
return RadialAxial;
})();
Shadings.Dummy = (function DummyClosure() {
function Dummy() {
this.type = 'Pattern';
}
Dummy.fromIR = function Dummy_fromIR() {
return 'hotpink';
};
Dummy.prototype = {
getIR: function Dummy_getIR() {
return ['Dummy'];
}
};
return Dummy;
})();
var TilingPattern = (function TilingPatternClosure() {
var PaintType = {
COLORED: 1,
UNCOLORED: 2
};
var MAX_PATTERN_SIZE = 512;
function TilingPattern(IR, color, ctx, objs) {
var operatorList = IR[2];
this.matrix = IR[3];
var bbox = IR[4];
var xstep = IR[5];
var ystep = IR[6];
var paintType = IR[7];
TODO('TilingType');
this.curMatrix = ctx.mozCurrentTransform;
this.invMatrix = ctx.mozCurrentTransformInverse;
this.ctx = ctx;
this.type = 'Pattern';
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];
// TODO: hack to avoid OOM, we would ideally compute the tiling
// pattern to be only as large as the acual size in device space
// This could be computed with .mozCurrentTransform, but still
// needs to be implemented
while (Math.abs(width) > MAX_PATTERN_SIZE ||
Math.abs(height) > MAX_PATTERN_SIZE) {
width = height = MAX_PATTERN_SIZE;
}
var tmpCanvas = createScratchCanvas(width, height);
// set the new canvas element context as the graphics context
var tmpCtx = tmpCanvas.getContext('2d');
var graphics = new CanvasGraphics(tmpCtx, objs);
switch (paintType) {
case PaintType.COLORED:
tmpCtx.fillStyle = ctx.fillStyle;
tmpCtx.strokeStyle = ctx.strokeStyle;
break;
case PaintType.UNCOLORED:
var cssColor = Util.makeCssRgb(this, color[0], color[1], color[2]);
tmpCtx.fillStyle = cssColor;
tmpCtx.strokeStyle = cssColor;
break;
default:
error('Unsupported paint type: ' + paintType);
}
var scale = [width / xstep, height / ystep];
this.scale = scale;
// transform coordinates to pattern space
var tmpTranslate = [1, 0, 0, 1, -topLeft[0], -topLeft[1]];
var tmpScale = [scale[0], 0, 0, scale[1], 0, 0];
graphics.transform.apply(graphics, tmpScale);
graphics.transform.apply(graphics, tmpTranslate);
if (bbox && isArray(bbox) && 4 == bbox.length) {
var bboxWidth = x1 - x0;
var bboxHeight = y1 - y0;
graphics.rectangle(x0, y0, bboxWidth, bboxHeight);
graphics.clip();
graphics.endPath();
}
graphics.executeOperatorList(operatorList);
this.canvas = tmpCanvas;
}
TilingPattern.getIR = function TilingPattern_getIR(operatorList, dict, args) {
var matrix = dict.get('Matrix');
var bbox = dict.get('BBox');
var xstep = dict.get('XStep');
var ystep = dict.get('YStep');
var paintType = dict.get('PaintType');
return [
'TilingPattern', args, operatorList, matrix, bbox, xstep, ystep, paintType
];
};
TilingPattern.prototype = {
getPattern: function TilingPattern_getPattern() {
var matrix = this.matrix;
var curMatrix = this.curMatrix;
var ctx = this.ctx;
if (curMatrix)
ctx.setTransform.apply(ctx, curMatrix);
if (matrix)
ctx.transform.apply(ctx, matrix);
var scale = this.scale;
ctx.scale(1 / scale[0], 1 / scale[1]);
return ctx.createPattern(this.canvas, 'repeat');
}
};
return TilingPattern;
})();