Ensure step plots draw lines to the start of missing values.
[dygraphs.git] / excanvas.js
1 // Copyright 2006 Google Inc.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15
16 // Known Issues:
17 //
18 // * Patterns are not implemented.
19 // * Radial gradient are not implemented. The VML version of these look very
20 // different from the canvas one.
21 // * Clipping paths are not implemented.
22 // * Coordsize. The width and height attribute have higher priority than the
23 // width and height style values which isn't correct.
24 // * Painting mode isn't implemented.
25 // * Canvas width/height should is using content-box by default. IE in
26 // Quirks mode will draw the canvas using border-box. Either change your
27 // doctype to HTML5
28 // (http://www.whatwg.org/specs/web-apps/current-work/#the-doctype)
29 // or use Box Sizing Behavior from WebFX
30 // (http://webfx.eae.net/dhtml/boxsizing/boxsizing.html)
31 // * Non uniform scaling does not correctly scale strokes.
32 // * Optimize. There is always room for speed improvements.
33
34 // Only add this code if we do not already have a canvas implementation
35 if (!document.createElement('canvas').getContext) {
36
37 (function() {
38
39 // alias some functions to make (compiled) code shorter
40 var m = Math;
41 var mr = m.round;
42 var ms = m.sin;
43 var mc = m.cos;
44 var abs = m.abs;
45 var sqrt = m.sqrt;
46
47 // this is used for sub pixel precision
48 var Z = 10;
49 var Z2 = Z / 2;
50
51 /**
52 * This funtion is assigned to the <canvas> elements as element.getContext().
53 * @this {HTMLElement}
54 * @return {CanvasRenderingContext2D_}
55 */
56 function getContext() {
57 return this.context_ ||
58 (this.context_ = new CanvasRenderingContext2D_(this));
59 }
60
61 var slice = Array.prototype.slice;
62
63 /**
64 * Binds a function to an object. The returned function will always use the
65 * passed in {@code obj} as {@code this}.
66 *
67 * Example:
68 *
69 * g = bind(f, obj, a, b)
70 * g(c, d) // will do f.call(obj, a, b, c, d)
71 *
72 * @param {Function} f The function to bind the object to
73 * @param {Object} obj The object that should act as this when the function
74 * is called
75 * @param {*} var_args Rest arguments that will be used as the initial
76 * arguments when the function is called
77 * @return {Function} A new function that has bound this
78 */
79 function bind(f, obj, var_args) {
80 var a = slice.call(arguments, 2);
81 return function() {
82 return f.apply(obj, a.concat(slice.call(arguments)));
83 };
84 }
85
86 var G_vmlCanvasManager_ = {
87 init: function(opt_doc) {
88 if (/MSIE/.test(navigator.userAgent) && !window.opera) {
89 var doc = opt_doc || document;
90 // Create a dummy element so that IE will allow canvas elements to be
91 // recognized.
92 doc.createElement('canvas');
93 doc.attachEvent('onreadystatechange', bind(this.init_, this, doc));
94 }
95 },
96
97 init_: function(doc) {
98 // create xmlns
99 if (!doc.namespaces['g_vml_']) {
100 doc.namespaces.add('g_vml_', 'urn:schemas-microsoft-com:vml',
101 '#default#VML');
102
103 }
104 if (!doc.namespaces['g_o_']) {
105 doc.namespaces.add('g_o_', 'urn:schemas-microsoft-com:office:office',
106 '#default#VML');
107 }
108
109 // Setup default CSS. Only add one style sheet per document
110 if (!doc.styleSheets['ex_canvas_']) {
111 var ss = doc.createStyleSheet();
112 ss.owningElement.id = 'ex_canvas_';
113 ss.cssText = 'canvas{display:inline-block;overflow:hidden;' +
114 // default size is 300x150 in Gecko and Opera
115 'text-align:left;width:300px;height:150px}' +
116 'g_vml_\\:*{behavior:url(#default#VML)}' +
117 'g_o_\\:*{behavior:url(#default#VML)}';
118
119 }
120
121 // find all canvas elements
122 var els = doc.getElementsByTagName('canvas');
123 for (var i = 0; i < els.length; i++) {
124 this.initElement(els[i]);
125 }
126 },
127
128 /**
129 * Public initializes a canvas element so that it can be used as canvas
130 * element from now on. This is called automatically before the page is
131 * loaded but if you are creating elements using createElement you need to
132 * make sure this is called on the element.
133 * @param {HTMLElement} el The canvas element to initialize.
134 * @return {HTMLElement} the element that was created.
135 */
136 initElement: function(el) {
137 if (!el.getContext) {
138
139 el.getContext = getContext;
140
141 // do not use inline function because that will leak memory
142 el.attachEvent('onpropertychange', onPropertyChange);
143 el.attachEvent('onresize', onResize);
144
145 var attrs = el.attributes;
146 if (attrs.width && attrs.width.specified) {
147 // TODO: use runtimeStyle and coordsize
148 // el.getContext().setWidth_(attrs.width.nodeValue);
149 el.style.width = attrs.width.nodeValue + 'px';
150 } else {
151 el.width = el.clientWidth;
152 }
153 if (attrs.height && attrs.height.specified) {
154 // TODO: use runtimeStyle and coordsize
155 // el.getContext().setHeight_(attrs.height.nodeValue);
156 el.style.height = attrs.height.nodeValue + 'px';
157 } else {
158 el.height = el.clientHeight;
159 }
160 //el.getContext().setCoordsize_()
161 }
162 return el;
163 }
164 };
165
166 function onPropertyChange(e) {
167 var el = e.srcElement;
168
169 switch (e.propertyName) {
170 case 'width':
171 el.style.width = el.attributes.width.nodeValue + 'px';
172 el.getContext().clearRect();
173 break;
174 case 'height':
175 el.style.height = el.attributes.height.nodeValue + 'px';
176 el.getContext().clearRect();
177 break;
178 }
179 }
180
181 function onResize(e) {
182 var el = e.srcElement;
183 if (el.firstChild) {
184 el.firstChild.style.width = el.clientWidth + 'px';
185 el.firstChild.style.height = el.clientHeight + 'px';
186 }
187 }
188
189 G_vmlCanvasManager_.init();
190
191 // precompute "00" to "FF"
192 var dec2hex = [];
193 for (var i = 0; i < 16; i++) {
194 for (var j = 0; j < 16; j++) {
195 dec2hex[i * 16 + j] = i.toString(16) + j.toString(16);
196 }
197 }
198
199 function createMatrixIdentity() {
200 return [
201 [1, 0, 0],
202 [0, 1, 0],
203 [0, 0, 1]
204 ];
205 }
206
207 function matrixMultiply(m1, m2) {
208 var result = createMatrixIdentity();
209
210 for (var x = 0; x < 3; x++) {
211 for (var y = 0; y < 3; y++) {
212 var sum = 0;
213
214 for (var z = 0; z < 3; z++) {
215 sum += m1[x][z] * m2[z][y];
216 }
217
218 result[x][y] = sum;
219 }
220 }
221 return result;
222 }
223
224 function copyState(o1, o2) {
225 o2.fillStyle = o1.fillStyle;
226 o2.lineCap = o1.lineCap;
227 o2.lineJoin = o1.lineJoin;
228 o2.lineWidth = o1.lineWidth;
229 o2.miterLimit = o1.miterLimit;
230 o2.shadowBlur = o1.shadowBlur;
231 o2.shadowColor = o1.shadowColor;
232 o2.shadowOffsetX = o1.shadowOffsetX;
233 o2.shadowOffsetY = o1.shadowOffsetY;
234 o2.strokeStyle = o1.strokeStyle;
235 o2.globalAlpha = o1.globalAlpha;
236 o2.arcScaleX_ = o1.arcScaleX_;
237 o2.arcScaleY_ = o1.arcScaleY_;
238 o2.lineScale_ = o1.lineScale_;
239 }
240
241 function processStyle(styleString) {
242 var str, alpha = 1;
243
244 styleString = String(styleString);
245 if (styleString.substring(0, 3) == 'rgb') {
246 var start = styleString.indexOf('(', 3);
247 var end = styleString.indexOf(')', start + 1);
248 var guts = styleString.substring(start + 1, end).split(',');
249
250 str = '#';
251 for (var i = 0; i < 3; i++) {
252 str += dec2hex[Number(guts[i])];
253 }
254
255 if (guts.length == 4 && styleString.substr(3, 1) == 'a') {
256 alpha = guts[3];
257 }
258 } else {
259 str = styleString;
260 }
261
262 return {color: str, alpha: alpha};
263 }
264
265 function processLineCap(lineCap) {
266 switch (lineCap) {
267 case 'butt':
268 return 'flat';
269 case 'round':
270 return 'round';
271 case 'square':
272 default:
273 return 'square';
274 }
275 }
276
277 /**
278 * This class implements CanvasRenderingContext2D interface as described by
279 * the WHATWG.
280 * @param {HTMLElement} surfaceElement The element that the 2D context should
281 * be associated with
282 */
283 function CanvasRenderingContext2D_(surfaceElement) {
284 this.m_ = createMatrixIdentity();
285
286 this.mStack_ = [];
287 this.aStack_ = [];
288 this.currentPath_ = [];
289
290 // Canvas context properties
291 this.strokeStyle = '#000';
292 this.fillStyle = '#000';
293
294 this.lineWidth = 1;
295 this.lineJoin = 'miter';
296 this.lineCap = 'butt';
297 this.miterLimit = Z * 1;
298 this.globalAlpha = 1;
299 this.canvas = surfaceElement;
300
301 var el = surfaceElement.ownerDocument.createElement('div');
302 el.style.width = surfaceElement.clientWidth + 'px';
303 el.style.height = surfaceElement.clientHeight + 'px';
304 el.style.overflow = 'hidden';
305 el.style.position = 'absolute';
306 surfaceElement.appendChild(el);
307
308 this.element_ = el;
309 this.arcScaleX_ = 1;
310 this.arcScaleY_ = 1;
311 this.lineScale_ = 1;
312 }
313
314 var contextPrototype = CanvasRenderingContext2D_.prototype;
315 contextPrototype.clearRect = function() {
316 this.element_.innerHTML = '';
317 this.currentPath_ = [];
318 };
319
320 contextPrototype.beginPath = function() {
321 // TODO: Branch current matrix so that save/restore has no effect
322 // as per safari docs.
323 this.currentPath_ = [];
324 };
325
326 contextPrototype.moveTo = function(aX, aY) {
327 var p = this.getCoords_(aX, aY);
328 this.currentPath_.push({type: 'moveTo', x: p.x, y: p.y});
329 this.currentX_ = p.x;
330 this.currentY_ = p.y;
331 };
332
333 contextPrototype.lineTo = function(aX, aY) {
334 var p = this.getCoords_(aX, aY);
335 this.currentPath_.push({type: 'lineTo', x: p.x, y: p.y});
336
337 this.currentX_ = p.x;
338 this.currentY_ = p.y;
339 };
340
341 contextPrototype.bezierCurveTo = function(aCP1x, aCP1y,
342 aCP2x, aCP2y,
343 aX, aY) {
344 var p = this.getCoords_(aX, aY);
345 var cp1 = this.getCoords_(aCP1x, aCP1y);
346 var cp2 = this.getCoords_(aCP2x, aCP2y);
347 bezierCurveTo(this, cp1, cp2, p);
348 };
349
350 // Helper function that takes the already fixed cordinates.
351 function bezierCurveTo(self, cp1, cp2, p) {
352 self.currentPath_.push({
353 type: 'bezierCurveTo',
354 cp1x: cp1.x,
355 cp1y: cp1.y,
356 cp2x: cp2.x,
357 cp2y: cp2.y,
358 x: p.x,
359 y: p.y
360 });
361 self.currentX_ = p.x;
362 self.currentY_ = p.y;
363 }
364
365 contextPrototype.quadraticCurveTo = function(aCPx, aCPy, aX, aY) {
366 // the following is lifted almost directly from
367 // http://developer.mozilla.org/en/docs/Canvas_tutorial:Drawing_shapes
368
369 var cp = this.getCoords_(aCPx, aCPy);
370 var p = this.getCoords_(aX, aY);
371
372 var cp1 = {
373 x: this.currentX_ + 2.0 / 3.0 * (cp.x - this.currentX_),
374 y: this.currentY_ + 2.0 / 3.0 * (cp.y - this.currentY_)
375 };
376 var cp2 = {
377 x: cp1.x + (p.x - this.currentX_) / 3.0,
378 y: cp1.y + (p.y - this.currentY_) / 3.0
379 };
380
381 bezierCurveTo(this, cp1, cp2, p);
382 };
383
384 contextPrototype.arc = function(aX, aY, aRadius,
385 aStartAngle, aEndAngle, aClockwise) {
386 aRadius *= Z;
387 var arcType = aClockwise ? 'at' : 'wa';
388
389 var xStart = aX + mc(aStartAngle) * aRadius - Z2;
390 var yStart = aY + ms(aStartAngle) * aRadius - Z2;
391
392 var xEnd = aX + mc(aEndAngle) * aRadius - Z2;
393 var yEnd = aY + ms(aEndAngle) * aRadius - Z2;
394
395 // IE won't render arches drawn counter clockwise if xStart == xEnd.
396 if (xStart == xEnd && !aClockwise) {
397 xStart += 0.125; // Offset xStart by 1/80 of a pixel. Use something
398 // that can be represented in binary
399 }
400
401 var p = this.getCoords_(aX, aY);
402 var pStart = this.getCoords_(xStart, yStart);
403 var pEnd = this.getCoords_(xEnd, yEnd);
404
405 this.currentPath_.push({type: arcType,
406 x: p.x,
407 y: p.y,
408 radius: aRadius,
409 xStart: pStart.x,
410 yStart: pStart.y,
411 xEnd: pEnd.x,
412 yEnd: pEnd.y});
413
414 };
415
416 contextPrototype.rect = function(aX, aY, aWidth, aHeight) {
417 this.moveTo(aX, aY);
418 this.lineTo(aX + aWidth, aY);
419 this.lineTo(aX + aWidth, aY + aHeight);
420 this.lineTo(aX, aY + aHeight);
421 this.closePath();
422 };
423
424 contextPrototype.strokeRect = function(aX, aY, aWidth, aHeight) {
425 // Will destroy any existing path (same as FF behaviour)
426 this.beginPath();
427 this.moveTo(aX, aY);
428 this.lineTo(aX + aWidth, aY);
429 this.lineTo(aX + aWidth, aY + aHeight);
430 this.lineTo(aX, aY + aHeight);
431 this.closePath();
432 this.stroke();
433 this.currentPath_ = [];
434 };
435
436 contextPrototype.fillRect = function(aX, aY, aWidth, aHeight) {
437 // Will destroy any existing path (same as FF behaviour)
438 this.beginPath();
439 this.moveTo(aX, aY);
440 this.lineTo(aX + aWidth, aY);
441 this.lineTo(aX + aWidth, aY + aHeight);
442 this.lineTo(aX, aY + aHeight);
443 this.closePath();
444 this.fill();
445 this.currentPath_ = [];
446 };
447
448 contextPrototype.createLinearGradient = function(aX0, aY0, aX1, aY1) {
449 var gradient = new CanvasGradient_('gradient');
450 gradient.x0_ = aX0;
451 gradient.y0_ = aY0;
452 gradient.x1_ = aX1;
453 gradient.y1_ = aY1;
454 return gradient;
455 };
456
457 contextPrototype.createRadialGradient = function(aX0, aY0, aR0,
458 aX1, aY1, aR1) {
459 var gradient = new CanvasGradient_('gradientradial');
460 gradient.x0_ = aX0;
461 gradient.y0_ = aY0;
462 gradient.r0_ = aR0;
463 gradient.x1_ = aX1;
464 gradient.y1_ = aY1;
465 gradient.r1_ = aR1;
466 return gradient;
467 };
468
469 contextPrototype.drawImage = function(image, var_args) {
470 var dx, dy, dw, dh, sx, sy, sw, sh;
471
472 // to find the original width we overide the width and height
473 var oldRuntimeWidth = image.runtimeStyle.width;
474 var oldRuntimeHeight = image.runtimeStyle.height;
475 image.runtimeStyle.width = 'auto';
476 image.runtimeStyle.height = 'auto';
477
478 // get the original size
479 var w = image.width;
480 var h = image.height;
481
482 // and remove overides
483 image.runtimeStyle.width = oldRuntimeWidth;
484 image.runtimeStyle.height = oldRuntimeHeight;
485
486 if (arguments.length == 3) {
487 dx = arguments[1];
488 dy = arguments[2];
489 sx = sy = 0;
490 sw = dw = w;
491 sh = dh = h;
492 } else if (arguments.length == 5) {
493 dx = arguments[1];
494 dy = arguments[2];
495 dw = arguments[3];
496 dh = arguments[4];
497 sx = sy = 0;
498 sw = w;
499 sh = h;
500 } else if (arguments.length == 9) {
501 sx = arguments[1];
502 sy = arguments[2];
503 sw = arguments[3];
504 sh = arguments[4];
505 dx = arguments[5];
506 dy = arguments[6];
507 dw = arguments[7];
508 dh = arguments[8];
509 } else {
510 throw Error('Invalid number of arguments');
511 }
512
513 var d = this.getCoords_(dx, dy);
514
515 var w2 = sw / 2;
516 var h2 = sh / 2;
517
518 var vmlStr = [];
519
520 var W = 10;
521 var H = 10;
522
523 // For some reason that I've now forgotten, using divs didn't work
524 vmlStr.push(' <g_vml_:group',
525 ' coordsize="', Z * W, ',', Z * H, '"',
526 ' coordorigin="0,0"' ,
527 ' style="width:', W, 'px;height:', H, 'px;position:absolute;');
528
529 // If filters are necessary (rotation exists), create them
530 // filters are bog-slow, so only create them if abbsolutely necessary
531 // The following check doesn't account for skews (which don't exist
532 // in the canvas spec (yet) anyway.
533
534 if (this.m_[0][0] != 1 || this.m_[0][1]) {
535 var filter = [];
536
537 // Note the 12/21 reversal
538 filter.push('M11=', this.m_[0][0], ',',
539 'M12=', this.m_[1][0], ',',
540 'M21=', this.m_[0][1], ',',
541 'M22=', this.m_[1][1], ',',
542 'Dx=', mr(d.x / Z), ',',
543 'Dy=', mr(d.y / Z), '');
544
545 // Bounding box calculation (need to minimize displayed area so that
546 // filters don't waste time on unused pixels.
547 var max = d;
548 var c2 = this.getCoords_(dx + dw, dy);
549 var c3 = this.getCoords_(dx, dy + dh);
550 var c4 = this.getCoords_(dx + dw, dy + dh);
551
552 max.x = m.max(max.x, c2.x, c3.x, c4.x);
553 max.y = m.max(max.y, c2.y, c3.y, c4.y);
554
555 vmlStr.push('padding:0 ', mr(max.x / Z), 'px ', mr(max.y / Z),
556 'px 0;filter:progid:DXImageTransform.Microsoft.Matrix(',
557 filter.join(''), ", sizingmethod='clip');")
558 } else {
559 vmlStr.push('top:', mr(d.y / Z), 'px;left:', mr(d.x / Z), 'px;');
560 }
561
562 vmlStr.push(' ">' ,
563 '<g_vml_:image src="', image.src, '"',
564 ' style="width:', Z * dw, 'px;',
565 ' height:', Z * dh, 'px;"',
566 ' cropleft="', sx / w, '"',
567 ' croptop="', sy / h, '"',
568 ' cropright="', (w - sx - sw) / w, '"',
569 ' cropbottom="', (h - sy - sh) / h, '"',
570 ' />',
571 '</g_vml_:group>');
572
573 this.element_.insertAdjacentHTML('BeforeEnd',
574 vmlStr.join(''));
575 };
576
577 contextPrototype.stroke = function(aFill) {
578 var lineStr = [];
579 var lineOpen = false;
580 var a = processStyle(aFill ? this.fillStyle : this.strokeStyle);
581 var color = a.color;
582 var opacity = a.alpha * this.globalAlpha;
583
584 var W = 10;
585 var H = 10;
586
587 lineStr.push('<g_vml_:shape',
588 ' filled="', !!aFill, '"',
589 ' style="position:absolute;width:', W, 'px;height:', H, 'px;"',
590 ' coordorigin="0 0" coordsize="', Z * W, ' ', Z * H, '"',
591 ' stroked="', !aFill, '"',
592 ' path="');
593
594 var newSeq = false;
595 var min = {x: null, y: null};
596 var max = {x: null, y: null};
597
598 for (var i = 0; i < this.currentPath_.length; i++) {
599 var p = this.currentPath_[i];
600 var c;
601
602 switch (p.type) {
603 case 'moveTo':
604 c = p;
605 lineStr.push(' m ', mr(p.x), ',', mr(p.y));
606 break;
607 case 'lineTo':
608 lineStr.push(' l ', mr(p.x), ',', mr(p.y));
609 break;
610 case 'close':
611 lineStr.push(' x ');
612 p = null;
613 break;
614 case 'bezierCurveTo':
615 lineStr.push(' c ',
616 mr(p.cp1x), ',', mr(p.cp1y), ',',
617 mr(p.cp2x), ',', mr(p.cp2y), ',',
618 mr(p.x), ',', mr(p.y));
619 break;
620 case 'at':
621 case 'wa':
622 lineStr.push(' ', p.type, ' ',
623 mr(p.x - this.arcScaleX_ * p.radius), ',',
624 mr(p.y - this.arcScaleY_ * p.radius), ' ',
625 mr(p.x + this.arcScaleX_ * p.radius), ',',
626 mr(p.y + this.arcScaleY_ * p.radius), ' ',
627 mr(p.xStart), ',', mr(p.yStart), ' ',
628 mr(p.xEnd), ',', mr(p.yEnd));
629 break;
630 }
631
632
633 // TODO: Following is broken for curves due to
634 // move to proper paths.
635
636 // Figure out dimensions so we can do gradient fills
637 // properly
638 if (p) {
639 if (min.x == null || p.x < min.x) {
640 min.x = p.x;
641 }
642 if (max.x == null || p.x > max.x) {
643 max.x = p.x;
644 }
645 if (min.y == null || p.y < min.y) {
646 min.y = p.y;
647 }
648 if (max.y == null || p.y > max.y) {
649 max.y = p.y;
650 }
651 }
652 }
653 lineStr.push(' ">');
654
655 if (!aFill) {
656 var lineWidth = this.lineScale_ * this.lineWidth;
657
658 // VML cannot correctly render a line if the width is less than 1px.
659 // In that case, we dilute the color to make the line look thinner.
660 if (lineWidth < 1) {
661 opacity *= lineWidth;
662 }
663
664 lineStr.push(
665 '<g_vml_:stroke',
666 ' opacity="', opacity, '"',
667 ' joinstyle="', this.lineJoin, '"',
668 ' miterlimit="', this.miterLimit, '"',
669 ' endcap="', processLineCap(this.lineCap), '"',
670 ' weight="', lineWidth, 'px"',
671 ' color="', color, '" />'
672 );
673 } else if (typeof this.fillStyle == 'object') {
674 var fillStyle = this.fillStyle;
675 var angle = 0;
676 var focus = {x: 0, y: 0};
677
678 // additional offset
679 var shift = 0;
680 // scale factor for offset
681 var expansion = 1;
682
683 if (fillStyle.type_ == 'gradient') {
684 var x0 = fillStyle.x0_ / this.arcScaleX_;
685 var y0 = fillStyle.y0_ / this.arcScaleY_;
686 var x1 = fillStyle.x1_ / this.arcScaleX_;
687 var y1 = fillStyle.y1_ / this.arcScaleY_;
688 var p0 = this.getCoords_(x0, y0);
689 var p1 = this.getCoords_(x1, y1);
690 var dx = p1.x - p0.x;
691 var dy = p1.y - p0.y;
692 angle = Math.atan2(dx, dy) * 180 / Math.PI;
693
694 // The angle should be a non-negative number.
695 if (angle < 0) {
696 angle += 360;
697 }
698
699 // Very small angles produce an unexpected result because they are
700 // converted to a scientific notation string.
701 if (angle < 1e-6) {
702 angle = 0;
703 }
704 } else {
705 var p0 = this.getCoords_(fillStyle.x0_, fillStyle.y0_);
706 var width = max.x - min.x;
707 var height = max.y - min.y;
708 focus = {
709 x: (p0.x - min.x) / width,
710 y: (p0.y - min.y) / height
711 };
712
713 width /= this.arcScaleX_ * Z;
714 height /= this.arcScaleY_ * Z;
715 var dimension = m.max(width, height);
716 shift = 2 * fillStyle.r0_ / dimension;
717 expansion = 2 * fillStyle.r1_ / dimension - shift;
718 }
719
720 // We need to sort the color stops in ascending order by offset,
721 // otherwise IE won't interpret it correctly.
722 var stops = fillStyle.colors_;
723 stops.sort(function(cs1, cs2) {
724 return cs1.offset - cs2.offset;
725 });
726
727 var length = stops.length;
728 var color1 = stops[0].color;
729 var color2 = stops[length - 1].color;
730 var opacity1 = stops[0].alpha * this.globalAlpha;
731 var opacity2 = stops[length - 1].alpha * this.globalAlpha;
732
733 var colors = [];
734 for (var i = 0; i < length; i++) {
735 var stop = stops[i];
736 colors.push(stop.offset * expansion + shift + ' ' + stop.color);
737 }
738
739 // When colors attribute is used, the meanings of opacity and o:opacity2
740 // are reversed.
741 lineStr.push('<g_vml_:fill type="', fillStyle.type_, '"',
742 ' method="none" focus="100%"',
743 ' color="', color1, '"',
744 ' color2="', color2, '"',
745 ' colors="', colors.join(','), '"',
746 ' opacity="', opacity2, '"',
747 ' g_o_:opacity2="', opacity1, '"',
748 ' angle="', angle, '"',
749 ' focusposition="', focus.x, ',', focus.y, '" />');
750 } else {
751 lineStr.push('<g_vml_:fill color="', color, '" opacity="', opacity,
752 '" />');
753 }
754
755 lineStr.push('</g_vml_:shape>');
756
757 this.element_.insertAdjacentHTML('beforeEnd', lineStr.join(''));
758 };
759
760 contextPrototype.fill = function() {
761 this.stroke(true);
762 }
763
764 contextPrototype.closePath = function() {
765 this.currentPath_.push({type: 'close'});
766 };
767
768 /**
769 * @private
770 */
771 contextPrototype.getCoords_ = function(aX, aY) {
772 var m = this.m_;
773 return {
774 x: Z * (aX * m[0][0] + aY * m[1][0] + m[2][0]) - Z2,
775 y: Z * (aX * m[0][1] + aY * m[1][1] + m[2][1]) - Z2
776 }
777 };
778
779 contextPrototype.save = function() {
780 var o = {};
781 copyState(this, o);
782 this.aStack_.push(o);
783 this.mStack_.push(this.m_);
784 this.m_ = matrixMultiply(createMatrixIdentity(), this.m_);
785 };
786
787 contextPrototype.restore = function() {
788 copyState(this.aStack_.pop(), this);
789 this.m_ = this.mStack_.pop();
790 };
791
792 contextPrototype.translate = function(aX, aY) {
793 var m1 = [
794 [1, 0, 0],
795 [0, 1, 0],
796 [aX, aY, 1]
797 ];
798
799 this.m_ = matrixMultiply(m1, this.m_);
800 };
801
802 contextPrototype.rotate = function(aRot) {
803 var c = mc(aRot);
804 var s = ms(aRot);
805
806 var m1 = [
807 [c, s, 0],
808 [-s, c, 0],
809 [0, 0, 1]
810 ];
811
812 this.m_ = matrixMultiply(m1, this.m_);
813 };
814
815 contextPrototype.scale = function(aX, aY) {
816 this.arcScaleX_ *= aX;
817 this.arcScaleY_ *= aY;
818 var m1 = [
819 [aX, 0, 0],
820 [0, aY, 0],
821 [0, 0, 1]
822 ];
823
824 var m = this.m_ = matrixMultiply(m1, this.m_);
825
826 // Get the line scale.
827 // Determinant of this.m_ means how much the area is enlarged by the
828 // transformation. So its square root can be used as a scale factor
829 // for width.
830 var det = m[0][0] * m[1][1] - m[0][1] * m[1][0];
831 this.lineScale_ = sqrt(abs(det));
832 };
833
834 /******** STUBS ********/
835 contextPrototype.clip = function() {
836 // TODO: Implement
837 };
838
839 contextPrototype.arcTo = function() {
840 // TODO: Implement
841 };
842
843 contextPrototype.createPattern = function() {
844 return new CanvasPattern_;
845 };
846
847 // Gradient / Pattern Stubs
848 function CanvasGradient_(aType) {
849 this.type_ = aType;
850 this.x0_ = 0;
851 this.y0_ = 0;
852 this.r0_ = 0;
853 this.x1_ = 0;
854 this.y1_ = 0;
855 this.r1_ = 0;
856 this.colors_ = [];
857 }
858
859 CanvasGradient_.prototype.addColorStop = function(aOffset, aColor) {
860 aColor = processStyle(aColor);
861 this.colors_.push({offset: aOffset,
862 color: aColor.color,
863 alpha: aColor.alpha});
864 };
865
866 function CanvasPattern_() {}
867
868 // set up externs
869 G_vmlCanvasManager = G_vmlCanvasManager_;
870 CanvasRenderingContext2D = CanvasRenderingContext2D_;
871 CanvasGradient = CanvasGradient_;
872 CanvasPattern = CanvasPattern_;
873
874 })();
875
876 } // if