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1 /*
2  * Copyright (C) 2006 Apple Computer, Inc.  All rights reserved.
3  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
4  * Copyright (C) 2008 Dirk Schulze <vbs85@gmx.de>
5  * Copyright (C) 2008 Nuanti Ltd.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
17  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
20  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
21  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
22  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
23  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
24  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include "config.h"
30 #include "GraphicsContext.h"
31 
32 #if PLATFORM(CAIRO)
33 
34 #include "TransformationMatrix.h"
35 #include "CairoPath.h"
36 #include "FloatRect.h"
37 #include "Font.h"
38 #include "ImageBuffer.h"
39 #include "IntRect.h"
40 #include "NotImplemented.h"
41 #include "Path.h"
42 #include "Pattern.h"
43 #include "SimpleFontData.h"
44 
45 #include <cairo.h>
46 #include <math.h>
47 #include <stdio.h>
48 #include <wtf/MathExtras.h>
49 
50 #if PLATFORM(GTK)
51 #include <gdk/gdk.h>
52 #include <pango/pango.h>
53 #elif PLATFORM(WIN)
54 #include <cairo-win32.h>
55 #endif
56 #include "GraphicsContextPrivate.h"
57 #include "GraphicsContextPlatformPrivateCairo.h"
58 
59 #ifndef M_PI
60 #define M_PI 3.14159265358979323846
61 #endif
62 
63 namespace WebCore {
64 
setColor(cairo_t * cr,const Color & col)65 static inline void setColor(cairo_t* cr, const Color& col)
66 {
67     float red, green, blue, alpha;
68     col.getRGBA(red, green, blue, alpha);
69     cairo_set_source_rgba(cr, red, green, blue, alpha);
70 }
71 
72 // A fillRect helper
fillRectSourceOver(cairo_t * cr,const FloatRect & rect,const Color & col)73 static inline void fillRectSourceOver(cairo_t* cr, const FloatRect& rect, const Color& col)
74 {
75     setColor(cr, col);
76     cairo_rectangle(cr, rect.x(), rect.y(), rect.width(), rect.height());
77     cairo_set_operator(cr, CAIRO_OPERATOR_OVER);
78     cairo_fill(cr);
79 }
80 
GraphicsContext(PlatformGraphicsContext * cr)81 GraphicsContext::GraphicsContext(PlatformGraphicsContext* cr)
82     : m_common(createGraphicsContextPrivate())
83     , m_data(new GraphicsContextPlatformPrivate)
84 {
85     m_data->cr = cairo_reference(cr);
86     m_data->syncContext(cr);
87     setPaintingDisabled(!cr);
88 }
89 
~GraphicsContext()90 GraphicsContext::~GraphicsContext()
91 {
92     destroyGraphicsContextPrivate(m_common);
93     delete m_data;
94 }
95 
getCTM() const96 TransformationMatrix GraphicsContext::getCTM() const
97 {
98     cairo_t* cr = platformContext();
99     cairo_matrix_t m;
100     cairo_get_matrix(cr, &m);
101     return TransformationMatrix(m.xx, m.yx, m.xy, m.yy, m.x0, m.y0);
102 }
103 
platformContext() const104 cairo_t* GraphicsContext::platformContext() const
105 {
106     return m_data->cr;
107 }
108 
savePlatformState()109 void GraphicsContext::savePlatformState()
110 {
111     cairo_save(m_data->cr);
112     m_data->save();
113 }
114 
restorePlatformState()115 void GraphicsContext::restorePlatformState()
116 {
117     cairo_restore(m_data->cr);
118     m_data->restore();
119 }
120 
121 // Draws a filled rectangle with a stroked border.
drawRect(const IntRect & rect)122 void GraphicsContext::drawRect(const IntRect& rect)
123 {
124     if (paintingDisabled())
125         return;
126 
127     cairo_t* cr = m_data->cr;
128     cairo_save(cr);
129 
130     if (fillColor().alpha())
131         fillRectSourceOver(cr, rect, fillColor());
132 
133     if (strokeStyle() != NoStroke) {
134         setColor(cr, strokeColor());
135         FloatRect r(rect);
136         r.inflate(-.5f);
137         cairo_rectangle(cr, r.x(), r.y(), r.width(), r.height());
138         cairo_set_line_width(cr, 1.0);
139         cairo_stroke(cr);
140     }
141 
142     cairo_restore(cr);
143 }
144 
145 // FIXME: Now that this is refactored, it should be shared by all contexts.
adjustLineToPixelBoundaries(FloatPoint & p1,FloatPoint & p2,float strokeWidth,StrokeStyle style)146 static void adjustLineToPixelBoundaries(FloatPoint& p1, FloatPoint& p2, float strokeWidth, StrokeStyle style)
147 {
148     // For odd widths, we add in 0.5 to the appropriate x/y so that the float arithmetic
149     // works out.  For example, with a border width of 3, KHTML will pass us (y1+y2)/2, e.g.,
150     // (50+53)/2 = 103/2 = 51 when we want 51.5.  It is always true that an even width gave
151     // us a perfect position, but an odd width gave us a position that is off by exactly 0.5.
152     if (style == DottedStroke || style == DashedStroke) {
153         if (p1.x() == p2.x()) {
154             p1.setY(p1.y() + strokeWidth);
155             p2.setY(p2.y() - strokeWidth);
156         }
157         else {
158             p1.setX(p1.x() + strokeWidth);
159             p2.setX(p2.x() - strokeWidth);
160         }
161     }
162 
163     if (static_cast<int>(strokeWidth) % 2) {
164         if (p1.x() == p2.x()) {
165             // We're a vertical line.  Adjust our x.
166             p1.setX(p1.x() + 0.5);
167             p2.setX(p2.x() + 0.5);
168         }
169         else {
170             // We're a horizontal line. Adjust our y.
171             p1.setY(p1.y() + 0.5);
172             p2.setY(p2.y() + 0.5);
173         }
174     }
175 }
176 
177 // This is only used to draw borders.
drawLine(const IntPoint & point1,const IntPoint & point2)178 void GraphicsContext::drawLine(const IntPoint& point1, const IntPoint& point2)
179 {
180     if (paintingDisabled())
181         return;
182 
183     StrokeStyle style = strokeStyle();
184     if (style == NoStroke)
185         return;
186 
187     cairo_t* cr = m_data->cr;
188     cairo_save(cr);
189 
190     float width = strokeThickness();
191     if (width < 1)
192         width = 1;
193 
194     FloatPoint p1 = point1;
195     FloatPoint p2 = point2;
196     bool isVerticalLine = (p1.x() == p2.x());
197 
198     adjustLineToPixelBoundaries(p1, p2, width, style);
199     cairo_set_line_width(cr, width);
200 
201     int patWidth = 0;
202     switch (style) {
203     case NoStroke:
204     case SolidStroke:
205         break;
206     case DottedStroke:
207         patWidth = static_cast<int>(width);
208         break;
209     case DashedStroke:
210         patWidth = 3*static_cast<int>(width);
211         break;
212     }
213 
214     setColor(cr, strokeColor());
215 
216     cairo_set_antialias(cr, CAIRO_ANTIALIAS_NONE);
217 
218     if (patWidth) {
219         // Do a rect fill of our endpoints.  This ensures we always have the
220         // appearance of being a border.  We then draw the actual dotted/dashed line.
221         if (isVerticalLine) {
222             fillRectSourceOver(cr, FloatRect(p1.x() - width/2, p1.y() - width, width, width), strokeColor());
223             fillRectSourceOver(cr, FloatRect(p2.x() - width/2, p2.y(), width, width), strokeColor());
224         } else {
225             fillRectSourceOver(cr, FloatRect(p1.x() - width, p1.y() - width/2, width, width), strokeColor());
226             fillRectSourceOver(cr, FloatRect(p2.x(), p2.y() - width/2, width, width), strokeColor());
227         }
228 
229         // Example: 80 pixels with a width of 30 pixels.
230         // Remainder is 20.  The maximum pixels of line we could paint
231         // will be 50 pixels.
232         int distance = (isVerticalLine ? (point2.y() - point1.y()) : (point2.x() - point1.x())) - 2*static_cast<int>(width);
233         int remainder = distance%patWidth;
234         int coverage = distance-remainder;
235         int numSegments = coverage/patWidth;
236 
237         float patternOffset = 0;
238         // Special case 1px dotted borders for speed.
239         if (patWidth == 1)
240             patternOffset = 1.0;
241         else {
242             bool evenNumberOfSegments = numSegments%2 == 0;
243             if (remainder)
244                 evenNumberOfSegments = !evenNumberOfSegments;
245             if (evenNumberOfSegments) {
246                 if (remainder) {
247                     patternOffset += patWidth - remainder;
248                     patternOffset += remainder/2;
249                 }
250                 else
251                     patternOffset = patWidth/2;
252             }
253             else if (!evenNumberOfSegments) {
254                 if (remainder)
255                     patternOffset = (patWidth - remainder)/2;
256             }
257         }
258 
259         double dash = patWidth;
260         cairo_set_dash(cr, &dash, 1, patternOffset);
261     }
262 
263     cairo_move_to(cr, p1.x(), p1.y());
264     cairo_line_to(cr, p2.x(), p2.y());
265 
266     cairo_stroke(cr);
267     cairo_restore(cr);
268 }
269 
270 // This method is only used to draw the little circles used in lists.
drawEllipse(const IntRect & rect)271 void GraphicsContext::drawEllipse(const IntRect& rect)
272 {
273     if (paintingDisabled())
274         return;
275 
276     cairo_t* cr = m_data->cr;
277     cairo_save(cr);
278     float yRadius = .5 * rect.height();
279     float xRadius = .5 * rect.width();
280     cairo_translate(cr, rect.x() + xRadius, rect.y() + yRadius);
281     cairo_scale(cr, xRadius, yRadius);
282     cairo_arc(cr, 0., 0., 1., 0., 2 * M_PI);
283     cairo_restore(cr);
284 
285     if (fillColor().alpha()) {
286         setColor(cr, fillColor());
287         cairo_fill_preserve(cr);
288     }
289 
290     if (strokeStyle() != NoStroke) {
291         setColor(cr, strokeColor());
292         cairo_set_line_width(cr, strokeThickness());
293         cairo_stroke(cr);
294     }
295 
296     cairo_new_path(cr);
297 }
298 
strokeArc(const IntRect & rect,int startAngle,int angleSpan)299 void GraphicsContext::strokeArc(const IntRect& rect, int startAngle, int angleSpan)
300 {
301     if (paintingDisabled() || strokeStyle() == NoStroke)
302         return;
303 
304     int x = rect.x();
305     int y = rect.y();
306     float w = rect.width();
307     float h = rect.height();
308     float scaleFactor = h / w;
309     float reverseScaleFactor = w / h;
310 
311     float hRadius = w / 2;
312     float vRadius = h / 2;
313     float fa = startAngle;
314     float falen =  fa + angleSpan;
315 
316     cairo_t* cr = m_data->cr;
317     cairo_save(cr);
318 
319     if (w != h)
320         cairo_scale(cr, 1., scaleFactor);
321 
322     cairo_arc_negative(cr, x + hRadius, (y + vRadius) * reverseScaleFactor, hRadius, -fa * M_PI/180, -falen * M_PI/180);
323 
324     if (w != h)
325         cairo_scale(cr, 1., reverseScaleFactor);
326 
327     float width = strokeThickness();
328     int patWidth = 0;
329 
330     switch (strokeStyle()) {
331         case DottedStroke:
332             patWidth = static_cast<int>(width / 2);
333             break;
334         case DashedStroke:
335             patWidth = 3 * static_cast<int>(width / 2);
336             break;
337         default:
338             break;
339     }
340 
341     setColor(cr, strokeColor());
342 
343     if (patWidth) {
344         // Example: 80 pixels with a width of 30 pixels.
345         // Remainder is 20.  The maximum pixels of line we could paint
346         // will be 50 pixels.
347         int distance;
348         if (hRadius == vRadius)
349             distance = static_cast<int>((M_PI * hRadius) / 2.0);
350         else // We are elliptical and will have to estimate the distance
351             distance = static_cast<int>((M_PI * sqrtf((hRadius * hRadius + vRadius * vRadius) / 2.0)) / 2.0);
352 
353         int remainder = distance % patWidth;
354         int coverage = distance - remainder;
355         int numSegments = coverage / patWidth;
356 
357         float patternOffset = 0.0;
358         // Special case 1px dotted borders for speed.
359         if (patWidth == 1)
360             patternOffset = 1.0;
361         else {
362             bool evenNumberOfSegments = numSegments % 2 == 0;
363             if (remainder)
364                 evenNumberOfSegments = !evenNumberOfSegments;
365             if (evenNumberOfSegments) {
366                 if (remainder) {
367                     patternOffset += patWidth - remainder;
368                     patternOffset += remainder / 2.0;
369                 } else
370                     patternOffset = patWidth / 2.0;
371             } else {
372                 if (remainder)
373                     patternOffset = (patWidth - remainder) / 2.0;
374             }
375         }
376 
377         double dash = patWidth;
378         cairo_set_dash(cr, &dash, 1, patternOffset);
379     }
380 
381     cairo_stroke(cr);
382     cairo_restore(cr);
383 }
384 
drawConvexPolygon(size_t npoints,const FloatPoint * points,bool shouldAntialias)385 void GraphicsContext::drawConvexPolygon(size_t npoints, const FloatPoint* points, bool shouldAntialias)
386 {
387     if (paintingDisabled())
388         return;
389 
390     if (npoints <= 1)
391         return;
392 
393     cairo_t* cr = m_data->cr;
394 
395     cairo_save(cr);
396     cairo_set_antialias(cr, shouldAntialias ? CAIRO_ANTIALIAS_DEFAULT : CAIRO_ANTIALIAS_NONE);
397     cairo_move_to(cr, points[0].x(), points[0].y());
398     for (size_t i = 1; i < npoints; i++)
399         cairo_line_to(cr, points[i].x(), points[i].y());
400     cairo_close_path(cr);
401 
402     if (fillColor().alpha()) {
403         setColor(cr, fillColor());
404         cairo_set_fill_rule(cr, CAIRO_FILL_RULE_EVEN_ODD);
405         cairo_fill_preserve(cr);
406     }
407 
408     if (strokeStyle() != NoStroke) {
409         setColor(cr, strokeColor());
410         cairo_set_line_width(cr, strokeThickness());
411         cairo_stroke(cr);
412     }
413 
414     cairo_new_path(cr);
415     cairo_restore(cr);
416 }
417 
fillPath()418 void GraphicsContext::fillPath()
419 {
420     if (paintingDisabled())
421         return;
422 
423     cairo_t* cr = m_data->cr;
424     cairo_save(cr);
425 
426     cairo_set_fill_rule(cr, fillRule() == RULE_EVENODD ? CAIRO_FILL_RULE_EVEN_ODD : CAIRO_FILL_RULE_WINDING);
427     switch (m_common->state.fillColorSpace) {
428     case SolidColorSpace:
429         setColor(cr, fillColor());
430         cairo_clip(cr);
431         cairo_paint_with_alpha(cr, m_common->state.globalAlpha);
432         break;
433     case PatternColorSpace: {
434         TransformationMatrix affine;
435         cairo_set_source(cr, m_common->state.fillPattern->createPlatformPattern(affine));
436         cairo_clip(cr);
437         cairo_paint_with_alpha(cr, m_common->state.globalAlpha);
438         break;
439     }
440     case GradientColorSpace:
441         cairo_pattern_t* pattern = m_common->state.fillGradient->platformGradient();
442         cairo_set_source(cr, pattern);
443         cairo_clip(cr);
444         cairo_paint_with_alpha(cr, m_common->state.globalAlpha);
445         break;
446     }
447     cairo_restore(cr);
448 }
449 
strokePath()450 void GraphicsContext::strokePath()
451 {
452     if (paintingDisabled())
453         return;
454 
455     cairo_t* cr = m_data->cr;
456     cairo_save(cr);
457     switch (m_common->state.strokeColorSpace) {
458     case SolidColorSpace:
459         float red, green, blue, alpha;
460         strokeColor().getRGBA(red, green, blue, alpha);
461         if (m_common->state.globalAlpha < 1.0f)
462             alpha *= m_common->state.globalAlpha;
463         cairo_set_source_rgba(cr, red, green, blue, alpha);
464         cairo_stroke(cr);
465         break;
466     case PatternColorSpace: {
467         TransformationMatrix affine;
468         cairo_set_source(cr, m_common->state.strokePattern->createPlatformPattern(affine));
469         if (m_common->state.globalAlpha < 1.0f) {
470             cairo_push_group(cr);
471             cairo_paint_with_alpha(cr, m_common->state.globalAlpha);
472             cairo_pop_group_to_source(cr);
473         }
474         cairo_stroke(cr);
475         break;
476     }
477     case GradientColorSpace:
478         cairo_pattern_t* pattern = m_common->state.strokeGradient->platformGradient();
479         cairo_set_source(cr, pattern);
480         if (m_common->state.globalAlpha < 1.0f) {
481             cairo_push_group(cr);
482             cairo_paint_with_alpha(cr, m_common->state.globalAlpha);
483             cairo_pop_group_to_source(cr);
484         }
485         cairo_stroke(cr);
486         break;
487     }
488     cairo_restore(cr);
489 }
490 
drawPath()491 void GraphicsContext::drawPath()
492 {
493     fillPath();
494     strokePath();
495 }
496 
fillRect(const FloatRect & rect)497 void GraphicsContext::fillRect(const FloatRect& rect)
498 {
499     if (paintingDisabled())
500         return;
501 
502     cairo_t* cr = m_data->cr;
503     cairo_rectangle(cr, rect.x(), rect.y(), rect.width(), rect.height());
504     fillPath();
505 }
506 
fillRect(const FloatRect & rect,const Color & color)507 void GraphicsContext::fillRect(const FloatRect& rect, const Color& color)
508 {
509     if (paintingDisabled())
510         return;
511 
512     if (color.alpha())
513         fillRectSourceOver(m_data->cr, rect, color);
514 }
515 
clip(const FloatRect & rect)516 void GraphicsContext::clip(const FloatRect& rect)
517 {
518     if (paintingDisabled())
519         return;
520 
521     cairo_t* cr = m_data->cr;
522     cairo_rectangle(cr, rect.x(), rect.y(), rect.width(), rect.height());
523     cairo_fill_rule_t savedFillRule = cairo_get_fill_rule(cr);
524     cairo_set_fill_rule(cr, CAIRO_FILL_RULE_WINDING);
525     cairo_clip(cr);
526     cairo_set_fill_rule(cr, savedFillRule);
527     m_data->clip(rect);
528 }
529 
clipPath(WindRule clipRule)530 void GraphicsContext::clipPath(WindRule clipRule)
531 {
532     if (paintingDisabled())
533         return;
534 
535     cairo_t* cr = m_data->cr;
536     cairo_set_fill_rule(cr, clipRule == RULE_EVENODD ? CAIRO_FILL_RULE_EVEN_ODD : CAIRO_FILL_RULE_WINDING);
537     cairo_clip(cr);
538 }
539 
drawFocusRing(const Color & color)540 void GraphicsContext::drawFocusRing(const Color& color)
541 {
542     if (paintingDisabled())
543         return;
544 
545     const Vector<IntRect>& rects = focusRingRects();
546     unsigned rectCount = rects.size();
547 
548     cairo_t* cr = m_data->cr;
549     cairo_save(cr);
550     cairo_push_group(cr);
551     cairo_new_path(cr);
552 
553 #if PLATFORM(GTK)
554     GdkRegion* reg = gdk_region_new();
555     for (unsigned i = 0; i < rectCount; i++) {
556         GdkRectangle rect = rects[i];
557         gdk_region_union_with_rect(reg, &rect);
558     }
559     gdk_cairo_region(cr, reg);
560     gdk_region_destroy(reg);
561 
562     setColor(cr, color);
563     cairo_set_line_width(cr, 2.0f);
564     setPlatformStrokeStyle(DottedStroke);
565 #else
566     int radius = (focusRingWidth() - 1) / 2;
567     for (unsigned i = 0; i < rectCount; i++)
568         addPath(Path::createRoundedRectangle(rects[i], FloatSize(radius, radius)));
569 
570     // Force the alpha to 50%.  This matches what the Mac does with outline rings.
571     Color ringColor(color.red(), color.green(), color.blue(), 127);
572     setColor(cr, ringColor);
573     cairo_set_line_width(cr, focusRingWidth());
574     setPlatformStrokeStyle(SolidStroke);
575 #endif
576 
577     cairo_set_operator(cr, CAIRO_OPERATOR_OVER);
578     cairo_stroke_preserve(cr);
579 
580     cairo_set_operator(cr, CAIRO_OPERATOR_CLEAR);
581     cairo_set_fill_rule(cr, CAIRO_FILL_RULE_WINDING);
582     cairo_fill(cr);
583 
584     cairo_pop_group_to_source(cr);
585     cairo_set_operator(cr, CAIRO_OPERATOR_OVER);
586     cairo_paint(cr);
587     cairo_restore(cr);
588 }
589 
drawLineForText(const IntPoint & origin,int width,bool printing)590 void GraphicsContext::drawLineForText(const IntPoint& origin, int width, bool printing)
591 {
592     if (paintingDisabled())
593         return;
594 
595     // This is a workaround for http://bugs.webkit.org/show_bug.cgi?id=15659
596     StrokeStyle savedStrokeStyle = strokeStyle();
597     setStrokeStyle(SolidStroke);
598 
599     IntPoint endPoint = origin + IntSize(width, 0);
600     drawLine(origin, endPoint);
601 
602     setStrokeStyle(savedStrokeStyle);
603 }
604 
drawLineForMisspellingOrBadGrammar(const IntPoint & origin,int width,bool grammar)605 void GraphicsContext::drawLineForMisspellingOrBadGrammar(const IntPoint& origin, int width, bool grammar)
606 {
607     if (paintingDisabled())
608         return;
609 
610     cairo_t* cr = m_data->cr;
611     cairo_save(cr);
612 
613     // Convention is green for grammar, red for spelling
614     // These need to become configurable
615     if (grammar)
616         cairo_set_source_rgb(cr, 0, 1, 0);
617     else
618         cairo_set_source_rgb(cr, 1, 0, 0);
619 
620 #if PLATFORM(GTK)
621     // We ignore most of the provided constants in favour of the platform style
622     pango_cairo_show_error_underline(cr, origin.x(), origin.y(), width, cMisspellingLineThickness);
623 #else
624     notImplemented();
625 #endif
626 
627     cairo_restore(cr);
628 }
629 
roundToDevicePixels(const FloatRect & frect)630 FloatRect GraphicsContext::roundToDevicePixels(const FloatRect& frect)
631 {
632     FloatRect result;
633     double x = frect.x();
634     double y = frect.y();
635     cairo_t* cr = m_data->cr;
636     cairo_user_to_device(cr, &x, &y);
637     x = round(x);
638     y = round(y);
639     cairo_device_to_user(cr, &x, &y);
640     result.setX(static_cast<float>(x));
641     result.setY(static_cast<float>(y));
642     x = frect.width();
643     y = frect.height();
644     cairo_user_to_device_distance(cr, &x, &y);
645     x = round(x);
646     y = round(y);
647     cairo_device_to_user_distance(cr, &x, &y);
648     result.setWidth(static_cast<float>(x));
649     result.setHeight(static_cast<float>(y));
650     return result;
651 }
652 
translate(float x,float y)653 void GraphicsContext::translate(float x, float y)
654 {
655     if (paintingDisabled())
656         return;
657 
658     cairo_t* cr = m_data->cr;
659     cairo_translate(cr, x, y);
660     m_data->translate(x, y);
661 }
662 
origin()663 IntPoint GraphicsContext::origin()
664 {
665     cairo_matrix_t matrix;
666     cairo_t* cr = m_data->cr;
667     cairo_get_matrix(cr, &matrix);
668     return IntPoint(static_cast<int>(matrix.x0), static_cast<int>(matrix.y0));
669 }
670 
setPlatformFillColor(const Color & col)671 void GraphicsContext::setPlatformFillColor(const Color& col)
672 {
673     // Cairo contexts can't hold separate fill and stroke colors
674     // so we set them just before we actually fill or stroke
675 }
676 
setPlatformStrokeColor(const Color & col)677 void GraphicsContext::setPlatformStrokeColor(const Color& col)
678 {
679     // Cairo contexts can't hold separate fill and stroke colors
680     // so we set them just before we actually fill or stroke
681 }
682 
setPlatformStrokeThickness(float strokeThickness)683 void GraphicsContext::setPlatformStrokeThickness(float strokeThickness)
684 {
685     if (paintingDisabled())
686         return;
687 
688     cairo_set_line_width(m_data->cr, strokeThickness);
689 }
690 
setPlatformStrokeStyle(const StrokeStyle & strokeStyle)691 void GraphicsContext::setPlatformStrokeStyle(const StrokeStyle& strokeStyle)
692 {
693     static double dashPattern[] = {5.0, 5.0};
694     static double dotPattern[] = {1.0, 1.0};
695 
696     if (paintingDisabled())
697         return;
698 
699     switch (strokeStyle) {
700     case NoStroke:
701         // FIXME: is it the right way to emulate NoStroke?
702         cairo_set_line_width(m_data->cr, 0);
703         break;
704     case SolidStroke:
705         cairo_set_dash(m_data->cr, 0, 0, 0);
706         break;
707     case DottedStroke:
708         cairo_set_dash(m_data->cr, dotPattern, 2, 0);
709         break;
710     case DashedStroke:
711         cairo_set_dash(m_data->cr, dashPattern, 2, 0);
712         break;
713     }
714 }
715 
setURLForRect(const KURL & link,const IntRect & destRect)716 void GraphicsContext::setURLForRect(const KURL& link, const IntRect& destRect)
717 {
718     notImplemented();
719 }
720 
concatCTM(const TransformationMatrix & transform)721 void GraphicsContext::concatCTM(const TransformationMatrix& transform)
722 {
723     if (paintingDisabled())
724         return;
725 
726     cairo_t* cr = m_data->cr;
727     const cairo_matrix_t matrix = cairo_matrix_t(transform);
728     cairo_transform(cr, &matrix);
729     m_data->concatCTM(transform);
730 }
731 
addInnerRoundedRectClip(const IntRect & rect,int thickness)732 void GraphicsContext::addInnerRoundedRectClip(const IntRect& rect, int thickness)
733 {
734     if (paintingDisabled())
735         return;
736 
737     clip(rect);
738 
739     Path p;
740     FloatRect r(rect);
741     // Add outer ellipse
742     p.addEllipse(r);
743     // Add inner ellipse
744     r.inflate(-thickness);
745     p.addEllipse(r);
746     addPath(p);
747 
748     cairo_t* cr = m_data->cr;
749     cairo_fill_rule_t savedFillRule = cairo_get_fill_rule(cr);
750     cairo_set_fill_rule(cr, CAIRO_FILL_RULE_EVEN_ODD);
751     cairo_clip(cr);
752     cairo_set_fill_rule(cr, savedFillRule);
753 }
754 
clipToImageBuffer(const FloatRect & rect,const ImageBuffer * imageBuffer)755 void GraphicsContext::clipToImageBuffer(const FloatRect& rect, const ImageBuffer* imageBuffer)
756 {
757     if (paintingDisabled())
758         return;
759 
760     notImplemented();
761 }
762 
setPlatformShadow(IntSize const &,int,Color const &)763 void GraphicsContext::setPlatformShadow(IntSize const&, int, Color const&)
764 {
765     notImplemented();
766 }
767 
clearPlatformShadow()768 void GraphicsContext::clearPlatformShadow()
769 {
770     notImplemented();
771 }
772 
beginTransparencyLayer(float opacity)773 void GraphicsContext::beginTransparencyLayer(float opacity)
774 {
775     if (paintingDisabled())
776         return;
777 
778     cairo_t* cr = m_data->cr;
779     cairo_push_group(cr);
780     m_data->layers.append(opacity);
781     m_data->beginTransparencyLayer();
782 }
783 
endTransparencyLayer()784 void GraphicsContext::endTransparencyLayer()
785 {
786     if (paintingDisabled())
787         return;
788 
789     cairo_t* cr = m_data->cr;
790 
791     cairo_pop_group_to_source(cr);
792     cairo_paint_with_alpha(cr, m_data->layers.last());
793     m_data->layers.removeLast();
794     m_data->endTransparencyLayer();
795 }
796 
clearRect(const FloatRect & rect)797 void GraphicsContext::clearRect(const FloatRect& rect)
798 {
799     if (paintingDisabled())
800         return;
801 
802     cairo_t* cr = m_data->cr;
803 
804     cairo_save(cr);
805     cairo_rectangle(cr, rect.x(), rect.y(), rect.width(), rect.height());
806     cairo_set_operator(cr, CAIRO_OPERATOR_CLEAR);
807     cairo_fill(cr);
808     cairo_restore(cr);
809 }
810 
strokeRect(const FloatRect & rect,float width)811 void GraphicsContext::strokeRect(const FloatRect& rect, float width)
812 {
813     if (paintingDisabled())
814         return;
815 
816     cairo_t* cr = m_data->cr;
817     cairo_save(cr);
818     cairo_rectangle(cr, rect.x(), rect.y(), rect.width(), rect.height());
819     cairo_set_line_width(cr, width);
820     strokePath();
821     cairo_restore(cr);
822 }
823 
setLineCap(LineCap lineCap)824 void GraphicsContext::setLineCap(LineCap lineCap)
825 {
826     if (paintingDisabled())
827         return;
828 
829     cairo_line_cap_t cairoCap = CAIRO_LINE_CAP_BUTT;
830     switch (lineCap) {
831         case ButtCap:
832             // no-op
833             break;
834         case RoundCap:
835             cairoCap = CAIRO_LINE_CAP_ROUND;
836             break;
837         case SquareCap:
838             cairoCap = CAIRO_LINE_CAP_SQUARE;
839             break;
840     }
841     cairo_set_line_cap(m_data->cr, cairoCap);
842 }
843 
setLineDash(const DashArray & dashes,float dashOffset)844 void GraphicsContext::setLineDash(const DashArray& dashes, float dashOffset)
845 {
846     cairo_set_dash(m_data->cr, dashes.data(), dashes.size(), dashOffset);
847 }
848 
setLineJoin(LineJoin lineJoin)849 void GraphicsContext::setLineJoin(LineJoin lineJoin)
850 {
851     if (paintingDisabled())
852         return;
853 
854     cairo_line_join_t cairoJoin = CAIRO_LINE_JOIN_MITER;
855     switch (lineJoin) {
856         case MiterJoin:
857             // no-op
858             break;
859         case RoundJoin:
860             cairoJoin = CAIRO_LINE_JOIN_ROUND;
861             break;
862         case BevelJoin:
863             cairoJoin = CAIRO_LINE_JOIN_BEVEL;
864             break;
865     }
866     cairo_set_line_join(m_data->cr, cairoJoin);
867 }
868 
setMiterLimit(float miter)869 void GraphicsContext::setMiterLimit(float miter)
870 {
871     if (paintingDisabled())
872         return;
873 
874     cairo_set_miter_limit(m_data->cr, miter);
875 }
876 
setAlpha(float alpha)877 void GraphicsContext::setAlpha(float alpha)
878 {
879     m_common->state.globalAlpha = alpha;
880 }
881 
getAlpha()882 float GraphicsContext::getAlpha()
883 {
884     return m_common->state.globalAlpha;
885 }
886 
toCairoOperator(CompositeOperator op)887 static inline cairo_operator_t toCairoOperator(CompositeOperator op)
888 {
889     switch (op) {
890         case CompositeClear:
891             return CAIRO_OPERATOR_CLEAR;
892         case CompositeCopy:
893             return CAIRO_OPERATOR_SOURCE;
894         case CompositeSourceOver:
895             return CAIRO_OPERATOR_OVER;
896         case CompositeSourceIn:
897             return CAIRO_OPERATOR_IN;
898         case CompositeSourceOut:
899             return CAIRO_OPERATOR_OUT;
900         case CompositeSourceAtop:
901             return CAIRO_OPERATOR_ATOP;
902         case CompositeDestinationOver:
903             return CAIRO_OPERATOR_DEST_OVER;
904         case CompositeDestinationIn:
905             return CAIRO_OPERATOR_DEST_IN;
906         case CompositeDestinationOut:
907             return CAIRO_OPERATOR_DEST_OUT;
908         case CompositeDestinationAtop:
909             return CAIRO_OPERATOR_DEST_ATOP;
910         case CompositeXOR:
911             return CAIRO_OPERATOR_XOR;
912         case CompositePlusDarker:
913             return CAIRO_OPERATOR_SATURATE;
914         case CompositeHighlight:
915             // There is no Cairo equivalent for CompositeHighlight.
916             return CAIRO_OPERATOR_OVER;
917         case CompositePlusLighter:
918             return CAIRO_OPERATOR_ADD;
919         default:
920             return CAIRO_OPERATOR_SOURCE;
921     }
922 }
923 
setCompositeOperation(CompositeOperator op)924 void GraphicsContext::setCompositeOperation(CompositeOperator op)
925 {
926     if (paintingDisabled())
927         return;
928 
929     cairo_set_operator(m_data->cr, toCairoOperator(op));
930 }
931 
beginPath()932 void GraphicsContext::beginPath()
933 {
934     if (paintingDisabled())
935         return;
936 
937     cairo_t* cr = m_data->cr;
938     cairo_new_path(cr);
939 }
940 
addPath(const Path & path)941 void GraphicsContext::addPath(const Path& path)
942 {
943     if (paintingDisabled())
944         return;
945 
946     cairo_t* cr = m_data->cr;
947     cairo_path_t* p = cairo_copy_path(path.platformPath()->m_cr);
948     cairo_append_path(cr, p);
949     cairo_path_destroy(p);
950 }
951 
clip(const Path & path)952 void GraphicsContext::clip(const Path& path)
953 {
954     if (paintingDisabled())
955         return;
956 
957     cairo_t* cr = m_data->cr;
958     cairo_path_t* p = cairo_copy_path(path.platformPath()->m_cr);
959     cairo_append_path(cr, p);
960     cairo_path_destroy(p);
961     cairo_fill_rule_t savedFillRule = cairo_get_fill_rule(cr);
962     cairo_set_fill_rule(cr, CAIRO_FILL_RULE_WINDING);
963     cairo_clip(cr);
964     cairo_set_fill_rule(cr, savedFillRule);
965     m_data->clip(path);
966 }
967 
clipOut(const Path & path)968 void GraphicsContext::clipOut(const Path& path)
969 {
970     if (paintingDisabled())
971         return;
972 
973 #if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1,4,0)
974     cairo_t* cr = m_data->cr;
975     double x1, y1, x2, y2;
976     cairo_clip_extents(cr, &x1, &y1, &x2, &y2);
977     cairo_rectangle(cr, x1, y1, x2 - x1, y2 - y1);
978     addPath(path);
979 
980     cairo_fill_rule_t savedFillRule = cairo_get_fill_rule(cr);
981     cairo_set_fill_rule(cr, CAIRO_FILL_RULE_EVEN_ODD);
982     cairo_clip(cr);
983     cairo_set_fill_rule(cr, savedFillRule);
984 #else
985     notImplemented();
986 #endif
987 }
988 
rotate(float radians)989 void GraphicsContext::rotate(float radians)
990 {
991     if (paintingDisabled())
992         return;
993 
994     cairo_rotate(m_data->cr, radians);
995     m_data->rotate(radians);
996 }
997 
scale(const FloatSize & size)998 void GraphicsContext::scale(const FloatSize& size)
999 {
1000     if (paintingDisabled())
1001         return;
1002 
1003     cairo_scale(m_data->cr, size.width(), size.height());
1004     m_data->scale(size);
1005 }
1006 
clipOut(const IntRect & r)1007 void GraphicsContext::clipOut(const IntRect& r)
1008 {
1009     if (paintingDisabled())
1010         return;
1011 
1012 #if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1,4,0)
1013     cairo_t* cr = m_data->cr;
1014     double x1, y1, x2, y2;
1015     cairo_clip_extents(cr, &x1, &y1, &x2, &y2);
1016     cairo_rectangle(cr, x1, x2, x2 - x1, y2 - y1);
1017     cairo_rectangle(cr, r.x(), r.y(), r.width(), r.height());
1018     cairo_fill_rule_t savedFillRule = cairo_get_fill_rule(cr);
1019     cairo_set_fill_rule(cr, CAIRO_FILL_RULE_EVEN_ODD);
1020     cairo_clip(cr);
1021     cairo_set_fill_rule(cr, savedFillRule);
1022 #else
1023     notImplemented();
1024 #endif
1025 }
1026 
clipOutEllipseInRect(const IntRect & r)1027 void GraphicsContext::clipOutEllipseInRect(const IntRect& r)
1028 {
1029     if (paintingDisabled())
1030         return;
1031 
1032     Path p;
1033     p.addEllipse(r);
1034     clipOut(p);
1035 }
1036 
fillRoundedRect(const IntRect & r,const IntSize & topLeft,const IntSize & topRight,const IntSize & bottomLeft,const IntSize & bottomRight,const Color & color)1037 void GraphicsContext::fillRoundedRect(const IntRect& r, const IntSize& topLeft, const IntSize& topRight, const IntSize& bottomLeft, const IntSize& bottomRight, const Color& color)
1038 {
1039     if (paintingDisabled())
1040         return;
1041 
1042     cairo_t* cr = m_data->cr;
1043     cairo_save(cr);
1044     beginPath();
1045     addPath(Path::createRoundedRectangle(r, topLeft, topRight, bottomLeft, bottomRight));
1046     setColor(cr, color);
1047     cairo_fill(cr);
1048     cairo_restore(cr);
1049 }
1050 
1051 #if PLATFORM(GTK)
setGdkExposeEvent(GdkEventExpose * expose)1052 void GraphicsContext::setGdkExposeEvent(GdkEventExpose* expose)
1053 {
1054     m_data->expose = expose;
1055 }
1056 
gdkExposeEvent() const1057 GdkEventExpose* GraphicsContext::gdkExposeEvent() const
1058 {
1059     return m_data->expose;
1060 }
1061 
gdkDrawable() const1062 GdkDrawable* GraphicsContext::gdkDrawable() const
1063 {
1064     if (!m_data->expose)
1065         return 0;
1066 
1067     return GDK_DRAWABLE(m_data->expose->window);
1068 }
1069 #endif
1070 
setPlatformShouldAntialias(bool enable)1071 void GraphicsContext::setPlatformShouldAntialias(bool enable)
1072 {
1073     if (paintingDisabled())
1074         return;
1075 
1076     // When true, use the default Cairo backend antialias mode (usually this
1077     // enables standard 'grayscale' antialiasing); false to explicitly disable
1078     // antialiasing. This is the same strategy as used in drawConvexPolygon().
1079     cairo_set_antialias(m_data->cr, enable ? CAIRO_ANTIALIAS_DEFAULT : CAIRO_ANTIALIAS_NONE);
1080 }
1081 
setImageInterpolationQuality(InterpolationQuality)1082 void GraphicsContext::setImageInterpolationQuality(InterpolationQuality)
1083 {
1084 }
1085 
imageInterpolationQuality() const1086 InterpolationQuality GraphicsContext::imageInterpolationQuality() const
1087 {
1088     return InterpolationDefault;
1089 }
1090 
1091 } // namespace WebCore
1092 
1093 #endif // PLATFORM(CAIRO)
1094