1 /*
2 * Copyright (C) 2004, 2005, 2006, 2007 Nikolas Zimmermann <zimmermann@kde.org>
3 * Copyright (C) 2004, 2005 Rob Buis <buis@kde.org>
4 * Copyright (C) 2005 Eric Seidel <eric@webkit.org>
5 * Copyright (C) 2013 Google Inc. All rights reserved.
6 *
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
11 *
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
16 *
17 * You should have received a copy of the GNU Library General Public License
18 * along with this library; see the file COPYING.LIB. If not, write to
19 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
20 * Boston, MA 02110-1301, USA.
21 */
22
23 #ifndef FEGaussianBlur_h
24 #define FEGaussianBlur_h
25
26 #include "platform/graphics/filters/Filter.h"
27 #include "platform/graphics/filters/FilterEffect.h"
28
29 namespace WebCore {
30
31 class PLATFORM_EXPORT FEGaussianBlur : public FilterEffect {
32 public:
33 static PassRefPtr<FEGaussianBlur> create(Filter*, float, float);
34
35 float stdDeviationX() const;
36 void setStdDeviationX(float);
37
38 float stdDeviationY() const;
39 void setStdDeviationY(float);
40
41 static float calculateStdDeviation(float);
42
43 virtual void determineAbsolutePaintRect();
44 virtual FloatRect mapRect(const FloatRect&, bool forward = true) OVERRIDE FINAL;
45 static void calculateKernelSize(Filter*, unsigned& kernelSizeX, unsigned& kernelSizeY, float stdX, float stdY);
46 static void calculateUnscaledKernelSize(unsigned& kernelSizeX, unsigned& kernelSizeY, float stdX, float stdY);
47
48 virtual TextStream& externalRepresentation(TextStream&, int indention) const;
49
50 private:
51 static const int s_minimalRectDimension = 100 * 100; // Empirical data limit for parallel jobs
52
53 template<typename Type>
54 friend class ParallelJobs;
55
56 struct PlatformApplyParameters {
57 FEGaussianBlur* filter;
58 RefPtr<Uint8ClampedArray> srcPixelArray;
59 RefPtr<Uint8ClampedArray> dstPixelArray;
60 int width;
61 int height;
62 unsigned kernelSizeX;
63 unsigned kernelSizeY;
64 };
65
66 static void platformApplyWorker(PlatformApplyParameters*);
67
68 FEGaussianBlur(Filter*, float, float);
69
70 virtual void applySoftware() OVERRIDE;
71 virtual bool applySkia() OVERRIDE;
72
73 static inline void kernelPosition(int boxBlur, unsigned& std, int& dLeft, int& dRight);
74 inline void platformApply(Uint8ClampedArray* srcPixelArray, Uint8ClampedArray* tmpPixelArray, unsigned kernelSizeX, unsigned kernelSizeY, IntSize& paintSize);
75
76 inline void platformApplyGeneric(Uint8ClampedArray* srcPixelArray, Uint8ClampedArray* tmpPixelArray, unsigned kernelSizeX, unsigned kernelSizeY, IntSize& paintSize);
77 virtual PassRefPtr<SkImageFilter> createImageFilter(SkiaImageFilterBuilder*) OVERRIDE;
78
79 float m_stdX;
80 float m_stdY;
81 };
82
kernelPosition(int boxBlur,unsigned & std,int & dLeft,int & dRight)83 inline void FEGaussianBlur::kernelPosition(int boxBlur, unsigned& std, int& dLeft, int& dRight)
84 {
85 // check http://www.w3.org/TR/SVG/filters.html#feGaussianBlurElement for details
86 switch (boxBlur) {
87 case 0:
88 if (!(std % 2)) {
89 dLeft = std / 2 - 1;
90 dRight = std - dLeft;
91 } else {
92 dLeft = std / 2;
93 dRight = std - dLeft;
94 }
95 break;
96 case 1:
97 if (!(std % 2)) {
98 dLeft++;
99 dRight--;
100 }
101 break;
102 case 2:
103 if (!(std % 2)) {
104 dRight++;
105 std++;
106 }
107 break;
108 }
109 }
110
111 } // namespace WebCore
112
113 #endif // FEGaussianBlur_h
114