1
2 /*
3 * Copyright 2011 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9 class ARGB32_Clamp_Bilinear_BitmapShader : public SkBitmapShader {
10 public:
ARGB32_Clamp_Bilinear_BitmapShader(const SkBitmap & src)11 ARGB32_Clamp_Bilinear_BitmapShader(const SkBitmap& src)
12 : SkBitmapShader(src, true,
13 SkShader::kClamp_TileMode, SkShader::kClamp_TileMode)
14 {}
15
16 virtual void shadeSpan(int x, int y, SkPMColor dstC[], int count);
17 };
18
19 SkPMColor sample_bilerp(SkFixed fx, SkFixed fy, unsigned srcMaxX, unsigned srcMaxY,
20 const SkPMColor* srcPixels, int srcRB, const SkFilterPtrProc* proc_table);
sample_bilerp(SkFixed fx,SkFixed fy,unsigned srcMaxX,unsigned srcMaxY,const SkPMColor * srcPixels,int srcRB,const SkFilterPtrProc * proc_table)21 SkPMColor sample_bilerp(SkFixed fx, SkFixed fy, unsigned srcMaxX, unsigned srcMaxY,
22 const SkPMColor* srcPixels, int srcRB, const SkFilterPtrProc* proc_table)
23 {
24 int ix = fx >> 16;
25 int iy = fy >> 16;
26
27 const SkPMColor *p00, *p01, *p10, *p11;
28
29 p00 = p01 = ((const SkPMColor*)((const char*)srcPixels
30 + SkClampMax(iy, srcMaxY) * srcRB))
31 + SkClampMax(ix, srcMaxX);
32
33 if ((unsigned)ix < srcMaxX)
34 p01 += 1;
35 p10 = p00;
36 p11 = p01;
37 if ((unsigned)iy < srcMaxY)
38 {
39 p10 = (const SkPMColor*)((const char*)p10 + srcRB);
40 p11 = (const SkPMColor*)((const char*)p11 + srcRB);
41 }
42
43 SkFilterPtrProc proc = SkGetBilinearFilterPtrProc(proc_table, fx, fy);
44 return proc(p00, p01, p10, p11);
45 }
46
sample_bilerpx(SkFixed fx,unsigned srcMaxX,const SkPMColor * srcPixels,int srcRB,const SkFilterPtrProc * proc_table)47 static inline SkPMColor sample_bilerpx(SkFixed fx, unsigned srcMaxX, const SkPMColor* srcPixels,
48 int srcRB, const SkFilterPtrProc* proc_table)
49 {
50 int ix = fx >> 16;
51
52 const SkPMColor *p00, *p01, *p10, *p11;
53
54 p00 = p01 = srcPixels + SkClampMax(ix, srcMaxX);
55 if ((unsigned)ix < srcMaxX)
56 p01 += 1;
57
58 p10 = (const SkPMColor*)((const char*)p00 + srcRB);
59 p11 = (const SkPMColor*)((const char*)p01 + srcRB);
60
61 SkFilterPtrProc proc = SkGetBilinearFilterPtrXProc(proc_table, fx);
62 return proc(p00, p01, p10, p11);
63 }
64
shadeSpan(int x,int y,SkPMColor dstC[],int count)65 void ARGB32_Clamp_Bilinear_BitmapShader::shadeSpan(int x, int y, SkPMColor dstC[], int count)
66 {
67 SkASSERT(count > 0);
68
69 unsigned srcScale = SkAlpha255To256(this->getPaintAlpha());
70
71 const SkMatrix& inv = this->getTotalInverse();
72 const SkBitmap& srcBitmap = this->getSrcBitmap();
73 unsigned srcMaxX = srcBitmap.width() - 1;
74 unsigned srcMaxY = srcBitmap.height() - 1;
75 unsigned srcRB = srcBitmap.rowBytes();
76
77 const SkFilterPtrProc* proc_table = SkGetBilinearFilterPtrProcTable();
78 const SkPMColor* srcPixels = (const SkPMColor*)srcBitmap.getPixels();
79
80 if (this->getInverseClass() == kPerspective_MatrixClass)
81 {
82 SkPerspIter iter(inv, SkIntToScalar(x) + SK_ScalarHalf,
83 SkIntToScalar(y) + SK_ScalarHalf, count);
84
85 if (256 == srcScale)
86 {
87 while ((count = iter.next()) != 0)
88 {
89 const SkFixed* srcXY = iter.getXY();
90 while (--count >= 0)
91 {
92 SkFixed fx = *srcXY++ - SK_FixedHalf;
93 SkFixed fy = *srcXY++ - SK_FixedHalf;
94 *dstC++ = sample_bilerp(fx, fy, srcMaxX, srcMaxY, srcPixels, srcRB, proc_table);
95 }
96 }
97 }
98 else // scale by srcScale
99 {
100 while ((count = iter.next()) != 0)
101 {
102 const SkFixed* srcXY = iter.getXY();
103 while (--count >= 0)
104 {
105 SkFixed fx = *srcXY++ - SK_FixedHalf;
106 SkFixed fy = *srcXY++ - SK_FixedHalf;
107 SkPMColor c = sample_bilerp(fx, fy, srcMaxX, srcMaxY, srcPixels, srcRB, proc_table);
108 *dstC++ = SkAlphaMulQ(c, srcScale);
109 }
110 }
111 }
112 }
113 else // linear case
114 {
115 SkFixed fx, fy, dx, dy;
116
117 // now init fx, fy, dx, dy
118 {
119 SkPoint srcPt;
120 this->getInverseMapPtProc()(inv, SkIntToScalar(x) + SK_ScalarHalf,
121 SkIntToScalar(y) + SK_ScalarHalf,
122 &srcPt);
123
124 fx = SkScalarToFixed(srcPt.fX) - SK_FixedHalf;
125 fy = SkScalarToFixed(srcPt.fY) - SK_FixedHalf;
126
127 if (this->getInverseClass() == kFixedStepInX_MatrixClass)
128 (void)inv.fixedStepInX(SkIntToScalar(y), &dx, &dy);
129 else
130 {
131 dx = SkScalarToFixed(inv.getScaleX());
132 dy = SkScalarToFixed(inv.getSkewY());
133 }
134 }
135
136 if (dy == 0 && (unsigned)(fy >> 16) < srcMaxY)
137 {
138 srcPixels = (const SkPMColor*)((const char*)srcPixels + (fy >> 16) * srcRB);
139 proc_table = SkGetBilinearFilterPtrProcYTable(proc_table, fy);
140 if (256 == srcScale)
141 {
142 do {
143 *dstC++ = sample_bilerpx(fx, srcMaxX, srcPixels, srcRB, proc_table);
144 fx += dx;
145 } while (--count != 0);
146 }
147 else
148 {
149 do {
150 SkPMColor c = sample_bilerpx(fx, srcMaxX, srcPixels, srcRB, proc_table);
151 *dstC++ = SkAlphaMulQ(c, srcScale);
152 fx += dx;
153 } while (--count != 0);
154 }
155 }
156 else // dy is != 0
157 {
158 if (256 == srcScale)
159 {
160 do {
161 *dstC++ = sample_bilerp(fx, fy, srcMaxX, srcMaxY, srcPixels, srcRB, proc_table);
162 fx += dx;
163 fy += dy;
164 } while (--count != 0);
165 }
166 else
167 {
168 do {
169 SkPMColor c = sample_bilerp(fx, fy, srcMaxX, srcMaxY, srcPixels, srcRB, proc_table);
170 *dstC++ = SkAlphaMulQ(c, srcScale);
171 fx += dx;
172 fy += dy;
173 } while (--count != 0);
174 }
175 }
176 }
177 }
178
179