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1 /*
2  * Copyright 2014 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #include "SkBitmap.h"
9 #include "SkCanvas.h"
10 #include "SkConfig8888.h"
11 #include "SkColorPriv.h"
12 #include "SkDither.h"
13 #include "SkMathPriv.h"
14 #include "SkUnPreMultiply.h"
15 
16 enum AlphaVerb {
17     kNothing_AlphaVerb,
18     kPremul_AlphaVerb,
19     kUnpremul_AlphaVerb,
20 };
21 
convert32(uint32_t c)22 template <bool doSwapRB, AlphaVerb doAlpha> uint32_t convert32(uint32_t c) {
23     if (doSwapRB) {
24         c = SkSwizzle_RB(c);
25     }
26 
27     // Lucky for us, in both RGBA and BGRA, the alpha component is always in the same place, so
28     // we can perform premul or unpremul the same way without knowing the swizzles for RGB.
29     switch (doAlpha) {
30         case kNothing_AlphaVerb:
31             // no change
32             break;
33         case kPremul_AlphaVerb:
34             c = SkPreMultiplyARGB(SkGetPackedA32(c), SkGetPackedR32(c),
35                                   SkGetPackedG32(c), SkGetPackedB32(c));
36             break;
37         case kUnpremul_AlphaVerb:
38             c = SkUnPreMultiply::UnPreMultiplyPreservingByteOrder(c);
39             break;
40     }
41     return c;
42 }
43 
44 template <bool doSwapRB, AlphaVerb doAlpha>
convert32_row(uint32_t * dst,const uint32_t * src,int count)45 void convert32_row(uint32_t* dst, const uint32_t* src, int count) {
46     // This has to be correct if src == dst (but not partial overlap)
47     for (int i = 0; i < count; ++i) {
48         dst[i] = convert32<doSwapRB, doAlpha>(src[i]);
49     }
50 }
51 
is_32bit_colortype(SkColorType ct)52 static bool is_32bit_colortype(SkColorType ct) {
53     return kRGBA_8888_SkColorType == ct || kBGRA_8888_SkColorType == ct;
54 }
55 
compute_AlphaVerb(SkAlphaType src,SkAlphaType dst)56 static AlphaVerb compute_AlphaVerb(SkAlphaType src, SkAlphaType dst) {
57     SkASSERT(kIgnore_SkAlphaType != src);
58     SkASSERT(kIgnore_SkAlphaType != dst);
59 
60     if (kOpaque_SkAlphaType == src || kOpaque_SkAlphaType == dst || src == dst) {
61         return kNothing_AlphaVerb;
62     }
63     if (kPremul_SkAlphaType == dst) {
64         SkASSERT(kUnpremul_SkAlphaType == src);
65         return kPremul_AlphaVerb;
66     } else {
67         SkASSERT(kPremul_SkAlphaType == src);
68         SkASSERT(kUnpremul_SkAlphaType == dst);
69         return kUnpremul_AlphaVerb;
70     }
71 }
72 
memcpy32_row(uint32_t * dst,const uint32_t * src,int count)73 static void memcpy32_row(uint32_t* dst, const uint32_t* src, int count) {
74     memcpy(dst, src, count * 4);
75 }
76 
convertPixelsTo(SkDstPixelInfo * dst,int width,int height) const77 bool SkSrcPixelInfo::convertPixelsTo(SkDstPixelInfo* dst, int width, int height) const {
78     if (width <= 0 || height <= 0) {
79         return false;
80     }
81 
82     if (!is_32bit_colortype(fColorType) || !is_32bit_colortype(dst->fColorType)) {
83         return false;
84     }
85 
86     void (*proc)(uint32_t* dst, const uint32_t* src, int count);
87     AlphaVerb doAlpha = compute_AlphaVerb(fAlphaType, dst->fAlphaType);
88     bool doSwapRB = fColorType != dst->fColorType;
89 
90     switch (doAlpha) {
91         case kNothing_AlphaVerb:
92             if (doSwapRB) {
93                 proc = convert32_row<true, kNothing_AlphaVerb>;
94             } else {
95                 if (fPixels == dst->fPixels) {
96                     return true;
97                 }
98                 proc = memcpy32_row;
99             }
100             break;
101         case kPremul_AlphaVerb:
102             if (doSwapRB) {
103                 proc = convert32_row<true, kPremul_AlphaVerb>;
104             } else {
105                 proc = convert32_row<false, kPremul_AlphaVerb>;
106             }
107             break;
108         case kUnpremul_AlphaVerb:
109             if (doSwapRB) {
110                 proc = convert32_row<true, kUnpremul_AlphaVerb>;
111             } else {
112                 proc = convert32_row<false, kUnpremul_AlphaVerb>;
113             }
114             break;
115     }
116 
117     uint32_t* dstP = static_cast<uint32_t*>(dst->fPixels);
118     const uint32_t* srcP = static_cast<const uint32_t*>(fPixels);
119     size_t srcInc = fRowBytes >> 2;
120     size_t dstInc = dst->fRowBytes >> 2;
121     for (int y = 0; y < height; ++y) {
122         proc(dstP, srcP, width);
123         dstP += dstInc;
124         srcP += srcInc;
125     }
126     return true;
127 }
128 
rect_memcpy(void * dst,size_t dstRB,const void * src,size_t srcRB,size_t bytesPerRow,int rowCount)129 static void rect_memcpy(void* dst, size_t dstRB, const void* src, size_t srcRB, size_t bytesPerRow,
130                         int rowCount) {
131     SkASSERT(bytesPerRow <= srcRB);
132     SkASSERT(bytesPerRow <= dstRB);
133     for (int i = 0; i < rowCount; ++i) {
134         memcpy(dst, src, bytesPerRow);
135         dst = (char*)dst + dstRB;
136         src = (const char*)src + srcRB;
137     }
138 }
139 
CopyPixels(const SkImageInfo & dstInfo,void * dstPixels,size_t dstRB,const SkImageInfo & srcInfo,const void * srcPixels,size_t srcRB,SkColorTable * ctable)140 bool SkPixelInfo::CopyPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRB,
141                              const SkImageInfo& srcInfo, const void* srcPixels, size_t srcRB,
142                              SkColorTable* ctable) {
143     if (srcInfo.dimensions() != dstInfo.dimensions()) {
144         return false;
145     }
146 
147     const int width = srcInfo.width();
148     const int height = srcInfo.height();
149 
150     // Handle fancy alpha swizzling if both are ARGB32
151     if (4 == srcInfo.bytesPerPixel() && 4 == dstInfo.bytesPerPixel()) {
152         SkDstPixelInfo dstPI;
153         dstPI.fColorType = dstInfo.colorType();
154         dstPI.fAlphaType = dstInfo.alphaType();
155         dstPI.fPixels = dstPixels;
156         dstPI.fRowBytes = dstRB;
157 
158         SkSrcPixelInfo srcPI;
159         srcPI.fColorType = srcInfo.colorType();
160         srcPI.fAlphaType = srcInfo.alphaType();
161         srcPI.fPixels = srcPixels;
162         srcPI.fRowBytes = srcRB;
163 
164         return srcPI.convertPixelsTo(&dstPI, width, height);
165     }
166 
167     // If they agree on colorType and the alphaTypes are compatible, then we just memcpy.
168     // Note: we've already taken care of 32bit colortypes above.
169     if (srcInfo.colorType() == dstInfo.colorType()) {
170         switch (srcInfo.colorType()) {
171             case kRGB_565_SkColorType:
172             case kAlpha_8_SkColorType:
173                 break;
174             case kIndex_8_SkColorType:
175             case kARGB_4444_SkColorType:
176                 if (srcInfo.alphaType() != dstInfo.alphaType()) {
177                     return false;
178                 }
179                 break;
180             default:
181                 return false;
182         }
183         rect_memcpy(dstPixels, dstRB, srcPixels, srcRB, width * srcInfo.bytesPerPixel(), height);
184         return true;
185     }
186 
187     /*
188      *  Begin section where we try to change colorTypes along the way. Not all combinations
189      *  are supported.
190      */
191 
192     // Can no longer draw directly into 4444, but we can manually whack it for a few combinations
193     if (kARGB_4444_SkColorType == dstInfo.colorType() &&
194         (kN32_SkColorType == srcInfo.colorType() || kIndex_8_SkColorType == srcInfo.colorType())) {
195         if (srcInfo.alphaType() == kUnpremul_SkAlphaType) {
196             // Our method for converting to 4444 assumes premultiplied.
197             return false;
198         }
199 
200         const SkPMColor* table = NULL;
201         if (kIndex_8_SkColorType == srcInfo.colorType()) {
202             if (NULL == ctable) {
203                 return false;
204             }
205             table = ctable->lockColors();
206         }
207 
208         for (int y = 0; y < height; ++y) {
209             DITHER_4444_SCAN(y);
210             SkPMColor16* SK_RESTRICT dstRow = (SkPMColor16*)dstPixels;
211             if (table) {
212                 const uint8_t* SK_RESTRICT srcRow = (const uint8_t*)srcPixels;
213                 for (int x = 0; x < width; ++x) {
214                     dstRow[x] = SkDitherARGB32To4444(table[srcRow[x]], DITHER_VALUE(x));
215                 }
216             } else {
217                 const SkPMColor* SK_RESTRICT srcRow = (const SkPMColor*)srcPixels;
218                 for (int x = 0; x < width; ++x) {
219                     dstRow[x] = SkDitherARGB32To4444(srcRow[x], DITHER_VALUE(x));
220                 }
221             }
222             dstPixels = (char*)dstPixels + dstRB;
223             srcPixels = (const char*)srcPixels + srcRB;
224         }
225 
226         if (table) {
227             ctable->unlockColors();
228         }
229         return true;
230     }
231 
232     if (dstInfo.alphaType() == kUnpremul_SkAlphaType) {
233         // We do not support drawing to unpremultiplied bitmaps.
234         return false;
235     }
236 
237     // Final fall-back, draw with a canvas
238     //
239     // Always clear the dest in case one of the blitters accesses it
240     // TODO: switch the allocation of tmpDst to call sk_calloc_throw
241     {
242         SkBitmap bm;
243         if (!bm.installPixels(srcInfo, const_cast<void*>(srcPixels), srcRB, ctable, NULL, NULL)) {
244             return false;
245         }
246         SkAutoTUnref<SkCanvas> canvas(SkCanvas::NewRasterDirect(dstInfo, dstPixels, dstRB));
247         if (NULL == canvas.get()) {
248             return false;
249         }
250 
251         SkPaint  paint;
252         paint.setDither(true);
253 
254         canvas->clear(0);
255         canvas->drawBitmap(bm, 0, 0, &paint);
256         return true;
257     }
258 }
259 
260