Allow decoding JPEG into A8.

src/images/SkScaledBitmapSampler.cpp

 /*
  * Copyright 2007 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "SkScaledBitmapSampler.h"
 #include "SkBitmap.h"
@@ skipping 271 matching lines @@
     } else {
         uint8_t* SK_RESTRICT dst = (uint8_t*)dstRow;
         for (int x = 0; x < width; x++) {
             dst[x] = src[0];
             src += deltaSrc;
         }
     }
     return false;
 }
 
+// A8
+static bool Sample_Gray_DA8(void* SK_RESTRICT dstRow,
+                            const uint8_t* SK_RESTRICT src,
+                            int width, int deltaSrc, int,
+                            const SkPMColor[]) {
+    memcpy(dstRow, src, width);
+    return true;
+}
+
 // 8888 Unpremul
 
 static bool Sample_Gray_D8888_Unpremul(void* SK_RESTRICT dstRow,
                                        const uint8_t* SK_RESTRICT src,
                                        int width, int deltaSrc, int,
                                        const SkPMColor[]) {
     uint32_t* SK_RESTRICT dst = reinterpret_cast<uint32_t*>(dstRow);
     for (int x = 0; x < width; x++) {
         dst[x] = SkPackARGB32NoCheck(0xFF, src[0], src[0], src[0]);
         src += deltaSrc;
@@ skipping 87 matching lines @@
         Sample_RGBx_D4444,              Sample_RGBx_D4444_D,
         Sample_RGBA_D4444,              Sample_RGBA_D4444_D,
         Sample_Index_D4444,             Sample_Index_D4444_D,
         NULL,                           NULL,
         // Index8
         NULL,                           NULL,
         NULL,                           NULL,
         NULL,                           NULL,
         Sample_Index_DI,                Sample_Index_DI,
         NULL,                           NULL,
+        // A8
+        Sample_Gray_DA8,                Sample_Gray_DA8,
+        NULL,                           NULL,
+        NULL,                           NULL,
+        NULL,                           NULL,
+        NULL,                           NULL,
         // 8888 Unpremul (no dither distinction)
         Sample_Gray_D8888_Unpremul,     Sample_Gray_D8888_Unpremul,
         Sample_RGBx_D8888,              Sample_RGBx_D8888,
         Sample_RGBA_D8888_Unpremul,     Sample_RGBA_D8888_Unpremul,
         Sample_Index_D8888,             Sample_Index_D8888,
         NULL,                           NULL,
     };
     // The jump between dst configs in the table
     static const int gProcDstConfigSpan = 10;
-    SK_COMPILE_ASSERT(SK_ARRAY_COUNT(gProcs) == 5 * gProcDstConfigSpan,
+    SK_COMPILE_ASSERT(SK_ARRAY_COUNT(gProcs) == 6 * gProcDstConfigSpan,
                       gProcs_has_the_wrong_number_of_entries);
 
     fCTable = ctable;
 
     int index = 0;
     if (dither) {
         index += 1;
     }
     switch (sc) {
         case SkScaledBitmapSampler::kGray:
@@ skipping 30 matching lines @@
             break;
         case SkBitmap::kRGB_565_Config:
             index += 1 * gProcDstConfigSpan;
             break;
         case SkBitmap::kARGB_4444_Config:
             index += 2 * gProcDstConfigSpan;
             break;
         case SkBitmap::kIndex8_Config:
             index += 3 * gProcDstConfigSpan;
             break;
+        case SkBitmap::kA8_Config:
+            index += 4 * gProcDstConfigSpan;
+            break;
         default:
             return false;
     }
 
     if (requireUnpremul) {
         if (dst->config() != SkBitmap::kARGB_8888_Config) {
             return false;
         }
-        index += 4 * gProcDstConfigSpan;
+        index += 5 * gProcDstConfigSpan;
     }
 
     fRowProc = gProcs[index];
     fDstRow = (char*)dst->getPixels();
     fDstRowBytes = dst->rowBytes();
     fCurrY = 0;
     return fRowProc != NULL;
 }
 
 bool SkScaledBitmapSampler::next(const uint8_t* SK_RESTRICT src) {
     SkASSERT((unsigned)fCurrY < (unsigned)fScaledHeight);
 
     bool hadAlpha = fRowProc(fDstRow, src + fX0 * fSrcPixelSize, fScaledWidth,
                              fDX * fSrcPixelSize, fCurrY, fCTable);
     fDstRow += fDstRowBytes;
     fCurrY += 1;
     return hadAlpha;
 }