Support more swizzles to 565 in SkCodec

src/codec/SkMaskSwizzler.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCodecPriv.h"
 #include "SkColorPriv.h"
 #include "SkMaskSwizzler.h"
@@ skipping 45 matching lines @@
         uint8_t red = masks->getRed(p);
         uint8_t green = masks->getGreen(p);
         uint8_t blue = masks->getBlue(p);
         uint8_t alpha = masks->getAlpha(p);
         UPDATE_RESULT_ALPHA(alpha);
         dstPtr[i] = SkPreMultiplyARGB(alpha, red, green, blue);
     }
     return COMPUTE_RESULT_ALPHA;
 }
 
+// TODO (msarett): We have promoted a two byte per pixel image to 8888, only to
+// convert it back to 565. Instead, we should swizzle to 565 directly.
+static SkSwizzler::ResultAlpha swizzle_mask16_to_565(
+        void* dstRow, const uint8_t* srcRow, int width, SkMasks* masks) {
+
+    // Use the masks to decode to the destination
+    uint16_t* srcPtr = (uint16_t*) srcRow;
+    uint16_t* dstPtr = (uint16_t*) dstRow;
+    for (int i = 0; i < width; i++) {
+        uint16_t p = srcPtr[i];
+        uint8_t red = masks->getRed(p);
+        uint8_t green = masks->getGreen(p);
+        uint8_t blue = masks->getBlue(p);
+        dstPtr[i] = SkPack888ToRGB16(red, green, blue);
+    }
+    return SkSwizzler::kOpaque_ResultAlpha;
+}
+
 static SkSwizzler::ResultAlpha swizzle_mask24_to_n32_opaque(
         void* dstRow, const uint8_t* srcRow, int width, SkMasks* masks) {
 
     // Use the masks to decode to the destination
     SkPMColor* dstPtr = (SkPMColor*) dstRow;
     for (int i = 0; i < 3*width; i += 3) {
         uint32_t p = srcRow[i] | (srcRow[i + 1] << 8) | srcRow[i + 2] << 16;
         uint8_t red = masks->getRed(p);
         uint8_t green = masks->getGreen(p);
         uint8_t blue = masks->getBlue(p);
@@ skipping 31 matching lines @@
         uint8_t red = masks->getRed(p);
         uint8_t green = masks->getGreen(p);
         uint8_t blue = masks->getBlue(p);
         uint8_t alpha = masks->getAlpha(p);
         UPDATE_RESULT_ALPHA(alpha);
         dstPtr[i/3] = SkPreMultiplyARGB(alpha, red, green, blue);
     }
     return COMPUTE_RESULT_ALPHA;
 }
 
+static SkSwizzler::ResultAlpha swizzle_mask24_to_565(
+        void* dstRow, const uint8_t* srcRow, int width, SkMasks* masks) {
+
+    // Use the masks to decode to the destination
+    uint16_t* dstPtr = (uint16_t*) dstRow;
+    for (int i = 0; i < 3*width; i += 3) {
+        uint32_t p = srcRow[i] | (srcRow[i + 1] << 8) | srcRow[i + 2] << 16;
+        uint8_t red = masks->getRed(p);
+        uint8_t green = masks->getGreen(p);
+        uint8_t blue = masks->getBlue(p);
+        dstPtr[i/3] = SkPack888ToRGB16(red, green, blue);
+    }
+    return SkSwizzler::kOpaque_ResultAlpha;
+}
+
 static SkSwizzler::ResultAlpha swizzle_mask32_to_n32_opaque(
         void* dstRow, const uint8_t* srcRow, int width, SkMasks* masks) {
 
     // Use the masks to decode to the destination
     uint32_t* srcPtr = (uint32_t*) srcRow;
     SkPMColor* dstPtr = (SkPMColor*) dstRow;
     for (int i = 0; i < width; i++) {
         uint32_t p = srcPtr[i];
         uint8_t red = masks->getRed(p);
         uint8_t green = masks->getGreen(p);
@@ skipping 34 matching lines @@
         uint8_t red = masks->getRed(p);
         uint8_t green = masks->getGreen(p);
         uint8_t blue = masks->getBlue(p);
         uint8_t alpha = masks->getAlpha(p);
         UPDATE_RESULT_ALPHA(alpha);
         dstPtr[i] = SkPreMultiplyARGB(alpha, red, green, blue);
     }
     return COMPUTE_RESULT_ALPHA;
 }
 
+static SkSwizzler::ResultAlpha swizzle_mask32_to_565(
+        void* dstRow, const uint8_t* srcRow, int width, SkMasks* masks) {
+    // Use the masks to decode to the destination
+    uint32_t* srcPtr = (uint32_t*) srcRow;
+    uint16_t* dstPtr = (uint16_t*) dstRow;
+    for (int i = 0; i < width; i++) {
+        uint32_t p = srcPtr[i];
+        uint8_t red = masks->getRed(p);
+        uint8_t green = masks->getGreen(p);
+        uint8_t blue = masks->getBlue(p);
+        dstPtr[i] = SkPack888ToRGB16(red, green, blue);
+    }
+    return SkSwizzler::kOpaque_ResultAlpha;
+}
+
 /*
  *
  * Create a new mask swizzler
  *
  */
 SkMaskSwizzler* SkMaskSwizzler::CreateMaskSwizzler(
         const SkImageInfo& info, SkMasks* masks, uint32_t bitsPerPixel) {
 
     // Choose the appropriate row procedure
     RowProc proc = NULL;
     switch (bitsPerPixel) {
         case 16:
             switch (info.colorType()) {
                 case kN32_SkColorType:
                     switch (info.alphaType()) {
                         case kUnpremul_SkAlphaType:
                             proc = &swizzle_mask16_to_n32_unpremul;
                             break;
                         case kPremul_SkAlphaType:
                             proc = &swizzle_mask16_to_n32_premul;
                             break;
                         case kOpaque_SkAlphaType:
                             proc = &swizzle_mask16_to_n32_opaque;
                             break;
                         default:
                             break;
                     }
                     break;
+                case kRGB_565_SkColorType:
+                    switch (info.alphaType()) {
+                        case kOpaque_SkAlphaType:
+                            proc = &swizzle_mask16_to_565;
+                            break;
+                        default:
+                            break;
+                    }
+                    break;
                 default:
                     break;
             }
             break;
         case 24:
             switch (info.colorType()) {
                 case kN32_SkColorType:
                     switch (info.alphaType()) {
                         case kUnpremul_SkAlphaType:
                             proc = &swizzle_mask24_to_n32_unpremul;
                             break;
                         case kPremul_SkAlphaType:
                             proc = &swizzle_mask24_to_n32_premul;
                             break;
                         case kOpaque_SkAlphaType:
                             proc = &swizzle_mask24_to_n32_opaque;
                             break;
                         default:
                             break;
                     }
                     break;
+                case kRGB_565_SkColorType:
+                    switch (info.alphaType()) {
+                        case kOpaque_SkAlphaType:
+                            proc = &swizzle_mask24_to_565;
+                            break;
+                        default:
+                            break;
+                    }
+                    break;
                 default:
                     break;
             }
             break;
         case 32:
             switch (info.colorType()) {
                 case kN32_SkColorType:
                     switch (info.alphaType()) {
                         case kUnpremul_SkAlphaType:
                             proc = &swizzle_mask32_to_n32_unpremul;
                             break;
                         case kPremul_SkAlphaType:
                             proc = &swizzle_mask32_to_n32_premul;
                             break;
                         case kOpaque_SkAlphaType:
                             proc = &swizzle_mask32_to_n32_opaque;
                             break;
                         default:
                             break;
                     }
                     break;
+                case kRGB_565_SkColorType:
+                    switch (info.alphaType()) {
+                        case kOpaque_SkAlphaType:
+                            proc = &swizzle_mask32_to_565;
+                            break;
+                        default:
+                            break;
+                    }
+                    break;
                 default:
                     break;
             }
             break;
         default:
             SkASSERT(false);
             return NULL;
     }
     return SkNEW_ARGS(SkMaskSwizzler, (info, masks, proc));
 }
@@ skipping 12 matching lines @@
 
 /*
  *
  * Swizzle the specified row
  *
  */
 SkSwizzler::ResultAlpha SkMaskSwizzler::swizzle(void* dst, const uint8_t* SK_RESTRICT src) {
     SkASSERT(NULL != dst && NULL != src);
     return fRowProc(dst, src, fDstInfo.width(), fMasks);
 }