Implementing filling for SkBmpCodec

src/codec/SkSwizzler.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 "SkSwizzler.h"
@@ skipping 405 matching lines @@
     
     // Choose the row
     void* row = SkTAddOffset<void>(fDstRow, y*fDstRowBytes);
 
     // Decode the row
     return fRowProc(row, src, fDstInfo.width(), fDeltaSrc, fCurrY,
             fColorTable);
 }
 
 void SkSwizzler::Fill(void* dst, const SkImageInfo& dstInfo, size_t dstRowBytes, uint32_t y,
-        uint32_t colorOrIndex, SkPMColor* colorTable) {
+        uint32_t colorOrIndex, const SkPMColor* colorTable, bool bottomUp) {
     SkASSERT(dst != NULL);
     SkASSERT(y < (uint32_t) dstInfo.height());
 
     // Get dst start row
-    void* dstRow = SkTAddOffset<void*>(dst, y * dstRowBytes);
+    void* dstRow;
+    if (bottomUp) {
+        dstRow = dst;
+    } else {
+        dstRow = SkTAddOffset<void*>(dst, y * dstRowBytes);
+    }
 
     // Calculate remaining bytes.  This is tricky since the final row may not be padded.
     const size_t totalBytes = dstInfo.getSafeSize(dstRowBytes);
     const size_t remainingBytes = totalBytes - y * dstRowBytes;

[scroggo, 2015/04/10 18:12:43]

It seems like if (bottomUp), the remaining bytes will be totalBytes -
(dstInfo.height() * y) * dstRowBytes, right?

[msarett, 2015/04/10 20:52:56]

This is in fact correct as is, but quite confusing.

A new design will take care of this.  We will now pass in the dstStartRow and
the number of rows to fill.

 
     // Use the proper memset routine to fill the remaining bytes
     switch(dstInfo.colorType()) {
         case kN32_SkColorType:
             // Assume input is an index if we have a color table
             uint32_t color;
             if (NULL != colorTable) {
                 SkASSERT(colorOrIndex == (uint8_t) colorOrIndex);
                 color = colorTable[colorOrIndex];
             // Otherwise, assume the input is a color
@@ skipping 21 matching lines @@
         case kIndex_8_SkColorType:
             SkASSERT(colorOrIndex == (uint8_t) colorOrIndex);
             memset(dstRow, colorOrIndex, remainingBytes);
             break;
         default:
             SkCodecPrintf("Error: Unsupported dst color type for fill().  Doing nothing.\n");
             SkASSERT(false);
             break;
     }
 }