Implement Fill() for incomplete decodes to RGBA_F16

src/codec/SkCodec.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 "SkBmpCodec.h"
 #include "SkCodec.h"
 #include "SkCodecPriv.h"
 #include "SkColorSpace.h"
 #include "SkData.h"
 #include "SkGifCodec.h"
+#include "SkHalf.h"
 #include "SkIcoCodec.h"
 #include "SkJpegCodec.h"
 #ifdef SK_HAS_PNG_LIBRARY
 #include "SkPngCodec.h"
 #endif
 #include "SkRawCodec.h"
 #include "SkStream.h"
 #include "SkWbmpCodec.h"
 #include "SkWebpCodec.h"
 
@@ skipping 322 matching lines @@
             return inputScanline;
         case kBottomUp_SkScanlineOrder:
             return this->getInfo().height() - inputScanline - 1;
         default:
             // This case indicates an interlaced gif and is implemented by SkGifCodec.
             SkASSERT(false);
             return 0;
     }
 }
 
+uint64_t SkCodec::onGetFillValue(const SkImageInfo& dstInfo) const {
+    switch (dstInfo.colorType()) {
+        case kRGBA_F16_SkColorType: {
+            static constexpr uint64_t transparentColor = 0;
+            static constexpr uint64_t opaqueColor = ((uint64_t) SK_Half1) << 48;
+            return (kOpaque_SkAlphaType == fSrcInfo.alphaType()) ? opaqueColor : transparentColor;
+        }
+        default: {
+            // This not only handles the kN32 case, but also k565, kGray8, kIndex8, since
+            // the low bits are zeros.
+            return (kOpaque_SkAlphaType == fSrcInfo.alphaType()) ?
+                    SK_ColorBLACK : SK_ColorTRANSPARENT;
+        }
+    }
+}
+
 static void fill_proc(const SkImageInfo& info, void* dst, size_t rowBytes,
-        uint32_t colorOrIndex, SkCodec::ZeroInitialized zeroInit, SkSampler* sampler) {
+        uint64_t colorOrIndex, SkCodec::ZeroInitialized zeroInit, SkSampler* sampler) {
     if (sampler) {
         sampler->fill(info, dst, rowBytes, colorOrIndex, zeroInit);
     } else {
         SkSampler::Fill(info, dst, rowBytes, colorOrIndex, zeroInit);
     }
 }
 
 void SkCodec::fillIncompleteImage(const SkImageInfo& info, void* dst, size_t rowBytes,
         ZeroInitialized zeroInit, int linesRequested, int linesDecoded) {
 
     void* fillDst;
-    const uint32_t fillValue = this->getFillValue(info.colorType());
+    const uint64_t fillValue = this->getFillValue(info);
     const int linesRemaining = linesRequested - linesDecoded;
     SkSampler* sampler = this->getSampler(false);
 
     int fillWidth = info.width();
     if (fOptions.fSubset) {
         fillWidth = fOptions.fSubset->width();
     }
 
     switch (this->getScanlineOrder()) {
         case kTopDown_SkScanlineOrder:
@@ skipping 13 matching lines @@
             SkASSERT(1 == linesRequested || this->getInfo().height() == linesRequested);
             const SkImageInfo fillInfo = info.makeWH(fillWidth, 1);
             for (int srcY = linesDecoded; srcY < linesRequested; srcY++) {
                 fillDst = SkTAddOffset<void>(dst, this->outputScanline(srcY) * rowBytes);
                 fill_proc(fillInfo, fillDst, rowBytes, fillValue, zeroInit, sampler);
             }
             break;
         }
     }
 }