Add SkEncodedInfo to report properties of encoded image data

src/codec/SkBmpCodec.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 "SkBmpMaskCodec.h"
 #include "SkBmpRLECodec.h"
@@ skipping 397 matching lines @@
         //                 Seems like we can just assume that the offset is zero and try to decode?
         //                 Maybe we don't want to try to decode corrupt images?
         SkCodecPrintf("Error: pixel data offset less than header size.\n");
         return false;
     }
 
 
 
     switch (inputFormat) {
         case kStandard_BmpInputFormat: {
-            // BMPs-in-ICOs often contain an alpha mask after the image, which
-            // means we cannot guarantee that an image is opaque, even if the
-            // embedded bmp is opaque.
-            // We use |isOpaque| to indicate if the BMP itself is opaque, but
-            // still need to recommend kUnpremul when it is contained in an ICO.
-            SkColorType colorType = kN32_SkColorType;
-            SkAlphaType alphaType = inIco ? kUnpremul_SkAlphaType : kOpaque_SkAlphaType;
+            // BMPs are generally opaque, however BMPs-in-ICOs may contain
+            // a transparency mask after the image.  Therefore, we mark the
+            // alpha as kBinary if the BMP is contained in an ICO.
+            // We use |isOpaque| to indicate if the BMP itself is opaque.
+            SkEncodedInfo::Alpha alpha = inIco ? SkEncodedInfo::kBinary_Alpha :
+                    SkEncodedInfo::kOpaque_Alpha;
             bool isOpaque = true;
+
+            SkEncodedInfo::Color color;
+            uint8_t bitsPerComponent;
             switch (bitsPerPixel) {
                 // Palette formats
                 case 1:
                 case 2:
                 case 4:
                 case 8:
-                    // We cannot recommend a palette color type for ICOs because they
-                    // may contain a transparency mask.
-                    if (!inIco) {
-                        colorType = kIndex_8_SkColorType;
+                    // In the case of ICO, kBGRA is actually the closest match,
+                    // since we will need to apply a transparency mask.
+                    if (inIco) {
+                        color = SkEncodedInfo::kBGRA_Color;
+                        bitsPerComponent = 8;
+                    } else {
+                        color = SkEncodedInfo::kPalette_Color;
+                        bitsPerComponent = (uint8_t) bitsPerPixel;
                     }
                     break;
                 case 24:
+                    color = SkEncodedInfo::kBGR_Color;
+                    bitsPerComponent = 8;
+                    break;
                 case 32:
                     // 32-bit BMP-in-ICOs actually use the alpha channel in place of a
                     // transparency mask.
                     if (inIco) {
                         isOpaque = false;
+                        alpha = SkEncodedInfo::kUnpremul_Alpha;
+                        color = SkEncodedInfo::kBGRA_Color;
+                    } else {
+                        color = SkEncodedInfo::kBGRX_Color;
                     }
+                    bitsPerComponent = 8;
                     break;
                 default:
                     SkCodecPrintf("Error: invalid input value for bits per pixel.\n");
                     return false;
             }
 
             if (codecOut) {
                 // We require streams to have a memory base for Bmp-in-Ico decodes.
                 SkASSERT(!inIco || nullptr != stream->getMemoryBase());
 
                 // Set the image info and create a codec.
-                const SkImageInfo imageInfo = SkImageInfo::Make(width, height, colorType,
-                        alphaType);
-                *codecOut = new SkBmpStandardCodec(imageInfo, stream, bitsPerPixel, numColors,
-                        bytesPerColor, offset - bytesRead, rowOrder, isOpaque, inIco);
-
+                const SkEncodedInfo info = SkEncodedInfo::Make(color, alpha, bitsPerComponent);
+                *codecOut = new SkBmpStandardCodec(width, height, info, stream, bitsPerPixel,
+                        numColors, bytesPerColor, offset - bytesRead, rowOrder, isOpaque, inIco);
             }
             return true;
         }
 
         case kBitMask_BmpInputFormat: {
             // Bmp-in-Ico must be standard mode
             if (inIco) {
                 SkCodecPrintf("Error: Icos may not use bit mask format.\n");
                 return false;
             }
@@ skipping 17 matching lines @@
             }
 
             if (codecOut) {
                 // Check that input bit masks are valid and create the masks object
                 SkAutoTDelete<SkMasks> masks(SkMasks::CreateMasks(inputMasks, bitsPerPixel));
                 if (nullptr == masks) {
                     SkCodecPrintf("Error: invalid input masks.\n");
                     return false;
                 }
 
-                // Set the image info
-                SkAlphaType alphaType = masks->getAlphaMask() ? kUnpremul_SkAlphaType :
-                        kOpaque_SkAlphaType;
-                const SkImageInfo imageInfo = SkImageInfo::Make(width, height, kN32_SkColorType,
-                        alphaType);
-                *codecOut = new SkBmpMaskCodec(imageInfo, stream, bitsPerPixel, masks.release(),
-                        rowOrder);
+                // Masked bmps are not a great fit for SkEncodedInfo, since they have
+                // arbitrary component orderings and bits per component.  Here we choose
+                // somewhat reasonable values - it's ok that we don't match exactly
+                // because SkBmpMaskCodec has its own mask swizzler anyway.
+                SkEncodedInfo::Color color;
+                SkEncodedInfo::Alpha alpha;
+                if (masks->getAlphaMask()) {
+                    color = SkEncodedInfo::kBGRA_Color;
+                    alpha = SkEncodedInfo::kUnpremul_Alpha;
+                } else {
+                    color = SkEncodedInfo::kBGR_Color;
+                    alpha = SkEncodedInfo::kOpaque_Alpha;
+                }
+                const SkEncodedInfo info = SkEncodedInfo::Make(color, alpha, 8);
+                *codecOut = new SkBmpMaskCodec(width, height, info, stream, bitsPerPixel,
+                        masks.release(), rowOrder);
             }
             return true;
         }
 
         case kRLE_BmpInputFormat: {
             // We should not reach this point without a valid value of bitsPerPixel.
             SkASSERT(4 == bitsPerPixel || 8 == bitsPerPixel || 24 == bitsPerPixel);
 
             // Check for a valid number of total bytes when in RLE mode
             if (totalBytes <= offset) {
                 SkCodecPrintf("Error: RLE requires valid input size.\n");
                 return false;
             }
             const size_t RLEBytes = totalBytes - offset;
 
             // Bmp-in-Ico must be standard mode
             // When inIco is true, this line cannot be reached, since we
             // require that RLE Bmps have a valid number of totalBytes, and
             // Icos skip the header that contains totalBytes.
             SkASSERT(!inIco);
 
             if (codecOut) {
                 // RLE inputs may skip pixels, leaving them as transparent.  This
                 // is uncommon, but we cannot be certain that an RLE bmp will be
-                // opaque.
-                const SkImageInfo imageInfo = SkImageInfo::Make(width, height, kN32_SkColorType,
-                        kUnpremul_SkAlphaType);
-                *codecOut = new SkBmpRLECodec(imageInfo, stream, bitsPerPixel, numColors,
+                // opaque or that we will be able to represent it with a palette.
+                // For that reason, we always indicate that we are kBGRA.
+                const SkEncodedInfo info = SkEncodedInfo::Make(SkEncodedInfo::kBGRA_Color,
+                        SkEncodedInfo::kBinary_Alpha, 8);
+                *codecOut = new SkBmpRLECodec(width, height, info, stream, bitsPerPixel, numColors,
                         bytesPerColor, offset - bytesRead, rowOrder, RLEBytes);
             }
             return true;
         }
         default:
             SkASSERT(false);
             return false;
     }
 }
 
 /*
  * Creates a bmp decoder
  * Reads enough of the stream to determine the image format
  */
 SkCodec* SkBmpCodec::NewFromStream(SkStream* stream, bool inIco) {
     SkAutoTDelete<SkStream> streamDeleter(stream);
     SkCodec* codec = nullptr;
     if (ReadHeader(stream, inIco, &codec)) {
         // codec has taken ownership of stream, so we do not need to
         // delete it.
         SkASSERT(codec);
         streamDeleter.release();
         return codec;
     }
     return nullptr;
 }
 
-SkBmpCodec::SkBmpCodec(const SkImageInfo& info, SkStream* stream,
+SkBmpCodec::SkBmpCodec(int width, int height, const SkEncodedInfo& info, SkStream* stream,
         uint16_t bitsPerPixel, SkCodec::SkScanlineOrder rowOrder)
-    : INHERITED(info, stream)
+    : INHERITED(width, height, info, stream)
     , fBitsPerPixel(bitsPerPixel)
     , fRowOrder(rowOrder)
-    , fSrcRowBytes(SkAlign4(compute_row_bytes(info.width(), fBitsPerPixel)))
+    , fSrcRowBytes(SkAlign4(compute_row_bytes(width, fBitsPerPixel)))
 {}
 
 bool SkBmpCodec::onRewind() {
     return SkBmpCodec::ReadHeader(this->stream(), this->inIco(), nullptr);
 }
 
 int32_t SkBmpCodec::getDstRow(int32_t y, int32_t height) const {
     if (SkCodec::kTopDown_SkScanlineOrder == fRowOrder) {
         return y;
     }
@@ skipping 20 matching lines @@
 }
 
 bool SkBmpCodec::skipRows(int count) {
     const size_t bytesToSkip = count * fSrcRowBytes;
     return this->stream()->skip(bytesToSkip) == bytesToSkip;
 }
 
 bool SkBmpCodec::onSkipScanlines(int count) {
     return this->skipRows(count);
 }