Enabling ico decoding with use of png and bmp decoders
BUG=skia:3257
NOPRESUBMIT=true
Review URL: https://codereview.chromium.org/1011343003
diff --git a/src/codec/SkCodec_libbmp.cpp b/src/codec/SkCodec_libbmp.cpp
index e9551cb..ac6cf3a 100644
--- a/src/codec/SkCodec_libbmp.cpp
+++ b/src/codec/SkCodec_libbmp.cpp
@@ -29,9 +29,6 @@
return src.alphaType() == dst.alphaType() ||
(kPremul_SkAlphaType == dst.alphaType() &&
kUnpremul_SkAlphaType == src.alphaType());
- case kRGB_565_SkColorType:
- return src.alphaType() == dst.alphaType() &&
- kOpaque_SkAlphaType == dst.alphaType();
default:
return false;
}
@@ -88,11 +85,31 @@
/*
*
* Assumes IsBmp was called and returned true
- * Creates a bitmap decoder
+ * Creates a bmp decoder
* Reads enough of the stream to determine the image format
*
*/
SkCodec* SkBmpCodec::NewFromStream(SkStream* stream) {
+ return SkBmpCodec::NewFromStream(stream, false);
+}
+
+/*
+ *
+ * Creates a bmp decoder for a bmp embedded in ico
+ * Reads enough of the stream to determine the image format
+ *
+ */
+SkCodec* SkBmpCodec::NewFromIco(SkStream* stream) {
+ return SkBmpCodec::NewFromStream(stream, true);
+}
+
+/*
+ *
+ * Creates a bmp decoder
+ * Reads enough of the stream to determine the image format
+ *
+ */
+SkCodec* SkBmpCodec::NewFromStream(SkStream* stream, bool isIco) {
// Header size constants
static const uint32_t kBmpHeaderBytes = 14;
static const uint32_t kBmpHeaderBytesPlusFour = kBmpHeaderBytes + 4;
@@ -106,37 +123,68 @@
static const uint32_t kBmpInfoV5Bytes = 124;
static const uint32_t kBmpMaskBytes = 12;
- // Read the first header and the size of the second header
- SkAutoTDeleteArray<uint8_t> hBuffer(
- SkNEW_ARRAY(uint8_t, kBmpHeaderBytesPlusFour));
- if (stream->read(hBuffer.get(), kBmpHeaderBytesPlusFour) !=
- kBmpHeaderBytesPlusFour) {
- SkDebugf("Error: unable to read first bitmap header.\n");
- return NULL;
- }
-
// The total bytes in the bmp file
- // We only need to use this value for RLE decoding, so we will only check
- // that it is valid in the RLE case.
- const uint32_t totalBytes = get_int(hBuffer.get(), 2);
-
+ // We only need to use this value for RLE decoding, so we will only
+ // check that it is valid in the RLE case.
+ uint32_t totalBytes;
// The offset from the start of the file where the pixel data begins
- const uint32_t offset = get_int(hBuffer.get(), 10);
- if (offset < kBmpHeaderBytes + kBmpOS2V1Bytes) {
- SkDebugf("Error: invalid starting location for pixel data\n");
- return NULL;
+ uint32_t offset;
+ // The size of the second (info) header in bytes
+ uint32_t infoBytes;
+
+ // Bmps embedded in Icos skip the first Bmp header
+ if (!isIco) {
+ // Read the first header and the size of the second header
+ SkAutoTDeleteArray<uint8_t> hBuffer(
+ SkNEW_ARRAY(uint8_t, kBmpHeaderBytesPlusFour));
+ if (stream->read(hBuffer.get(), kBmpHeaderBytesPlusFour) !=
+ kBmpHeaderBytesPlusFour) {
+ SkDebugf("Error: unable to read first bitmap header.\n");
+ return NULL;
+ }
+
+ totalBytes = get_int(hBuffer.get(), 2);
+ offset = get_int(hBuffer.get(), 10);
+ if (offset < kBmpHeaderBytes + kBmpOS2V1Bytes) {
+ SkDebugf("Error: invalid starting location for pixel data\n");
+ return NULL;
+ }
+
+ // The size of the second (info) header in bytes
+ // The size is the first field of the second header, so we have already
+ // read the first four infoBytes.
+ infoBytes = get_int(hBuffer.get(), 14);
+ if (infoBytes < kBmpOS2V1Bytes) {
+ SkDebugf("Error: invalid second header size.\n");
+ return NULL;
+ }
+ } else {
+ // This value is only used by RLE compression. Bmp in Ico files do not
+ // use RLE. If the compression field is incorrectly signaled as RLE,
+ // we will catch this and signal an error below.
+ totalBytes = 0;
+
+ // Bmps in Ico cannot specify an offset. We will always assume that
+ // pixel data begins immediately after the color table. This value
+ // will be corrected below.
+ offset = 0;
+
+ // Read the size of the second header
+ SkAutoTDeleteArray<uint8_t> hBuffer(
+ SkNEW_ARRAY(uint8_t, 4));
+ if (stream->read(hBuffer.get(), 4) != 4) {
+ SkDebugf("Error: unable to read size of second bitmap header.\n");
+ return NULL;
+ }
+ infoBytes = get_int(hBuffer.get(), 0);
+ if (infoBytes < kBmpOS2V1Bytes) {
+ SkDebugf("Error: invalid second header size.\n");
+ return NULL;
+ }
}
- // The size of the second (info) header in bytes
- // The size is the first field of the second header, so we have already
- // read the first four infoBytes.
- const uint32_t infoBytes = get_int(hBuffer.get(), 14);
- if (infoBytes < kBmpOS2V1Bytes) {
- SkDebugf("Error: invalid second header size.\n");
- return NULL;
- }
+ // We already read the first four bytes of the info header to get the size
const uint32_t infoBytesRemaining = infoBytes - 4;
- hBuffer.free();
// Read the second header
SkAutoTDeleteArray<uint8_t> iBuffer(
@@ -243,6 +291,11 @@
height = -height;
rowOrder = kTopDown_RowOrder;
}
+ // The height field for bmp in ico is double the actual height because they
+ // contain an XOR mask followed by an AND mask
+ if (isIco) {
+ height /= 2;
+ }
static const int kBmpMaxDim = 1 << 16;
if (width < 0 || width >= kBmpMaxDim || height >= kBmpMaxDim) {
// TODO: Decide if we want to support really large bmps.
@@ -344,16 +397,19 @@
// Most versions of bmps should be rendered as opaque. Either they do
// not have an alpha channel, or they expect the alpha channel to be
- // ignored. V4+ bmp files introduce an alpha mask and allow the creator
+ // ignored. V3+ bmp files introduce an alpha mask and allow the creator
// of the image to use the alpha channels. However, many of these images
- // leave the alpha channel blank and expect to be rendered as opaque. For
- // this reason, we set the alpha type to kUnknown for V4+ bmps and figure
- // out the alpha type during the decode.
+ // leave the alpha channel blank and expect to be rendered as opaque. This
+ // is the case for almost all V3 images, so we render these as opaque. For
+ // V4+, we will use the alpha channel, and fix the image later if it turns
+ // out to be fully transparent.
+ // As an exception, V3 bmp-in-ico may use an alpha mask.
SkAlphaType alphaType = kOpaque_SkAlphaType;
- if (kInfoV4_BitmapHeaderType == headerType ||
+ if ((kInfoV3_BitmapHeaderType == headerType && isIco) ||
+ kInfoV4_BitmapHeaderType == headerType ||
kInfoV5_BitmapHeaderType == headerType) {
// Header types are matched based on size. If the header is
- // V4+, we are guaranteed to be able to read at least this size.
+ // V3+, we are guaranteed to be able to read at least this size.
SkASSERT(infoBytesRemaining > 52);
inputMasks.alpha = get_int(iBuffer.get(), 48);
if (inputMasks.alpha != 0) {
@@ -362,6 +418,11 @@
}
iBuffer.free();
+ // Additionally, 32 bit bmp-in-icos use the alpha channel
+ if (isIco && 32 == bitsPerPixel) {
+ alphaType = kUnpremul_SkAlphaType;
+ }
+
// Check for valid bits per pixel input
switch (bitsPerPixel) {
// In addition to more standard pixel compression formats, bmp supports
@@ -406,7 +467,7 @@
// Calculate the number of bytes read so far
const uint32_t bytesRead = kBmpHeaderBytes + infoBytes + maskBytes;
- if (offset < bytesRead) {
+ if (!isIco && offset < bytesRead) {
SkDebugf("Error: pixel data offset less than header size.\n");
return NULL;
}
@@ -420,7 +481,7 @@
return SkNEW_ARGS(SkBmpCodec, (imageInfo, stream, bitsPerPixel,
inputFormat, masks.detach(), numColors,
bytesPerColor, offset - bytesRead,
- rowOrder, RLEBytes));
+ rowOrder, RLEBytes, isIco));
}
/*
@@ -433,7 +494,7 @@
uint16_t bitsPerPixel, BitmapInputFormat inputFormat,
SkMasks* masks, uint32_t numColors,
uint32_t bytesPerColor, uint32_t offset,
- RowOrder rowOrder, size_t RLEBytes)
+ RowOrder rowOrder, size_t RLEBytes, bool isIco)
: INHERITED(info, stream)
, fBitsPerPixel(bitsPerPixel)
, fInputFormat(inputFormat)
@@ -444,6 +505,8 @@
, fOffset(offset)
, fRowOrder(rowOrder)
, fRLEBytes(RLEBytes)
+ , fIsIco(isIco)
+
{}
/*
@@ -459,11 +522,11 @@
if (!this->rewindIfNeeded()) {
return kCouldNotRewind;
}
- if (dstInfo.dimensions() != this->getOriginalInfo().dimensions()) {
+ if (dstInfo.dimensions() != this->getInfo().dimensions()) {
SkDebugf("Error: scaling not supported.\n");
return kInvalidScale;
}
- if (!conversion_possible(dstInfo, this->getOriginalInfo())) {
+ if (!conversion_possible(dstInfo, this->getInfo())) {
SkDebugf("Error: cannot convert input type to output type.\n");
return kInvalidConversion;
}
@@ -553,26 +616,29 @@
}
}
- // Check that we have not read past the pixel array offset
- if(fOffset < colorBytes) {
- // This may occur on OS 2.1 and other old versions where the color
- // table defaults to max size, and the bmp tries to use a smaller color
- // table. This is invalid, and our decision is to indicate an error,
- // rather than try to guess the intended size of the color table.
- SkDebugf("Error: pixel data offset less than color table size.\n");
- return false;
- }
+ // Bmp-in-Ico files do not use an offset to indicate where the pixel data
+ // begins. Pixel data always begins immediately after the color table.
+ if (!fIsIco) {
+ // Check that we have not read past the pixel array offset
+ if(fOffset < colorBytes) {
+ // This may occur on OS 2.1 and other old versions where the color
+ // table defaults to max size, and the bmp tries to use a smaller
+ // color table. This is invalid, and our decision is to indicate
+ // an error, rather than try to guess the intended size of the
+ // color table.
+ SkDebugf("Error: pixel data offset less than color table size.\n");
+ return false;
+ }
- // After reading the color table, skip to the start of the pixel array
- if (stream()->skip(fOffset - colorBytes) != fOffset - colorBytes) {
- SkDebugf("Error: unable to skip to image data.\n");
- return false;
+ // After reading the color table, skip to the start of the pixel array
+ if (stream()->skip(fOffset - colorBytes) != fOffset - colorBytes) {
+ SkDebugf("Error: unable to skip to image data.\n");
+ return false;
+ }
}
// Set the color table and return true on success
- if (maxColors > 0) {
- fColorTable.reset(SkNEW_ARGS(SkColorTable, (colorTable, maxColors)));
- }
+ fColorTable.reset(SkNEW_ARGS(SkColorTable, (colorTable, maxColors)));
return true;
}
@@ -989,7 +1055,6 @@
// SkSwizzler does not support. Firstly, all bmp images that contain
// alpha are masked by the alpha mask. Secondly, many fully transparent
// bmp images are intended to be opaque. Here, we make those corrections.
- // Modifying alpha is safe because colors are stored unpremultiplied.
/*
SkPMColor* dstRow = (SkPMColor*) dst;
if (SkSwizzler::kBGRA == config) {
@@ -1006,6 +1071,41 @@
}
*/
+ // Finally, apply the AND mask for bmp-in-ico images
+ if (fIsIco) {
+ // The AND mask is always 1 bit per pixel
+ const size_t rowBytes = SkAlign4(compute_row_bytes(width, 1));
+
+ SkPMColor* dstPtr = (SkPMColor*) dst;
+ for (int y = 0; y < height; y++) {
+ // The srcBuffer will at least be large enough
+ if (stream()->read(srcBuffer.get(), rowBytes) != rowBytes) {
+ SkDebugf("Warning: incomplete AND mask for bmp-in-ico.\n");
+ return kIncompleteInput;
+ }
+
+ int row;
+ if (kBottomUp_RowOrder == fRowOrder) {
+ row = height - y - 1;
+ } else {
+ row = y;
+ }
+
+ SkPMColor* dstRow =
+ SkTAddOffset<SkPMColor>(dstPtr, row * dstRowBytes);
+
+ for (int x = 0; x < width; x++) {
+ int quotient;
+ int modulus;
+ SkTDivMod(x, 8, "ient, &modulus);
+ uint32_t shift = 7 - modulus;
+ uint32_t alphaBit =
+ (srcBuffer.get()[quotient] >> shift) & 0x1;
+ dstRow[x] &= alphaBit - 1;
+ }
+ }
+ }
+
// Finished decoding the entire image
return kSuccess;
}