Allow decoding JPEG into A8.
If the original image is grayscale, allow decoding into A8.
Change the size of PrefConfigTable to allow for 8bit gray, a new source config.
Add a new sampler to SkScaledBitmapSampler to 'convert' to A8.
FIXME: Should there be a dithered option for gray scale?
R=reed@google.com
Review URL: https://codereview.chromium.org/18083026
git-svn-id: http://skia.googlecode.com/svn/trunk@10157 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/images/SkImageDecoder_libjpeg.cpp b/src/images/SkImageDecoder_libjpeg.cpp
index bea1e98..e4d7ace 100644
--- a/src/images/SkImageDecoder_libjpeg.cpp
+++ b/src/images/SkImageDecoder_libjpeg.cpp
@@ -289,21 +289,33 @@
/* this gives another few percents */
cinfo.do_block_smoothing = 0;
+ SrcDepth srcDepth = k32Bit_SrcDepth;
/* default format is RGB */
if (cinfo.jpeg_color_space == JCS_CMYK) {
// libjpeg cannot convert from CMYK to RGB - here we set up
// so libjpeg will give us CMYK samples back and we will
// later manually convert them to RGB
cinfo.out_color_space = JCS_CMYK;
+ } else if (cinfo.jpeg_color_space == JCS_GRAYSCALE) {
+ cinfo.out_color_space = JCS_GRAYSCALE;
+ srcDepth = k8BitGray_SrcDepth;
} else {
cinfo.out_color_space = JCS_RGB;
}
- SkBitmap::Config config = this->getPrefConfig(k32Bit_SrcDepth, false);
+ SkBitmap::Config config = this->getPrefConfig(srcDepth, false);
// only these make sense for jpegs
- if (config != SkBitmap::kARGB_8888_Config &&
- config != SkBitmap::kARGB_4444_Config &&
- config != SkBitmap::kRGB_565_Config) {
+ if (SkBitmap::kA8_Config == config) {
+ if (cinfo.jpeg_color_space != JCS_GRAYSCALE) {
+ // Converting from a non grayscale image to A8 is
+ // not currently supported.
+ config = SkBitmap::kARGB_8888_Config;
+ // Change the output from jpeg back to RGB.
+ cinfo.out_color_space = JCS_RGB;
+ }
+ } else if (config != SkBitmap::kARGB_8888_Config &&
+ config != SkBitmap::kARGB_4444_Config &&
+ config != SkBitmap::kRGB_565_Config) {
config = SkBitmap::kARGB_8888_Config;
}