Merge "Add support for CMYK jpeg images." into jb-mr2-dev
diff --git a/src/images/SkImageDecoder_libjpeg.cpp b/src/images/SkImageDecoder_libjpeg.cpp
index 2f72c2d..81344b3 100644
--- a/src/images/SkImageDecoder_libjpeg.cpp
+++ b/src/images/SkImageDecoder_libjpeg.cpp
@@ -189,6 +189,29 @@
return false; // must always return false
}
+// Convert a scanline of CMYK samples to RGBX in place. Note that this
+// method moves the "scanline" pointer in its processing
+static void convert_CMYK_to_RGB(uint8_t* scanline, unsigned int width) {
+ // At this point we've received CMYK pixels from libjpeg. We
+ // perform a crude conversion to RGB (based on the formulae
+ // from easyrgb.com):
+ // CMYK -> CMY
+ // C = ( C * (1 - K) + K ) // for each CMY component
+ // CMY -> RGB
+ // R = ( 1 - C ) * 255 // for each RGB component
+ // Unfortunately we are seeing inverted CMYK so all the original terms
+ // are 1-. This yields:
+ // CMYK -> CMY
+ // C = ( (1-C) * (1 - (1-K) + (1-K) ) -> C = 1 - C*K
+ // The conversion from CMY->RGB remains the same
+ for (unsigned int x = 0; x < width; ++x, scanline += 4) {
+ scanline[0] = SkMulDiv255Round(scanline[0], scanline[3]);
+ scanline[1] = SkMulDiv255Round(scanline[1], scanline[3]);
+ scanline[2] = SkMulDiv255Round(scanline[2], scanline[3]);
+ scanline[3] = 255;
+ }
+}
+
bool SkJPEGImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) {
#ifdef TIME_DECODE
AutoTimeMillis atm("JPEG Decode");
@@ -249,7 +272,14 @@
cinfo.do_block_smoothing = 0;
/* default format is RGB */
- cinfo.out_color_space = JCS_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 {
+ cinfo.out_color_space = JCS_RGB;
+ }
SkBitmap::Config config = this->getPrefConfig(k32Bit_SrcDepth, false);
// only these make sense for jpegs
@@ -261,9 +291,9 @@
#ifdef ANDROID_RGB
cinfo.dither_mode = JDITHER_NONE;
- if (config == SkBitmap::kARGB_8888_Config) {
+ if (SkBitmap::kARGB_8888_Config == config && JCS_CMYK != cinfo.out_color_space) {
cinfo.out_color_space = JCS_RGBA_8888;
- } else if (config == SkBitmap::kRGB_565_Config) {
+ } else if (SkBitmap::kRGB_565_Config == config && JCS_CMYK != cinfo.out_color_space) {
cinfo.out_color_space = JCS_RGB_565;
if (this->getDitherImage()) {
cinfo.dither_mode = JDITHER_ORDERED;
@@ -368,7 +398,10 @@
// check for supported formats
SkScaledBitmapSampler::SrcConfig sc;
- if (3 == cinfo.out_color_components && JCS_RGB == cinfo.out_color_space) {
+ if (JCS_CMYK == cinfo.out_color_space) {
+ // In this case we will manually convert the CMYK values to RGB
+ sc = SkScaledBitmapSampler::kRGBX;
+ } else if (3 == cinfo.out_color_components && JCS_RGB == cinfo.out_color_space) {
sc = SkScaledBitmapSampler::kRGB;
#ifdef ANDROID_RGB
} else if (JCS_RGBA_8888 == cinfo.out_color_space) {
@@ -416,6 +449,7 @@
return return_false(cinfo, *bm, "sampler.begin");
}
+ // The CMYK work-around relies on 4 components per pixel here
uint8_t* srcRow = (uint8_t*)srcStorage.reset(cinfo.output_width * 4);
// Possibly skip initial rows [sampler.srcY0]
@@ -433,7 +467,11 @@
if (this->shouldCancelDecode()) {
return return_false(cinfo, *bm, "shouldCancelDecode");
}
-
+
+ if (JCS_CMYK == cinfo.out_color_space) {
+ convert_CMYK_to_RGB(srcRow, cinfo.output_width);
+ }
+
sampler.next(srcRow);
if (bm->height() - 1 == y) {
// we're done
