Add support for writing ICC profiles in png encodes

BUG=skia:

Change-Id: I99eb2f157f249ed09d724461ec4a1e31db70816a
Reviewed-on: https://skia-review.googlesource.com/9782
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Matt Sarett <msarett@google.com>

4 files changed, 23 insertions, 7 deletions

diff --git a/src/images/SkImageEncoderPriv.h b/src/images/SkImageEncoderPriv.h
index 5f7560d2de..69d45fbf8c 100644
--- a/src/images/SkImageEncoderPriv.h
+++ b/src/images/SkImageEncoderPriv.h
@@ -11,15 +11,15 @@
 #include "SkImageEncoder.h"
 
 struct SkEncodeOptions {
-    enum class PremulBehavior {
+    enum class ColorBehavior {
          // Convert to a linear space before premultiplying or unpremultiplying.
-        kGammaCorrect,
+        kCorrect,
 
         // Ignore the transfer function when premultiplying or unpremultiplying.
         kLegacy,
     };
 
-    PremulBehavior fPremulBehavior = PremulBehavior::kLegacy;
+    ColorBehavior fColorBehavior = ColorBehavior::kLegacy;
 };
 
 #ifdef SK_HAS_JPEG_LIBRARY
diff --git a/src/images/SkJPEGImageEncoder.cpp b/src/images/SkJPEGImageEncoder.cpp
index c37aa4687e..1f8f0d6394 100644
--- a/src/images/SkJPEGImageEncoder.cpp
+++ b/src/images/SkJPEGImageEncoder.cpp
@@ -86,10 +86,10 @@ bool SkEncodeImageAsJPEG(SkWStream* stream, const SkPixmap& pixmap, const SkEnco
             pixmap.colorSpace()->gammaIsLinear());
 
     SkPixmap src = pixmap;
-    if (SkEncodeOptions::PremulBehavior::kLegacy == opts.fPremulBehavior) {
+    if (SkEncodeOptions::ColorBehavior::kLegacy == opts.fColorBehavior) {
         src.setColorSpace(nullptr);
     } else {
-        // kGammaCorrect behavior requires a color space.  It's not actually critical in the
+        // kCorrect behavior requires a color space.  It's not actually critical in the
         // jpeg case (since jpegs are opaque), but Skia color correct behavior generally
         // requires pixels to be tagged with color spaces.
         if (!src.colorSpace()) {
diff --git a/src/images/SkPNGImageEncoder.cpp b/src/images/SkPNGImageEncoder.cpp
index e4a60f917a..69a7b0780a 100644
--- a/src/images/SkPNGImageEncoder.cpp
+++ b/src/images/SkPNGImageEncoder.cpp
@@ -12,6 +12,7 @@
 #include "SkColor.h"
 #include "SkColorPriv.h"
 #include "SkDither.h"
+#include "SkICC.h"
 #include "SkMath.h"
 #include "SkStream.h"
 #include "SkTemplates.h"
@@ -168,7 +169,7 @@ bool SkEncodeImageAsPNG(SkWStream* stream, const SkPixmap& src, const SkEncodeOp
              src.colorSpace()->gammaIsLinear());
 
     SkPixmap pixmap = src;
-    if (SkEncodeOptions::PremulBehavior::kLegacy == opts.fPremulBehavior) {
+    if (SkEncodeOptions::ColorBehavior::kLegacy == opts.fColorBehavior) {
         pixmap.setColorSpace(nullptr);
     } else {
         if (!pixmap.colorSpace()) {
@@ -334,6 +335,21 @@ static bool do_encode(SkWStream* stream, const SkPixmap& pixmap,
         }
     }
 
+    if (pixmap.colorSpace()) {
+        SkColorSpaceTransferFn fn;
+        SkMatrix44 toXYZD50(SkMatrix44::kUninitialized_Constructor);
+        if (pixmap.colorSpace()->isSRGB()) {
+            png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_PERCEPTUAL);
+        } else if (pixmap.colorSpace()->isNumericalTransferFn(&fn) &&
+                   pixmap.colorSpace()->toXYZD50(&toXYZD50))
+        {
+            sk_sp<SkData> icc = SkICC::WriteToICC(fn, toXYZD50);
+            png_set_iCCP(png_ptr, info_ptr, "Skia", 0, icc->bytes(), icc->size());
+        }
+
+        // TODO: Should we support writing ICC profiles for additional color spaces?
+    }
+
     png_set_sBIT(png_ptr, info_ptr, &sig_bit);
     png_write_info(png_ptr, info_ptr);
     int pngBytesPerPixel = num_components(pngColorType) * (bitDepth / 8);
diff --git a/src/images/SkWEBPImageEncoder.cpp b/src/images/SkWEBPImageEncoder.cpp
index 5928f97861..8797ff5925 100644
--- a/src/images/SkWEBPImageEncoder.cpp
+++ b/src/images/SkWEBPImageEncoder.cpp
@@ -126,7 +126,7 @@ static bool do_encode(SkWStream* stream, const SkPixmap& srcPixmap, const SkEnco
             srcPixmap.colorSpace()->gammaIsLinear());
 
     SkPixmap pixmap = srcPixmap;
-    if (SkEncodeOptions::PremulBehavior::kLegacy == opts.fPremulBehavior) {
+    if (SkEncodeOptions::ColorBehavior::kLegacy == opts.fColorBehavior) {
         pixmap.setColorSpace(nullptr);
     } else {
         if (!pixmap.colorSpace()) {