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author Matt Sarett <msarett@google.com> 2015-12-14 13:08:33 -0500
committer Matt Sarett <msarett@google.com> 2016-01-07 18:17:33 +0000
commit3b1b68d6c764a4f60d034e57a94879b7df65fd43 (patch)
tree6f478d0afc03ca5aae4928eda211a9a4baa81e3a
parentcc5061f73e8acde4e91b34187f41bdd131cf85ec (diff)
Allow ninepatches to be encoded using non-RGBA modes
The original intention for forcing ninepatches to be encoded as RGBA (with alpha) was to avoid the possibility of the decoder producing 565 output. 565 output is bad for ninepatches because dithering tiny images that we intend to scale later leads to bad results. I would argue that, since the new BitmapFactory does not dither, we might now be ok to allow 565 decodes for ninepatches. However, we will maintain the old behavior by disabling 565 decodes for ninepatch. There are two changes to PNG encodings: (1) Allows ninepatch images to be encoded in any mode. Forcing them to RGBA makes things awkward for the decoder. Currently, BitmapFactory's png decoder checks every pixel for alpha. That way, RGBA images that are actually opaque can be marked as opaque, in order to optimize drawing. We want to remove this complexity from the decoder. (2) Make sure ninepatch chunks are stored in the png header. That way we know immediately that the png is a ninepatch, and can refuse to decode to 565 (if we feel this is best). Change-Id: I724f5dbefb1be7b412f9b362dff83cbc0603f0bf
-rw-r--r--core/jni/android/graphics/BitmapFactory.cpp19
-rw-r--r--tools/aapt/Images.cpp16
2 files changed, 11 insertions, 24 deletions
diff --git a/core/jni/android/graphics/BitmapFactory.cpp b/core/jni/android/graphics/BitmapFactory.cpp
index d8ec22a0f697..92f781268732 100644
--- a/core/jni/android/graphics/BitmapFactory.cpp
+++ b/core/jni/android/graphics/BitmapFactory.cpp
@@ -260,6 +260,15 @@ static jobject doDecode(JNIEnv* env, SkStreamRewindable* stream, jobject padding
return nullObjectReturn("SkAndroidCodec::NewFromStream returned null");
}
+ // Do not allow ninepatch decodes to 565. In the past, decodes to 565
+ // would dither, and we do not want to pre-dither ninepatches, since we
+ // know that they will be stretched. We no longer dither 565 decodes,
+ // but we continue to prevent ninepatches from decoding to 565, in order
+ // to maintain the old behavior.
+ if (peeker.mPatch && kRGB_565_SkColorType == prefColorType) {
+ prefColorType = kN32_SkColorType;
+ }
+
// Determine the output size and return if the client only wants the size.
SkISize size = codec->getSampledDimensions(sampleSize);
if (options != NULL) {
@@ -369,15 +378,7 @@ static jobject doDecode(JNIEnv* env, SkStreamRewindable* stream, jobject padding
case SkCodec::kIncompleteInput:
break;
default:
- return nullObjectReturn("codec->getAndoridPixels() failed.");
- }
-
- // Some images may initially report that they have alpha due to the format
- // of the encoded data, but then never use any colors which have alpha
- // less than 100%. Here we check if the image really had alpha, and
- // mark it as opaque if it is actually opaque.
- if (kOpaque_SkAlphaType != alphaType && !codec->reallyHasAlpha()) {
- decodingBitmap.setAlphaType(kOpaque_SkAlphaType);
+ return nullObjectReturn("codec->getAndroidPixels() failed.");
}
int scaledWidth = size.width();
diff --git a/tools/aapt/Images.cpp b/tools/aapt/Images.cpp
index e4738f5eda7d..5ad337949bee 100644
--- a/tools/aapt/Images.cpp
+++ b/tools/aapt/Images.cpp
@@ -1095,13 +1095,6 @@ static void write_png(const char* imageName,
analyze_image(imageName, imageInfo, grayscaleTolerance, rgbPalette, alphaPalette,
&paletteEntries, &hasTransparency, &color_type, outRows);
- // If the image is a 9-patch, we need to preserve it as a ARGB file to make
- // sure the pixels will not be pre-dithered/clamped until we decide they are
- if (imageInfo.is9Patch && (color_type == PNG_COLOR_TYPE_RGB ||
- color_type == PNG_COLOR_TYPE_GRAY || color_type == PNG_COLOR_TYPE_PALETTE)) {
- color_type = PNG_COLOR_TYPE_RGB_ALPHA;
- }
-
if (kIsDebug) {
switch (color_type) {
case PNG_COLOR_TYPE_PALETTE:
@@ -1180,18 +1173,11 @@ static void write_png(const char* imageName,
}
for (int i = 0; i < chunk_count; i++) {
- unknowns[i].location = PNG_HAVE_PLTE;
+ unknowns[i].location = PNG_HAVE_IHDR;
}
png_set_keep_unknown_chunks(write_ptr, PNG_HANDLE_CHUNK_ALWAYS,
chunk_names, chunk_count);
png_set_unknown_chunks(write_ptr, write_info, unknowns, chunk_count);
-#if PNG_LIBPNG_VER < 10600
- /* Deal with unknown chunk location bug in 1.5.x and earlier */
- png_set_unknown_chunk_location(write_ptr, write_info, 0, PNG_HAVE_PLTE);
- if (imageInfo.haveLayoutBounds) {
- png_set_unknown_chunk_location(write_ptr, write_info, 1, PNG_HAVE_PLTE);
- }
-#endif
}