diff options
author | Matt Sarett <msarett@google.com> | 2017-05-08 12:11:44 -0400 |
---|---|---|
committer | Skia Commit-Bot <skia-commit-bot@chromium.org> | 2017-05-08 16:43:44 +0000 |
commit | be4c9b0a8b9a508cf0de66c0fa401fc1217a32db (patch) | |
tree | b7056689ef3dd73e9906bdc8b461238efad5cc06 | |
parent | 9bbed5ecd0b9bd78cd4e73c8a0658461740bff50 (diff) |
Add filtering and zlib-level options to SkPngEncoder
Bug: skia:6409
Bug: 713862
Change-Id: If287e2bcad5af990fac11e9091305f45ec903dbf
Reviewed-on: https://skia-review.googlesource.com/15647
Commit-Queue: Matt Sarett <msarett@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
Reviewed-by: Mike Klein <mtklein@chromium.org>
-rw-r--r-- | src/images/SkPngEncoder.cpp | 20 | ||||
-rw-r--r-- | src/images/SkPngEncoder.h | 41 | ||||
-rw-r--r-- | tests/EncodeTest.cpp | 61 |
3 files changed, 116 insertions, 6 deletions
diff --git a/src/images/SkPngEncoder.cpp b/src/images/SkPngEncoder.cpp index 38c7d888c6..6c14f50930 100644 --- a/src/images/SkPngEncoder.cpp +++ b/src/images/SkPngEncoder.cpp @@ -17,6 +17,13 @@ #include "png.h" +static_assert(PNG_FILTER_NONE == (int)SkPngEncoder::FilterFlag::kNone, "Skia libpng filter err."); +static_assert(PNG_FILTER_SUB == (int)SkPngEncoder::FilterFlag::kSub, "Skia libpng filter err."); +static_assert(PNG_FILTER_UP == (int)SkPngEncoder::FilterFlag::kUp, "Skia libpng filter err."); +static_assert(PNG_FILTER_AVG == (int)SkPngEncoder::FilterFlag::kAvg, "Skia libpng filter err."); +static_assert(PNG_FILTER_PAETH == (int)SkPngEncoder::FilterFlag::kPaeth, "Skia libpng filter err."); +static_assert(PNG_ALL_FILTERS == (int)SkPngEncoder::FilterFlag::kAll, "Skia libpng filter err."); + static constexpr bool kSuppressPngEncodeWarnings = true; static void sk_error_fn(png_structp png_ptr, png_const_charp msg) { @@ -43,7 +50,7 @@ public: */ static std::unique_ptr<SkPngEncoderMgr> Make(SkWStream* stream); - bool setHeader(const SkImageInfo& srcInfo); + bool setHeader(const SkImageInfo& srcInfo, const SkPngEncoder::Options& options); bool setPalette(const SkImageInfo& srcInfo, SkColorTable* colorTable, SkTransferFunctionBehavior); bool setColorSpace(SkColorSpace* colorSpace); @@ -89,7 +96,7 @@ std::unique_ptr<SkPngEncoderMgr> SkPngEncoderMgr::Make(SkWStream* stream) { return std::unique_ptr<SkPngEncoderMgr>(new SkPngEncoderMgr(pngPtr, infoPtr)); } -bool SkPngEncoderMgr::setHeader(const SkImageInfo& srcInfo) { +bool SkPngEncoderMgr::setHeader(const SkImageInfo& srcInfo, const SkPngEncoder::Options& options) { if (setjmp(png_jmpbuf(fPngPtr))) { return false; } @@ -161,6 +168,13 @@ bool SkPngEncoderMgr::setHeader(const SkImageInfo& srcInfo) { PNG_FILTER_TYPE_BASE); png_set_sBIT(fPngPtr, fInfoPtr, &sigBit); + int filters = (int)options.fFilterFlags & (int)SkPngEncoder::FilterFlag::kAll; + SkASSERT(filters == (int)options.fFilterFlags); + png_set_filter(fPngPtr, PNG_FILTER_TYPE_BASE, filters); + + int zlibLevel = SkTMin(SkTMax(0, options.fZLibLevel), 9); + SkASSERT(zlibLevel == options.fZLibLevel); + png_set_compression_level(fPngPtr, zlibLevel); return true; } @@ -379,7 +393,7 @@ std::unique_ptr<SkPngEncoder> SkPngEncoder::Make(SkWStream* dst, const SkPixmap& return nullptr; } - if (!encoderMgr->setHeader(src.info())) { + if (!encoderMgr->setHeader(src.info(), options)) { return nullptr; } diff --git a/src/images/SkPngEncoder.h b/src/images/SkPngEncoder.h index 813790e74b..0664c06149 100644 --- a/src/images/SkPngEncoder.h +++ b/src/images/SkPngEncoder.h @@ -16,11 +16,43 @@ class SkWStream; class SkPngEncoder : public SkEncoder { public: - // TODO (skbug.com/6409): - // Add options for png filters and zlib compression. + enum class FilterFlag : int { + kZero = 0x00, + kNone = 0x08, + kSub = 0x10, + kUp = 0x20, + kAvg = 0x40, + kPaeth = 0x80, + kAll = kNone | kSub | kUp | kAvg | kPaeth, + }; struct Options { /** + * Selects which filtering strategies to use. + * + * If a single filter is chosen, libpng will use that filter for every row. + * + * If multiple filters are chosen, libpng will use a heuristic to guess which filter + * will encode smallest, then apply that filter. This happens on a per row basis, + * different rows can use different filters. + * + * Using a single filter (or less filters) is typically faster. Trying all of the + * filters may help minimize the output file size. + * + * Our default value matches libpng's default. + */ + FilterFlag fFilterFlags = FilterFlag::kAll; + + /** + * Must be in [0, 9] where 9 corresponds to maximal compression. This value is passed + * directly to zlib. 0 is a special case to skip zlib entirely, creating dramatically + * larger pngs. + * + * Our default value matches libpng's default. + */ + int fZLibLevel = 6; + + /** * If the input is premultiplied, this controls the unpremultiplication behavior. * The encoder can convert to linear before unpremultiplying or ignore the transfer * function and unpremultiply the input as is. @@ -58,4 +90,9 @@ protected: typedef SkEncoder INHERITED; }; +static inline SkPngEncoder::FilterFlag operator|(SkPngEncoder::FilterFlag x, + SkPngEncoder::FilterFlag y) { + return (SkPngEncoder::FilterFlag)((int)x | (int)y); +} + #endif diff --git a/tests/EncodeTest.cpp b/tests/EncodeTest.cpp index 7be0f6cdbf..45a0ff83aa 100644 --- a/tests/EncodeTest.cpp +++ b/tests/EncodeTest.cpp @@ -10,6 +10,7 @@ #include "SkBitmap.h" #include "SkEncodedImageFormat.h" +#include "SkImage.h" #include "SkJpegEncoder.h" #include "SkPngEncoder.h" #include "SkStream.h" @@ -80,7 +81,65 @@ static void test_encode(skiatest::Reporter* r, SkEncodedImageFormat format) { REPORTER_ASSERT(r, data0->equals(data3.get())); } -DEF_TEST(Encoder, r) { +DEF_TEST(Encode, r) { test_encode(r, SkEncodedImageFormat::kJPEG); test_encode(r, SkEncodedImageFormat::kPNG); } + +static inline bool equals(const SkBitmap& a, const SkBitmap& b) { + if (a.info() != b.info()) { + return false; + } + + SkASSERT(kN32_SkColorType == a.colorType()); + for (int y = 0; y < a.height(); y++) { + for (int x = 0; x < a.width(); x++) { + if (*a.getAddr32(x, y) != *b.getAddr32(x, y)) { + return false; + } + } + } + + return true; +} + +DEF_TEST(Encode_PngOptions, r) { + SkBitmap bitmap; + bool success = GetResourceAsBitmap("mandrill_128.png", &bitmap); + if (!success) { + return; + } + + SkPixmap src; + success = bitmap.peekPixels(&src); + REPORTER_ASSERT(r, success); + if (!success) { + return; + } + + SkDynamicMemoryWStream dst0, dst1, dst2; + SkPngEncoder::Options options; + success = SkPngEncoder::Encode(&dst0, src, options); + REPORTER_ASSERT(r, success); + + options.fFilterFlags = SkPngEncoder::FilterFlag::kUp; + success = SkPngEncoder::Encode(&dst1, src, options); + REPORTER_ASSERT(r, success); + + options.fZLibLevel = 3; + success = SkPngEncoder::Encode(&dst2, src, options); + REPORTER_ASSERT(r, success); + + sk_sp<SkData> data0 = dst0.detachAsData(); + sk_sp<SkData> data1 = dst1.detachAsData(); + sk_sp<SkData> data2 = dst2.detachAsData(); + REPORTER_ASSERT(r, data0->size() < data1->size()); + REPORTER_ASSERT(r, data1->size() < data2->size()); + + SkBitmap bm0, bm1, bm2; + SkImage::MakeFromEncoded(data0)->asLegacyBitmap(&bm0, SkImage::kRO_LegacyBitmapMode); + SkImage::MakeFromEncoded(data1)->asLegacyBitmap(&bm1, SkImage::kRO_LegacyBitmapMode); + SkImage::MakeFromEncoded(data2)->asLegacyBitmap(&bm2, SkImage::kRO_LegacyBitmapMode); + REPORTER_ASSERT(r, equals(bm0, bm1)); + REPORTER_ASSERT(r, equals(bm0, bm2)); +} |