Files
squoosh/codecs/jxl/dec/jxl_dec.cpp
2020-10-30 12:30:29 +00:00

83 lines
3.2 KiB
C++

#include <emscripten/bind.h>
#include <emscripten/val.h>
#include <jxl/decode.h>
#include "lib/jxl/color_encoding_internal.h"
#include "skcms.h"
using namespace emscripten;
thread_local const val Uint8ClampedArray = val::global("Uint8ClampedArray");
thread_local const val ImageData = val::global("ImageData");
#define EXPECT_EQ(a, b) \
if ((a) != (b)) { \
JxlDecoderDestroy(dec); \
return val::null(); \
}
val decode(std::string data) {
JxlDecoder* dec = JxlDecoderCreate(nullptr);
EXPECT_EQ(JXL_DEC_SUCCESS,
JxlDecoderSubscribeEvents(
dec, JXL_DEC_BASIC_INFO | JXL_DEC_COLOR_ENCODING | JXL_DEC_FULL_IMAGE));
auto next_in = (const uint8_t*)data.c_str();
auto avail_in = data.size();
EXPECT_EQ(JXL_DEC_BASIC_INFO, JxlDecoderProcessInput(dec, &next_in, &avail_in));
size_t buffer_size;
const JxlPixelFormat format = {4, JXL_LITTLE_ENDIAN, JXL_TYPE_FLOAT};
EXPECT_EQ(JXL_DEC_SUCCESS, JxlDecoderImageOutBufferSize(dec, &format, &buffer_size));
JxlBasicInfo info;
EXPECT_EQ(JXL_DEC_SUCCESS, JxlDecoderGetBasicInfo(dec, &info));
EXPECT_EQ(JXL_DEC_COLOR_ENCODING, JxlDecoderProcessInput(dec, &next_in, &avail_in));
size_t icc_size;
EXPECT_EQ(JXL_DEC_SUCCESS,
JxlDecoderGetICCProfileSize(dec, JXL_COLOR_PROFILE_TARGET_DATA, &icc_size));
std::vector<uint8_t> icc_profile(icc_size);
EXPECT_EQ(JXL_DEC_SUCCESS,
JxlDecoderGetColorAsICCProfile(dec, JXL_COLOR_PROFILE_TARGET_DATA, icc_profile.data(),
icc_profile.size()));
std::unique_ptr<float[]> float_pixels(new float[(buffer_size + 3) / 4]);
EXPECT_EQ(JXL_DEC_SUCCESS,
JxlDecoderSetImageOutBuffer(
dec, &format, reinterpret_cast<uint8_t*>(float_pixels.get()), buffer_size));
EXPECT_EQ(JXL_DEC_FULL_IMAGE, JxlDecoderProcessInput(dec, &next_in, &avail_in));
JxlDecoderDestroy(dec);
#undef EXPECT_EQ
#define EXPECT_TRUE(a) \
if (!(a)) { \
return val::null(); \
}
std::unique_ptr<uint8_t[]> pixels(new uint8_t[info.xsize * info.ysize * 4]);
// Convert to sRGB.
skcms_ICCProfile jxl_profile;
// If the image is encoded in its original color space, the decoded data will be in the color
// space defined by the decoded ICC profile. Otherwise, it is in Linear sRGB. TODO: the decoded
// color profile should also be Linear sRGB if !uses_original_profile.
if (info.uses_original_profile) {
EXPECT_TRUE(skcms_Parse(icc_profile.data(), icc_profile.size(), &jxl_profile));
} else {
auto s = jxl::ColorEncoding::LinearSRGB(/*gray=*/false);
EXPECT_TRUE(s.CreateICC());
EXPECT_TRUE(skcms_Parse(s.ICC().data(), s.ICC().size(), &jxl_profile));
}
EXPECT_TRUE(skcms_Transform(
float_pixels.get(), skcms_PixelFormat_RGBA_ffff,
info.alpha_premultiplied ? skcms_AlphaFormat_PremulAsEncoded : skcms_AlphaFormat_Unpremul,
&jxl_profile, pixels.get(), skcms_PixelFormat_RGBA_8888, skcms_AlphaFormat_Unpremul,
skcms_sRGB_profile(), info.xsize * info.ysize));
return ImageData.new_(
Uint8ClampedArray.new_(typed_memory_view(info.xsize * info.ysize * 4, pixels.get())),
info.xsize, info.ysize);
}
EMSCRIPTEN_BINDINGS(my_module) {
function("decode", &decode);
}