ladybird/Libraries/LibGfx/PNGLoader.cpp
Peter Nelson d22bb92764 LibGfx: Add support for animated images to ImageDecoder{Plugin}
Adds methods to determine whether an image is animated, how many times
the animation loops, the number of frames, and to get individual frames.

Implements stubs of these methods for PNGImageDecoderPlugin and
GIFImageDecoderPlugin.
2020-05-09 12:01:59 +02:00

860 lines
27 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <AK/ByteBuffer.h>
#include <AK/FileSystemPath.h>
#include <AK/MappedFile.h>
#include <AK/NetworkOrdered.h>
#include <LibCore/puff.h>
#include <LibGfx/PNGLoader.h>
#include <LibM/math.h>
#include <fcntl.h>
#include <serenity.h>
#include <stdio.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
namespace Gfx {
static const u8 png_header[8] = { 0x89, 'P', 'N', 'G', 13, 10, 26, 10 };
struct PNG_IHDR {
NetworkOrdered<u32> width;
NetworkOrdered<u32> height;
u8 bit_depth { 0 };
u8 color_type { 0 };
u8 compression_method { 0 };
u8 filter_method { 0 };
u8 interlace_method { 0 };
};
static_assert(sizeof(PNG_IHDR) == 13);
struct Scanline {
u8 filter { 0 };
ByteBuffer data {};
};
struct [[gnu::packed]] PaletteEntry
{
u8 r;
u8 g;
u8 b;
//u8 a;
};
struct [[gnu::packed]] Tuple
{
u8 gray;
u8 a;
};
struct [[gnu::packed]] Tuple16
{
u16 gray;
u16 a;
};
struct [[gnu::packed]] Triplet
{
u8 r;
u8 g;
u8 b;
};
struct [[gnu::packed]] Triplet16
{
u16 r;
u16 g;
u16 b;
};
struct [[gnu::packed]] Quad16
{
u16 r;
u16 g;
u16 b;
u16 a;
};
struct PNGLoadingContext {
enum State {
NotDecoded = 0,
Error,
HeaderDecoded,
SizeDecoded,
ChunksDecoded,
BitmapDecoded,
};
State state { State::NotDecoded };
const u8* data { nullptr };
size_t data_size { 0 };
int width { -1 };
int height { -1 };
u8 bit_depth { 0 };
u8 color_type { 0 };
u8 compression_method { 0 };
u8 filter_method { 0 };
u8 interlace_method { 0 };
u8 channels { 0 };
bool has_seen_zlib_header { false };
bool has_alpha() const { return color_type & 4 || palette_transparency_data.size() > 0; }
Vector<Scanline> scanlines;
RefPtr<Gfx::Bitmap> bitmap;
u8* decompression_buffer { nullptr };
int decompression_buffer_size { 0 };
Vector<u8> compressed_data;
Vector<PaletteEntry> palette_data;
Vector<u8> palette_transparency_data;
};
class Streamer {
public:
Streamer(const u8* data, int size)
: m_original_data(data)
, m_original_size(size)
, m_data_ptr(data)
, m_size_remaining(size)
{
}
template<typename T>
bool read(T& value)
{
if (m_size_remaining < (int)sizeof(T))
return false;
value = *((const NetworkOrdered<T>*)m_data_ptr);
m_data_ptr += sizeof(T);
m_size_remaining -= sizeof(T);
return true;
}
bool read_bytes(u8* buffer, int count)
{
if (m_size_remaining < count)
return false;
memcpy(buffer, m_data_ptr, count);
m_data_ptr += count;
m_size_remaining -= count;
return true;
}
bool wrap_bytes(ByteBuffer& buffer, int count)
{
if (m_size_remaining < count)
return false;
buffer = ByteBuffer::wrap(m_data_ptr, count);
m_data_ptr += count;
m_size_remaining -= count;
return true;
}
bool at_end() const { return !m_size_remaining; }
private:
const u8* m_original_data;
int m_original_size;
const u8* m_data_ptr;
int m_size_remaining;
};
static RefPtr<Gfx::Bitmap> load_png_impl(const u8*, int);
static bool process_chunk(Streamer&, PNGLoadingContext& context, bool decode_size_only);
RefPtr<Gfx::Bitmap> load_png(const StringView& path)
{
MappedFile mapped_file(path);
if (!mapped_file.is_valid())
return nullptr;
auto bitmap = load_png_impl((const u8*)mapped_file.data(), mapped_file.size());
if (bitmap)
bitmap->set_mmap_name(String::format("Gfx::Bitmap [%dx%d] - Decoded PNG: %s", bitmap->width(), bitmap->height(), canonicalized_path(path).characters()));
return bitmap;
}
RefPtr<Gfx::Bitmap> load_png_from_memory(const u8* data, size_t length)
{
auto bitmap = load_png_impl(data, length);
if (bitmap)
bitmap->set_mmap_name(String::format("Gfx::Bitmap [%dx%d] - Decoded PNG: <memory>", bitmap->width(), bitmap->height()));
return bitmap;
}
ALWAYS_INLINE static u8 paeth_predictor(int a, int b, int c)
{
int p = a + b - c;
int pa = abs(p - a);
int pb = abs(p - b);
int pc = abs(p - c);
if (pa <= pb && pa <= pc)
return a;
if (pb <= pc)
return b;
return c;
}
union [[gnu::packed]] Pixel
{
RGBA32 rgba { 0 };
u8 v[4];
struct {
u8 r;
u8 g;
u8 b;
u8 a;
};
};
static_assert(sizeof(Pixel) == 4);
template<bool has_alpha, u8 filter_type>
ALWAYS_INLINE static void unfilter_impl(Gfx::Bitmap& bitmap, int y, const void* dummy_scanline_data)
{
auto* dummy_scanline = (const Pixel*)dummy_scanline_data;
if constexpr (filter_type == 0) {
auto* pixels = (Pixel*)bitmap.scanline(y);
for (int i = 0; i < bitmap.width(); ++i) {
auto& x = pixels[i];
swap(x.r, x.b);
}
}
if constexpr (filter_type == 1) {
auto* pixels = (Pixel*)bitmap.scanline(y);
swap(pixels[0].r, pixels[0].b);
for (int i = 1; i < bitmap.width(); ++i) {
auto& x = pixels[i];
swap(x.r, x.b);
auto& a = (const Pixel&)pixels[i - 1];
x.v[0] += a.v[0];
x.v[1] += a.v[1];
x.v[2] += a.v[2];
if constexpr (has_alpha)
x.v[3] += a.v[3];
}
return;
}
if constexpr (filter_type == 2) {
auto* pixels = (Pixel*)bitmap.scanline(y);
auto* pixels_y_minus_1 = y == 0 ? dummy_scanline : (Pixel*)bitmap.scanline(y - 1);
for (int i = 0; i < bitmap.width(); ++i) {
auto& x = pixels[i];
swap(x.r, x.b);
const Pixel& b = pixels_y_minus_1[i];
x.v[0] += b.v[0];
x.v[1] += b.v[1];
x.v[2] += b.v[2];
if constexpr (has_alpha)
x.v[3] += b.v[3];
}
return;
}
if constexpr (filter_type == 3) {
auto* pixels = (Pixel*)bitmap.scanline(y);
auto* pixels_y_minus_1 = y == 0 ? dummy_scanline : (Pixel*)bitmap.scanline(y - 1);
for (int i = 0; i < bitmap.width(); ++i) {
auto& x = pixels[i];
swap(x.r, x.b);
Pixel a;
if (i != 0)
a = pixels[i - 1];
const Pixel& b = pixels_y_minus_1[i];
x.v[0] = x.v[0] + ((a.v[0] + b.v[0]) / 2);
x.v[1] = x.v[1] + ((a.v[1] + b.v[1]) / 2);
x.v[2] = x.v[2] + ((a.v[2] + b.v[2]) / 2);
if constexpr (has_alpha)
x.v[3] = x.v[3] + ((a.v[3] + b.v[3]) / 2);
}
return;
}
if constexpr (filter_type == 4) {
auto* pixels = (Pixel*)bitmap.scanline(y);
auto* pixels_y_minus_1 = y == 0 ? dummy_scanline : (Pixel*)bitmap.scanline(y - 1);
for (int i = 0; i < bitmap.width(); ++i) {
auto& x = pixels[i];
swap(x.r, x.b);
Pixel a;
const Pixel& b = pixels_y_minus_1[i];
Pixel c;
if (i != 0) {
a = pixels[i - 1];
c = pixels_y_minus_1[i - 1];
}
x.v[0] += paeth_predictor(a.v[0], b.v[0], c.v[0]);
x.v[1] += paeth_predictor(a.v[1], b.v[1], c.v[1]);
x.v[2] += paeth_predictor(a.v[2], b.v[2], c.v[2]);
if constexpr (has_alpha)
x.v[3] += paeth_predictor(a.v[3], b.v[3], c.v[3]);
}
}
}
NEVER_INLINE FLATTEN static void unfilter(PNGLoadingContext& context)
{
// First unpack the scanlines to RGBA:
switch (context.color_type) {
case 0:
if (context.bit_depth == 8) {
for (int y = 0; y < context.height; ++y) {
auto* gray_values = (u8*)context.scanlines[y].data.data();
for (int i = 0; i < context.width; ++i) {
auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
pixel.r = gray_values[i];
pixel.g = gray_values[i];
pixel.b = gray_values[i];
pixel.a = 0xff;
}
}
} else if (context.bit_depth == 16) {
for (int y = 0; y < context.height; ++y) {
auto* gray_values = (u16*)context.scanlines[y].data.data();
for (int i = 0; i < context.width; ++i) {
auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
pixel.r = gray_values[i] & 0xFF;
pixel.g = gray_values[i] & 0xFF;
pixel.b = gray_values[i] & 0xFF;
pixel.a = 0xff;
}
}
} else if (context.bit_depth == 1 || context.bit_depth == 2 || context.bit_depth == 4) {
auto pixels_per_byte = 8 / context.bit_depth;
auto mask = (1 << context.bit_depth) - 1;
for (int y = 0; y < context.height; ++y) {
auto* gray_values = (u8*)context.scanlines[y].data.data();
for (int i = 0; i < context.width; ++i) {
auto bit_offset = (8 - context.bit_depth) - (context.bit_depth * (i % pixels_per_byte));
auto value = (gray_values[i / pixels_per_byte] >> bit_offset) & mask;
auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
pixel.r = value * (0xff / pow(context.bit_depth, 2));
pixel.g = value * (0xff / pow(context.bit_depth, 2));
pixel.b = value * (0xff / pow(context.bit_depth, 2));
pixel.a = 0xff;
}
}
} else {
ASSERT_NOT_REACHED();
}
break;
case 4:
if (context.bit_depth == 8) {
for (int y = 0; y < context.height; ++y) {
auto* tuples = (Tuple*)context.scanlines[y].data.data();
for (int i = 0; i < context.width; ++i) {
auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
pixel.r = tuples[i].gray;
pixel.g = tuples[i].gray;
pixel.b = tuples[i].gray;
pixel.a = tuples[i].a;
}
}
} else if (context.bit_depth == 16) {
for (int y = 0; y < context.height; ++y) {
auto* tuples = (Tuple16*)context.scanlines[y].data.data();
for (int i = 0; i < context.width; ++i) {
auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
pixel.r = tuples[i].gray & 0xFF;
pixel.g = tuples[i].gray & 0xFF;
pixel.b = tuples[i].gray & 0xFF;
pixel.a = tuples[i].a & 0xFF;
}
}
} else {
ASSERT_NOT_REACHED();
}
break;
case 2:
if (context.bit_depth == 8) {
for (int y = 0; y < context.height; ++y) {
auto* triplets = (Triplet*)context.scanlines[y].data.data();
for (int i = 0; i < context.width; ++i) {
auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
pixel.r = triplets[i].r;
pixel.g = triplets[i].g;
pixel.b = triplets[i].b;
pixel.a = 0xff;
}
}
} else if (context.bit_depth == 16) {
for (int y = 0; y < context.height; ++y) {
auto* triplets = (Triplet16*)context.scanlines[y].data.data();
for (int i = 0; i < context.width; ++i) {
auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
pixel.r = triplets[i].r & 0xFF;
pixel.g = triplets[i].g & 0xFF;
pixel.b = triplets[i].b & 0xFF;
pixel.a = 0xff;
}
}
} else {
ASSERT_NOT_REACHED();
}
break;
case 6:
if (context.bit_depth == 8) {
for (int y = 0; y < context.height; ++y) {
memcpy(context.bitmap->scanline(y), context.scanlines[y].data.data(), context.scanlines[y].data.size());
}
} else if (context.bit_depth == 16) {
for (int y = 0; y < context.height; ++y) {
auto* triplets = (Quad16*)context.scanlines[y].data.data();
for (int i = 0; i < context.width; ++i) {
auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
pixel.r = triplets[i].r & 0xFF;
pixel.g = triplets[i].g & 0xFF;
pixel.b = triplets[i].b & 0xFF;
pixel.a = triplets[i].a & 0xFF;
}
}
} else {
ASSERT_NOT_REACHED();
}
break;
case 3:
if (context.bit_depth == 8) {
for (int y = 0; y < context.height; ++y) {
auto* palette_index = (u8*)context.scanlines[y].data.data();
for (int i = 0; i < context.width; ++i) {
auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
auto& color = context.palette_data.at((int)palette_index[i]);
auto transparency = context.palette_transparency_data.size() >= palette_index[i] + 1u
? context.palette_transparency_data.data()[palette_index[i]]
: 0xff;
pixel.r = color.r;
pixel.g = color.g;
pixel.b = color.b;
pixel.a = transparency;
}
}
} else if (context.bit_depth == 1 || context.bit_depth == 2 || context.bit_depth == 4) {
auto pixels_per_byte = 8 / context.bit_depth;
auto mask = (1 << context.bit_depth) - 1;
for (int y = 0; y < context.height; ++y) {
auto* palette_indexes = (u8*)context.scanlines[y].data.data();
for (int i = 0; i < context.width; ++i) {
auto bit_offset = (8 - context.bit_depth) - (context.bit_depth * (i % pixels_per_byte));
auto palette_index = (palette_indexes[i / pixels_per_byte] >> bit_offset) & mask;
auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
auto& color = context.palette_data.at(palette_index);
auto transparency = context.palette_transparency_data.size() >= palette_index + 1u
? context.palette_transparency_data.data()[palette_index]
: 0xff;
pixel.r = color.r;
pixel.g = color.g;
pixel.b = color.b;
pixel.a = transparency;
}
}
} else {
ASSERT_NOT_REACHED();
}
break;
default:
ASSERT_NOT_REACHED();
break;
}
auto dummy_scanline = ByteBuffer::create_zeroed(context.width * sizeof(RGBA32));
for (int y = 0; y < context.height; ++y) {
auto filter = context.scanlines[y].filter;
if (filter == 0) {
if (context.has_alpha())
unfilter_impl<true, 0>(*context.bitmap, y, dummy_scanline.data());
else
unfilter_impl<false, 0>(*context.bitmap, y, dummy_scanline.data());
continue;
}
if (filter == 1) {
if (context.has_alpha())
unfilter_impl<true, 1>(*context.bitmap, y, dummy_scanline.data());
else
unfilter_impl<false, 1>(*context.bitmap, y, dummy_scanline.data());
continue;
}
if (filter == 2) {
if (context.has_alpha())
unfilter_impl<true, 2>(*context.bitmap, y, dummy_scanline.data());
else
unfilter_impl<false, 2>(*context.bitmap, y, dummy_scanline.data());
continue;
}
if (filter == 3) {
if (context.has_alpha())
unfilter_impl<true, 3>(*context.bitmap, y, dummy_scanline.data());
else
unfilter_impl<false, 3>(*context.bitmap, y, dummy_scanline.data());
continue;
}
if (filter == 4) {
if (context.has_alpha())
unfilter_impl<true, 4>(*context.bitmap, y, dummy_scanline.data());
else
unfilter_impl<false, 4>(*context.bitmap, y, dummy_scanline.data());
continue;
}
}
}
static bool decode_png_header(PNGLoadingContext& context)
{
if (context.state >= PNGLoadingContext::HeaderDecoded)
return true;
if (!context.data || context.data_size < sizeof(png_header)) {
dbg() << "Missing PNG header";
context.state = PNGLoadingContext::State::Error;
return false;
}
if (memcmp(context.data, png_header, sizeof(png_header)) != 0) {
dbg() << "Invalid PNG header";
context.state = PNGLoadingContext::State::Error;
return false;
}
context.state = PNGLoadingContext::HeaderDecoded;
return true;
}
static bool decode_png_size(PNGLoadingContext& context)
{
if (context.state >= PNGLoadingContext::SizeDecoded)
return true;
if (context.state < PNGLoadingContext::HeaderDecoded) {
if (!decode_png_header(context))
return false;
}
const u8* data_ptr = context.data + sizeof(png_header);
size_t data_remaining = context.data_size - sizeof(png_header);
Streamer streamer(data_ptr, data_remaining);
while (!streamer.at_end()) {
if (!process_chunk(streamer, context, true)) {
context.state = PNGLoadingContext::State::Error;
return false;
}
if (context.width && context.height) {
context.state = PNGLoadingContext::State::SizeDecoded;
return true;
}
}
return false;
}
static bool decode_png_chunks(PNGLoadingContext& context)
{
if (context.state >= PNGLoadingContext::State::ChunksDecoded)
return true;
if (context.state < PNGLoadingContext::HeaderDecoded) {
if (!decode_png_header(context))
return false;
}
const u8* data_ptr = context.data + sizeof(png_header);
int data_remaining = context.data_size - sizeof(png_header);
context.compressed_data.ensure_capacity(context.data_size);
Streamer streamer(data_ptr, data_remaining);
while (!streamer.at_end()) {
if (!process_chunk(streamer, context, false)) {
context.state = PNGLoadingContext::State::Error;
return false;
}
}
context.state = PNGLoadingContext::State::ChunksDecoded;
return true;
}
static bool decode_png_bitmap(PNGLoadingContext& context)
{
if (context.state < PNGLoadingContext::State::ChunksDecoded) {
if (!decode_png_chunks(context))
return false;
}
if (context.state >= PNGLoadingContext::State::BitmapDecoded)
return true;
unsigned long srclen = context.compressed_data.size() - 6;
unsigned long destlen = context.decompression_buffer_size;
int ret = puff(context.decompression_buffer, &destlen, context.compressed_data.data() + 2, &srclen);
if (ret < 0) {
context.state = PNGLoadingContext::State::Error;
return false;
}
context.compressed_data.clear();
context.scanlines.ensure_capacity(context.height);
Streamer streamer(context.decompression_buffer, context.decompression_buffer_size);
for (int y = 0; y < context.height; ++y) {
u8 filter;
if (!streamer.read(filter)) {
context.state = PNGLoadingContext::State::Error;
return false;
}
context.scanlines.append({ filter });
auto& scanline_buffer = context.scanlines.last().data;
auto row_size = ((context.width * context.channels * context.bit_depth) + 7) / 8;
if (!streamer.wrap_bytes(scanline_buffer, row_size)) {
context.state = PNGLoadingContext::State::Error;
return false;
}
}
context.bitmap = Bitmap::create_purgeable(context.has_alpha() ? BitmapFormat::RGBA32 : BitmapFormat::RGB32, { context.width, context.height });
unfilter(context);
munmap(context.decompression_buffer, context.decompression_buffer_size);
context.decompression_buffer = nullptr;
context.decompression_buffer_size = 0;
context.state = PNGLoadingContext::State::BitmapDecoded;
return true;
}
static RefPtr<Gfx::Bitmap> load_png_impl(const u8* data, int data_size)
{
PNGLoadingContext context;
context.data = data;
context.data_size = data_size;
if (!decode_png_chunks(context))
return nullptr;
if (!decode_png_bitmap(context))
return nullptr;
return context.bitmap;
}
static bool process_IHDR(const ByteBuffer& data, PNGLoadingContext& context, bool decode_size_only = false)
{
if (data.size() < (int)sizeof(PNG_IHDR))
return false;
auto& ihdr = *(const PNG_IHDR*)data.data();
context.width = ihdr.width;
context.height = ihdr.height;
context.bit_depth = ihdr.bit_depth;
context.color_type = ihdr.color_type;
context.compression_method = ihdr.compression_method;
context.filter_method = ihdr.filter_method;
context.interlace_method = ihdr.interlace_method;
#ifdef PNG_DEBUG
printf("PNG: %dx%d (%d bpp)\n", context.width, context.height, context.bit_depth);
printf(" Color type: %d\n", context.color_type);
printf("Compress Method: %d\n", context.compression_method);
printf(" Filter Method: %d\n", context.filter_method);
printf(" Interlace type: %d\n", context.interlace_method);
#endif
// FIXME: Implement Adam7 deinterlacing
if (context.interlace_method != 0) {
dbgprintf("PNGLoader::process_IHDR: Interlaced PNGs not currently supported.\n");
return false;
}
switch (context.color_type) {
case 0: // Each pixel is a grayscale sample.
context.channels = 1;
break;
case 4: // Each pixel is a grayscale sample, followed by an alpha sample.
context.channels = 2;
break;
case 2: // Each pixel is an RGB sample
context.channels = 3;
break;
case 3: // Each pixel is a palette index; a PLTE chunk must appear.
context.channels = 1;
break;
case 6: // Each pixel is an RGB sample, followed by an alpha sample.
context.channels = 4;
break;
default:
ASSERT_NOT_REACHED();
}
if (!decode_size_only) {
// Calculate number of bytes per row (+1 for filter)
auto row_size = ((context.width * context.channels * context.bit_depth) + 7) / 8 + 1;
context.decompression_buffer_size = row_size * context.height;
context.decompression_buffer = (u8*)mmap_with_name(nullptr, context.decompression_buffer_size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0, "PNG decompression buffer");
}
return true;
}
static bool process_IDAT(const ByteBuffer& data, PNGLoadingContext& context)
{
context.compressed_data.append(data.data(), data.size());
return true;
}
static bool process_PLTE(const ByteBuffer& data, PNGLoadingContext& context)
{
context.palette_data.append((const PaletteEntry*)data.data(), data.size() / 3);
return true;
}
static bool process_tRNS(const ByteBuffer& data, PNGLoadingContext& context)
{
switch (context.color_type) {
case 3:
context.palette_transparency_data.append(data.data(), data.size());
break;
}
return true;
}
static bool process_chunk(Streamer& streamer, PNGLoadingContext& context, bool decode_size_only)
{
u32 chunk_size;
if (!streamer.read(chunk_size)) {
printf("Bail at chunk_size\n");
return false;
}
u8 chunk_type[5];
chunk_type[4] = '\0';
if (!streamer.read_bytes(chunk_type, 4)) {
printf("Bail at chunk_type\n");
return false;
}
ByteBuffer chunk_data;
if (!streamer.wrap_bytes(chunk_data, chunk_size)) {
printf("Bail at chunk_data\n");
return false;
}
u32 chunk_crc;
if (!streamer.read(chunk_crc)) {
printf("Bail at chunk_crc\n");
return false;
}
#ifdef PNG_DEBUG
printf("Chunk type: '%s', size: %u, crc: %x\n", chunk_type, chunk_size, chunk_crc);
#endif
if (!strcmp((const char*)chunk_type, "IHDR"))
return process_IHDR(chunk_data, context, decode_size_only);
if (!strcmp((const char*)chunk_type, "IDAT"))
return process_IDAT(chunk_data, context);
if (!strcmp((const char*)chunk_type, "PLTE"))
return process_PLTE(chunk_data, context);
if (!strcmp((const char*)chunk_type, "tRNS"))
return process_tRNS(chunk_data, context);
return true;
}
PNGImageDecoderPlugin::PNGImageDecoderPlugin(const u8* data, size_t size)
{
m_context = make<PNGLoadingContext>();
m_context->data = data;
m_context->data_size = size;
}
PNGImageDecoderPlugin::~PNGImageDecoderPlugin()
{
}
Size PNGImageDecoderPlugin::size()
{
if (m_context->state == PNGLoadingContext::State::Error)
return {};
if (m_context->state < PNGLoadingContext::State::SizeDecoded) {
bool success = decode_png_size(*m_context);
if (!success)
return {};
}
return { m_context->width, m_context->height };
}
RefPtr<Gfx::Bitmap> PNGImageDecoderPlugin::bitmap()
{
if (m_context->state == PNGLoadingContext::State::Error)
return nullptr;
if (m_context->state < PNGLoadingContext::State::BitmapDecoded) {
// NOTE: This forces the chunk decoding to happen.
bool success = decode_png_bitmap(*m_context);
if (!success)
return nullptr;
}
ASSERT(m_context->bitmap);
return m_context->bitmap;
}
void PNGImageDecoderPlugin::set_volatile()
{
if (m_context->bitmap)
m_context->bitmap->set_volatile();
}
bool PNGImageDecoderPlugin::set_nonvolatile()
{
if (!m_context->bitmap)
return false;
return m_context->bitmap->set_nonvolatile();
}
bool PNGImageDecoderPlugin::sniff()
{
return decode_png_header(*m_context);
}
bool PNGImageDecoderPlugin::is_animated()
{
return false;
}
size_t PNGImageDecoderPlugin::loop_count()
{
return 0;
}
size_t PNGImageDecoderPlugin::frame_count()
{
return 1;
}
ImageFrameDescriptor PNGImageDecoderPlugin::frame(size_t i)
{
if (i > 0) {
return { bitmap(), 0 };
}
return {};
}
}