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ladybird/Libraries/LibDraw/PNGLoader.cpp
Brandon Scott aac8b091a4 LibDraw: Implemented support for more PNG formats (#614) 
- Implemented support for more PNG formats including 16-bit per channel
  and 8-bit indexed with palette.
- Made the library a little more resistant to crashes by returning
  false for known but unsupported formats.
2019-09-29 09:55:28 +02:00

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#include <AK/FileSystemPath.h>
#include <AK/MappedFile.h>
#include <AK/NetworkOrdered.h>
#include <LibDraw/PNGLoader.h>
#include <LibDraw/puff.c>
#include <fcntl.h>
#include <serenity.h>
#include <stdio.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
//#define PNG_STOPWATCH_DEBUG
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]] 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 {
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 bytes_per_pixel { 0 };
bool has_seen_zlib_header { false };
bool has_alpha() const { return color_type & 4 || palette_transparency_data.size() > 0; }
Vector<Scanline> scanlines;
RefPtr<GraphicsBitmap> 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<GraphicsBitmap> load_png_impl(const u8*, int);
static bool process_chunk(Streamer&, PNGLoadingContext& context);
RefPtr<GraphicsBitmap> 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.pointer(), mapped_file.size());
if (bitmap)
bitmap->set_mmap_name(String::format("GraphicsBitmap [%dx%d] - Decoded PNG: %s", bitmap->width(), bitmap->height(), canonicalized_path(path).characters()));
return bitmap;
}
RefPtr<GraphicsBitmap> 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("GraphicsBitmap [%dx%d] - Decoded PNG: <memory>", bitmap->width(), bitmap->height()));
return bitmap;
}
[[gnu::always_inline]] static inline 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>
[[gnu::always_inline]] static inline void unfilter_impl(GraphicsBitmap& 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]);
}
}
}
[[gnu::noinline]] static void unfilter(PNGLoadingContext& context)
{
{
#ifdef PNG_STOPWATCH_DEBUG
Stopwatch sw("load_png_impl: unfilter: unpack");
#endif
// First unpack the scanlines to RGBA:
switch (context.color_type) {
case 2:
if (context.bit_depth == 8) {
for (int y = 0; y < context.height; ++y) {
auto* triplets = (Triplet*)context.scanlines[y].data.pointer();
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.pointer();
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.pointer(), 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.pointer();
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:
for (int y = 0; y < context.height; ++y) {
auto* palette_index = (u8*)context.scanlines[y].data.pointer();
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] + 1
? (int)context.palette_transparency_data.data()[palette_index[i]]
: 0xFF;
pixel.r = color.r;
pixel.g = color.g;
pixel.b = color.b;
pixel.a = transparency;
}
}
break;
default:
ASSERT_NOT_REACHED();
break;
}
}
auto dummy_scanline = ByteBuffer::create_zeroed(context.width * sizeof(RGBA32));
#ifdef PNG_STOPWATCH_DEBUG
Stopwatch sw("load_png_impl: unfilter: process");
#endif
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.pointer());
else
unfilter_impl<false, 0>(*context.bitmap, y, dummy_scanline.pointer());
continue;
}
if (filter == 1) {
if (context.has_alpha())
unfilter_impl<true, 1>(*context.bitmap, y, dummy_scanline.pointer());
else
unfilter_impl<false, 1>(*context.bitmap, y, dummy_scanline.pointer());
continue;
}
if (filter == 2) {
if (context.has_alpha())
unfilter_impl<true, 2>(*context.bitmap, y, dummy_scanline.pointer());
else
unfilter_impl<false, 2>(*context.bitmap, y, dummy_scanline.pointer());
continue;
}
if (filter == 3) {
if (context.has_alpha())
unfilter_impl<true, 3>(*context.bitmap, y, dummy_scanline.pointer());
else
unfilter_impl<false, 3>(*context.bitmap, y, dummy_scanline.pointer());
continue;
}
if (filter == 4) {
if (context.has_alpha())
unfilter_impl<true, 4>(*context.bitmap, y, dummy_scanline.pointer());
else
unfilter_impl<false, 4>(*context.bitmap, y, dummy_scanline.pointer());
continue;
}
}
}
static RefPtr<GraphicsBitmap> load_png_impl(const u8* data, int data_size)
{
#ifdef PNG_STOPWATCH_DEBUG
Stopwatch sw("load_png_impl: total");
#endif
const u8* data_ptr = data;
int data_remaining = data_size;
const u8 png_header[8] = { 0x89, 'P', 'N', 'G', 13, 10, 26, 10 };
if (memcmp(data, png_header, sizeof(png_header))) {
dbgprintf("Invalid PNG header\n");
return nullptr;
}
PNGLoadingContext context;
context.compressed_data.ensure_capacity(data_size);
data_ptr += sizeof(png_header);
data_remaining -= sizeof(png_header);
{
#ifdef PNG_STOPWATCH_DEBUG
Stopwatch sw("load_png_impl: read chunks");
#endif
Streamer streamer(data_ptr, data_remaining);
while (!streamer.at_end()) {
if (!process_chunk(streamer, context)) {
return nullptr;
}
}
}
{
#ifdef PNG_STOPWATCH_DEBUG
Stopwatch sw("load_png_impl: uncompress");
#endif
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)
return nullptr;
context.compressed_data.clear();
}
{
#ifdef PNG_STOPWATCH_DEBUG
Stopwatch sw("load_png_impl: extract scanlines");
#endif
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))
return nullptr;
context.scanlines.append({ filter });
auto& scanline_buffer = context.scanlines.last().data;
if (!streamer.wrap_bytes(scanline_buffer, context.width * context.bytes_per_pixel))
return nullptr;
}
}
{
#ifdef PNG_STOPWATCH_DEBUG
Stopwatch sw("load_png_impl: create bitmap");
#endif
context.bitmap = GraphicsBitmap::create(context.has_alpha() ? GraphicsBitmap::Format::RGBA32 : GraphicsBitmap::Format::RGB32, { context.width, context.height });
}
unfilter(context);
munmap(context.decompression_buffer, context.decompression_buffer_size);
context.decompression_buffer = nullptr;
context.decompression_buffer_size = 0;
return context.bitmap;
}
static bool process_IHDR(const ByteBuffer& data, PNGLoadingContext& context)
{
if (data.size() < (int)sizeof(PNG_IHDR))
return false;
auto& ihdr = *(const PNG_IHDR*)data.pointer();
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.
case 4: // Each pixel is a grayscale sample, followed by an alpha sample.
// FIXME: Implement grayscale PNG support.
dbgprintf("PNGLoader::process_IHDR: Unsupported grayscale format.\n");
return false;
case 2:
context.bytes_per_pixel = 3 * (ihdr.bit_depth / 8);
break;
case 3: // Each pixel is a palette index; a PLTE chunk must appear.
// FIXME: Implement support for 1/2/4 bit palette based images.
if (ihdr.bit_depth != 8) {
dbgprintf("PNGLoader::process_IHDR: Unsupported index-based format (%d bpp).\n", context.bit_depth);
return false;
}
context.bytes_per_pixel = 1;
break;
case 6:
context.bytes_per_pixel = 4 * (ihdr.bit_depth / 8);
break;
default:
ASSERT_NOT_REACHED();
}
context.decompression_buffer_size = (context.width * context.height * context.bytes_per_pixel + 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.pointer(), data.size());
return true;
}
static bool process_PLTE(const ByteBuffer& data, PNGLoadingContext& context)
{
context.palette_data.append((const PaletteEntry*)data.pointer(), 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.pointer(), data.size());
break;
}
return true;
}
static bool process_chunk(Streamer& streamer, PNGLoadingContext& context)
{
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);
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;
}
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