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https://github.com/RGBCube/serenity
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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.
This commit is contained in:
Brandon Scott
Andreas Kling
parent
dba74abe93
commit
aac8b091a4
1 changed files with 138 additions and 25 deletions
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@ -27,7 +27,37 @@ static_assert(sizeof(PNG_IHDR) == 13);
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struct Scanline {
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u8 filter { 0 };
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ByteBuffer data { };
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ByteBuffer data {};
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};
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struct [[gnu::packed]] PaletteEntry
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{
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u8 r;
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u8 g;
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u8 b;
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//u8 a;
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};
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struct [[gnu::packed]] Triplet
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{
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u8 r;
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u8 g;
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u8 b;
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};
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struct [[gnu::packed]] Triplet16
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{
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u16 r;
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u16 g;
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u16 b;
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};
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struct [[gnu::packed]] Quad16
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{
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u16 r;
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u16 g;
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u16 b;
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u16 a;
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};
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struct PNGLoadingContext {
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@ -40,12 +70,14 @@ struct PNGLoadingContext {
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u8 interlace_method { 0 };
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u8 bytes_per_pixel { 0 };
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bool has_seen_zlib_header { false };
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bool has_alpha() const { return color_type & 4; }
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bool has_alpha() const { return color_type & 4 || palette_transparency_data.size() > 0; }
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Vector<Scanline> scanlines;
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RefPtr<GraphicsBitmap> bitmap;
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u8* decompression_buffer { nullptr };
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int decompression_buffer_size { 0 };
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Vector<u8> compressed_data;
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Vector<PaletteEntry> palette_data;
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Vector<u8> palette_transparency_data;
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};
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class Streamer {
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@ -237,26 +269,66 @@ template<bool has_alpha, u8 filter_type>
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// First unpack the scanlines to RGBA:
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switch (context.color_type) {
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case 2:
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for (int y = 0; y < context.height; ++y) {
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struct [[gnu::packed]] Triplet
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{
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u8 r;
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u8 g;
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u8 b;
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};
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auto* triplets = (Triplet*)context.scanlines[y].data.pointer();
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for (int i = 0; i < context.width; ++i) {
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auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
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pixel.r = triplets[i].r;
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pixel.g = triplets[i].g;
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pixel.b = triplets[i].b;
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pixel.a = 0xff;
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if (context.bit_depth == 8) {
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for (int y = 0; y < context.height; ++y) {
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auto* triplets = (Triplet*)context.scanlines[y].data.pointer();
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for (int i = 0; i < context.width; ++i) {
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auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
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pixel.r = triplets[i].r;
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pixel.g = triplets[i].g;
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pixel.b = triplets[i].b;
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pixel.a = 0xff;
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}
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}
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} else if (context.bit_depth == 16) {
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for (int y = 0; y < context.height; ++y) {
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auto* triplets = (Triplet16*)context.scanlines[y].data.pointer();
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for (int i = 0; i < context.width; ++i) {
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auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
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pixel.r = triplets[i].r & 0xFF;
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pixel.g = triplets[i].g & 0xFF;
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pixel.b = triplets[i].b & 0xFF;
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pixel.a = 0xff;
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}
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}
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} else {
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ASSERT_NOT_REACHED();
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}
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break;
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case 6:
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if (context.bit_depth == 8) {
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for (int y = 0; y < context.height; ++y) {
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memcpy(context.bitmap->scanline(y), context.scanlines[y].data.pointer(), context.scanlines[y].data.size());
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}
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} else if (context.bit_depth == 16) {
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for (int y = 0; y < context.height; ++y) {
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auto* triplets = (Quad16*)context.scanlines[y].data.pointer();
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for (int i = 0; i < context.width; ++i) {
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auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
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pixel.r = triplets[i].r & 0xFF;
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pixel.g = triplets[i].g & 0xFF;
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pixel.b = triplets[i].b & 0xFF;
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pixel.a = triplets[i].a & 0xFF;
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}
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}
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} else {
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ASSERT_NOT_REACHED();
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}
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break;
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case 3:
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for (int y = 0; y < context.height; ++y) {
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memcpy(context.bitmap->scanline(y), context.scanlines[y].data.pointer(), context.scanlines[y].data.size());
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auto* palette_index = (u8*)context.scanlines[y].data.pointer();
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for (int i = 0; i < context.width; ++i) {
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auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
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auto& color = context.palette_data.at((int)palette_index[i]);
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auto transparency = context.palette_transparency_data.size() >= palette_index[i] + 1
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? (int)context.palette_transparency_data.data()[palette_index[i]]
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: 0xFF;
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pixel.r = color.r;
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pixel.g = color.g;
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pixel.b = color.b;
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pixel.a = transparency;
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}
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}
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break;
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default:
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@ -402,23 +474,44 @@ static bool process_IHDR(const ByteBuffer& data, PNGLoadingContext& context)
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context.filter_method = ihdr.filter_method;
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context.interlace_method = ihdr.interlace_method;
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#ifdef PNG_DEBUG
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printf("PNG: %dx%d (%d bpp)\n", context.width, context.height, context.bit_depth);
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printf(" Color type: %d\n", context.color_type);
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printf("Compress Method: %d\n", context.compression_method);
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printf(" Filter Method: %d\n", context.filter_method);
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printf(" Interlace type: %d\n", context.interlace_method);
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#endif
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// FIXME: Implement Adam7 deinterlacing
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if (context.interlace_method != 0) {
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dbgprintf("PNGLoader::process_IHDR: Interlaced PNGs not currently supported.\n");
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return false;
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}
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switch (context.color_type) {
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case 0: // Each pixel is a grayscale sample.
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case 4: // Each pixel is a grayscale sample, followed by an alpha sample.
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// FIXME: Implement grayscale PNG support.
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dbgprintf("PNGLoader::process_IHDR: Unsupported grayscale format.\n");
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return false;
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case 2:
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context.bytes_per_pixel = 3;
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context.bytes_per_pixel = 3 * (ihdr.bit_depth / 8);
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break;
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case 3: // Each pixel is a palette index; a PLTE chunk must appear.
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// FIXME: Implement support for 1/2/4 bit palette based images.
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if (ihdr.bit_depth != 8) {
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dbgprintf("PNGLoader::process_IHDR: Unsupported index-based format (%d bpp).\n", context.bit_depth);
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return false;
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}
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context.bytes_per_pixel = 1;
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break;
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case 6:
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context.bytes_per_pixel = 4;
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context.bytes_per_pixel = 4 * (ihdr.bit_depth / 8);
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break;
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default:
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ASSERT_NOT_REACHED();
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}
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#ifdef PNG_DEBUG
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printf("PNG: %dx%d (%d bpp)\n", context.width, context.height, context.bit_depth);
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printf(" Color type: %b\n", context.color_type);
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printf(" Interlace type: %b\n", context.interlace_method);
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#endif
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context.decompression_buffer_size = (context.width * context.height * context.bytes_per_pixel + context.height);
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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");
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return true;
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@ -430,6 +523,22 @@ static bool process_IDAT(const ByteBuffer& data, PNGLoadingContext& context)
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return true;
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}
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static bool process_PLTE(const ByteBuffer& data, PNGLoadingContext& context)
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{
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context.palette_data.append((const PaletteEntry*)data.pointer(), data.size() / 3);
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return true;
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}
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static bool process_tRNS(const ByteBuffer& data, PNGLoadingContext& context)
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{
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switch (context.color_type) {
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case 3:
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context.palette_transparency_data.append(data.pointer(), data.size());
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break;
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}
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return true;
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}
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static bool process_chunk(Streamer& streamer, PNGLoadingContext& context)
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{
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u32 chunk_size;
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@ -461,5 +570,9 @@ static bool process_chunk(Streamer& streamer, PNGLoadingContext& context)
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return process_IHDR(chunk_data, context);
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if (!strcmp((const char*)chunk_type, "IDAT"))
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return process_IDAT(chunk_data, context);
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if (!strcmp((const char*)chunk_type, "PLTE"))
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return process_PLTE(chunk_data, context);
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if (!strcmp((const char*)chunk_type, "tRNS"))
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return process_tRNS(chunk_data, context);
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return true;
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}
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