LibGfx/ILBMLoader: Add support for PC DeluxePaint files

Author: https://github.com/warpdesign
Commit: https://github.com/SerenityOS/serenity/commit/cd6c7f3fc4
Pull-request: https://github.com/SerenityOS/serenity/pull/22209
Reviewed-by: https://github.com/LucasChollet ✅

Base/res/apps/ImageViewer.af

@@ -4,4 +4,4 @@ Executable=/bin/ImageViewer
 Category=Graphics
 
 [Launcher]
-FileTypes=bmp,dds,gif,ico,iff,jpeg,jpg,jxl,pbm,pgm,png,ppm,qoi,tga,tiff,tif,tvg
+FileTypes=bmp,dds,gif,ico,iff,jpeg,jpg,jxl,lbm,pbm,pgm,png,ppm,qoi,tga,tiff,tif,tvg

Tests/LibGfx/TestImageDecoder.cpp

@@ -149,6 +149,17 @@ TEST_CASE(test_ilbm_ham6)
     EXPECT_EQ(frame.image->get_pixel(77, 107), Gfx::Color(0xf0, 0x40, 0x40, 0xff));
 }
 
+TEST_CASE(test_ilbm_dos)
+{
+    auto file = MUST(Core::MappedFile::map(TEST_INPUT("ilbm/serenity.lbm"sv)));
+    EXPECT(Gfx::ILBMImageDecoderPlugin::sniff(file->bytes()));
+    auto plugin_decoder = TRY_OR_FAIL(Gfx::ILBMImageDecoderPlugin::create(file->bytes()));
+
+    auto frame = TRY_OR_FAIL(expect_single_frame_of_size(*plugin_decoder, { 640, 480 }));
+
+    EXPECT_EQ(frame.image->get_pixel(315, 134), Gfx::Color::NamedColor::Red);
+}
+
 TEST_CASE(test_ilbm_malformed_header)
 {
     Array test_inputs = {

Userland/Libraries/LibCore/MimeData.cpp

@@ -123,7 +123,7 @@ static Array const s_registered_mime_type = {
     MimeType { .name = "image/vnd.ms-dds"sv, .common_extensions = { ".dds"sv }, .description = "DDS image data"sv, .magic_bytes = Vector<u8> { 'D', 'D', 'S', ' ' } },
     MimeType { .name = "image/webp"sv, .common_extensions = { ".webp"sv }, .description = "WebP image data"sv, .magic_bytes = Vector<u8> { 'W', 'E', 'B', 'P' }, .offset = 8 },
     MimeType { .name = "image/x-icon"sv, .common_extensions = { ".ico"sv }, .description = "ICO image data"sv },
-    MimeType { .name = "image/x-ilbm"sv, .common_extensions = { ".iff"sv }, .description = "Interleaved bitmap image data"sv, .magic_bytes = Vector<u8> { 0x46, 0x4F, 0x52, 0x4F } },
+    MimeType { .name = "image/x-ilbm"sv, .common_extensions = { ".iff"sv, ".lbm"sv }, .description = "Interleaved bitmap image data"sv, .magic_bytes = Vector<u8> { 0x46, 0x4F, 0x52, 0x4F } },
     MimeType { .name = "image/x-portable-bitmap"sv, .common_extensions = { ".pbm"sv }, .description = "PBM image data"sv, .magic_bytes = Vector<u8> { 0x50, 0x31, 0x0A } },
     MimeType { .name = "image/x-portable-graymap"sv, .common_extensions = { ".pgm"sv }, .description = "PGM image data"sv, .magic_bytes = Vector<u8> { 0x50, 0x32, 0x0A } },
     MimeType { .name = "image/x-portable-pixmap"sv, .common_extensions = { ".ppm"sv }, .description = "PPM image data"sv, .magic_bytes = Vector<u8> { 0x50, 0x33, 0x0A } },

Userland/Libraries/LibGfx/Bitmap.h

@@ -25,6 +25,7 @@
     __ENUMERATE_IMAGE_FORMAT(jpeg, ".jpeg") \
     __ENUMERATE_IMAGE_FORMAT(jpeg, ".jpg")  \
     __ENUMERATE_IMAGE_FORMAT(jxl, ".jxl")   \
+    __ENUMERATE_IMAGE_FORMAT(iff, ".lbm")   \
     __ENUMERATE_IMAGE_FORMAT(pbm, ".pbm")   \
     __ENUMERATE_IMAGE_FORMAT(pgm, ".pgm")   \
     __ENUMERATE_IMAGE_FORMAT(png, ".png")   \

Userland/Libraries/LibGfx/ImageFormats/ILBMLoader.cpp

@@ -46,6 +46,13 @@ enum class ViewportMode : u32 {
     HAM = 0x800
 };
 
+enum class Format : u8 {
+    // Amiga interleaved format
+    ILBM = 0,
+    // PC-DeluxePaint chunky format
+    PBM = 1
+};
+
 AK_ENUM_BITWISE_OPERATORS(ViewportMode);
 
 struct ChunkHeader {
@@ -96,6 +103,8 @@ struct ILBMLoadingContext {
     RefPtr<Gfx::Bitmap> bitmap;
 
     BMHDHeader bm_header;
+
+    Format format;
 };
 
 static ErrorOr<void> decode_iff_ilbm_header(ILBMLoadingContext& context)
@@ -107,9 +116,12 @@ static ErrorOr<void> decode_iff_ilbm_header(ILBMLoadingContext& context)
         return Error::from_string_literal("Missing IFF header");
 
     auto& header = *bit_cast<IFFHeader const*>(context.data.data());
-    if (header.form != FourCC("FORM") || header.format != FourCC("ILBM"))
+
+    if (header.form != FourCC("FORM") || (header.format != FourCC("ILBM") && header.format != FourCC("PBM ")))
         return Error::from_string_literal("Invalid IFF-ILBM header");
 
+    context.format = header.format == FourCC("ILBM") ? Format::ILBM : Format::PBM;
+
     return {};
 }
 
@@ -292,9 +304,15 @@ static ErrorOr<void> decode_body_chunk(Chunk body_chunk, ILBMLoadingContext& con
 
     if (context.bm_header.compression == CompressionType::ByteRun) {
         auto plane_data = TRY(uncompress_byte_run(body_chunk.data, context));
-        pixel_data = TRY(planar_to_chunky(plane_data, context));
+        if (context.format == Format::ILBM)
+            pixel_data = TRY(planar_to_chunky(plane_data, context));
+        else
+            pixel_data = plane_data;
     } else {
-        pixel_data = TRY(planar_to_chunky(body_chunk.data, context));
+        if (context.format == Format::ILBM)
+            pixel_data = TRY(planar_to_chunky(body_chunk.data, context));
+        else
+            pixel_data = TRY(ByteBuffer::copy(body_chunk.data.data(), body_chunk.data.size()));
     }
 
     // Some files already have 64 colors defined in the palette,