LibGfx: Let PNGWriter optionally embed an ICC profile

2 files changed, 30 insertions, 2 deletions

diff --git a/Userland/Libraries/LibGfx/PNGWriter.cpp b/Userland/Libraries/LibGfx/PNGWriter.cpp
index 985ff9f1cb..efd47d83f0 100644
--- a/Userland/Libraries/LibGfx/PNGWriter.cpp
+++ b/Userland/Libraries/LibGfx/PNGWriter.cpp
@@ -146,6 +146,21 @@ ErrorOr<void> PNGWriter::add_IHDR_chunk(u32 width, u32 height, u8 bit_depth, PNG
     return {};
 }
 
+ErrorOr<void> PNGWriter::add_iCCP_chunk(ReadonlyBytes icc_data)
+{
+    // https://www.w3.org/TR/png/#11iCCP
+    PNGChunk chunk { "iCCP" };
+
+    TRY(chunk.add("embedded profile"sv.bytes()));
+    TRY(chunk.add_u8(0)); // \0-terminate profile name
+
+    TRY(chunk.add_u8(0)); // compression method deflate
+    TRY(chunk.compress_and_add(icc_data));
+
+    TRY(add_chunk(chunk));
+    return {};
+}
+
 ErrorOr<void> PNGWriter::add_IEND_chunk()
 {
     PNGChunk png_chunk { "IEND" };
@@ -273,11 +288,13 @@ ErrorOr<void> PNGWriter::add_IDAT_chunk(Gfx::Bitmap const& bitmap)
     return {};
 }
 
-ErrorOr<ByteBuffer> PNGWriter::encode(Gfx::Bitmap const& bitmap)
+ErrorOr<ByteBuffer> PNGWriter::encode(Gfx::Bitmap const& bitmap, Options options)
 {
     PNGWriter writer;
     TRY(writer.add_png_header());
     TRY(writer.add_IHDR_chunk(bitmap.width(), bitmap.height(), 8, PNG::ColorType::TruecolorWithAlpha, 0, 0, 0));
+    if (options.icc_data.has_value())
+        TRY(writer.add_iCCP_chunk(options.icc_data.value()));
     TRY(writer.add_IDAT_chunk(bitmap));
     TRY(writer.add_IEND_chunk());
     return ByteBuffer::copy(writer.m_data);
diff --git a/Userland/Libraries/LibGfx/PNGWriter.h b/Userland/Libraries/LibGfx/PNGWriter.h
index 2f53fe9907..9a19e3b91b 100644
--- a/Userland/Libraries/LibGfx/PNGWriter.h
+++ b/Userland/Libraries/LibGfx/PNGWriter.h
@@ -7,6 +7,7 @@
 
 #pragma once
 
+#include <AK/Optional.h>
 #include <AK/Vector.h>
 #include <LibGfx/Forward.h>
 #include <LibGfx/PNGShared.h>
@@ -15,9 +16,18 @@ namespace Gfx {
 
 class PNGChunk;
 
+// This is not a nested struct to work around https://llvm.org/PR36684
+struct PNGWriterOptions {
+    // Data for the iCCP chunk.
+    // FIXME: Allow writing cICP, sRGB, or gAMA instead too.
+    Optional<ReadonlyBytes> icc_data;
+};
+
 class PNGWriter {
 public:
-    static ErrorOr<ByteBuffer> encode(Gfx::Bitmap const&);
+    using Options = PNGWriterOptions;
+
+    static ErrorOr<ByteBuffer> encode(Gfx::Bitmap const&, Options options = Options {});
 
 private:
     PNGWriter() = default;
@@ -26,6 +36,7 @@ private:
     ErrorOr<void> add_chunk(PNGChunk&);
     ErrorOr<void> add_png_header();
     ErrorOr<void> add_IHDR_chunk(u32 width, u32 height, u8 bit_depth, PNG::ColorType color_type, u8 compression_method, u8 filter_method, u8 interlace_method);
+    ErrorOr<void> add_iCCP_chunk(ReadonlyBytes icc_data);
     ErrorOr<void> add_IDAT_chunk(Gfx::Bitmap const&);
     ErrorOr<void> add_IEND_chunk();
 };