From e770cf06b0d8cf1ea630d99353f6e63453094616 Mon Sep 17 00:00:00 2001
From: Nico Weber <thakis@chromium.org>
Date: Sun, 7 Jan 2024 22:12:20 -0500
Subject: [PATCH] LibPDF: Send jpeg data down the same path as all other data

JPEG images now honor decode arrays and color spaces.
---
 Userland/Libraries/LibPDF/Filter.cpp   | 36 ++++++++++++++++++++++----
 Userland/Libraries/LibPDF/Renderer.cpp |  5 ----
 2 files changed, 31 insertions(+), 10 deletions(-)

diff --git a/Userland/Libraries/LibPDF/Filter.cpp b/Userland/Libraries/LibPDF/Filter.cpp
index 00f4dfe5891..2fd170391f9 100644
--- a/Userland/Libraries/LibPDF/Filter.cpp
+++ b/Userland/Libraries/LibPDF/Filter.cpp
@@ -226,12 +226,38 @@ PDFErrorOr<ByteBuffer> Filter::decode_jbig2(ReadonlyBytes)
 
 PDFErrorOr<ByteBuffer> Filter::decode_dct(ReadonlyBytes bytes)
 {
-    if (Gfx::JPEGImageDecoderPlugin::sniff({ bytes.data(), bytes.size() })) {
-        auto decoder = TRY(Gfx::JPEGImageDecoderPlugin::create_with_options({ bytes.data(), bytes.size() }, { .cmyk = Gfx::JPEGDecoderOptions::CMYK::PDF }));
-        auto frame = TRY(decoder->frame(0));
-        return TRY(frame.image->serialize_to_byte_buffer());
+    if (!Gfx::JPEGImageDecoderPlugin::sniff({ bytes.data(), bytes.size() }))
+        return AK::Error::from_string_literal("Not a JPEG image!");
+
+    auto decoder = TRY(Gfx::JPEGImageDecoderPlugin::create_with_options({ bytes.data(), bytes.size() }, { .cmyk = Gfx::JPEGDecoderOptions::CMYK::PDF }));
+    auto internal_format = decoder->natural_frame_format();
+
+    if (internal_format == Gfx::NaturalFrameFormat::CMYK) {
+        auto bitmap = TRY(decoder->cmyk_frame());
+        // FIXME: Could give CMYKBitmap a method to steal its internal ByteBuffer.
+        auto size = bitmap->size().width() * bitmap->size().height() * 4;
+        auto buffer = TRY(ByteBuffer::create_uninitialized(size));
+        buffer.overwrite(0, bitmap->scanline(0), size);
+        return buffer;
     }
-    return AK::Error::from_string_literal("Not a JPEG image!");
+
+    auto bitmap = TRY(decoder->frame(0)).image;
+    auto size = bitmap->size().width() * bitmap->size().height() * (internal_format == Gfx::NaturalFrameFormat::Grayscale ? 1 : 3);
+    ByteBuffer buffer;
+    TRY(buffer.try_ensure_capacity(size));
+
+    for (auto& pixel : *bitmap) {
+        Color color = Color::from_argb(pixel);
+        if (internal_format == Gfx::NaturalFrameFormat::Grayscale) {
+            // Either channel is fine, they're all the same.
+            buffer.append(color.red());
+        } else {
+            buffer.append(color.red());
+            buffer.append(color.green());
+            buffer.append(color.blue());
+        }
+    }
+    return buffer;
 }
 
 PDFErrorOr<ByteBuffer> Filter::decode_jpx(ReadonlyBytes)
diff --git a/Userland/Libraries/LibPDF/Renderer.cpp b/Userland/Libraries/LibPDF/Renderer.cpp
index 508088285b1..87d166b52dd 100644
--- a/Userland/Libraries/LibPDF/Renderer.cpp
+++ b/Userland/Libraries/LibPDF/Renderer.cpp
@@ -1124,11 +1124,6 @@ PDFErrorOr<Renderer::LoadedImage> Renderer::load_image(NonnullRefPtr<StreamObjec
         component_value_decoders.empend(0.0f, 255.0f, dmin, dmax);
     }
 
-    if (TRY(is_filter(CommonNames::DCTDecode))) {
-        // TODO: stream objects could store Variant<bytes/Bitmap> to avoid serialisation/deserialisation here
-        return LoadedImage { TRY(Gfx::Bitmap::create_from_serialized_bytes(image->bytes())), is_image_mask };
-    }
-
     auto bitmap = MUST(Gfx::Bitmap::create(Gfx::BitmapFormat::BGRA8888, { width, height }));
     int x = 0;
     int y = 0;