LibGfx: Remove Gfx::ImageDecoder::bitmap() in favor of frame(index)

To transparently support multi-frame images, all decoder plugins have
already been updated to return their only bitmap for frame(0).

This patch completes the remaining cleanup work by removing the
ImageDecoder::bitmap() API and having all clients call frame() instead.

Userland/Libraries/LibGUI/ImageWidget.cpp

@@ -81,7 +81,8 @@ void ImageWidget::load_from_file(const StringView& path)
     m_image_decoder = Gfx::ImageDecoder::try_create(mapped_file.bytes());
     VERIFY(m_image_decoder);
 
-    auto bitmap = m_image_decoder->bitmap();
+    auto frame = m_image_decoder->frame(0);
+    auto bitmap = frame.image;
     VERIFY(bitmap);
 
     set_bitmap(bitmap);

Userland/Libraries/LibGfx/BMPLoader.cpp

@@ -1397,7 +1397,8 @@ size_t BMPImageDecoderPlugin::frame_count()
 ImageFrameDescriptor BMPImageDecoderPlugin::frame(size_t i)
 {
     if (i > 0)
-        return { bitmap(), 0 };
+        return {};
-    return {};
+    return { bitmap(), 0 };
 }
+
 }

Userland/Libraries/LibGfx/DDSLoader.cpp

@@ -1046,9 +1046,11 @@ size_t DDSImageDecoderPlugin::frame_count()
     return 1;
 }
 
-ImageFrameDescriptor DDSImageDecoderPlugin::frame([[maybe_unused]] size_t i)
+ImageFrameDescriptor DDSImageDecoderPlugin::frame(size_t i)
 {
-    // We have "frames", but they are all the same image, so lets just use the largest version.
+    if (i > 0)
+        return {};
     return { bitmap(), 0 };
 }
+
 }

Userland/Libraries/LibGfx/ICOLoader.cpp

@@ -382,10 +382,9 @@ size_t ICOImageDecoderPlugin::frame_count()
 
 ImageFrameDescriptor ICOImageDecoderPlugin::frame(size_t i)
 {
-    if (i > 0) {
+    if (i > 0)
-        return { bitmap(), 0 };
+        return {};
-    }
+    return { bitmap(), 0 };
-    return {};
 }
 
 }

Userland/Libraries/LibGfx/ImageDecoder.cpp

@@ -78,9 +78,4 @@ ImageDecoder::~ImageDecoder()
 {
 }
 
-RefPtr<Gfx::Bitmap> ImageDecoder::bitmap() const
-{
-    return m_plugin->bitmap();
-}
-
 }

Userland/Libraries/LibGfx/ImageDecoder.h

@@ -30,7 +30,6 @@ public:
     virtual ~ImageDecoderPlugin() { }
 
     virtual IntSize size() = 0;
-    virtual RefPtr<Gfx::Bitmap> bitmap() = 0;
 
     virtual void set_volatile() = 0;
     [[nodiscard]] virtual bool set_nonvolatile(bool& was_purged) = 0;
@@ -43,6 +42,8 @@ public:
     virtual ImageFrameDescriptor frame(size_t i) = 0;
 
 protected:
+    virtual RefPtr<Gfx::Bitmap> bitmap() = 0;
+
     ImageDecoderPlugin() { }
 };
 
@@ -54,7 +55,6 @@ public:
     IntSize size() const { return m_plugin->size(); }
     int width() const { return size().width(); }
     int height() const { return size().height(); }
-    RefPtr<Gfx::Bitmap> bitmap() const;
     void set_volatile() { m_plugin->set_volatile(); }
     [[nodiscard]] bool set_nonvolatile(bool& was_purged) { return m_plugin->set_nonvolatile(was_purged); }
     bool sniff() const { return m_plugin->sniff(); }

Userland/Libraries/LibGfx/JPGLoader.cpp

@@ -1327,9 +1327,9 @@ size_t JPGImageDecoderPlugin::frame_count()
 
 ImageFrameDescriptor JPGImageDecoderPlugin::frame(size_t i)
 {
-    if (i > 0) {
+    if (i > 0)
-        return { bitmap(), 0 };
+        return {};
-    }
+    return { bitmap(), 0 };
-    return {};
 }
+
 }

Userland/Libraries/LibGfx/PBMLoader.cpp

@@ -195,11 +195,9 @@ size_t PBMImageDecoderPlugin::frame_count()
 
 ImageFrameDescriptor PBMImageDecoderPlugin::frame(size_t i)
 {
-    if (i > 0) {
+    if (i > 0)
-        return { bitmap(), 0 };
+        return {};
-    }
+    return { bitmap(), 0 };
-
-    return {};
 }
 
 }

Userland/Libraries/LibGfx/PGMLoader.cpp

@@ -198,11 +198,9 @@ size_t PGMImageDecoderPlugin::frame_count()
 
 ImageFrameDescriptor PGMImageDecoderPlugin::frame(size_t i)
 {
-    if (i > 0) {
+    if (i > 0)
-        return { bitmap(), 0 };
+        return {};
-    }
+    return { bitmap(), 0 };
-
-    return {};
 }
 
 }

Userland/Libraries/LibGfx/PNGLoader.cpp

@@ -1013,10 +1013,9 @@ size_t PNGImageDecoderPlugin::frame_count()
 
 ImageFrameDescriptor PNGImageDecoderPlugin::frame(size_t i)
 {
-    if (i > 0) {
+    if (i > 0)
-        return { bitmap(), 0 };
+        return {};
-    }
+    return { bitmap(), 0 };
-    return {};
 }
 
 }

Userland/Libraries/LibGfx/PPMLoader.cpp

@@ -200,11 +200,9 @@ size_t PPMImageDecoderPlugin::frame_count()
 
 ImageFrameDescriptor PPMImageDecoderPlugin::frame(size_t i)
 {
-    if (i > 0) {
+    if (i > 0)
-        return { bitmap(), 0 };
+        return {};
-    }
+    return { bitmap(), 0 };
-
-    return {};
 }
 
 }

Userland/Libraries/LibWeb/Loader/FrameLoader.cpp

@@ -71,7 +71,8 @@ static bool build_image_document(DOM::Document& document, const ByteBuffer& data
     auto image_decoder = Gfx::ImageDecoder::try_create(data.bytes());
     if (!image_decoder)
         return false;
-    auto bitmap = image_decoder->bitmap();
+    auto frame = image_decoder->frame(0);
+    auto bitmap = frame.image;
     if (!bitmap)
         return false;
 
@@ -171,7 +172,8 @@ bool FrameLoader::load(const LoadRequest& request, Type type)
                     dbgln("No image decoder plugin for favicon {}", favicon_url);
                     return;
                 }
-                auto bitmap = decoder->bitmap();
+                auto frame = decoder->frame(0);
+                auto bitmap = frame.image;
                 if (!bitmap) {
                     dbgln("Could not decode favicon {}", favicon_url);
                     return;

Userland/Services/ImageDecoder/ClientConnection.cpp

@@ -52,14 +52,7 @@ Messages::ImageDecoderServer::DecodeImageResponse ClientConnection::decode_image
     Vector<Gfx::ShareableBitmap> bitmaps;
     Vector<u32> durations;
     for (size_t i = 0; i < decoder->frame_count(); ++i) {
-        // FIXME: All image decoder plugins should be rewritten to return frame() instead of bitmap().
+        auto frame = decoder->frame(i);
-        //        Non-animated images can simply return 1 frame.
-        Gfx::ImageFrameDescriptor frame;
-        if (decoder->is_animated()) {
-            frame = decoder->frame(i);
-        } else {
-            frame.image = decoder->bitmap();
-        }
         if (frame.image)
             bitmaps.append(frame.image->to_shareable_bitmap());
         else