PixelPaint: Add exporting to the QOI image format

Userland/Applications/PixelPaint/Image.cpp

@@ -19,6 +19,7 @@
 #include <LibGfx/BMPWriter.h>
 #include <LibGfx/Bitmap.h>
 #include <LibGfx/PNGWriter.h>
+#include <LibGfx/QOIWriter.h>
 #include <LibImageDecoderClient/Client.h>
 #include <stdio.h>
 
@@ -212,6 +213,17 @@ ErrorOr<void> Image::export_png_to_file(Core::File& file, bool preserve_alpha_ch
     return {};
 }
 
+ErrorOr<void> Image::export_qoi_to_file(Core::File& file) const
+{
+    auto bitmap = TRY(try_compose_bitmap(Gfx::BitmapFormat::BGRA8888));
+
+    auto encoded_data = Gfx::QOIWriter::encode(bitmap);
+    if (!file.write(encoded_data.data(), encoded_data.size()))
+        return Error::from_errno(file.error());
+
+    return {};
+}
+
 void Image::add_layer(NonnullRefPtr<Layer> layer)
 {
     for (auto& existing_layer : m_layers) {

Userland/Applications/PixelPaint/Image.h

@@ -71,6 +71,7 @@ public:
     ErrorOr<void> write_to_file(String const& file_path) const;
     ErrorOr<void> export_bmp_to_file(Core::File&, bool preserve_alpha_channel);
     ErrorOr<void> export_png_to_file(Core::File&, bool preserve_alpha_channel);
+    ErrorOr<void> export_qoi_to_file(Core::File&) const;
 
     void move_layer_to_front(Layer&);
     void move_layer_to_back(Layer&);

Userland/Applications/PixelPaint/MainWidget.cpp

@@ -191,6 +191,19 @@ void MainWidget::initialize_menubar(GUI::Window& window)
                     GUI::MessageBox::show_error(&window, String::formatted("Export to PNG failed: {}", result.error()));
             }));
 
+    m_export_submenu->add_action(
+        GUI::Action::create(
+            "As &QOI", [&](auto&) {
+                auto* editor = current_image_editor();
+                VERIFY(editor);
+                auto response = FileSystemAccessClient::Client::the().try_save_file(&window, "untitled", "qoi");
+                if (response.is_error())
+                    return;
+                auto result = editor->image().export_qoi_to_file(response.value());
+                if (result.is_error())
+                    GUI::MessageBox::show_error(&window, String::formatted("Export to QOI failed: {}", result.error()));
+            }));
+
     m_export_submenu->set_icon(g_icon_bag.file_export);
 
     file_menu.add_separator();