PDFViewer: Add actions to rotate the displayed PDF

This implements the rotate cw/ccw actions in PDFViewer.
Since the rendered pages are stored in a HashMap for caching,
the bitmap is wrapped in a struct with the current rotation.
This way the caching works as expected while zooming, and a new bitmap
is rendered when the page is rotated.

Userland/Applications/PDFViewer/PDFViewer.cpp

@@ -29,7 +29,7 @@ void PDFViewer::set_document(RefPtr<PDF::Document> document)
 
     m_rendered_page_list.ensure_capacity(document->get_page_count());
     for (u32 i = 0; i < document->get_page_count(); i++)
-        m_rendered_page_list.unchecked_append(HashMap<u32, RefPtr<Gfx::Bitmap>>());
+        m_rendered_page_list.unchecked_append(HashMap<u32, RenderedPage>());
 
     update();
 }
@@ -38,11 +38,11 @@ RefPtr<Gfx::Bitmap> PDFViewer::get_rendered_page(u32 index)
 {
     auto& rendered_page_map = m_rendered_page_list[index];
     auto existing_rendered_page = rendered_page_map.get(m_zoom_level);
-    if (existing_rendered_page.has_value())
-        return existing_rendered_page.value();
+    if (existing_rendered_page.has_value() && existing_rendered_page.value().rotation == m_rotations)
+        return existing_rendered_page.value().bitmap;
 
     auto rendered_page = render_page(m_document->get_page(index));
-    rendered_page_map.set(m_zoom_level, rendered_page);
+    rendered_page_map.set(m_zoom_level, { rendered_page, m_rotations });
     return rendered_page;
 }
 
@@ -167,6 +167,12 @@ void PDFViewer::reset_zoom()
     update();
 }
 
+void PDFViewer::rotate(int degrees)
+{
+    m_rotations = (m_rotations + degrees + 360) % 360;
+    update();
+}
+
 RefPtr<Gfx::Bitmap> PDFViewer::render_page(const PDF::Page& page)
 {
     auto zoom_scale_factor = static_cast<float>(zoom_levels[m_zoom_level]) / 100.0f;
@@ -181,8 +187,8 @@ RefPtr<Gfx::Bitmap> PDFViewer::render_page(const PDF::Page& page)
 
     PDF::Renderer::render(*m_document, page, bitmap);
 
-    if (page.rotate != 0) {
-        int rotation_count = (page.rotate / 90) % 4;
+    if (page.rotate + m_rotations != 0) {
+        int rotation_count = ((page.rotate + m_rotations) / 90) % 4;
         if (rotation_count == 3) {
             bitmap = bitmap->rotated(Gfx::RotationDirection::CounterClockwise).release_value_but_fixme_should_propagate_errors();
         } else {

Userland/Applications/PDFViewer/PDFViewer.h

@@ -52,6 +52,7 @@ public:
     void zoom_in();
     void zoom_out();
     void reset_zoom();
+    void rotate(int degrees);
 
 protected:
     PDFViewer();
@@ -64,14 +65,20 @@ protected:
     virtual void timer_event(Core::TimerEvent&) override;
 
 private:
+    struct RenderedPage {
+        RefPtr<Gfx::Bitmap> bitmap;
+        int rotation;
+    };
+
     RefPtr<Gfx::Bitmap> get_rendered_page(u32 index);
     RefPtr<Gfx::Bitmap> render_page(const PDF::Page&);
 
     RefPtr<PDF::Document> m_document;
     u32 m_current_page_index { 0 };
-    Vector<HashMap<u32, RefPtr<Gfx::Bitmap>>> m_rendered_page_list;
+    Vector<HashMap<u32, RenderedPage>> m_rendered_page_list;
 
     u8 m_zoom_level { initial_zoom_level };
 
     Gfx::IntPoint m_pan_starting_position;
+    int m_rotations { 0 };
 };

Userland/Applications/PDFViewer/PDFViewerWidget.cpp

@@ -130,13 +130,25 @@ void PDFViewerWidget::create_toolbar()
         m_viewer->reset_zoom();
     });
 
+    m_rotate_counterclockwise_action = GUI::CommonActions::make_rotate_counterclockwise_action([&](auto&) {
+        m_viewer->rotate(-90);
+    });
+
+    m_rotate_clockwise_action = GUI::CommonActions::make_rotate_clockwise_action([&](auto&) {
+        m_viewer->rotate(90);
+    });
+
     m_zoom_in_action->set_enabled(false);
     m_zoom_out_action->set_enabled(false);
     m_reset_zoom_action->set_enabled(false);
+    m_rotate_counterclockwise_action->set_enabled(false);
+    m_rotate_clockwise_action->set_enabled(false);
 
     toolbar.add_action(*m_zoom_in_action);
     toolbar.add_action(*m_zoom_out_action);
     toolbar.add_action(*m_reset_zoom_action);
+    toolbar.add_action(*m_rotate_counterclockwise_action);
+    toolbar.add_action(*m_rotate_clockwise_action);
 }
 
 void PDFViewerWidget::open_file(int fd, String const& path)
@@ -167,6 +179,8 @@ void PDFViewerWidget::open_file(int fd, String const& path)
     m_zoom_in_action->set_enabled(true);
     m_zoom_out_action->set_enabled(true);
     m_reset_zoom_action->set_enabled(true);
+    m_rotate_counterclockwise_action->set_enabled(true);
+    m_rotate_clockwise_action->set_enabled(true);
 
     if (document->outline()) {
         auto outline = document->outline();

Userland/Applications/PDFViewer/PDFViewerWidget.h

@@ -38,6 +38,8 @@ private:
     RefPtr<GUI::Action> m_zoom_in_action;
     RefPtr<GUI::Action> m_zoom_out_action;
     RefPtr<GUI::Action> m_reset_zoom_action;
+    RefPtr<GUI::Action> m_rotate_counterclockwise_action;
+    RefPtr<GUI::Action> m_rotate_clockwise_action;
 
     bool m_sidebar_open { false };
     ByteBuffer m_buffer;