1 files changed, 26 insertions, 4 deletions

diff --git a/src/ImageViewer.cpp b/src/ImageViewer.cpp
index d00c375..1176046 100644
--- a/src/ImageViewer.cpp
+++ b/src/ImageViewer.cpp
@@ -194,6 +194,22 @@ namespace QuickMedia {
         return value >= 0.0 ? 1.0 : -1.0;
     }
 
+    static bool is_key_scroll_up(const mgl::Event::KeyEvent &key) {
+        return (!key.control && key.code == mgl::Keyboard::Up) || (!key.alt && key.control && key.code == mgl::Keyboard::K);
+    }
+
+    static bool is_key_scroll_down(const mgl::Event::KeyEvent &key) {
+        return (!key.control && key.code == mgl::Keyboard::Down) || (!key.alt && key.control && key.code == mgl::Keyboard::J);
+    }
+
+    static bool is_key_previous_chapter(const mgl::Event::KeyEvent &key) {
+        return (key.control && key.code == mgl::Keyboard::Up) || (key.alt && key.control && key.code == mgl::Keyboard::K);
+    }
+
+    static bool is_key_next_chapter(const mgl::Event::KeyEvent &key) {
+        return (key.control && key.code == mgl::Keyboard::Down) || (key.alt && key.control && key.code == mgl::Keyboard::J);
+    }
+
     ImageViewerAction ImageViewer::draw() {
         const double frame_delta = frame_timer.restart();
         const double scroll_speed_key_input = 200.0;
@@ -229,11 +245,17 @@ namespace QuickMedia {
                 window_size.x = event.size.width;
                 window_size.y = event.size.height;
             } else if(event.type == mgl::Event::KeyPressed) {
-                if(event.key.code == mgl::Keyboard::Up || (event.key.control && event.key.code == mgl::Keyboard::K))
+                if(is_key_scroll_up(event.key))
                     up_pressed = true;
-                if(event.key.code == mgl::Keyboard::Down || (event.key.control && event.key.code == mgl::Keyboard::J))
+                if(is_key_scroll_down(event.key))
                     down_pressed = true;
 
+                if(is_key_previous_chapter(event.key))
+                    return ImageViewerAction::PREVIOUS_CHAPTER;
+
+                if(is_key_next_chapter(event.key))
+                    return ImageViewerAction::NEXT_CHAPTER;
+
                 if(event.key.code == mgl::Keyboard::Escape)
                     return ImageViewerAction::RETURN;
                 
@@ -243,9 +265,9 @@ namespace QuickMedia {
                 if(event.key.code == mgl::Keyboard::F)
                     *fit_image_to_window = !*fit_image_to_window;
             } else if(event.type == mgl::Event::KeyReleased) {
-                if(event.key.code == mgl::Keyboard::Up || (event.key.control && event.key.code == mgl::Keyboard::K))
+                if(is_key_scroll_up(event.key))
                     up_pressed = false;
-                if(event.key.code == mgl::Keyboard::Down || (event.key.control && event.key.code == mgl::Keyboard::J))
+                if(is_key_scroll_down(event.key))
                     down_pressed = false;
             } else if(event.type == mgl::Event::MouseWheelScrolled/* && event.mouse_wheel_scroll.wheel == mgl::Mouse::VerticalWheel*/) {
                 scroll_speed += scroll_speed_mouse_wheel * event.mouse_wheel_scroll.delta * frame_delta;