Add image preview tooltip on clipboard menu hover

libdiodon/clipboard-item.vala

@@ -66,6 +66,13 @@ namespace Diodon
          */
         public abstract Gtk.Image? get_image();
 
+        /**
+         * preview pixbuf for tooltip display
+         *
+         * @return scaled preview pixbuf or null if not available
+         */
+        public abstract Gdk.Pixbuf? get_preview_pixbuf();
+
         /**
          * icon to represent type of clipboard item
          *

libdiodon/clipboard-menu-item.vala

@@ -28,6 +28,10 @@ namespace Diodon
     class ClipboardMenuItem : Gtk.ImageMenuItem
     {
         private string _checksum;
+        private IClipboardItem _item;
+        private Gdk.Pixbuf? _cached_preview;
+        private bool _preview_loaded;
+        private static Gtk.Window? _preview_window;
 
         /**
          * Clipboard item constructor
@@ -37,6 +41,7 @@ namespace Diodon
         public ClipboardMenuItem(IClipboardItem item)
         {
             _checksum = item.get_checksum();
+            _item = item;
             set_label(item.get_label());
 
             // check if image needs to be shown
@@ -45,6 +50,84 @@ namespace Diodon
                 set_image(image);
                 set_always_show_image(true);
             }
+
+            debug("ClipboardMenuItem: connecting select/deselect for %s", _checksum);
+            select.connect(on_item_select);
+            deselect.connect(on_item_deselect);
+        }
+
+        private Gdk.Pixbuf? get_preview()
+        {
+            if (!_preview_loaded) {
+                _cached_preview = _item.get_preview_pixbuf();
+                _preview_loaded = true;
+            }
+            return _cached_preview;
+        }
+
+        private void on_item_select()
+        {
+            debug("on_item_select: checksum=%s", _checksum);
+            Gdk.Pixbuf? preview = get_preview();
+            if (preview == null) {
+                debug("on_item_select: no preview available");
+                return;
+            }
+            debug("on_item_select: preview %dx%d", preview.width, preview.height);
+            if (_preview_window == null) {
+                _preview_window = new Gtk.Window(Gtk.WindowType.POPUP);
+                _preview_window.set_type_hint(Gdk.WindowTypeHint.TOOLTIP);
+                _preview_window.set_app_paintable(true);
+                Gdk.Screen screen = _preview_window.get_screen();
+                Gdk.Visual? visual = screen.get_rgba_visual();
+                if (visual != null) {
+                    _preview_window.set_visual(visual);
+                }
+            }
+            _preview_window.foreach((child) => { _preview_window.remove(child); });
+            Gtk.Image preview_image = new Gtk.Image.from_pixbuf(preview);
+            Gtk.CssProvider css = new Gtk.CssProvider();
+            try {
+                css.load_from_data("frame { border: 1px solid #888888; }", -1);
+            } catch (Error e) {
+                warning("Failed to load preview CSS: %s", e.message);
+            }
+            Gtk.Frame frame = new Gtk.Frame(null);
+            frame.set_shadow_type(Gtk.ShadowType.NONE);
+            frame.get_style_context().add_provider(css, Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION);
+            frame.add(preview_image);
+            _preview_window.add(frame);
+            _preview_window.resize(preview.width, preview.height);
+            Gdk.Display? display = Gdk.Display.get_default();
+            Gdk.Seat? seat = display != null ? display.get_default_seat() : null;
+            if (seat != null) {
+                int mouse_x, mouse_y;
+                seat.get_pointer().get_position(null, out mouse_x, out mouse_y);
+                int x = mouse_x + 16;
+                int y = mouse_y + 16;
+                Gdk.Screen screen = _preview_window.get_screen();
+                int screen_height = screen.get_height();
+                if (y + preview.height > screen_height) {
+                    y = screen_height - preview.height;
+                }
+                if (y < 0) {
+                    y = 0;
+                }
+                _preview_window.move(x, y);
+            }
+            _preview_window.show_all();
+        }
+
+        private static void on_item_deselect()
+        {
+            hide_preview();
+        }
+
+        public static void hide_preview()
+        {
+            if (_preview_window != null) {
+                _preview_window.hide();
+            }
         }
 
         /**

libdiodon/clipboard-menu.vala

@@ -89,6 +89,7 @@ namespace Diodon
             show_all();
 
             this.key_press_event.connect(on_key_pressed);
+            this.hide.connect(() => { ClipboardMenuItem.hide_preview(); });
         }
 
         /**

libdiodon/file-clipboard-item.vala

@@ -153,6 +153,29 @@ namespace Diodon
             return image;
         }
 
+        /**
+	     * {@inheritDoc}
+	     */
+        public Gdk.Pixbuf? get_preview_pixbuf()
+        {
+            string[] paths = convert_to_paths(_paths);
+            if (paths.length == 0) {
+                return null;
+            }
+            string path = paths[0];
+            string mime_type = get_mime_type();
+            if (!mime_type.has_prefix("image/")) {
+                return null;
+            }
+            try {
+                Gdk.Pixbuf pixbuf = new Gdk.Pixbuf.from_file(path);
+                return ImageClipboardItem.create_preview_pixbuf(pixbuf);
+            } catch (Error e) {
+                warning("Could not load preview for file %s: %s", path, e.message);
+                return null;
+            }
+        }
+
         /**
 	     * {@inheritDoc}
 	     */

libdiodon/image-clipboard-item.vala

@@ -150,6 +150,14 @@ namespace Diodon
             return new Gtk.Image.from_pixbuf(pixbuf_preview);
         }
 
+        /**
+	     * {@inheritDoc}
+	     */
+        public Gdk.Pixbuf? get_preview_pixbuf()
+        {
+            return create_preview_pixbuf(_pixbuf);
+        }
+
         /**
 	     * {@inheritDoc}
 	     */
@@ -224,6 +232,20 @@ namespace Diodon
          *
          * @param pixbuf scaled pixbuf
          */
+        public static Gdk.Pixbuf create_preview_pixbuf(Gdk.Pixbuf pixbuf)
+        {
+            int max_size = 500;
+            int width = pixbuf.width;
+            int height = pixbuf.height;
+            if (width <= max_size && height <= max_size) {
+                return pixbuf;
+            }
+            double scale = double.min((double) max_size / width, (double) max_size / height);
+            int new_width = (int) (width * scale);
+            int new_height = (int) (height * scale);
+            return pixbuf.scale_simple(new_width, new_height, Gdk.InterpType.BILINEAR);
+        }
+
         private static Gdk.Pixbuf create_scaled_pixbuf(Gdk.Pixbuf pixbuf)
         {
             // get menu icon size

libdiodon/text-clipboard-item.vala

@@ -117,6 +117,14 @@ namespace Diodon
             return null; // no image available for text content
         }
 
+        /**
+	     * {@inheritDoc}
+	     */
+        public Gdk.Pixbuf? get_preview_pixbuf()
+        {
+            return null;
+        }
+
         /**
 	     * {@inheritDoc}
 	     */