From f2f69c7c46102c3a9b57e2d53bc1496e9fd8f3ab Mon Sep 17 00:00:00 2001 From: Přemysl Eric Janouch Date: Mon, 15 Dec 2025 19:10:10 +0100 Subject: Add support for the pinch gesture Given the way our viewport works, it behaves a bit oddly. --- fiv-view.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 68 insertions(+), 16 deletions(-) diff --git a/fiv-view.c b/fiv-view.c index 98c8eb6..42c2585 100644 --- a/fiv-view.c +++ b/fiv-view.c @@ -77,6 +77,9 @@ struct _FivView { bool fixate : 1; ///< Keep zoom and position double scale; ///< Scaling factor double drag_start[2]; ///< Adjustment values for drag origin + double zoom_gesture_initial_scale; ///< Pinch gesture initial scale + double zoom_gesture_center[2]; ///< Pinch gesture widget coordinates + double zoom_gesture_surface[2]; ///< Pinch gesture surface coordinates FivIoImage *enhance_swap; ///< Quick swap in/out FivIoProfile *screen_cms_profile; ///< Target colour profile for widget @@ -1128,28 +1131,14 @@ widget_to_surface(FivView *self, double *x, double *y) } static gboolean -set_scale(FivView *self, double scale, const GdkEvent *event) +set_scale_with_focus(FivView *self, double scale, + double focus_x, double focus_y, double surface_x, double surface_y) { - // FIXME: Zooming to exactly 1:1 breaks rendering with some images - // when using a native X11 Window. This is a silly workaround. - GdkWindow *window = gtk_widget_get_window(GTK_WIDGET(self)); - if (window && gdk_window_has_native(window) && scale == 1) - scale = 0.999999999999999; - if (self->scale == scale) goto out; GtkAllocation allocation; gtk_widget_get_allocation(GTK_WIDGET(self), &allocation); - double focus_x = 0, focus_y = 0; - if (!event || !gdk_event_get_coords(event, &focus_x, &focus_y)) { - focus_x = 0.5 * allocation.width; - focus_y = 0.5 * allocation.height; - } - - double surface_x = focus_x; - double surface_y = focus_y; - widget_to_surface(self, &surface_x, &surface_y); self->scale = scale; g_object_notify_by_pspec(G_OBJECT(self), view_properties[PROP_SCALE]); @@ -1174,6 +1163,31 @@ out: return set_scale_to_fit(self, false); } +static gboolean +set_scale(FivView *self, double scale, const GdkEvent *event) +{ + // FIXME: Zooming to exactly 1:1 breaks rendering with some images + // when using a native X11 Window. This is a silly workaround. + GdkWindow *window = gtk_widget_get_window(GTK_WIDGET(self)); + if (window && gdk_window_has_native(window) && scale == 1) + scale = 0.999999999999999; + + GtkAllocation allocation; + gtk_widget_get_allocation(GTK_WIDGET(self), &allocation); + double focus_x = 0, focus_y = 0; + if (!event || !gdk_event_get_coords(event, &focus_x, &focus_y)) { + focus_x = 0.5 * allocation.width; + focus_y = 0.5 * allocation.height; + } + + double surface_x = focus_x; + double surface_y = focus_y; + widget_to_surface(self, &surface_x, &surface_y); + + return set_scale_with_focus( + self, scale, focus_x, focus_y, surface_x, surface_y); +} + static void set_scale_to_fit_width(FivView *self) { @@ -1418,6 +1432,33 @@ on_drag_end(GtkGestureDrag *drag, G_GNUC_UNUSED gdouble start_x, gdk_window_set_cursor(window, NULL); } +static void +on_zoom_begin(GtkGestureZoom *gesture, + G_GNUC_UNUSED GdkEventSequence *sequence, gpointer user_data) +{ + FivView *self = FIV_VIEW(user_data); + self->zoom_gesture_initial_scale = self->scale; + + double x = 0, y = 0; + gtk_gesture_get_bounding_box_center(GTK_GESTURE(gesture), &x, &y); + self->zoom_gesture_center[0] = x; + self->zoom_gesture_center[1] = y; + + widget_to_surface(self, &x, &y); + self->zoom_gesture_surface[0] = x; + self->zoom_gesture_surface[1] = y; +} + +static void +on_zoom_scale_changed( + G_GNUC_UNUSED GtkGestureZoom *gesture, gdouble scale, gpointer user_data) +{ + FivView *self = FIV_VIEW(user_data); + set_scale_with_focus(self, self->zoom_gesture_initial_scale * scale, + self->zoom_gesture_center[0], self->zoom_gesture_center[1], + self->zoom_gesture_surface[0], self->zoom_gesture_surface[1]); +} + // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - static void @@ -1903,6 +1944,17 @@ fiv_view_init(FivView *self) G_CALLBACK(on_drag_update), self); g_signal_connect(drag, "drag-end", G_CALLBACK(on_drag_end), self); + + GtkGesture *zoom = gtk_gesture_zoom_new(GTK_WIDGET(self)); + gtk_event_controller_set_propagation_phase( + GTK_EVENT_CONTROLLER(zoom), GTK_PHASE_BUBBLE); + g_object_set_data_full( + G_OBJECT(self), "fiv-view-zoom-gesture", zoom, g_object_unref); + + g_signal_connect(zoom, "begin", + G_CALLBACK(on_zoom_begin), self); + g_signal_connect(zoom, "scale-changed", + G_CALLBACK(on_zoom_scale_changed), self); } // --- Public interface -------------------------------------------------------- -- cgit v1.2.3-70-g09d2