[gtk+/gestures: 9/13] gtk-demo: Add simple gestures demo

[Carlos Garnacho <carlosg src gnome org>]

commit 9d4d4a81b350d8a01ab513db9fff696139635ebe
Author: Carlos Garnacho <carlos lanedo com>
Date:   Thu Jan 17 21:12:39 2013 +0100

    gtk-demo: Add simple gestures demo

 demos/gtk-demo/Makefile.am        |    1 +
 demos/gtk-demo/demo.gresource.xml |    1 +
 demos/gtk-demo/gestures.c         |  173 +++++++++++++++++++++++++++++++++++++
 3 files changed, 175 insertions(+), 0 deletions(-)
---
diff --git a/demos/gtk-demo/Makefile.am b/demos/gtk-demo/Makefile.am
index 89a25dc..62cd333 100644
--- a/demos/gtk-demo/Makefile.am
+++ b/demos/gtk-demo/Makefile.am
@@ -24,6 +24,7 @@ demos =                                               \
        entry_completion.c                      \
        event_axes.c                            \
        expander.c                              \
+       gestures.c                              \
        headerbar.c                             \
        hypertext.c                             \
        iconview.c                              \
diff --git a/demos/gtk-demo/demo.gresource.xml b/demos/gtk-demo/demo.gresource.xml
index 76bb304..4f90eb4 100644
--- a/demos/gtk-demo/demo.gresource.xml
+++ b/demos/gtk-demo/demo.gresource.xml
@@ -94,6 +94,7 @@
     <file>event_axes.c</file>
     <file>expander.c</file>
     <file>flowbox.c</file>
+    <file>gestures.c</file>
     <file>headerbar.c</file>
     <file>hypertext.c</file>
     <file>iconview.c</file>
diff --git a/demos/gtk-demo/gestures.c b/demos/gtk-demo/gestures.c
new file mode 100644
index 0000000..c33dbb4
--- /dev/null
+++ b/demos/gtk-demo/gestures.c
@@ -0,0 +1,173 @@
+/* Gestures
+ *
+ * Perform gestures on touchscreens and other input devices. This
+ * demo reacts to long presses and swipes from all devices, plus
+ * multi-touch rotate and zoom gestures.
+ */
+
+#include <gtk/gtk.h>
+
+static GtkWidget *window = NULL;
+static GtkGesture *swipe = NULL;
+static GtkGesture *rotate = NULL;
+static GtkGesture *zoom = NULL;
+static GtkGesture *long_press = NULL;
+static gdouble swipe_x = 0;
+static gdouble swipe_y = 0;
+static gboolean long_pressed = FALSE;
+
+static void
+swipe_gesture_swept (GtkGestureSwipe *gesture,
+                     gdouble          velocity_x,
+                     gdouble          velocity_y)
+{
+  swipe_x = velocity_x / 10;
+  swipe_y = velocity_y / 10;
+}
+
+static void
+long_press_gesture_pressed (GtkGestureLongPress *gesture,
+                            gdouble              x,
+                            gdouble              y)
+{
+  long_pressed = TRUE;
+  gtk_widget_queue_draw (window);
+}
+
+static void
+long_press_gesture_end (GtkGesture *gesture)
+{
+  long_pressed = FALSE;
+  gtk_widget_queue_draw (window);
+}
+
+static gboolean
+drawing_area_draw (GtkWidget *widget,
+                   cairo_t   *cr)
+{
+  GtkAllocation allocation;
+
+  gtk_widget_get_allocation (widget, &allocation);
+
+  if (swipe_x != 0 || swipe_y != 0)
+    {
+      cairo_save (cr);
+      cairo_set_line_width (cr, 6);
+      cairo_move_to (cr, allocation.width / 2,
+                     allocation.height / 2);
+      cairo_rel_line_to (cr, swipe_x, swipe_y);
+      cairo_set_source_rgba (cr, 1, 0, 0, 0.5);
+      cairo_stroke (cr);
+      cairo_restore (cr);
+    }
+
+  if (gtk_gesture_is_active (rotate) || gtk_gesture_is_active (zoom))
+    {
+      cairo_pattern_t *pat;
+      cairo_matrix_t matrix;
+      gdouble angle, scale;
+
+      cairo_matrix_init_translate (&matrix,
+                                   allocation.width / 2,
+                                   allocation.height / 2);
+
+      cairo_save (cr);
+
+      if (gtk_gesture_rotate_get_angle_delta (GTK_GESTURE_ROTATE (rotate), &angle))
+        cairo_matrix_rotate (&matrix, angle);
+
+      if (gtk_gesture_zoom_get_scale_delta (GTK_GESTURE_ZOOM (zoom), &scale))
+        cairo_matrix_scale (&matrix, scale, scale);
+
+      cairo_set_matrix (cr, &matrix);
+      cairo_rectangle (cr, -100, -100, 200, 200);
+
+      pat = cairo_pattern_create_linear (-100, 0, 200, 0);
+      cairo_pattern_add_color_stop_rgb (pat, 0, 0, 0, 1);
+      cairo_pattern_add_color_stop_rgb (pat, 1, 1, 0, 0);
+      cairo_set_source (cr, pat);
+      cairo_fill (cr);
+
+      cairo_restore (cr);
+
+      cairo_pattern_destroy (pat);
+    }
+
+  if (long_pressed)
+    {
+      cairo_save (cr);
+      cairo_arc (cr, allocation.width / 2,
+                 allocation.height / 2,
+                 50, 0, 2 * G_PI);
+
+      cairo_set_source_rgba (cr, 0, 1, 0, 0.5);
+      cairo_stroke (cr);
+
+      cairo_restore (cr);
+    }
+
+  return TRUE;
+}
+
+static gboolean
+drawing_area_event (GtkWidget *widget,
+                    GdkEvent  *event)
+{
+  gtk_event_controller_handle_event (GTK_EVENT_CONTROLLER (swipe), event);
+  gtk_event_controller_handle_event (GTK_EVENT_CONTROLLER (rotate), event);
+  gtk_event_controller_handle_event (GTK_EVENT_CONTROLLER (zoom), event);
+  gtk_event_controller_handle_event (GTK_EVENT_CONTROLLER (long_press), event);
+
+  gtk_widget_queue_draw (widget);
+
+  return FALSE;
+}
+
+GtkWidget *
+do_gestures (GtkWidget *do_widget)
+{
+  GtkWidget *drawing_area;
+
+  if (!window)
+    {
+      window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+      gtk_window_set_default_size (GTK_WINDOW (window), 400, 400);
+      gtk_window_set_title (GTK_WINDOW (window), "Gestures demo");
+      g_signal_connect (window, "destroy",
+                        G_CALLBACK (gtk_widget_destroyed), &window);
+
+      drawing_area = gtk_drawing_area_new ();
+      gtk_container_add (GTK_CONTAINER (window), drawing_area);
+      gtk_widget_add_events (drawing_area,
+                             GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK |
+                             GDK_POINTER_MOTION_MASK | GDK_TOUCH_MASK);
+
+      g_signal_connect (drawing_area, "draw",
+                        G_CALLBACK (drawing_area_draw), NULL);
+      g_signal_connect (drawing_area, "event",
+                        G_CALLBACK (drawing_area_event), NULL);
+
+      swipe = gtk_gesture_swipe_new (drawing_area);
+      g_signal_connect (swipe, "swipe",
+                        G_CALLBACK (swipe_gesture_swept), NULL);
+
+      long_press = gtk_gesture_long_press_new (drawing_area);
+      g_signal_connect (long_press, "pressed",
+                        G_CALLBACK (long_press_gesture_pressed), NULL);
+      g_signal_connect (long_press, "end",
+                        G_CALLBACK (long_press_gesture_end), NULL);
+
+      rotate = gtk_gesture_rotate_new (drawing_area);
+      zoom = gtk_gesture_zoom_new (drawing_area);
+    }
+
+  if (!gtk_widget_get_visible (window))
+    gtk_widget_show_all (window);
+  else
+    {
+      gtk_widget_destroy (window);
+      window = NULL;
+    }
+
+  return window;
+}