[gtk+] gtk-demo: Add a new overlay demo

[Matthias Clasen <matthiasc src gnome org>]

commit 481ba13e8efbdac53d752363f5b6a10b4d0a797d
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Oct 6 21:58:56 2017 -0400

    gtk-demo: Add a new overlay demo
    
    Replace the not very impressive transparent demo with
    the blur-behind example.

 demos/gtk-demo/demo.gresource.xml |    3 +
 demos/gtk-demo/portland-rose.jpg  |  Bin 0 -> 469879 bytes
 demos/gtk-demo/transparent.c      |  235 ++++++-------------------------------
 3 files changed, 38 insertions(+), 200 deletions(-)
---
diff --git a/demos/gtk-demo/demo.gresource.xml b/demos/gtk-demo/demo.gresource.xml
index 17eb5c4..583d29e 100644
--- a/demos/gtk-demo/demo.gresource.xml
+++ b/demos/gtk-demo/demo.gresource.xml
@@ -232,6 +232,9 @@
     <file>decor1.png</file>
     <file>decor2.png</file>
   </gresource>
+  <gresource prefix="/transparent">
+    <file>portland-rose.jpg</file>
+  </gresource>
   <gresource prefix="/markup">
     <file>markup.txt</file>
   </gresource>
diff --git a/demos/gtk-demo/portland-rose.jpg b/demos/gtk-demo/portland-rose.jpg
new file mode 100644
index 0000000..89974da
Binary files /dev/null and b/demos/gtk-demo/portland-rose.jpg differ
diff --git a/demos/gtk-demo/transparent.c b/demos/gtk-demo/transparent.c
index c307de4..5d87dba 100644
--- a/demos/gtk-demo/transparent.c
+++ b/demos/gtk-demo/transparent.c
@@ -1,184 +1,10 @@
 /* Overlay/Transparency
  *
- * Use transparent background on GdkWindows to create a shadow effect on a GtkOverlay widget.
+ * Blur the background behind an overlay.
  */
 
 #include <gtk/gtk.h>
 
-#define SHADOW_OFFSET_X 7
-#define SHADOW_OFFSET_Y 7
-#define SHADOW_RADIUS 5
-
-static void
-draw_shadow_box (cairo_t   *cr,
-                 GdkRectangle rect,
-                 double radius,
-                 double transparency)
-{
-  cairo_pattern_t *pattern;
-  double x0, x1, x2, x3;
-  double y0, y1, y2, y3;
-
-  x0 = rect.x;
-  x1 = rect.x + radius;
-  x2 = rect.x + rect.width - radius;
-  x3 = rect.x + rect.width;
-
-  y0 = rect.y;
-  y1 = rect.y + radius;
-  y2 = rect.y + rect.height - radius;
-  y3 = rect.y + rect.height;
-
-   /* Fill non-border part */
-  cairo_set_source_rgba (cr, 0, 0, 0, transparency);
-  cairo_rectangle (cr,
-                   x1, y1, x2 - x1, y2 - y1);
-  cairo_fill (cr);
-
-  /* Upper border */
-
-  pattern = cairo_pattern_create_linear (0, y0, 0, y1);
-
-  cairo_pattern_add_color_stop_rgba (pattern, 0.0, 0.0, 0, 0, 0.0);
-  cairo_pattern_add_color_stop_rgba (pattern, 1.0, 0.0, 0, 0, transparency);
-
-  cairo_set_source (cr, pattern);
-  cairo_pattern_destroy (pattern);
-
-  cairo_rectangle (cr,
-                   x1, y0,
-                   x2 - x1, y1 - y0);
-  cairo_fill (cr);
-
-  /* Bottom border */
-
-  pattern = cairo_pattern_create_linear (0, y2, 0, y3);
-
-  cairo_pattern_add_color_stop_rgba (pattern, 0.0, 0.0, 0, 0, transparency);
-  cairo_pattern_add_color_stop_rgba (pattern, 1.0, 0.0, 0, 0, 0.0);
-
-  cairo_set_source (cr, pattern);
-  cairo_pattern_destroy (pattern);
-
-  cairo_rectangle (cr,
-                   x1, y2,
-                   x2 - x1, y3 - y2);
-  cairo_fill (cr);
-
-  /* Left border */
-
-  pattern = cairo_pattern_create_linear (x0, 0, x1, 0);
-
-  cairo_pattern_add_color_stop_rgba (pattern, 0.0, 0.0, 0, 0, 0.0);
-  cairo_pattern_add_color_stop_rgba (pattern, 1.0, 0.0, 0, 0, transparency);
-
-  cairo_set_source (cr, pattern);
-  cairo_pattern_destroy (pattern);
-
-  cairo_rectangle (cr,
-                   x0, y1,
-                   x1 - x0, y2 - y1);
-  cairo_fill (cr);
-
-  /* Right border */
-
-  pattern = cairo_pattern_create_linear (x2, 0, x3, 0);
-
-  cairo_pattern_add_color_stop_rgba (pattern, 0.0, 0.0, 0, 0, transparency);
-  cairo_pattern_add_color_stop_rgba (pattern, 1.0, 0.0, 0, 0, 0.0);
-
-  cairo_set_source (cr, pattern);
-  cairo_pattern_destroy (pattern);
-
-  cairo_rectangle (cr,
-                   x2, y1,
-                   x3 - x2, y2 - y1);
-  cairo_fill (cr);
-
-  /* NW corner */
-
-  pattern = cairo_pattern_create_radial (x1, y1, 0,
-                                         x1, y1, radius);
-
-  cairo_pattern_add_color_stop_rgba (pattern, 0.0, 0.0, 0, 0, transparency);
-  cairo_pattern_add_color_stop_rgba (pattern, 1.0, 0.0, 0, 0, 0.0);
-
-  cairo_set_source (cr, pattern);
-  cairo_pattern_destroy (pattern);
-
-  cairo_rectangle (cr,
-                   x0, y0,
-                   x1 - x0, y1 - y0);
-  cairo_fill (cr);
-
-  /* NE corner */
-
-  pattern = cairo_pattern_create_radial (x2, y1, 0,
-                                         x2, y1, radius);
-
-  cairo_pattern_add_color_stop_rgba (pattern, 0.0, 0.0, 0, 0, transparency);
-  cairo_pattern_add_color_stop_rgba (pattern, 1.0, 0.0, 0, 0, 0.0);
-
-  cairo_set_source (cr, pattern);
-  cairo_pattern_destroy (pattern);
-
-  cairo_rectangle (cr,
-                   x2, y0,
-                   x3 - x2, y1 - y0);
-  cairo_fill (cr);
-
-  /* SW corner */
-
-  pattern = cairo_pattern_create_radial (x1, y2, 0,
-                                         x1, y2, radius);
-
-  cairo_pattern_add_color_stop_rgba (pattern, 0.0, 0.0, 0, 0, transparency);
-  cairo_pattern_add_color_stop_rgba (pattern, 1.0, 0.0, 0, 0, 0.0);
-
-  cairo_set_source (cr, pattern);
-  cairo_pattern_destroy (pattern);
-
-  cairo_rectangle (cr,
-                   x0, y2,
-                   x1 - x0, y3 - y2);
-  cairo_fill (cr);
-
-  /* SE corner */
-
-  pattern = cairo_pattern_create_radial (x2, y2, 0,
-                                         x2, y2, radius);
-
-  cairo_pattern_add_color_stop_rgba (pattern, 0.0, 0.0, 0, 0, transparency);
-  cairo_pattern_add_color_stop_rgba (pattern, 1.0, 0.0, 0, 0, 0.0);
-
-  cairo_set_source (cr, pattern);
-  cairo_pattern_destroy (pattern);
-
-  cairo_rectangle (cr,
-                   x2, y2,
-                   x3 - x2, y3 - y2);
-  cairo_fill (cr);
-}
-
-static gboolean
-draw_callback (GtkWidget *widget,
-               cairo_t   *cr,
-               gpointer   data)
-{
-  GdkRectangle rect;
-
-  gtk_widget_get_allocation (widget, &rect);
-  rect.x += SHADOW_OFFSET_X;
-  rect.y += SHADOW_OFFSET_Y;
-  rect.width -= SHADOW_OFFSET_X;
-  rect.height -= SHADOW_OFFSET_Y;
-
-  draw_shadow_box (cr,
-                   rect, SHADOW_RADIUS, 0.4);
-
-  return FALSE;
-}
-
 GtkWidget *
 do_transparent (GtkWidget *do_widget)
 {
@@ -186,12 +12,12 @@ do_transparent (GtkWidget *do_widget)
 
   if (!window)
     {
-      GtkWidget *view;
       GtkWidget *sw;
       GtkWidget *overlay;
-      GtkWidget *entry;
-      GtkCssProvider *provider;
-      gchar *css;
+      GtkWidget *button;
+      GtkWidget *label;
+      GtkWidget *box;
+      GtkWidget *image;
 
       window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
       gtk_window_set_screen (GTK_WINDOW (window),
@@ -203,33 +29,42 @@ do_transparent (GtkWidget *do_widget)
 
       gtk_window_set_title (GTK_WINDOW (window), "Transparency");
 
-      view = gtk_text_view_new ();
+      overlay = gtk_overlay_new ();
+      gtk_container_add (GTK_CONTAINER (window), overlay);
+
+      button = gtk_button_new_with_label ("Don't click this button!");
+      label = gtk_bin_get_child (GTK_BIN (button));
+      g_object_set (label, "margin", 50, NULL);
+
+      gtk_widget_set_opacity (button, 0.7);
+      gtk_widget_set_halign (button, GTK_ALIGN_FILL);
+      gtk_widget_set_valign (button, GTK_ALIGN_START);
+
+      gtk_overlay_add_overlay (GTK_OVERLAY (overlay), button);
+      gtk_container_child_set (GTK_CONTAINER (overlay), button, "blur", 5.0, NULL);
+
+      button = gtk_button_new_with_label ("Maybe this one?");
+      label = gtk_bin_get_child (GTK_BIN (button));
+      g_object_set (label, "margin", 50, NULL);
+
+      gtk_widget_set_opacity (button, 0.7);
+      gtk_widget_set_halign (button, GTK_ALIGN_FILL);
+      gtk_widget_set_valign (button, GTK_ALIGN_END);
+
+      gtk_overlay_add_overlay (GTK_OVERLAY (overlay), button);
+      gtk_container_child_set (GTK_CONTAINER (overlay), button, "blur", 5.0, NULL);
 
       sw = gtk_scrolled_window_new (NULL, NULL);
+      sw = gtk_scrolled_window_new (NULL, NULL);
+      gtk_container_add (GTK_CONTAINER (overlay), sw);
       gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (sw),
                                       GTK_POLICY_AUTOMATIC,
                                       GTK_POLICY_AUTOMATIC);
-      gtk_container_add (GTK_CONTAINER (sw), view);
-
-      overlay = gtk_overlay_new ();
-      gtk_container_add (GTK_CONTAINER (overlay), sw);
-      gtk_container_add (GTK_CONTAINER (window), overlay);
+      box = gtk_box_new (GTK_ORIENTATION_VERTICAL, 0);
+      gtk_container_add (GTK_CONTAINER (sw), box);
+      image = gtk_image_new_from_resource ("/transparent/portland-rose.jpg");
 
-      entry = gtk_entry_new ();
-      provider = gtk_css_provider_new ();
-      css = g_strdup_printf ("* { border-width: 0px %dpx %dpx 0px; }",
-                             SHADOW_OFFSET_X, SHADOW_OFFSET_Y);
-      gtk_css_provider_load_from_data (provider, css, -1);
-      g_free (css);
-      gtk_style_context_add_provider (gtk_widget_get_style_context (entry),
-                                      GTK_STYLE_PROVIDER (provider),
-                                      GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
-      g_signal_connect (entry, "draw", G_CALLBACK (draw_callback), NULL);
-      gtk_overlay_add_overlay (GTK_OVERLAY (overlay), entry);
-      gtk_widget_set_halign (entry, GTK_ALIGN_CENTER);
-      gtk_widget_set_valign (entry, GTK_ALIGN_START);
-
-      gtk_widget_show (overlay);
+      gtk_container_add (GTK_CONTAINER (box), image);
     }
 
   if (!gtk_widget_get_visible (window))