Introduce new viewport_size_changed signal

3 files changed, 108 insertions, 51 deletions

diff --git a/main.c b/main.c
index 8f4289c..03c1cd1 100644
--- a/main.c
+++ b/main.c
@@ -76,47 +76,61 @@ on_main_paint (FooScrollArea *scroll_area,
 }
 
 static void
-on_viewport_changed (FooScrollArea *scroll_area, 
-                     GdkRectangle  *viewport,
-                     GdkRectangle  *old_viewport)
+on_viewport_size_changed (FooScrollArea *scroll_area,
+			  GdkRectangle  *viewport,
+			  GdkRectangle  *old_viewport)
 {
-    int th;
+#if 0
     double ratio;
-
-    if (old_viewport)
-    {
-	slide_width = viewport->width - 2 * MARGIN;
-	slide_height = slide_width / RATIO;
-	
-	th = N_SLIDES * slide_height + (N_SLIDES + 1) * MARGIN;
-	
-	g_print ("new slide height: %d, new y: %d\n", slide_height, viewport->y);
-	
-	/* FIXME: We can recurse infinitely here when the area gets
-	 * narrow enough that the scrollbar disappears causing the area
-	 * to widen a little causing the scrollbar to appear causing
-	 * the arrow to narrow causing ...
-	 *
-	 * For now we work around by have POLICY_ALWAYS on the scrollbar,
-	 * it needs to be thought through and fixed in the scroll area
-	 */
-	
-	ratio = (double)viewport->width / old_viewport->width;
-	
-	g_print ("ratio: %f (%d %d)\n", ratio, old_viewport->y, (int)(old_viewport->y * ratio));
-	
-	foo_scroll_area_set_size_fixed_y (scroll_area, viewport->width, th,
-					  old_viewport->y + 100,
-					  (old_viewport->y + 100) * ratio + 0.5);
-    }
+    int th;
+    
+    g_print ("new slide height: %d, new y: %d\n", slide_height, viewport->y);
+    
+    /* FIXME: We can recurse infinitely here when the area gets
+     * narrow enough that the scrollbar disappears causing the area
+     * to widen a little causing the scrollbar to appear causing
+     * the arrow to narrow causing ...
+     *
+     * For now we work around by have POLICY_ALWAYS on the scrollbar,
+     * it needs to be thought through and fixed in the scroll area
+     */
+    
+    ratio = (double)viewport->width / old_viewport->width;
     
 #if 0
-    foo_scroll_area_set_size (scroll_area, viewport->width, th);
+    g_print ("ratio: %f (%d %d)\n", ratio, old_viewport->y, (int)(old_viewport->y * ratio));
+    
+    g_print ("old, new: %f %f\n", slide_n, MARGIN + slide_n * (MARGIN + (double)slide_height));
 #endif
+    
+    foo_scroll_area_set_size_fixed_y (scroll_area, viewport->width, th,
+				      slide_n,
+				      MARGIN + slide_n * (MARGIN + slide_height));
+#endif
+    
+    int th;
+    double slide_n;
+    
+    slide_width = viewport->width - 2 * MARGIN;
+    slide_height = slide_width / RATIO;
+    
+    th = N_SLIDES * slide_height + (N_SLIDES + 1) * MARGIN;
+    foo_scroll_area_set_size (scroll_area, viewport->width, th);
+
+    g_print ("size changed - set size %d %d\n", viewport->width, th);
+    
     foo_scroll_area_invalidate (scroll_area);
 }
 
 static void
+on_viewport_changed (FooScrollArea *scroll_area, 
+                     GdkRectangle  *viewport,
+                     GdkRectangle  *old_viewport)
+{
+    g_print ("viewport changed\n");
+}
+
+static void
 set_size (GtkWindow *window)
 {
     GdkScreen *screen;
@@ -146,8 +160,8 @@ main (int argc, char **argv)
     app = g_new0 (App, 1);
     app->xml = glade_xml_new (GLADE_FILE, NULL, NULL);
     
-    app->main_area = foo_scroll_area_new();
-    app->thumbnails = foo_scroll_area_new();
+    app->main_area = (FooScrollArea *)foo_scroll_area_new();
+    app->thumbnails = (FooScrollArea *)foo_scroll_area_new();
 
     gtk_container_add (
 	GTK_CONTAINER (get_widget (app, "main_area_scrolled_window")),
@@ -163,6 +177,8 @@ main (int argc, char **argv)
 		      G_CALLBACK (on_main_paint), app);
     g_signal_connect (app->main_area, "viewport_changed",
 		      G_CALLBACK (on_viewport_changed), app);
+    g_signal_connect (app->main_area, "viewport_size_changed",
+		      G_CALLBACK (on_viewport_size_changed), app);
     
     g_signal_connect (app->thumbnails, "paint",
 		      G_CALLBACK (on_thumbs_paint), app);
diff --git a/scrollarea.c b/scrollarea.c
index b5a85f6..1d88534 100644
--- a/scrollarea.c
+++ b/scrollarea.c
@@ -83,6 +83,7 @@ struct FooScrollAreaPrivate
 
 enum
 {
+    VIEWPORT_SIZE_CHANGED,
     VIEWPORT_CHANGED,
     PAINT,
     INPUT,
@@ -178,7 +179,21 @@ foo_scroll_area_class_init (FooScrollAreaClass *class)
     class->set_scroll_adjustments = foo_scroll_area_set_scroll_adjustments;
     
     parent_class = g_type_class_peek_parent (class);
-    
+
+    /* Emitted when the viewport changes size, but not when it only changes position */
+    signals[VIEWPORT_SIZE_CHANGED] =
+	g_signal_new ("viewport_size_changed",
+		      G_OBJECT_CLASS_TYPE (object_class),
+		      G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,
+		      G_STRUCT_OFFSET (FooScrollAreaClass,
+				       viewport_size_changed),
+		      NULL, NULL,
+		      foo_marshal_VOID__BOXED_BOXED,
+		      G_TYPE_NONE, 2,
+		      GDK_TYPE_RECTANGLE,
+		      GDK_TYPE_RECTANGLE);
+
+    /* Emitted when the viewport changes position or size or both */
     signals[VIEWPORT_CHANGED] =
 	g_signal_new ("viewport_changed",
 		      G_OBJECT_CLASS_TYPE (object_class),
@@ -617,24 +632,45 @@ process_event (FooScrollArea	       *scroll_area,
 	       int			button);
 
 static void
-emit_viewport_changed (FooScrollArea *scroll_area,
+emit_viewport_signals (FooScrollArea *scroll_area,
 		       GdkRectangle  *new_viewport,
 		       GdkRectangle  *old_viewport)
 {
     int px, py;
+    gboolean position_changed;
+    gboolean size_changed;
 
-    g_signal_emit (scroll_area, signals[VIEWPORT_CHANGED], 0, 
-		   new_viewport, old_viewport);
-
-    if (new_viewport->x != old_viewport->x		||
-	new_viewport->y != old_viewport->y		||
-	new_viewport->width != old_viewport->width	||
-	new_viewport->height != old_viewport->height)
+    size_changed = (new_viewport->width != old_viewport->width ||
+		    new_viewport->height != old_viewport->height);
+    
+    position_changed = (new_viewport->x != old_viewport->x ||
+			new_viewport->y != old_viewport->y);
+    
+    if (size_changed || position_changed)
     {
+	g_signal_emit (scroll_area, signals[VIEWPORT_CHANGED], 0, 
+		       new_viewport, old_viewport);
+
+	if (size_changed)
+	{
+	    g_signal_emit (scroll_area, signals[VIEWPORT_SIZE_CHANGED], 0,
+			   new_viewport, old_viewport);
+	}
+	else
+	{
+	    g_print ("old size: %d %d\n", old_viewport->width, old_viewport->height);
+	    g_print ("new size: %d %d\n", new_viewport->width, new_viewport->height);
+	}
+	    
 	gdk_window_get_pointer (GTK_WIDGET (scroll_area)->window, &px, &py, NULL);
-	
+	    
 	process_event (scroll_area, FOO_MOTION, px, py, 0);
     }
+    else
+    {
+	g_print ("old pos: %d %d\n", old_viewport->x, old_viewport->y);
+	g_print ("new pos: %d %d\n", new_viewport->x, new_viewport->y);
+    }
 }
 
 static void
@@ -660,7 +696,7 @@ set_adjustment_values (FooScrollArea *scroll_area)
     
     GtkAdjustment *hadj = scroll_area->priv->hadj;
     GtkAdjustment *vadj = scroll_area->priv->vadj;
-    
+
     /* Horizontal */
     hadj->page_size = allocation->width;
     hadj->step_increment = 0.1 * allocation->width;
@@ -674,7 +710,7 @@ set_adjustment_values (FooScrollArea *scroll_area)
     vadj->page_increment = 0.9 * allocation->height;
     vadj->lower = 0.0;
     vadj->upper = scroll_area->priv->height;
-    
+
     clamp_adjustment (hadj);
     clamp_adjustment (vadj);
     
@@ -688,8 +724,6 @@ foo_scroll_area_realize (GtkWidget *widget)
     GdkWindowAttr attributes;
     gint attributes_mask;
 
-    g_print ("realizing\n");
-    
     GTK_WIDGET_SET_FLAGS (widget, GTK_REALIZED);
     
     attributes.window_type = GDK_WINDOW_CHILD;
@@ -787,7 +821,7 @@ foo_scroll_area_size_allocate (GtkWidget     *widget,
     
     get_viewport (scroll_area, &new_viewport);
 
-    emit_viewport_changed (scroll_area, &new_viewport, &old_viewport);
+    emit_viewport_signals (scroll_area, &new_viewport, &old_viewport);
 }
 
 static void
@@ -1181,6 +1215,8 @@ foo_scrollbar_adjustment_changed (GtkAdjustment *adj,
     gint dy = 0;
     GdkRectangle old_viewport, new_viewport;
 
+    g_print ("adjustment changed\n");
+    
     /* FIXME: When dragging diagonally, this function will be called
      * twice, causing two separate scrolls in the backing store.
      *
@@ -1216,7 +1252,7 @@ foo_scrollbar_adjustment_changed (GtkAdjustment *adj,
     
     get_viewport (scroll_area, &new_viewport);
     
-    emit_viewport_changed (scroll_area, &new_viewport, &old_viewport);
+    emit_viewport_signals (scroll_area, &new_viewport, &old_viewport);
 }
 
 static void
diff --git a/scrollarea.h b/scrollarea.h
index 1c95c9a..5a5236f 100644
--- a/scrollarea.h
+++ b/scrollarea.h
@@ -48,7 +48,12 @@ struct FooScrollAreaClass
 				    GtkAdjustment *vadjustment);
 
     void (*viewport_changed) (FooScrollArea *scroll_area,
-			      GdkRectangle  *viewport);
+			      GdkRectangle  *viewport,
+			      GdkRectangle  *old_viewport);
+
+    void (*viewport_size_changed) (FooScrollArea *scroll_area,
+				   GdkRectangle  *viewport,
+				   GdkRectangle  *old_viewport);
 
     void (*paint) (FooScrollArea *scroll_area,
 		   cairo_t       *cr,