From bbccf96981fa7db1152d5519c6edd2c5dde81d4f Mon Sep 17 00:00:00 2001
From: Pietro Gagliardi <pietro10@mac.com>
Date: Sun, 23 Mar 2014 21:31:29 -0400
Subject: [PATCH] Fixed the shrinking not working: the Cairo clip rect
 apparently can fall outside the actual size of the widget. (I did notice this
 before.)

---
 area_unix.go     | 7 +++++++
 gtkcalls_unix.go | 4 ----
 sysdata_unix.go  | 1 -
 test/main.go     | 1 -
 4 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/area_unix.go b/area_unix.go
index 83aafc5..8f9fc8f 100644
--- a/area_unix.go
+++ b/area_unix.go
@@ -45,11 +45,18 @@ func gtkAreaGetControl(scrollarea *gtkWidget) *gtkWidget {
 //export our_area_draw_callback
 func our_area_draw_callback(widget *C.GtkWidget, cr *C.cairo_t, data C.gpointer) C.gboolean {
 	var x, y, w, h C.double
+	var maxwid, maxht C.gint
 
 	s := (*sysData)(unsafe.Pointer(data))
 	// thanks to desrt in irc.gimp.net/#gtk+
 	C.cairo_clip_extents(cr, &x, &y, &w, &h)
 	cliprect := image.Rect(int(x), int(y), int(w), int(h))
+	// the cliprect can actually fall outside the size of the Area; clip it by intersecting the two rectangles
+	C.gtk_widget_get_size_request(widget, &maxwid, &maxht)
+	cliprect = image.Rect(0, 0, int(maxwid), int(maxht)).Intersect(cliprect)
+	if cliprect.Empty() {			// no intersection; nothing to paint
+		return C.FALSE			// signals handled without stopping the event chain (thanks to desrt again)
+	}
 	i := s.handler.Paint(cliprect)
 	// pixel order is [R G B A] (see Example 1 on https://developer.gnome.org/gdk-pixbuf/2.26/gdk-pixbuf-The-GdkPixbuf-Structure.html) so we don't have to convert anything
 	// gdk-pixbuf is not alpha-premultiplied (thanks to desrt in irc.gimp.net/#gtk+)
diff --git a/gtkcalls_unix.go b/gtkcalls_unix.go
index 3591e65..c7b409a 100644
--- a/gtkcalls_unix.go
+++ b/gtkcalls_unix.go
@@ -217,7 +217,3 @@ func gtk_progress_bar_set_fraction(w *gtkWidget, percent int) {
 func gtk_progress_bar_pulse(w *gtkWidget) {
 	C.gtk_progress_bar_pulse(togtkprogressbar(w))
 }
-
-func gtk_widget_queue_draw(widget *gtkWidget) {
-	C.gtk_widget_queue_draw(togtkwidget(widget))
-}
diff --git a/sysdata_unix.go b/sysdata_unix.go
index 6100606..be9a827 100644
--- a/sysdata_unix.go
+++ b/sysdata_unix.go
@@ -357,7 +357,6 @@ func (s *sysData) setAreaSize(width int, height int) {
 	uitask <- func() {
 		c := gtkAreaGetControl(s.widget)
 		gtk_widget_set_size_request(c, width, height)
-		gtk_widget_queue_draw(c)		// force repaint (TODO doesn't have an effect when shrinking?)
 		ret <- struct{}{}
 	}
 	<-ret
diff --git a/test/main.go b/test/main.go
index a2d683e..056ab1a 100644
--- a/test/main.go
+++ b/test/main.go
@@ -194,7 +194,6 @@ func areaTest() {
 			if err != nil { println(err); continue }
 			height, err := strconv.Atoi(heightbox.Text())
 			if err != nil { println(err); continue }
-println(width, height)
 			a.SetSize(width, height)
 		}
 	}