Hacked around the cairo issue for now; hooked everything together and fixed a few things. Added the Area test to the test program. Now to just hook up the draw event.

area_unix.go

@@ -1,25 +1,32 @@
-// +build ignore
-// (ignored pending Go issues 7409 and 7548)
-// x+build !windows,!darwin,!plan9
+// +build !windows,!darwin,!plan9
 
 // 14 march 2014
 
 package ui
 
 import (
+	"unsafe"
 	"image"
 )
 
 // #cgo pkg-config: gtk+-3.0
+// /* GTK+ 3.8 deprecates gtk_scrolled_window_add_with_viewport(); we need 3.4 miniimum though
+// setting MIN_REQUIRED ensures nothing older; setting MAX_ALLOWED disallows newer functions - thanks to desrt in irc.gimp.net/#gtk+
+// TODO add this to the other files too */
+// #define GDK_VERSION_MIN_REQUIRED GDK_VERSION_3_4
+// #define GDK_VERSION_MAX_ALLOWED GDK_VERSION_3_4
 // #include <gtk/gtk.h>
 // extern gboolean our_draw_callback(GtkWidget *, cairo_t *, gpointer);
+// /* HACK - see https://code.google.com/p/go/issues/detail?id=7548 */
+// struct _cairo {};
 import "C"
 
 func gtkAreaNew() *gtkWidget {
 	drawingarea := C.gtk_drawing_area_new()
+	C.gtk_widget_set_size_request(drawingarea, 320, 240)
 	scrollarea := C.gtk_scrolled_window_new((*C.GtkAdjustment)(nil), (*C.GtkAdjustment)(nil))
 	// need a viewport because GtkDrawingArea isn't natively scrollable
-	C.gtk_scrolled_window_add_with_viewport(scrollarea, drawingarea)
+	C.gtk_scrolled_window_add_with_viewport((*C.GtkScrolledWindow)(unsafe.Pointer(scrollarea)), drawingarea)
 	return fromgtkwidget(scrollarea)
 }
 
@@ -54,7 +61,7 @@ func our_draw_callback(widget *C.GtkWidget, cr *C.cairo_t, data C.gpointer) C.gb
 		C.gdouble(cliprect.Min.X),
 		C.gdouble(cliprect.Min.Y))
 	C.g_object_unref((C.gpointer)(unsafe.Pointer(pixbuf)))		// free pixbuf
-	return C.FALSE		// TODO what does this return value mean? docs don't say
+	return C.FALSE		// signals handled without stopping the event chain (thanks to desrt again)
 }
 
 var draw_callback = C.GCallback(C.our_draw_callback)

sysdata_unix.go

@@ -92,6 +92,9 @@ var classTypes = [nctypes]*classData{
 	c_progressbar:		&classData{
 		make:		gtk_progress_bar_new,
 	},
+	c_area:			&classData{
+		make:		gtkAreaNew,
+	},
 }
 
 func (s *sysData) make(initText string, window *sysData) error {

test/main.go

@@ -4,6 +4,9 @@ package main
 import (
 	"fmt"
 	"flag"
+	"image"
+	"image/color"
+	"image/draw"
 	. "github.com/andlabs/ui"
 )
 
@@ -110,7 +113,43 @@ func invalidTest(c *Combobox, l *Listbox, s *Stack, g *Grid) {
 
 var invalidBefore = flag.Bool("invalid", false, "run invalid test before opening window")
 
+var doArea = flag.Bool("area", false, "run area test instead")
+func areaTest() {
+	img := [2]*image.NRGBA{}
+	img[0] = image.NewNRGBA(image.Rect(0, 0, 320, 240))
+	color0 := color.NRGBA{128, 128, 0, 255}
+	draw.Draw(img[0], img[0].Rect, image.NewUniform(color0), image.ZP, draw.Over)
+	img[1] = image.NewNRGBA(image.Rect(0, 0, 320, 240))
+	color1 := color.NRGBA{0, 128, 128, 255}
+	draw.Draw(img[1], img[1].Rect, image.NewUniform(color1), image.ZP, draw.Over)
+	i := 0
+	lastrect := image.ZR
+	w := NewWindow("Area Test", 100, 100)
+	a := NewArea()
+	err := w.Open(a)
+	if err != nil {
+		panic(err)
+	}
+	for {
+		select {
+		case <-w.Closing:
+			return
+		case req := <-a.Paint:
+fmt.Println(req)
+			req.Out <- img[i].SubImage(req.Rect).(*image.NRGBA)
+			if lastrect != req.Rect {
+				lastrect = req.Rect
+				i = 1 - i
+			}
+		}
+	}
+}
+
 func myMain() {
+	if *doArea {
+		areaTest()
+		return
+	}
 	w := NewWindow("Main Window", 320, 240)
 	b := NewButton("Click Me")
 	b2 := NewButton("Or Me")