Finished the Area.Repaint() test and fixed found bugs. There's some weird issue left in GTK+ Areas...

redo/area_unix.go

@@ -75,7 +75,8 @@ func (a *area) Repaint(r image.Rectangle) {
 	if r.Empty() {
 		return
 	}
-	C.gtk_widget_queue_draw_area(a._widget, C.gint(r.Min.X), C.gint(r.Max.Y), C.gint(r.Dx()), C.gint(r.Dy()))
+println(a._widget, C.gint(r.Min.X), C.gint(r.Min.Y), C.gint(r.Dx()), C.gint(r.Dy()))
+	C.gtk_widget_queue_draw_area(a._widget, C.gint(r.Min.X), C.gint(r.Min.Y), C.gint(r.Dx()), C.gint(r.Dy()))
 }
 
 func (a *area) RepaintAll() {

redo/future

@@ -17,9 +17,7 @@ Tab
 		// After Delete(), the effect of accessing the Control of the deleted tab or any of its children is undefned. [TODO reword?]
 	investigate close buttons (especially for LikeTab)
 Area
-	Repaint(rect image.Rectangle)
 	keyboard scrolling
-		GTK+ port: our_area_focus_callback() has something to do with it
 	OpenTextFieldAt() and OpenTextAreaAt() to allow editing of text from within Areas
 Tree
 	Mac OS X: make sure newScrollView() has the correct parameters for Table and Tree (and that Area has the appropriate ones from both + its own no border)

redo/yz_repaint_test.go

@@ -4,6 +4,9 @@ package ui
 
 import (
 	"image"
+	"image/color"
+	"image/draw"
+	"strconv"
 )
 
 type repainter struct {
@@ -16,6 +19,11 @@ type repainter struct {
 	repaint	Button
 	all		Button
 	stack	Stack
+
+	xv		int
+	yv		int
+	wv		int
+	hv		int
 }
 
 func newRepainter(times int) *repainter {
@@ -23,11 +31,17 @@ func newRepainter(times int) *repainter {
 	r.img = tileImage(times)
 	r.area = NewArea(r.img.Rect.Dx(), r.img.Rect.Dy(), r)
 	r.x = NewTextField()
+	r.x.OnChanged(r.setx)
 	r.y = NewTextField()
+	r.y.OnChanged(r.sety)
 	r.width = NewTextField()
+	r.width.OnChanged(r.setwidth)
 	r.height = NewTextField()
+	r.height.OnChanged(r.setheight)
 	r.repaint = NewButton("Rect")
+	r.repaint.OnClicked(r.dorect)
 	r.all = NewButton("All")
+	r.all.OnClicked(r.doall)
 	r.stack = NewHorizontalStack(r.x, r.y, r.width, r.height, r.repaint, r.all)
 	r.stack.SetStretchy(0)
 	r.stack.SetStretchy(1)
@@ -44,3 +58,58 @@ func  (r *repainter) Paint(rect image.Rectangle) *image.RGBA {
 
 func (r *repainter) Mouse(me MouseEvent) {}
 func (r *repainter) Key(ke KeyEvent) bool { return false }
+
+func (r *repainter) setx() {
+	i, err := strconv.Atoi(r.x.Text())
+	if err != nil {
+		r.x.Invalid(err.Error())
+		return
+	}
+	r.x.Invalid("")
+	r.xv = i
+}
+
+func (r *repainter) sety() {
+	i, err := strconv.Atoi(r.y.Text())
+	if err != nil {
+		r.y.Invalid(err.Error())
+		return
+	}
+	r.y.Invalid("")
+	r.yv = i
+}
+
+func (r *repainter) setwidth() {
+	i, err := strconv.Atoi(r.width.Text())
+	if err != nil {
+		r.width.Invalid(err.Error())
+		return
+	}
+	r.width.Invalid("")
+	r.wv = i
+}
+
+func (r *repainter) setheight() {
+	i, err := strconv.Atoi(r.height.Text())
+	if err != nil {
+		r.height.Invalid(err.Error())
+		return
+	}
+	r.height.Invalid("")
+	r.hv = i
+}
+
+func (r *repainter) alter(rect image.Rectangle, c color.Color) {
+	draw.Draw(r.img, rect, &image.Uniform{c}, image.ZP, draw.Over)
+}
+
+func (r *repainter) dorect() {
+	rect := image.Rect(r.xv, r.yv, r.xv + r.wv, r.yv + r.hv)
+	r.alter(rect, color.RGBA{255, 0, 255, 128})
+	r.area.Repaint(rect)
+}
+
+func (r *repainter) doall() {
+	r.alter(r.img.Rect, color.RGBA{255, 255, 0, 128})
+	r.area.RepaintAll()
+}