Added clipping for Overflow/ScrollControl.

ui/overflow.go

@@ -11,6 +11,9 @@ type overflow struct {
 
 	Background color.Color
 
+	ClipHorizontal bool
+	ClipVertical   bool
+
 	barWidth float32
 	desired  geom.PointF32
 	bounds   geom.RectangleF32
@@ -26,18 +29,30 @@ type overflow struct {
 type ScrollControl interface {
 	Control
 
+	SetBackgroundColor(color.Color)
+	SetClipHorizontal(bool)
+	SetClipVertical(bool)
 	SetScrollbarColor(bar color.Color, hover color.Color)
 }
 
+func BuildOverflow(content Control, build func(c ScrollControl)) ScrollControl {
+	o := &overflow{Proxy: Proxy{Content: content}}
+	o.hor = BuildScrollbar(OrientationHorizontal, func(*Scrollbar) {})
+	o.ver = BuildScrollbar(OrientationVertical, func(*Scrollbar) {})
+	if build != nil {
+		build(o)
+	}
+	return o
+}
+
 func Overflow(content Control) ScrollControl {
 	return OverflowBackground(content, nil)
 }
 
 func OverflowBackground(content Control, back color.Color) ScrollControl {
-	var o = &overflow{Proxy: Proxy{Content: content}, Background: back}
+	return BuildOverflow(content, func(c ScrollControl) {
-	o.hor = BuildScrollbar(OrientationHorizontal, func(*Scrollbar) {})
+		c.SetBackgroundColor(back)
-	o.ver = BuildScrollbar(OrientationVertical, func(*Scrollbar) {})
+	})
-	return o
 }
 
 func (o *overflow) shouldScroll(bounds geom.RectangleF32) (hor bool, ver bool) {
@@ -53,6 +68,8 @@ func (o *overflow) shouldScroll(bounds geom.RectangleF32) (hor bool, ver bool) {
 	if hor && !ver {
 		ver = scroll(size.Y+o.barWidth, bounds.Dy())
 	}
+	hor = hor && !o.ClipHorizontal
+	ver = ver && !o.ClipVertical
 	return
 }
 
@@ -158,6 +175,17 @@ func (o *overflow) Render(ctx Context) {
 		bar.Render(ctx)
 	})
 }
+func (o *overflow) SetBackgroundColor(c color.Color) {
+	o.Background = c
+}
+
+func (o *overflow) SetClipHorizontal(clip bool) {
+	o.ClipHorizontal = clip
+}
+
+func (o *overflow) SetClipVertical(clip bool) {
+	o.ClipVertical = clip
+}
 
 func (o *overflow) SetScrollbarColor(bar color.Color, hover color.Color) {
 	o.hor.BarColor = bar