Added OnSelectedChanged to Checkbox.

Updated graphics for Checkbox.

ui/checkbox.go

@@ -4,9 +4,13 @@ import (
 	"opslag.de/schobers/geom"
 )
 
+type SelectedChangedFn func(ctx Context, c Control, selected bool)
+
 type Checkbox struct {
 	ControlBase
 
+	onSelectedChanged SelectedChangedFn
+
 	Selected bool
 	Text     string
 }
@@ -26,15 +30,21 @@ func (c *Checkbox) desiredSize(ctx Context) geom.PointF32 {
 	if len(c.Text) != 0 {
 		w += pad + font.WidthOf(c.Text)
 	}
-	icon, _ := ctx.Images().ScaledHeight(c.icon(ctx, false), h)
+	icon, _ := ctx.Images().ScaledHeight(c.getOrCreateNormalIcon(ctx), h)
 	w += pad + icon.Width()
 	return geom.PtF32(w+pad, pad+h+pad)
 }
 
-func (c *Checkbox) icon(ctx Context, selected bool) Image {
+func (c *Checkbox) icon(ctx Context) Image {
-	if selected {
+	if c.Selected {
 		return GetOrCreateIcon(ctx, "ui-default-checkbox-selected", c.selectedIcon)
+	} else if c.over {
+		return GetOrCreateIcon(ctx, "ui-default-checkbox-hover", c.hoverIcon)
 	}
+	return c.getOrCreateNormalIcon(ctx)
+}
+
+func (c *Checkbox) getOrCreateNormalIcon(ctx Context) Image {
 	return GetOrCreateIcon(ctx, "ui-default-checkbox", c.normalIcon)
 }
 
@@ -47,6 +57,22 @@ func (c *Checkbox) iconBorder() geom.PolygonF32 {
 	)
 }
 
+func (c *Checkbox) checkMark() geom.PointsF32 {
+	return geom.PointsF32{
+		geom.PtF32(96, 256),
+		geom.PtF32(180, 340),
+		geom.PtF32(340, 150),
+	}
+}
+
+func (c *Checkbox) hoverIcon() IconPixelTestFn {
+	border := c.iconBorder()
+	check := c.checkMark()
+	return func(pt geom.PointF32) bool {
+		return (pt.DistanceToPolygon(border) < 48 && !pt.InPolygon(border)) || pt.DistanceToLines(check) < 24
+	}
+}
+
 func (c *Checkbox) normalIcon() IconPixelTestFn {
 	border := c.iconBorder()
 	return func(pt geom.PointF32) bool {
@@ -56,11 +82,7 @@ func (c *Checkbox) normalIcon() IconPixelTestFn {
 
 func (c *Checkbox) selectedIcon() IconPixelTestFn {
 	border := c.iconBorder()
-	check := geom.PointsF32{
+	check := c.checkMark()
-		geom.PtF32(84, 256),
-		geom.PtF32(180, 352),
-		geom.PtF32(352, 150),
-	}
 	return func(pt geom.PointF32) bool {
 		if pt.DistanceToPolygon(border) < 48 || pt.InPolygon(border) {
 			return pt.DistanceToLines(check) > 24
@@ -76,6 +98,10 @@ func (c *Checkbox) Handle(ctx Context, e Event) {
 	case *MouseButtonDownEvent:
 		if e.Button == MouseButtonLeft && c.over {
 			c.Selected = !c.Selected
+			onSelectedChanged := c.onSelectedChanged
+			if onSelectedChanged != nil {
+				onSelectedChanged(ctx, c, c.Selected)
+			}
 		}
 	}
 	c.ControlBase.Handle(ctx, e)
@@ -84,23 +110,25 @@ func (c *Checkbox) Handle(ctx Context, e Event) {
 	}
 }
 
+func (c *Checkbox) OnSelectedChanged(fn SelectedChangedFn) {
+	c.onSelectedChanged = fn
+}
+
 func (c *Checkbox) Render(ctx Context) {
+	c.RenderBackground(ctx)
+
 	var style = ctx.Style()
 	var palette = style.Palette
 	fore := c.FontColor(ctx)
-	size := c.desiredSize(ctx)
 	bounds := c.bounds
-	deltaX, deltaY := bounds.Dx()-size.X, bounds.Dy()-size.Y
-	bounds.Min.X += .5 * deltaX
-	bounds.Min.Y += .5 * deltaY
 
 	var pad = style.Dimensions.TextPadding
 	bounds = bounds.Inset(pad)
 	pos := bounds.Min
-	icon, _ := ctx.Images().ScaledHeight(c.icon(ctx, c.Selected), bounds.Dy())
+	icon, _ := ctx.Images().ScaledHeight(c.icon(ctx), bounds.Dy())
 	if icon != nil {
 		iconColor := fore
-		if c.Selected {
+		if c.Selected && c.Font.Color == nil {
 			iconColor = palette.Primary
 		}
 		ctx.Renderer().DrawImageOptions(icon, geom.PtF32(pos.X, pos.Y+.5*(bounds.Dy()-icon.Height())), DrawOptions{Tint: iconColor})