Added support for a fixed icon height on buttons.

ui/button.go

@@ -10,7 +10,8 @@ type Button struct {
 	ControlBase
 
 	HoverColor color.Color
-	Icon       string
+	Icon       string  // optional: icon to display in front of the text.
+	IconHeight float32 // overrides the height of the icon (overrides auto-scaling when text is provided).
 	Text       string
 	Type       ButtonType
 
@@ -40,25 +41,40 @@ func (b *Button) desiredSize(ctx Context) geom.PointF32 {
 	var pad = ctx.Style().Dimensions.TextPadding
 	var font = ctx.Fonts().Font(b.FontName(ctx))
 	var w, h float32 = 0, font.Height()
-	if len(b.Text) != 0 {
+
-		w += pad + font.WidthOf(b.Text)
+	icon, iconW, iconH := b.icon(ctx)
+	if len(b.Text) == 0 {
+		if icon != nil && iconH > 0 {
+			w = pad + iconW + pad
+			h = iconH
+		}
+	} else {
+		w += pad + font.WidthOf(b.Text) + pad
+		if icon != nil && iconH > 0 {
+			if b.IconHeight == 0 {
+				iconW = iconW * h / iconH
+				// iconH = h
+			}
+			w += iconW + pad
 		}
-	icon := b.icon(ctx)
-	if icon != nil && icon.Height() > 0 {
-		iconW := icon.Width() * h / icon.Height()
-		w += pad + iconW
 	}
 	if w == 0 {
 		return geom.ZeroPtF32
 	}
-	return geom.PtF32(w+pad, pad+h+pad)
+	return geom.PtF32(w, pad+h+pad)
 }
 
-func (b *Button) icon(ctx Context) Texture {
+func (b *Button) icon(ctx Context) (Texture, float32, float32) {
 	if b.Icon == "" {
-		return nil
+		return nil, 0, 0
 	}
-	return ctx.Textures().Texture(b.Icon)
+	icon := ctx.Textures().Texture(b.Icon)
+	iconW, iconH := icon.Width(), icon.Height()
+	if b.IconHeight != 0 {
+		iconW = b.IconHeight * iconW / iconH
+		iconH = b.IconHeight
+	}
+	return icon, iconW, iconH
 }
 
 func (b *Button) ButtonClicked() ControlClickedEventHandler { return &b.clicked }
@@ -92,6 +108,10 @@ func (b *Button) Notify(ctx Context, state interface{}) bool {
 }
 
 func (b *Button) fillColor(p *Palette) color.Color {
+	if b.Type == ButtonTypeIcon {
+		return nil
+	}
+
 	if b.Disabled {
 		if b.Background != nil {
 			return p.Disabled
@@ -116,7 +136,6 @@ func (b *Button) fillColor(p *Palette) color.Color {
 		switch b.Type {
 		case ButtonTypeContained:
 			return p.PrimaryLight
-		case ButtonTypeIcon:
 		default:
 			return p.PrimaryHighlight
 		}
@@ -124,8 +143,6 @@ func (b *Button) fillColor(p *Palette) color.Color {
 	switch b.Type {
 	case ButtonTypeContained:
 		return p.Primary
-	case ButtonTypeIcon:
-	default:
 	}
 	return nil
 }
@@ -149,6 +166,9 @@ func (b *Button) textColor(p *Palette) color.Color {
 		return p.TextOnPrimary
 	case ButtonTypeIcon:
 		if b.over {
+			if b.HoverColor != nil {
+				return b.HoverColor
+			}
 			return p.Primary
 		}
 		return p.Text
@@ -175,15 +195,22 @@ func (b *Button) Render(ctx Context) {
 	bounds = bounds.Inset(pad)
 	boundsH := bounds.Dy()
 	pos := bounds.Min
-	icon := b.icon(ctx)
+	icon, iconW, iconH := b.icon(ctx)
-	if icon != nil && icon.Height() > 0 {
+	var iconOffsetY float32
-		scaled, _ := ctx.Textures().ScaledHeight(icon, boundsH) // try to pre-scale scaled
+	if icon != nil && iconH > 0 {
-		if scaled == nil {                                      // let the renderer scale
+		if b.Text != "" {
-			scaled = icon
+			if b.IconHeight == 0 {
+				iconH = boundsH
+				scaled, _ := ctx.Textures().ScaledHeight(icon, iconH) // try to pre-scale scaled
+				if scaled != nil {                                    // let the renderer scale
+					icon = scaled
 				}
-		_, iconWidth := ScaleToHeight(SizeOfTexture(scaled), boundsH)
+				_, iconW = ScaleToHeight(SizeOfTexture(icon), iconH)
-		ctx.Renderer().DrawTextureOptions(scaled, geom.RectRelF32(pos.X, pos.Y, iconWidth, boundsH), DrawOptions{Tint: textColor})
+			}
-		pos.X += iconWidth + pad
+			iconOffsetY = .5 * (boundsH - iconH)
+		}
+		ctx.Renderer().DrawTextureOptions(icon, geom.RectRelF32(pos.X, pos.Y+iconOffsetY, iconW, iconH), DrawOptions{Tint: textColor})
+		pos.X += iconW + pad
 	}
 	if len(b.Text) != 0 {
 		fontName := b.FontName(ctx)