Add SetTextureCenter

box.go

@@ -9,6 +9,11 @@ import "git.tebibyte.media/tomo/tomo/input"
 import "git.tebibyte.media/tomo/tomo/event"
 import "git.tebibyte.media/tomo/tomo/canvas"
 
+type textureMode int; const (
+	textureModeTile textureMode = iota
+	textureModeCenter
+)
+
 type box struct {
 	backend *Backend
 	parent   parent
@@ -26,6 +31,7 @@ type box struct {
 	border      []tomo.Border
 	color       color.Color
 	texture     *xcanvas.Texture
+	textureMode textureMode
 
 	dndData   data.Data
 	dndAccept []data.Mime
@@ -116,12 +122,20 @@ func (this *box) SetColor (c color.Color) {
 	this.invalidateDraw()
 }
 
-func (this *box) SetTexture (texture canvas.Texture) {
-	if this.texture == texture { return }
+func (this *box) SetTextureTile (texture canvas.Texture) {
+	if this.texture == texture && this.textureMode == textureModeTile { return }
+	this.textureMode = textureModeTile
 	this.texture = xcanvas.AssertTexture(texture)
 	this.invalidateDraw()
 }
 
+func (this *box) SetTextureCenter (texture canvas.Texture) {
+	if this.texture == texture && this.textureMode == textureModeCenter { return }
+	this.texture = xcanvas.AssertTexture(texture)
+	this.textureMode = textureModeCenter
+	this.invalidateDraw()
+}
+
 func (this *box) SetBorder (borders ...tomo.Border) {
 	previousBorderSum := this.borderSum()
 	previousBorders   := this.border
@@ -299,13 +313,30 @@ func (this *box) handleKeyUp (key input.Key, numberPad bool) {
 func (this *box) Draw (can canvas.Canvas) {
 	if can == nil { return }
 	pen := can.Pen()
-	pen.Fill(this.color)
-	pen.Texture(this.texture)
+	bounds := this.Bounds()
 
+	// background
+	pen.Fill(this.color)
+	if this.textureMode == textureModeTile {
+		pen.Texture(this.texture)
+	}
 	if this.transparent() && this.parent != nil {
 		this.parent.drawBackgroundPart(can)
 	}
-	pen.Rectangle(this.Bounds())
+	pen.Rectangle(bounds)
+
+	// centered texture
+	if this.textureMode == textureModeCenter {
+		textureBounds := this.texture.Bounds()
+		textureOrigin := image.Pt (
+			textureBounds.Dx() / -2,
+			textureBounds.Dy() / -2).
+			Add(bounds.Min)
+	
+		pen.Fill(color.Transparent)
+		pen.Texture(this.texture)
+		pen.Rectangle(textureBounds.Sub(textureBounds.Min).Add(textureOrigin))
+	}
 }
 
 func (this *box) drawBorders (can canvas.Canvas) {