Add SetDebug

game.go

@@ -3,6 +3,7 @@ package etk
 import (
 	"fmt"
 	"image"
+	"image/color"
 	"math"
 	"runtime/debug"
 	"strings"
@@ -16,6 +17,8 @@ import (
 
 var root Widget
 
+var drawDebug bool
+
 var (
 	lastWidth, lastHeight int
 
@@ -34,6 +37,8 @@ var (
 	runeBuffer []rune
 )
 
+var debugColor = color.RGBA{0, 0, 255, 255}
+
 const (
 	backspaceRepeatWait = 500 * time.Millisecond
 	backspaceRepeatTime = 75 * time.Millisecond
@@ -103,6 +108,12 @@ func BoundString(f font.Face, s string) image.Rectangle {
 	return int26ToRect(bounds)
 }
 
+// SetDebug sets whether debug information is drawn on screen. When enabled,
+// all visible widgets are outlined.
+func SetDebug(debug bool) {
+	drawDebug = debug
+}
+
 // Layout sets the current screen size and resizes the root widget.
 func Layout(outsideWidth, outsideHeight int) {
 	if outsideWidth != lastWidth || outsideHeight != lastHeight {
@@ -318,6 +329,18 @@ func draw(w Widget, screen *ebiten.Image) error {
 		return fmt.Errorf("failed to draw widget: %s", err)
 	}
 
+	if drawDebug {
+		r := w.Rect()
+		if !r.Empty() {
+			x, y := r.Min.X, r.Min.Y
+			w, h := r.Dx(), r.Dy()
+			screen.SubImage(image.Rect(x, y, x+w, y+1)).(*ebiten.Image).Fill(debugColor)
+			screen.SubImage(image.Rect(x, y+h-1, x+w, y+h)).(*ebiten.Image).Fill(debugColor)
+			screen.SubImage(image.Rect(x, y, x+1, y+h)).(*ebiten.Image).Fill(debugColor)
+			screen.SubImage(image.Rect(x+w-1, y, x+w, y+h)).(*ebiten.Image).Fill(debugColor)
+		}
+	}
+
 	children := w.Children()
 	for _, child := range children {
 		err = draw(child, screen)