add text label widget

2 files changed, 34 insertions, 8 deletions

diff --git a/gui/widget/text.go b/gui/widget/text.go
index 4723eda..5e37d70 100644
--- a/gui/widget/text.go
+++ b/gui/widget/text.go
@@ -14,11 +14,12 @@ import (
 )
 
 var (
-	FONT               = goregular.TTF
-	FONT_SIZE  float64 = 15
-	DPI        float64 = 72
-	BG_COLOR           = image.White
-	TEXT_COLOR         = image.Black
+	FONT       = goregular.TTF
+	FONT_SIZE  = 15
+	DPI        = 72
+	PADDING    = 3
+	BG_COLOR   = image.White
+	TEXT_COLOR = image.Black
 )
 
 var face *concurrentFace
@@ -29,8 +30,8 @@ func init() {
 		log.Fatal(err)
 	}
 	fce, err := opentype.NewFace(fnt, &opentype.FaceOptions{
-		Size: FONT_SIZE,
-		DPI:  DPI,
+		Size: float64(FONT_SIZE),
+		DPI:  float64(DPI),
 	})
 	if err != nil {
 		log.Fatal(err)
@@ -38,6 +39,14 @@ func init() {
 	face = &concurrentFace{sync.Mutex{}, fce}
 }
 
+func TextWidth(nchars int) int {
+	return nchars*FONT_SIZE + 2*PADDING // very rough estimation
+}
+
+func TextHeight() int {
+	return FONT_SIZE + 2*PADDING
+}
+
 func drawText(text []byte, dst draw.Image, r image.Rectangle) {
 	drawer := font.Drawer{
 		Src:  TEXT_COLOR,
diff --git a/gui/widget/widget.go b/gui/widget/widget.go
index fbf866a..82738bd 100644
--- a/gui/widget/widget.go
+++ b/gui/widget/widget.go
@@ -11,7 +11,24 @@ import (
 	"volute/gui/win"
 )
 
-func Input(env gui.Env, r image.Rectangle, val chan<- float64) {
+func Label(text string, r image.Rectangle, env gui.Env) {
+	redraw := func(drw draw.Image) image.Rectangle {
+		drawText([]byte(text), drw, r)
+		return r
+	}
+	env.Draw() <- redraw
+	for event := range env.Events() {
+		switch event := event.(type) {
+		case win.WiFocus:
+			if event.Focused {
+				env.Draw() <- redraw
+			}
+		}
+	}
+	close(env.Draw())
+}
+
+func Input(val chan<- float64, r image.Rectangle, env gui.Env) {
 	redraw := func(text []byte) func(draw.Image) image.Rectangle {
 		return func(drw draw.Image) image.Rectangle {
 			drawText(text, drw, r)