examples: add imageviewer

1 files changed, 61 insertions, 0 deletions

diff --git a/examples/imageviewer/button.go b/examples/imageviewer/button.go
new file mode 100644
index 0000000..0078774
--- /dev/null
+++ b/examples/imageviewer/button.go
@@ -0,0 +1,61 @@
+package main
+
+import (
+	"image"
+	"image/color"
+	"image/draw"
+
+	"github.com/faiface/gui"
+)
+
+func Button(env gui.Env, theme *Theme, text string, action func()) {
+	textImg := DrawText(text, theme.Face, theme.Text)
+
+	redraw := func(r image.Rectangle, over, pressed bool) func(draw.Image) image.Rectangle {
+		return func(drw draw.Image) image.Rectangle {
+			var clr color.Color
+			if pressed {
+				clr = theme.ButtonDown
+			} else if over {
+				clr = theme.ButtonOver
+			} else {
+				clr = theme.ButtonUp
+			}
+			draw.Draw(drw, r, &image.Uniform{clr}, image.ZP, draw.Src)
+			DrawCentered(drw, r, textImg, draw.Over)
+			return r
+		}
+	}
+
+	var (
+		r       image.Rectangle
+		over    bool
+		pressed bool
+	)
+
+	for e := range env.Events() {
+		var x, y, minX, minY, maxX, maxY int
+
+		switch {
+		case e.Matches("resize/%d/%d/%d/%d", &minX, &minY, &maxX, &maxY):
+			r = image.Rect(minX, minY, maxX, maxY)
+			env.Draw() <- redraw(r, over, pressed)
+
+		case e.Matches("mo/down/%d/%d/left", &x, &y):
+			newPressed := image.Pt(x, y).In(r)
+			if newPressed != pressed {
+				pressed = newPressed
+				env.Draw() <- redraw(r, over, pressed)
+			}
+
+		case e.Matches("mo/up/%d/%d/left", &x, &y):
+			if pressed {
+				action()
+				pressed = false
+				env.Draw() <- redraw(r, over, pressed)
+			}
+		}
+	}
+
+	close(env.Draw())
+}