examples: add imageviewer

1 files changed, 65 insertions, 0 deletions

diff --git a/examples/imageviewer/viewer.go b/examples/imageviewer/viewer.go
new file mode 100644
index 0000000..e783d78
--- /dev/null
+++ b/examples/imageviewer/viewer.go
@@ -0,0 +1,65 @@
+package main
+
+import (
+	"image"
+	"image/draw"
+	"os"
+
+	"github.com/faiface/gui"
+
+	_ "image/gif"
+	_ "image/jpeg"
+	_ "image/png"
+
+	_ "golang.org/x/image/bmp"
+)
+
+func Viewer(env gui.Env, theme *Theme, view <-chan string) {
+	redraw := func(r image.Rectangle, img image.Image) func(draw.Image) image.Rectangle {
+		return func(drw draw.Image) image.Rectangle {
+			draw.Draw(drw, r, &image.Uniform{theme.Empty}, image.ZP, draw.Src)
+			DrawCentered(drw, r, img, draw.Over)
+			return r
+		}
+	}
+
+	invalid := DrawText("Invalid image", theme.Face, theme.Text)
+
+	var (
+		r   image.Rectangle
+		img image.Image
+	)
+
+	for {
+		select {
+		case path := <-view:
+			func() {
+				f, err := os.Open(path)
+				if err != nil {
+					img = invalid
+					return
+				}
+				defer f.Close()
+				img, _, err = image.Decode(f)
+				if err != nil {
+					img = invalid
+					return
+				}
+			}()
+			env.Draw() <- redraw(r, img)
+
+		case e, ok := <-env.Events():
+			if !ok {
+				close(env.Draw())
+				return
+			}
+
+			var 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, img)
+			}
+		}
+	}
+}