examples: add imageviewer

1 files changed, 181 insertions, 0 deletions

diff --git a/examples/imageviewer/browser.go b/examples/imageviewer/browser.go
new file mode 100644
index 0000000..087e596
--- /dev/null
+++ b/examples/imageviewer/browser.go
@@ -0,0 +1,181 @@
+package main
+
+import (
+	"image"
+	"image/color"
+	"image/draw"
+	"os"
+	"path/filepath"
+
+	"github.com/faiface/gui"
+	"golang.org/x/image/math/fixed"
+)
+
+func Browser(env gui.Env, theme *Theme, dir string, cd <-chan string, view chan<- string) {
+	reload := func(dir string) (names []string, lineHeight int, namesImage *image.RGBA) {
+		names = nil
+
+		filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
+			if path == dir {
+				return nil
+			}
+			rel, err := filepath.Rel(dir, path)
+			if err != nil {
+				return nil
+			}
+			if info.IsDir() {
+				names = append(names, rel+string(filepath.Separator))
+				return filepath.SkipDir
+			}
+			names = append(names, rel)
+			return nil
+		})
+
+		var images []image.Image
+		for _, name := range names {
+			images = append(images, DrawText(name, theme.Face, theme.Text))
+		}
+
+		const inset = 4
+
+		var width int
+		for _, img := range images {
+			if img.Bounds().Dx() > width {
+				width = img.Bounds().Inset(-inset).Dx()
+			}
+		}
+
+		metrics := theme.Face.Metrics()
+		lineHeight = (metrics.Height + 2*fixed.I(inset)).Ceil()
+		height := lineHeight * len(names)
+
+		namesImage = image.NewRGBA(image.Rect(0, 0, width+2*inset, height+2*inset))
+		for i := range images {
+			r := image.Rect(
+				0, lineHeight*i,
+				width, lineHeight*(i+1),
+			)
+			DrawLeftCentered(namesImage, r.Inset(inset), images[i], draw.Over)
+		}
+
+		return names, lineHeight, namesImage
+	}
+
+	redraw := func(r image.Rectangle, selected int, position image.Point, lineHeight int, namesImage image.Image) func(draw.Image) image.Rectangle {
+		return func(drw draw.Image) image.Rectangle {
+			draw.Draw(drw, r, &image.Uniform{theme.Background}, image.ZP, draw.Src)
+			draw.Draw(drw, r, namesImage, position, draw.Over)
+			if selected >= 0 {
+				highlightR := image.Rect(
+					namesImage.Bounds().Min.X,
+					namesImage.Bounds().Min.Y+lineHeight*selected,
+					namesImage.Bounds().Max.X,
+					namesImage.Bounds().Min.Y+lineHeight*(selected+1),
+				)
+				highlightR = highlightR.Sub(position).Add(r.Min)
+				draw.DrawMask(
+					drw, highlightR.Intersect(r),
+					&image.Uniform{theme.Highlight}, image.ZP,
+					&image.Uniform{color.Alpha{64}}, image.ZP,
+					draw.Over,
+				)
+			}
+			return r
+		}
+	}
+
+	names, lineHeight, namesImage := reload(dir)
+
+	var (
+		r        image.Rectangle
+		position = image.ZP
+		selected = -1
+	)
+
+	for {
+		select {
+		case path := <-cd:
+			if filepath.IsAbs(path) {
+				dir = path
+			} else {
+				dir = filepath.Join(dir, path)
+			}
+			names, lineHeight, namesImage = reload(dir)
+			position = image.ZP
+			selected = -1
+			env.Draw() <- redraw(r, selected, position, lineHeight, namesImage)
+
+		case e, ok := <-env.Events():
+			if !ok {
+				close(env.Draw())
+				return
+			}
+
+			var (
+				minX, minY, maxX, maxY int
+				x, y                   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, selected, position, lineHeight, namesImage)
+
+			case e.Matches("mo/down/%d/%d", &x, &y):
+				if !image.Pt(x, y).In(r) {
+					continue
+				}
+				click := image.Pt(x, y).Sub(r.Min).Add(position)
+				i := click.Y / lineHeight
+				if i < 0 || i >= len(names) {
+					continue
+				}
+				if selected == i {
+					func() {
+						path := filepath.Join(dir, names[selected])
+						f, err := os.Open(path)
+						if err != nil {
+							return
+						}
+						defer f.Close()
+						info, err := f.Stat()
+						if err != nil {
+							return
+						}
+						if info.IsDir() {
+							dir = path
+							names, lineHeight, namesImage = reload(dir)
+							position = image.ZP
+							selected = -1
+							env.Draw() <- redraw(r, selected, position, lineHeight, namesImage)
+						} else {
+							view <- path
+						}
+					}()
+				} else {
+					selected = i
+					env.Draw() <- redraw(r, selected, position, lineHeight, namesImage)
+				}
+
+			case e.Matches("mo/scroll/%d/%d", &y, &x):
+				newP := position.Sub(image.Pt(int(x*16), int(y*16)))
+				if newP.X > namesImage.Bounds().Max.X-r.Dx() {
+					newP.X = namesImage.Bounds().Max.X - r.Dx()
+				}
+				if newP.Y > namesImage.Bounds().Max.Y-r.Dy() {
+					newP.Y = namesImage.Bounds().Max.Y - r.Dy()
+				}
+				if newP.X < namesImage.Bounds().Min.X {
+					newP.X = namesImage.Bounds().Min.X
+				}
+				if newP.Y < namesImage.Bounds().Min.Y {
+					newP.Y = namesImage.Bounds().Min.Y
+				}
+				if newP != position {
+					position = newP
+					env.Draw() <- redraw(r, selected, position, lineHeight, namesImage)
+				}
+			}
+		}
+	}
+}