examples: add imageviewer

7 files changed, 608 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)
+				}
+			}
+		}
+	}
+}
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())
+}
diff --git a/examples/imageviewer/main.go b/examples/imageviewer/main.go
new file mode 100644
index 0000000..056bf1f
--- /dev/null
+++ b/examples/imageviewer/main.go
@@ -0,0 +1,66 @@
+package main
+
+import (
+	"os/user"
+
+	"github.com/faiface/gui"
+	"github.com/faiface/gui/win"
+	"github.com/faiface/mainthread"
+	"github.com/golang/image/font/gofont/goregular"
+	"golang.org/x/image/colornames"
+)
+
+func run() {
+	face, err := TTFToFace(goregular.TTF, 18)
+	if err != nil {
+		panic(err)
+	}
+
+	theme := &Theme{
+		Face:       face,
+		Background: colornames.White,
+		Empty:      colornames.Darkgrey,
+		Text:       colornames.Black,
+		Highlight:  colornames.Blueviolet,
+		ButtonUp:   colornames.Lightgrey,
+		ButtonDown: colornames.Grey,
+	}
+
+	w, err := win.New(win.Title("Image Viewer"), win.Size(900, 600), win.Resizable())
+	if err != nil {
+		panic(err)
+	}
+
+	mux, env := gui.NewMux(w)
+
+	cd := make(chan string)
+	view := make(chan string)
+
+	go Browser(FixedBottom(FixedLeft(mux.MakeEnv(), 300), 30), theme, ".", cd, view)
+	go Viewer(FixedRight(mux.MakeEnv(), 300), theme, view)
+
+	go Button(EvenHorizontal(FixedTop(FixedLeft(mux.MakeEnv(), 300), 30), 0, 1, 3), theme, "Dir Up", func() {
+		cd <- ".."
+	})
+	go Button(EvenHorizontal(FixedTop(FixedLeft(mux.MakeEnv(), 300), 30), 1, 2, 3), theme, "Refresh", func() {
+		cd <- "."
+	})
+	go Button(EvenHorizontal(FixedTop(FixedLeft(mux.MakeEnv(), 300), 30), 2, 3, 3), theme, "Home", func() {
+		user, err := user.Current()
+		if err != nil {
+			return
+		}
+		cd <- user.HomeDir
+	})
+
+	for e := range env.Events() {
+		switch {
+		case e.Matches("wi/close"):
+			close(env.Draw())
+		}
+	}
+}
+
+func main() {
+	mainthread.Run(run)
+}
diff --git a/examples/imageviewer/splits.go b/examples/imageviewer/splits.go
new file mode 100644
index 0000000..041a770
--- /dev/null
+++ b/examples/imageviewer/splits.go
@@ -0,0 +1,112 @@
+package main
+
+import (
+	"image"
+	"image/draw"
+
+	"github.com/faiface/gui"
+)
+
+type envPair struct {
+	events <-chan gui.Event
+	draw   chan<- func(draw.Image) image.Rectangle
+}
+
+func (ep *envPair) Events() <-chan gui.Event                      { return ep.events }
+func (ep *envPair) Draw() chan<- func(draw.Image) image.Rectangle { return ep.draw }
+
+func FixedLeft(env gui.Env, maxX int) gui.Env {
+	out, in := gui.MakeEventsChan()
+
+	go func() {
+		for e := range env.Events() {
+			var minX, minY, dummy, maxY int
+			switch {
+			case e.Matches("resize/%d/%d/%d/%d", &minX, &minY, &dummy, &maxY):
+				in <- gui.Eventf("resize/%d/%d/%d/%d", minX, minY, maxX, maxY)
+			default:
+				in <- e
+			}
+		}
+		close(in)
+	}()
+
+	return &envPair{out, env.Draw()}
+}
+
+func FixedRight(env gui.Env, minX int) gui.Env {
+	out, in := gui.MakeEventsChan()
+
+	go func() {
+		for e := range env.Events() {
+			var dummy, minY, maxX, maxY int
+			switch {
+			case e.Matches("resize/%d/%d/%d/%d", &dummy, &minY, &maxX, &maxY):
+				in <- gui.Eventf("resize/%d/%d/%d/%d", minX, minY, maxX, maxY)
+			default:
+				in <- e
+			}
+		}
+		close(in)
+	}()
+
+	return &envPair{out, env.Draw()}
+}
+
+func FixedTop(env gui.Env, maxY int) gui.Env {
+	out, in := gui.MakeEventsChan()
+
+	go func() {
+		for e := range env.Events() {
+			var minX, minY, maxX, dummy int
+			switch {
+			case e.Matches("resize/%d/%d/%d/%d", &minX, &minY, &maxX, &dummy):
+				in <- gui.Eventf("resize/%d/%d/%d/%d", minX, minY, maxX, maxY)
+			default:
+				in <- e
+			}
+		}
+		close(in)
+	}()
+
+	return &envPair{out, env.Draw()}
+}
+
+func FixedBottom(env gui.Env, minY int) gui.Env {
+	out, in := gui.MakeEventsChan()
+
+	go func() {
+		for e := range env.Events() {
+			var minX, dummy, maxX, maxY int
+			switch {
+			case e.Matches("resize/%d/%d/%d/%d", &minX, &dummy, &maxX, &maxY):
+				in <- gui.Eventf("resize/%d/%d/%d/%d", minX, minY, maxX, maxY)
+			default:
+				in <- e
+			}
+		}
+		close(in)
+	}()
+
+	return &envPair{out, env.Draw()}
+}
+
+func EvenHorizontal(env gui.Env, minI, maxI, n int) gui.Env {
+	out, in := gui.MakeEventsChan()
+
+	go func() {
+		for e := range env.Events() {
+			var minX, minY, maxX, maxY int
+			switch {
+			case e.Matches("resize/%d/%d/%d/%d", &minX, &minY, &maxX, &maxY):
+				minX, maxX := minX+(maxX-minX)*minI/n, minX+(maxX-minX)*maxI/n
+				in <- gui.Eventf("resize/%d/%d/%d/%d", minX, minY, maxX, maxY)
+			default:
+				in <- e
+			}
+		}
+		close(in)
+	}()
+
+	return &envPair{out, env.Draw()}
+}
diff --git a/examples/imageviewer/theme.go b/examples/imageviewer/theme.go
new file mode 100644
index 0000000..e37c0c0
--- /dev/null
+++ b/examples/imageviewer/theme.go
@@ -0,0 +1,19 @@
+package main
+
+import (
+	"image/color"
+
+	"golang.org/x/image/font"
+)
+
+type Theme struct {
+	Face font.Face
+
+	Background color.Color
+	Empty      color.Color
+	Text       color.Color
+	Highlight  color.Color
+	ButtonUp   color.Color
+	ButtonOver color.Color
+	ButtonDown color.Color
+}
diff --git a/examples/imageviewer/util.go b/examples/imageviewer/util.go
new file mode 100644
index 0000000..94f25fb
--- /dev/null
+++ b/examples/imageviewer/util.go
@@ -0,0 +1,104 @@
+package main
+
+import (
+	"image"
+	"image/color"
+	"image/draw"
+	"sync"
+
+	"github.com/golang/freetype/truetype"
+
+	"golang.org/x/image/font"
+	"golang.org/x/image/math/fixed"
+)
+
+type concurrentFace struct {
+	mu   sync.Mutex
+	face font.Face
+}
+
+func (cf *concurrentFace) Close() error {
+	cf.mu.Lock()
+	defer cf.mu.Unlock()
+	return cf.face.Close()
+}
+
+func (cf *concurrentFace) Glyph(dot fixed.Point26_6, r rune) (dr image.Rectangle, mask image.Image, maskp image.Point, advance fixed.Int26_6, ok bool) {
+	cf.mu.Lock()
+	defer cf.mu.Unlock()
+	return cf.face.Glyph(dot, r)
+}
+
+func (cf *concurrentFace) GlyphBounds(r rune) (bounds fixed.Rectangle26_6, advance fixed.Int26_6, ok bool) {
+	cf.mu.Lock()
+	defer cf.mu.Unlock()
+	return cf.face.GlyphBounds(r)
+}
+
+func (cf *concurrentFace) GlyphAdvance(r rune) (advance fixed.Int26_6, ok bool) {
+	cf.mu.Lock()
+	defer cf.mu.Unlock()
+	return cf.face.GlyphAdvance(r)
+}
+
+func (cf *concurrentFace) Kern(r0, r1 rune) fixed.Int26_6 {
+	cf.mu.Lock()
+	defer cf.mu.Unlock()
+	return cf.face.Kern(r0, r1)
+}
+
+func (cf *concurrentFace) Metrics() font.Metrics {
+	cf.mu.Lock()
+	defer cf.mu.Unlock()
+	return cf.face.Metrics()
+}
+
+func TTFToFace(ttf []byte, size float64) (font.Face, error) {
+	font, err := truetype.Parse(ttf)
+	if err != nil {
+		return nil, err
+	}
+	return &concurrentFace{face: truetype.NewFace(font, &truetype.Options{
+		Size: size,
+	})}, nil
+}
+
+func DrawText(text string, face font.Face, clr color.Color) image.Image {
+	drawer := &font.Drawer{
+		Src:  &image.Uniform{clr},
+		Face: face,
+		Dot:  fixed.P(0, 0),
+	}
+	b26_6, _ := drawer.BoundString(text)
+	bounds := image.Rect(
+		b26_6.Min.X.Floor(),
+		b26_6.Min.Y.Floor(),
+		b26_6.Max.X.Ceil(),
+		b26_6.Max.Y.Ceil(),
+	)
+	drawer.Dst = image.NewRGBA(bounds)
+	drawer.DrawString(text)
+	return drawer.Dst
+}
+
+func DrawCentered(dst draw.Image, r image.Rectangle, src image.Image, op draw.Op) {
+	if src == nil {
+		return
+	}
+	bounds := src.Bounds()
+	center := bounds.Min.Add(bounds.Max).Div(2)
+	target := r.Min.Add(r.Max).Div(2)
+	delta := target.Sub(center)
+	draw.Draw(dst, bounds.Add(delta).Intersect(r), src, bounds.Min, op)
+}
+
+func DrawLeftCentered(dst draw.Image, r image.Rectangle, src image.Image, op draw.Op) {
+	if src == nil {
+		return
+	}
+	bounds := src.Bounds()
+	leftCenter := image.Pt(bounds.Min.X, (bounds.Min.Y+bounds.Max.Y)/2)
+	target := image.Pt(r.Min.X, (r.Min.Y+r.Max.Y)/2)
+	delta := target.Sub(leftCenter)
+	draw.Draw(dst, bounds.Add(delta).Intersect(r), src, bounds.Min, op)
+}
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)
+			}
+		}
+	}
+}