added layout basics

6 files changed, 568 insertions, 0 deletions

diff --git a/examples/layout/button.go b/examples/layout/button.go
new file mode 100644
index 0000000..6c907e3
--- /dev/null
+++ b/examples/layout/button.go
@@ -0,0 +1,64 @@
+package main
+
+import (
+	"image"
+	"image/color"
+	"image/draw"
+	"log"
+
+	"github.com/faiface/gui"
+	"github.com/faiface/gui/win"
+)
+
+func Button(env gui.Env, theme *Theme, text string, action func()) {
+	textImg := MakeTextImage(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() {
+		switch e := e.(type) {
+		case gui.Resize:
+			r = e.Rectangle
+			log.Print("button ", e)
+			env.Draw() <- redraw(r, over, pressed)
+
+		case win.MoDown:
+			newPressed := e.Point.In(r)
+			if newPressed != pressed {
+				pressed = newPressed
+				env.Draw() <- redraw(r, over, pressed)
+			}
+
+		case win.MoUp:
+			if pressed {
+				if e.Point.In(r) {
+					action()
+				}
+				pressed = false
+				env.Draw() <- redraw(r, over, pressed)
+			}
+		}
+	}
+
+	close(env.Draw())
+}
diff --git a/examples/layout/main.go b/examples/layout/main.go
new file mode 100644
index 0000000..47364a9
--- /dev/null
+++ b/examples/layout/main.go
@@ -0,0 +1,128 @@
+package main
+
+import (
+	"image"
+	"image/draw"
+	"log"
+	"time"
+
+	"github.com/faiface/gui"
+	"github.com/faiface/gui/fixedgrid"
+	"github.com/faiface/gui/win"
+	"github.com/faiface/mainthread"
+	"golang.org/x/image/colornames"
+	"golang.org/x/image/font/gofont/goregular"
+)
+
+func Blinker(env gui.Env, closed bool) {
+	defer func() {
+		if recover() != nil {
+			log.Print("recovered blinker")
+		}
+	}()
+
+	var r image.Rectangle
+	var visible bool = true
+	// redraw takes a bool and produces a draw command
+	redraw := func() func(draw.Image) image.Rectangle {
+		return func(drw draw.Image) image.Rectangle {
+			if visible {
+				draw.Draw(drw, r, image.White, image.ZP, draw.Src)
+			} else {
+				draw.Draw(drw, r, &image.Uniform{colornames.Firebrick}, image.ZP, draw.Src)
+			}
+			return r
+		}
+	}
+
+	// first we draw a white rectangle
+	env.Draw() <- redraw()
+	go func() {
+		for event := range env.Events() {
+			switch event := event.(type) {
+			case win.MoDown:
+				if event.Point.In(r) {
+					go func() {
+						for i := 0; i < 3; i++ {
+							visible = false
+							env.Draw() <- redraw()
+							time.Sleep(time.Second / 3)
+							visible = true
+							env.Draw() <- redraw()
+							time.Sleep(time.Second / 3)
+						}
+					}()
+				}
+			case gui.Resize:
+				log.Print(event)
+				r = event.Rectangle
+				env.Draw() <- redraw()
+			}
+		}
+	}()
+
+	if closed {
+		time.Sleep(time.Second * 1)
+		close(env.Draw())
+	}
+}
+
+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("gui test"),
+		win.Resizable(),
+	)
+	if err != nil {
+		panic(err)
+	}
+	mux, env := gui.NewMux(w)
+	gr := fixedgrid.New(mux.MakeEnv(),
+		fixedgrid.Rows(5),
+		fixedgrid.Columns(2),
+		fixedgrid.Gap(10),
+	)
+	log.Print(gr)
+	go Blinker(gr.GetEnv("0;0"), false)
+	go Blinker(gr.GetEnv("0;1"), true)
+	go Blinker(gr.GetEnv("1;1"), false)
+	go Blinker(gr.GetEnv("0;2"), false)
+	go Blinker(gr.GetEnv("0;3"), false)
+	go Blinker(gr.GetEnv("0;4"), false)
+	sgr := fixedgrid.New(gr.GetEnv("1;0"),
+		fixedgrid.Columns(3),
+		fixedgrid.Gap(4),
+		fixedgrid.Background(colornames.Darkgrey),
+	)
+	go Button(sgr.GetEnv("0;0"), theme, "Hey", func() {
+		log.Print("hey")
+	})
+	go Button(sgr.GetEnv("1;0"), theme, "Ho", func() {
+		log.Print("ho")
+	})
+	go Button(sgr.GetEnv("2;0"), theme, "Hu", func() {
+		log.Print("hu")
+	})
+	// we use the master env now, w is used by the mux
+	for event := range env.Events() {
+		switch event.(type) {
+		case win.WiClose:
+			close(env.Draw())
+		}
+	}
+}
+
+func main() {
+	mainthread.Run(run)
+}
diff --git a/examples/layout/theme.go b/examples/layout/theme.go
new file mode 100644
index 0000000..e37c0c0
--- /dev/null
+++ b/examples/layout/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/layout/utils.go b/examples/layout/utils.go
new file mode 100644
index 0000000..e799988
--- /dev/null
+++ b/examples/layout/utils.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 MakeTextImage(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/layout/fixedgrid/fixedgrid.go b/layout/fixedgrid/fixedgrid.go
new file mode 100644
index 0000000..a9fabf8
--- /dev/null
+++ b/layout/fixedgrid/fixedgrid.go
@@ -0,0 +1,88 @@
+package fixedgrid
+
+import (
+	"fmt"
+	"image"
+	"image/color"
+	"image/draw"
+
+	"github.com/faiface/gui"
+	"github.com/faiface/gui/layout"
+)
+
+type FixedGrid struct {
+	Columns    int
+	Rows       int
+	Background color.Color
+	Gap        int
+
+	*layout.Layout
+}
+
+func New(env gui.Env, options ...func(*FixedGrid)) *FixedGrid {
+	ret := &FixedGrid{
+		// Bounds:     image.ZR,
+		Background: image.Black,
+		Columns:    1,
+		Rows:       1,
+		Gap:        0,
+	}
+
+	for _, f := range options {
+		f(ret)
+	}
+
+	ret.Layout = layout.New(env, ret.layout, ret.redraw)
+	return ret
+}
+
+func (g *FixedGrid) layout(bounds image.Rectangle) map[string]image.Rectangle {
+	gap := g.Gap
+	cols := g.Columns
+	rows := g.Rows
+
+	w := (bounds.Dx() - (cols+1)*gap) / cols
+	h := (bounds.Dy() - (rows+1)*gap) / rows
+
+	ret := make(map[string]image.Rectangle)
+	X := gap + bounds.Min.X
+	Y := gap + bounds.Min.Y
+	for x := 0; x < cols; x++ {
+		for y := 0; y < rows; y++ {
+			ret[fmt.Sprintf("%d;%d", x, y)] = image.Rect(X, Y, X+w, Y+h)
+			Y += gap + h
+		}
+		Y = gap + bounds.Min.Y
+		X += gap + w
+	}
+
+	return ret
+}
+
+func Background(c color.Color) func(*FixedGrid) {
+	return func(grid *FixedGrid) {
+		grid.Background = c
+	}
+}
+
+func Gap(g int) func(*FixedGrid) {
+	return func(grid *FixedGrid) {
+		grid.Gap = g
+	}
+}
+
+func Columns(cols int) func(*FixedGrid) {
+	return func(grid *FixedGrid) {
+		grid.Columns = cols
+	}
+}
+
+func Rows(rows int) func(*FixedGrid) {
+	return func(grid *FixedGrid) {
+		grid.Rows = rows
+	}
+}
+
+func (g *FixedGrid) redraw(drw draw.Image, bounds image.Rectangle) {
+	draw.Draw(drw, bounds, image.NewUniform(g.Background), image.ZP, draw.Src)
+}
diff --git a/layout/layout.go b/layout/layout.go
new file mode 100644
index 0000000..3601629
--- /dev/null
+++ b/layout/layout.go
@@ -0,0 +1,165 @@
+package layout
+
+import (
+	"image"
+	"image/draw"
+	"sync"
+
+	"github.com/faiface/gui"
+)
+
+type Layout struct {
+	masterEnv *MuxEnv
+	inEvent   chan<- gui.Event
+
+	mu         sync.Mutex
+	lastResize gui.Event
+	eventsIns  map[string]chan<- gui.Event
+	draw       chan<- func(draw.Image) image.Rectangle
+
+	Lay    func(image.Rectangle) map[string]image.Rectangle
+	Redraw func(draw.Image, image.Rectangle)
+}
+
+func New(
+	env gui.Env,
+	lay func(image.Rectangle) map[string]image.Rectangle,
+	redraw func(draw.Image, image.Rectangle),
+) *Layout {
+
+	mux := &Layout{
+		Lay:    lay,
+		Redraw: redraw,
+	}
+	drawChan := make(chan func(draw.Image) image.Rectangle)
+	mux.draw = drawChan
+	mux.masterEnv = mux.makeEnv("master", true)
+	mux.inEvent = mux.masterEnv.In
+	mux.eventsIns = make(map[string]chan<- gui.Event)
+	go func() {
+		for d := range drawChan {
+			env.Draw() <- d
+		}
+		close(env.Draw())
+	}()
+
+	go func() {
+		for e := range env.Events() {
+			mux.inEvent <- e
+		}
+	}()
+
+	go func() {
+		for e := range mux.masterEnv.Events() {
+			mux.mu.Lock()
+			if resize, ok := e.(gui.Resize); ok {
+				mux.lastResize = resize
+				rect := resize.Rectangle
+
+				mux.draw <- func(drw draw.Image) image.Rectangle {
+					mux.Redraw(drw, rect)
+					return rect
+				}
+				l := mux.Lay(rect)
+
+				for key, eventsIn := range mux.eventsIns {
+					func(rz gui.Resize) {
+						rz.Rectangle = l[key]
+						eventsIn <- rz
+					}(resize)
+				}
+			} else {
+				for _, eventsIn := range mux.eventsIns {
+					eventsIn <- e
+				}
+			}
+			mux.mu.Unlock()
+		}
+		mux.mu.Lock()
+		for _, eventsIn := range mux.eventsIns {
+			close(eventsIn)
+		}
+		mux.mu.Unlock()
+	}()
+
+	return mux
+}
+
+func (mux *Layout) GetEnv(name string) gui.Env {
+	return mux.makeEnv(name, false)
+}
+
+type MuxEnv struct {
+	In     chan<- gui.Event
+	events <-chan gui.Event
+	draw   chan<- func(draw.Image) image.Rectangle
+}
+
+func (m *MuxEnv) Events() <-chan gui.Event                      { return m.events }
+func (m *MuxEnv) Draw() chan<- func(draw.Image) image.Rectangle { return m.draw }
+
+// We do not store master env
+func (mux *Layout) makeEnv(envName string, master bool) *MuxEnv {
+	eventsOut, eventsIn := gui.MakeEventsChan()
+	drawChan := make(chan func(draw.Image) image.Rectangle)
+	env := &MuxEnv{eventsIn, eventsOut, drawChan}
+
+	mux.mu.Lock()
+	if !master {
+		mux.eventsIns[envName] = eventsIn
+	}
+
+	// make sure to always send a resize event to a new Env if we got the size already
+	// that means it missed the resize event by the root Env
+	if mux.lastResize != nil {
+		eventsIn <- mux.lastResize
+	}
+	mux.mu.Unlock()
+
+	go func() {
+		func() {
+			// When the master Env gets its Draw() channel closed, it closes all the Events()
+			// channels of all the children Envs, and it also closes the internal draw channel
+			// of the Mux. Otherwise, closing the Draw() channel of the master Env wouldn't
+			// close the Env the Mux is muxing. However, some child Envs of the Mux may still
+			// send some drawing commmands before they realize that their Events() channel got
+			// closed.
+			//
+			// That is perfectly fine if their drawing commands simply get ignored. This down here
+			// is a little hacky, but (I hope) perfectly fine solution to the problem.
+			//
+			// When the internal draw channel of the Mux gets closed, the line marked with ! will
+			// cause panic. We recover this panic, then we receive, but ignore all furhter draw
+			// commands, correctly draining the Env until it closes itself.
+			defer func() {
+				if recover() != nil {
+					for range drawChan {
+					}
+				}
+			}()
+			for d := range drawChan {
+				mux.draw <- d // !
+			}
+		}()
+		if master {
+			mux.mu.Lock()
+			for _, eventsIn := range mux.eventsIns {
+				close(eventsIn)
+			}
+			mux.eventsIns = nil
+			close(mux.draw)
+			mux.mu.Unlock()
+		} else {
+			mux.mu.Lock()
+			delete(mux.eventsIns, envName)
+
+			close(eventsIn)
+			mux.mu.Unlock()
+		}
+		if mux.lastResize != nil {
+			mux.inEvent <- mux.lastResize
+		}
+	}()
+
+	return env
+}