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package main
import (
"image"
"image/color"
"image/draw"
"github.com/faiface/gui"
"github.com/faiface/gui/win"
"github.com/faiface/mainthread"
"github.com/fogleman/gg"
)
func ColorPicker(env gui.Env, pick chan<- color.Color, r image.Rectangle, clr color.Color) {
env.Draw() <- func(drw draw.Image) image.Rectangle {
draw.Draw(drw, r, &image.Uniform{clr}, r.Min, draw.Src)
return r
}
for event := range env.Events() {
switch event := event.(type) {
case win.MoDown:
if event.Point.In(r) {
pick <- clr
}
}
}
close(env.Draw())
}
func Canvas(env gui.Env, pick <-chan color.Color, r image.Rectangle) {
canvas := image.NewRGBA(r)
draw.Draw(canvas, r, image.White, r.Min, draw.Src)
dc := gg.NewContextForRGBA(canvas)
env.Draw() <- func(drw draw.Image) image.Rectangle {
draw.Draw(drw, r, canvas, image.ZP, draw.Src)
return r
}
var (
clr = color.Color(color.Black)
pressed = false
prev image.Point
)
for {
select {
case clr = <-pick:
case event, ok := <-env.Events():
if !ok {
close(env.Draw())
return
}
switch event := event.(type) {
case win.MoDown:
if event.Point.In(r) {
pressed = true
prev = event.Point
}
case win.MoUp:
pressed = false
case win.MoMove:
if pressed {
x0, y0, x1, y1 := prev.X, prev.Y, event.X, event.Y
prev = event.Point
env.Draw() <- func(drw draw.Image) image.Rectangle {
dc.SetColor(clr)
dc.SetLineCapRound()
dc.SetLineWidth(5)
dc.DrawLine(float64(x0), float64(y0), float64(x1), float64(y1))
dc.Stroke()
rect := image.Rect(x0, y0, x1, y1)
rect.Min.X -= 5
rect.Min.Y -= 5
rect.Max.X += 5
rect.Max.Y += 5
draw.Draw(drw, rect, canvas, rect.Min, draw.Src)
return rect
}
}
}
}
}
}
func run() {
w, err := win.New(win.Title("Paint"), win.Size(800, 600))
if err != nil {
panic(err)
}
mux, env := gui.NewMux(w)
pick := make(chan color.Color)
for i, clr := range []color.Color{
color.RGBA{255, 0, 0, 255},
color.RGBA{255, 255, 0, 255},
color.RGBA{0, 255, 0, 255},
color.RGBA{0, 255, 255, 255},
color.RGBA{0, 0, 255, 255},
color.RGBA{255, 0, 255, 255},
color.RGBA{255, 255, 255, 255},
color.RGBA{0, 0, 0, 255},
} {
go ColorPicker(mux.MakeEnv(), pick, image.Rect(750, i*75, 800, (i+1)*75), clr)
}
go Canvas(mux.MakeEnv(), pick, image.Rect(0, 0, 750, 600))
for event := range env.Events() {
switch event.(type) {
case win.WiClose:
close(env.Draw())
}
}
}
func main() {
mainthread.Run(run)
}
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