GUI experiment with two routines drawing parts of the window (foo draws the upper half, bar the bottom half)

gui-experiment.go

package main

import (
	"image"
	"image/draw"

	"github.com/peterhellberg/gfx"
	"github.com/peterhellberg/gui"
)

func main() {
	gui.Run(func() {
		win, err := gui.Open(gui.Size(512, 512))
		if err != nil {
			return
		}

		mux, env := gui.NewMux(win)
		go foo(mux.Env(), gfx.IR(0, 0, 512, 256))
		go bar(mux.Env(), gfx.IR(0, 256, 512, 512))

		for event := range env.Events() {
			switch event := event.(type) {
			case gui.EventClose:
				env.Close()
			case gui.EventKeyboardDown:
				if event.Key == "escape" {
					env.Close()
				}
			}
		}
	})
}

func foo(env gui.Env, bounds image.Rectangle) {
	drawCircle := func(pt image.Point) func(draw.Image) image.Rectangle {
		return func(dst draw.Image) image.Rectangle {
			if pt.In(bounds) {
				c := gfx.PaletteArne16.Random()
				gfx.DrawPointCircle(dst, pt, 30, 15, c)
			}

			return bounds
		}
	}

	for event := range env.Events() {
		switch event := event.(type) {
		case gui.EventMouseMove:
			env.Draw(drawCircle(event.Point))
		case gui.EventResize:
			env.Draw(func(dst draw.Image) image.Rectangle {
				gfx.EachPixel(bounds, func(x, y int) {
					v := uint8(x ^ y)
					c := gfx.ColorNRGBA(v%192, v, v, 255)

					dst.Set(x, y, c)
				})

				return bounds
			})
		}
	}
}

func bar(env gui.Env, bounds image.Rectangle) {
	drawSquare := func(pt image.Point) func(draw.Image) image.Rectangle {
		return func(dst draw.Image) image.Rectangle {
			if pt.In(bounds) {
				c := gfx.PaletteEDG16.Random()
				n := 30
				r := gfx.IR(pt.X-n, pt.Y-n, pt.X+n, pt.Y+n)

				gfx.DrawColor(dst, r, c)
			}

			return bounds
		}
	}

	for event := range env.Events() {
		switch event := event.(type) {
		case gui.EventMouseMove:
			env.Draw(drawSquare(event.Point))
		case gui.EventResize:
			env.Draw(func(dst draw.Image) image.Rectangle {
				gfx.EachPixel(bounds, func(x, y int) {
					v := uint8(x ^ y)
					c := gfx.ColorNRGBA(v, v%192, v, 255)

					dst.Set(x, y, c)
				})

				return bounds
			})
		}
	}
}