giowrap/cmd/scroll/main.go

package main

import (
	"fmt"
	"image/color"
	"log"

	gio "git.wow.st/gmp/giowrap"

	"gioui.org/ui"
	"gioui.org/ui/app"
	"gioui.org/ui/layout"
	"gioui.org/ui/text"

	"golang.org/x/image/font/gofont/goregular"
	"golang.org/x/image/font/sfnt"
)

var (
	face  text.Face
	black color.RGBA = color.RGBA{A: 0xff, R: 0x00, G: 0x00, B: 0x00}
	gray2 color.RGBA = color.RGBA{A: 0xff, R: 0xc0, G: 0xc0, B: 0xc0}
	gray1 color.RGBA = color.RGBA{A: 0xff, R: 0x70, G: 0x70, B: 0x70}
)

type SLabel struct {
	w      gio.Clickable
	bg     *gio.Background
	active *bool
}

func NewSLabel(t string, active *bool, lops ...gio.LabelOption) *SLabel {
	ret := &SLabel{}
	lops = append([]gio.LabelOption{gio.Face(face)}, lops...)
	lbl := gio.NewLabel(t, lops...)
	bg := &gio.Background{
		Color:  gray2,
		Radius: ui.Dp(4),
		Inset:  layout.UniformInset(ui.Dp(4)),
	}
	if *active {
		bg.Color = gray1
	}
	l := gio.AsClickable(gio.Enclose(bg, lbl))
	ret.w = l
	ret.bg = bg
	ret.active = active
	return ret
}

func (w *SLabel) Layout(ctx *gio.Context) {
	if *w.active {
		w.bg.Color = gray1
	} else {
		w.bg.Color = gray2
	}
	w.w.Layout(ctx)
	if w.w.Clicked(ctx) {
		if *w.active {
			*w.active = false
		} else {
			*w.active = true
		}
	}
}

func main() {
	log.Print("Staring event loop")
	go eventloop()
	app.Main()
	log.Print("App closed")
}

func diffInsets(x, y app.Insets) bool {
	return x.Top != y.Top ||
		x.Bottom != y.Bottom ||
		x.Left != y.Left ||
		x.Right != y.Right
}

func eventloop() {
	w := app.NewWindow(
		app.WithWidth(ui.Dp(400)),
		app.WithHeight(ui.Dp(400)),
		app.WithTitle("Tickets"))
	ctx := gio.NewContext(w)

	regular, err := sfnt.Parse(goregular.TTF)
	face = ctx.Faces.For(regular, ui.Sp(16))
	if err != nil {
		log.Fatal("Cannot parse font.")
	}

	sysbg := gio.NewBackground(gio.Color(black))
	bg := gio.NewBackground(gio.Color(gray2))

	margin := gio.NewInset(gio.Size(ui.Dp(10)))
	f1 := gio.NewFlex(gio.Axis(layout.Horizontal))
	lbar := gio.NewLabel("    ", gio.Face(face))
	f2 := gio.NewFlex(gio.Axis(layout.Vertical))
	topbar := gio.NewLabel("Scroll X and Y. Click to select", gio.Face(face))

	sh := gio.HScroll(gio.NewFlex(gio.Axis(layout.Horizontal)))
	sv := gio.VScroll(gio.NewFlex(gio.Axis(layout.Vertical)))

	numlabs := 50
	labs := make([][]gio.Widget, numlabs)
	sels := make([][]bool, numlabs)
	for i := 0; i < 16; i++ {
		labs[i] = make([]gio.Widget, numlabs)
		sels[i] = make([]bool, numlabs)
		for j := 0; j < numlabs; j++ {
			labs[i][j] = NewSLabel(fmt.Sprintf("%03d", i*16+j), &sels[i][j])
		}
	}

	sysinset := gio.NewInset(gio.Size(ui.Dp(0)))
	resetSysinset := func(x app.Insets) {
		sysinset = gio.NewInset(gio.Top(x.Top), gio.Bottom(x.Bottom),
			gio.Left(x.Left), gio.Right(x.Right))
	}

	var oldInsets app.Insets

	for {
		select {
		case e := <-w.Events():
			switch e := e.(type) {
			case app.DestroyEvent:
				return
			case app.UpdateEvent:
				ctx.Reset(e)
				if diffInsets(e.Insets, oldInsets) {
					oldInsets = e.Insets
					resetSysinset(e.Insets)
				}

				sysbg(sysinset(bg(margin(
					f1(lbar, f2(topbar, sh(
						sv(labs[0]...),
						sv(labs[1]...),
						sv(labs[2]...),
						sv(labs[3]...),
						sv(labs[4]...),
						sv(labs[5]...),
						sv(labs[6]...),
						sv(labs[7]...),
						sv(labs[8]...),
						sv(labs[9]...),
						sv(labs[10]...),
						sv(labs[11]...),
						sv(labs[12]...),
						sv(labs[13]...),
						sv(labs[14]...),
						sv(labs[15]...),
					))))))).Layout(ctx)
				ctx.Update()
			}
		}
	}
}