86 lines
2.2 KiB
Go
86 lines
2.2 KiB
Go
package input
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import (
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"fmt"
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"math"
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"time"
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"github.com/egoist/mygo/ui"
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"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
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)
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type JoystickOptions struct {
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Disabled bool
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}
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type JoystickResult struct {
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Element *ui.Element
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// X and Y are in −1…1; Y grows downward.
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X, Y float64
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Moved bool
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}
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type stickKey struct{}
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// stick is the knob and its last key nudge.
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type stick struct {
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x, y float64
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key time.Time
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}
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const (
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stickSize = 40
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// stickReach is how far the knob travels, in dots.
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stickReach = 12
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)
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// Joystick drags a knob in a ring; arrows nudge it.
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func Joystick(c *ui.Context, text string, o JoystickOptions) JoystickResult {
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k := pixel.K(c)
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shell, base, st := pixel.Shell(c, func() *ui.Element {
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return ui.Box(c).Focusable().Role(ui.RoleGroup).Label(text).Disabled(o.Disabled)
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})
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s := ui.Local(base, stickKey{}, func() stick { return stick{} })
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ox, oy, now := s.x, s.y, k.Now()
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for _, m := range []struct {
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key ui.Key
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dx, dy float64
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}{{ui.KeyLeft, -0.25, 0}, {ui.KeyRight, 0.25, 0}, {ui.KeyUp, 0, -0.25}, {ui.KeyDown, 0, 0.25}} {
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if base.Shortcut(0, m.key) {
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s.x, s.y, s.key = s.x+m.dx, s.y+m.dy, now
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}
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}
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_, _, held := base.Dragged()
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switch {
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case held && !o.Disabled:
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px, py, _ := base.PointerPosition()
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s.x = (float64(px/k.Dot()) - stickSize/2) / stickReach
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s.y = (float64(py/k.Dot()) - stickSize/2) / stickReach
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s.key = time.Time{}
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case now.Sub(s.key) > repeatGap:
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s.x, s.y = 0, 0
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default:
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k.Tick(c, 10)
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}
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if l := math.Hypot(s.x, s.y); l > 1 {
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s.x, s.y = s.x/l, s.y/l
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}
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base.Description(fmt.Sprintf("%.2f, %.2f", s.x, s.y))
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x, y := stickSize/2+int(math.Round(s.x*stickReach)), stickSize/2+int(math.Round(s.y*stickReach))
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shell.Size(k.D(stickSize), k.D(stickSize)).Draw(func(p *ui.Painter, r ui.Rect) {
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g := k.Canvas(p, r)
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const m = stickSize / 2
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g.Disc(m, m, m-1, pixel.Edge)
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g.Disc(m, m, m-2, pixel.Well)
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g.Dither(m-2, 4, 4, stickSize-8, pixel.Well, pixel.Shade, 4)
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g.Dither(4, m-2, stickSize-8, 4, pixel.Well, pixel.Shade, 4)
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g.Disc(x+1, y+1, 7, pixel.Shade)
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g.Disc(x, y, 7, pixel.Edge)
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g.Disc(x, y, 6, pixel.Accent)
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g.Disc(x-2, y-2, 2, pixel.AccentLit)
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g.Finish(st)
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})
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return JoystickResult{Element: shell, X: s.x, Y: s.y, Moved: s.x != ox || s.y != oy}
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}
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