54 lines
1.4 KiB
Go
54 lines
1.4 KiB
Go
package text
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import (
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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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const scrambleRunes = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789#$%&*+?"
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type ScrambleTextOptions struct {
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Slot pixel.Slot
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Scale int
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// FPS is zero for 30; two steps settle a character.
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FPS int
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}
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type scrambleKey struct{}
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type scrambleState struct {
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text string
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start, step int
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}
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// ScrambleText settles from random glyphs to s, left to right.
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func ScrambleText(c *ui.Context, s string, o ScrambleTextOptions) *ui.Element {
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k, sc := pixel.K(c), scale(o.Scale)
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fps := pixel.Or("ScrambleText FPS", o.FPS, 30)
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rs := []rune(s)
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e := ui.Box(c).Size(k.D(pixel.Measure(s)*sc), k.D(pixel.LineHeight*sc)).Label(s).Role(ui.RoleText)
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st := ui.Local(e, scrambleKey{}, func() scrambleState { return scrambleState{start: -1} })
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if st.text != s {
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*st = scrambleState{text: s, start: -1}
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}
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settled := len(rs)
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if !k.Reduce() && (st.start < 0 || (st.step-st.start)/2 < len(rs)) {
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st.step = k.Tick(c, fps)
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if st.start < 0 {
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st.start = st.step
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}
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settled = min(len(rs), (st.step-st.start)/2)
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}
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step := st.step
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return e.Draw(func(p *ui.Painter, r ui.Rect) {
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g := k.Canvas(p, r)
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each(s, sc, func(i int, ch rune, x int) {
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if i >= settled && ch != ' ' {
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ch = rune(scrambleRunes[noise(len(rs), i, step)%uint32(len(scrambleRunes))])
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}
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g.Text(x, 0, string(ch), o.Slot, sc)
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})
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})
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}
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