63 lines
1.8 KiB
Go
63 lines
1.8 KiB
Go
package mujica
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import (
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"github.com/egoist/mygo/ui"
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"mujicaui/theme"
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)
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// ScrollDirection is the way a ScrollArea scrolls. The zero value is vertical.
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type ScrollDirection int
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const (
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ScrollVertical ScrollDirection = iota
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ScrollHorizontal
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ScrollBoth
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)
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// ScrollAreaOptions configure a ScrollArea.
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type ScrollAreaOptions struct {
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Direction ScrollDirection
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// Label names the region for assistive technology.
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Label string
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}
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// ScrollArea scrolls its children with the wheel, its scroll bars and the keyboard.
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// state keeps the offset across frames: set X or Y to scroll there, math.MaxFloat32 for the end.
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// A nil state keeps the offset by the area's place in the view.
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// The area takes the focus while its content overflows, so the keys reach it.
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func ScrollArea(c *ui.Context, state *ui.ScrollState, opts ScrollAreaOptions, children func()) *ui.Element {
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if children == nil {
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panic("mujica: ScrollArea needs children")
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}
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var e *ui.Element
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switch opts.Direction {
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case ScrollVertical:
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e = ui.Scroll(c)
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case ScrollHorizontal:
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e = ui.ScrollHorizontal(c)
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case ScrollBoth:
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e = ui.ScrollBoth(c)
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default:
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panic("mujica: invalid ScrollDirection")
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}
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if state == nil {
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state = ui.Local(e, "scroll_area.state", func() ui.ScrollState { return ui.ScrollState{} })
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}
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e.TrackScroll(state)
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if state.MaxX > 0 || state.MaxY > 0 {
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focus := Tokens(c).Focus
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// The ring goes inside: areas often fill a clipped pane edge to edge.
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e.Focusable().FocusRing(false).DrawOver(func(p *ui.Painter, r ui.Rect) {
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if e.FocusVisible() {
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in := theme.FocusWidth / 2
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p.Stroke(ui.Rect{X: r.X + in, Y: r.Y + in, W: r.W - 2*in, H: r.H - 2*in}, focus, theme.ControlRadius, theme.FocusWidth)
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}
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})
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}
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if opts.Label != "" {
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e.Label(opts.Label)
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}
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return e.Children(children)
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}
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