140 lines
3.3 KiB
Go
140 lines
3.3 KiB
Go
package ui
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import (
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"image/color"
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"opslag.de/schobers/geom"
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)
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type overflow struct {
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Proxy
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Background color.Color
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barWidth float32
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desired geom.PointF32
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bounds geom.RectangleF32
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offset geom.PointF32
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content Buffer
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hor *Scrollbar
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ver *Scrollbar
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}
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func Overflow(content Control) Control {
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return OverflowBackground(content, nil)
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}
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func OverflowBackground(content Control, back color.Color) Control {
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var o = &overflow{Proxy: Proxy{Content: content}, Background: back}
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o.hor = BuildScrollbar(OrientationHorizontal, func(*Scrollbar) {})
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o.ver = BuildScrollbar(OrientationVertical, func(*Scrollbar) {})
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return o
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}
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func (o *overflow) shouldScroll(bounds geom.RectangleF32) (hor bool, ver bool) {
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var scroll = func(need, actual float32) bool {
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return !geom.IsNaN32(need) && need > actual
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}
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var size = o.desired
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hor = scroll(size.X, bounds.Dx())
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ver = scroll(size.Y, bounds.Dy())
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if ver && !hor {
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hor = scroll(size.X+o.barWidth, bounds.Dx())
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}
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if hor && !ver {
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ver = scroll(size.Y+o.barWidth, bounds.Dy())
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}
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return
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}
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func (o *overflow) doOnVisibleBars(fn func(bar *Scrollbar)) {
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hor, ver := o.shouldScroll(o.bounds)
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if hor {
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fn(o.hor)
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}
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if ver {
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fn(o.ver)
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}
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}
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func (o *overflow) Arrange(ctx Context, bounds geom.RectangleF32, offset geom.PointF32) {
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o.barWidth = ctx.Style().Dimensions.ScrollbarWidth
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o.desired = o.Content.DesiredSize(ctx)
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o.bounds = bounds
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o.offset = offset
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var hor, ver = o.shouldScroll(bounds)
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var contentX, contentY float32 = 0, 0
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var contentW, contentH = bounds.Dx(), bounds.Dy()
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if hor {
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contentX -= o.hor.Offset
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contentH = geom.Max32(0, contentH-o.barWidth)
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}
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if ver {
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contentY -= o.ver.Offset
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contentW = geom.Max32(0, contentW-o.barWidth)
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}
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o.Content.Arrange(ctx, geom.RectF32(contentX, contentY, contentW, contentH), offset.Add(bounds.Min))
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if hor {
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o.hor.Content = o.desired.X
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o.hor.Arrange(ctx, geom.RectF32(bounds.Min.X, bounds.Min.Y+contentH, bounds.Min.X+contentW, bounds.Max.Y), offset)
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}
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if ver {
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o.ver.Content = o.desired.Y
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o.ver.Arrange(ctx, geom.RectF32(bounds.Min.X+contentW, bounds.Min.Y, bounds.Max.X, bounds.Max.Y), offset)
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}
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}
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func (o *overflow) DesiredSize(ctx Context) geom.PointF32 {
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return geom.PtF32(geom.NaN32(), geom.NaN32())
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}
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func (o *overflow) Handle(ctx Context, e Event) {
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hor, ver := o.shouldScroll(o.bounds)
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if hor {
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o.hor.Handle(ctx, e)
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}
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if ver {
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o.ver.Handle(ctx, e)
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}
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switch e := e.(type) {
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case *MouseMoveEvent:
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if ver {
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var contentO = o.Content.Offset()
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var content = o.Content.Bounds()
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content.Min = contentO
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content.Max = content.Max.Add(contentO)
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if e.MouseWheel != 0 && e.Pos().In(content) {
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o.ver.Offset = geom.Max32(0, geom.Min32(o.ver.Content-content.Dy(), o.ver.Offset-36*e.MouseWheel))
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}
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}
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}
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o.Content.Handle(ctx, e)
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}
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func (o *overflow) Offset() geom.PointF32 { return o.offset }
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func (o *overflow) Render(ctx Context) {
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var renderer = ctx.Renderer()
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if o.Background != nil {
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ctx.Renderer().FillRectangle(o.bounds, o.Background)
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}
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var content = o.Content.Bounds()
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content.Min = geom.ZeroPtF32
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err := o.content.Update(ctx, content.Size())
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if err != nil {
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panic(err)
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}
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o.content.Render(ctx, o.bounds.Min, func(Context, geom.PointF32) {
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renderer.Clear(color.Transparent)
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o.Content.Render(ctx)
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})
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o.doOnVisibleBars(func(bar *Scrollbar) {
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bar.Render(ctx)
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})
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}
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