func insertIndex(holder gxui.PanelHolder, at math.Point) int {
count := holder.PanelCount()
bestIndex := count
bestScore := float32(1e20)
score := func(point math.Point, index int) {
score := point.Sub(at).Len()
if score < bestScore {
bestIndex = index
bestScore = score
}
}
for i := 0; i < holder.PanelCount(); i++ {
tab := holder.Tab(i)
size := tab.Size()
ml := math.Point{Y: size.H / 2}
mr := math.Point{Y: size.H / 2, X: size.W}
score(gxui.TransformCoordinate(ml, tab, holder), i)
score(gxui.TransformCoordinate(mr, tab, holder), i+1)
}
return bestIndex
}
func beginTabDragging(holder gxui.PanelHolder, panel gxui.Control, name string, window gxui.Window) {
var mms, mos gxui.EventSubscription
mms = window.OnMouseMove(func(ev gxui.MouseEvent) {
for _, c := range gxui.TopControlsUnder(ev.WindowPoint, ev.Window) {
if over, ok := c.C.(gxui.PanelHolder); ok {
insertAt := insertIndex(over, c.P)
if over == holder {
if insertAt > over.PanelIndex(panel) {
insertAt--
}
}
holder.RemovePanel(panel)
holder = over
holder.AddPanelAt(panel, name, insertAt)
holder.Select(insertAt)
}
}
})
mos = window.OnMouseUp(func(gxui.MouseEvent) {
mms.Unlisten()
mos.Unlisten()
})
}