zntg/ui/margin.go

package ui

import "opslag.de/schobers/geom"

type margin struct {
	Wrapper
	Left, Top, Right, Bottom float32
}

func Margin(c Control, m float32) Control {
	return &margin{Wrap(c), m, m, m, m}
}

func LeftMargin(c Control, m float32) Control {
	return &margin{Wrap(c), m, 0, 0, 0}
}

func TopMargin(c Control, m float32) Control {
	return &margin{Wrap(c), 0, m, 0, 0}
}

func HorizontalMargin(c Control, m float32) Control {
	return &margin{Wrap(c), m, 0, m, 0}
}

func VerticalMargin(c Control, m float32) Control {
	return &margin{Wrap(c), 0, m, 0, m}
}

func (m *margin) DesiredSize(ctx Context) geom.PointF32 {
	var sz = m.Wrapper.DesiredSize(ctx)
	return geom.PtF32(sz.X+m.Left+m.Right, sz.Y+m.Top+m.Bottom)
}

func (m *margin) Arrange(ctx Context, rect geom.RectangleF32) {
	m.Wrapper.SetRect(rect)
	rect.Min.X += m.Left
	rect.Min.Y += m.Top
	rect.Max.X -= m.Right
	rect.Max.Y -= m.Bottom
	if rect.Min.X > rect.Max.X {
		var x = .5 * (rect.Min.X + rect.Max.X)
		rect.Min.X, rect.Max.X = x, x
	}
	if rect.Min.Y > rect.Max.Y {
		var y = .5 * (rect.Min.Y + rect.Max.Y)
		rect.Min.Y, rect.Max.Y = y, y
	}
	Arrange(ctx, m.Wrapped, rect)
}