gui/views/view_constrain.go

package views

import (
	"git.milar.in/milarin/gmath"
	"git.milar.in/milarin/gui"
)

// ConstrainView is a gui.Wrapper which constrains the dimensions of its View
type ConstrainView struct {
	gui.WrapperTmpl
	MaxWidth  int
	MaxHeight int
}

var _ gui.Wrapper = &ConstrainView{}

func NewConstrainView(view gui.View, maxWidth, maxHeight int) *ConstrainView {
	v := new(ConstrainView)
	v.SetView(view)
	v.Constrain(maxWidth, maxHeight)
	return v
}

func (v *ConstrainView) Constrain(maxWidth, maxHeight int) {
	v.MaxWidth, v.MaxHeight = maxWidth, maxHeight
}

func (v *ConstrainView) Layout(ctx gui.AppContext) (prefWidth, prefHeight int) {
	if v.View() == nil {
		return v.MaxWidth, v.MaxHeight
	}

	vw, vh := v.View().Layout(ctx)

	if v.MaxWidth >= 0 {
		prefWidth = iff(vw >= 0, gmath.Min(vw, v.MaxWidth), v.MaxWidth)
	} else {
		prefWidth = vw
	}

	if v.MaxHeight >= 0 {
		prefHeight = iff(vh >= 0, gmath.Min(vh, v.MaxHeight), v.MaxHeight)
	} else {
		prefHeight = vh
	}

	return
}