zntg/ui/dockpanel.go

package ui

import (
	"math"

	"opslag.de/schobers/geom"
)

type DockPanel interface {
	Container
	Append(o Dock, children ...Control) error
	AppendCreate(ctx Context, o Dock, children ...Control) error
}

type Dock int

const (
	DockLeft Dock = iota
	DockTop
	DockRight
	DockBottom
)

type dockPanel struct {
	ContainerBase
	docks []Dock
}

func NewDockPanel(parent Container) DockPanel {
	return &dockPanel{ContainerBase: ContainerBase{parent: parent}}
}

func (p *dockPanel) Append(d Dock, children ...Control) error {
	for _, child := range children {
		p.ContainerBase.Append(child)
		p.docks = append(p.docks, d)
	}
	return nil
}

func (p *dockPanel) AppendCreate(ctx Context, d Dock, children ...Control) error {
	for _, child := range children {
		err := p.ContainerBase.AppendCreate(ctx, child)
		if nil != err {
			return err
		}
		p.docks = append(p.docks, d)
	}
	return nil
}

func (p *dockPanel) DesiredSize(ctx Context) geom.PointF {
	var width, height float64 = 0, 0
	for i, child := range p.children {
		var d = p.docks[i]
		var desired = child.DesiredSize(ctx)
		switch {
		case d == DockLeft || d == DockRight:
			if !math.IsNaN(width) {
				if math.IsNaN(desired.X) {
					width = desired.X
				} else {
					width += desired.X
				}
			}
			if !math.IsNaN(desired.Y) {
				height = math.Max(height, desired.Y)
			}
		case d == DockTop || d == DockBottom:
			if !math.IsNaN(height) {
				if math.IsNaN(desired.Y) {
					height = desired.Y
				} else {
					height += desired.Y
				}
			}
			if !math.IsNaN(desired.X) {
				width = math.Max(width, desired.X)
			}
		}
	}
	return geom.PtF(width, height)
}

func (p *dockPanel) arrangeChildren(ctx Context) []geom.RectangleF {
	var n = len(p.children)
	var rects = make([]geom.RectangleF, n)

	var rem = p.Bounds
	var last = n - 1
	for i, child := range p.children {
		if last == i {
			rects[i] = rem
		} else {
			var d = p.docks[i]
			var desired = child.DesiredSize(ctx)
			var width, height, top, left float64
			switch {
			case d == DockLeft || d == DockRight:
				width = rem.Dx()
				if !math.IsNaN(desired.X) {
					width = math.Min(desired.X, width)
				}
				if d == DockLeft {
					left = rem.Min.X
				} else {
					left = rem.Max.X - width
				}
				top = rem.Min.Y
				height = rem.Dy()
			case d == DockTop || d == DockBottom:
				height = rem.Dy()
				if !math.IsNaN(desired.Y) {
					height = math.Min(desired.Y, height)
				}
				if d == DockTop {
					top = rem.Min.Y
				} else {
					top = rem.Max.Y - height
				}
				left = rem.Min.X
				width = rem.Dx()
			}
			rects[i] = geom.RectF(left, top, left+width, top+height)
			switch d {
			case DockLeft:
				rem = geom.RectF(rem.Min.X+width, rem.Min.Y, rem.Max.X, rem.Max.Y)
			case DockTop:
				rem = geom.RectF(rem.Min.X, rem.Min.Y+height, rem.Max.X, rem.Max.Y)
			case DockRight:
				rem = geom.RectF(rem.Min.X, rem.Min.Y, rem.Max.X-width, rem.Max.Y)
			case DockBottom:
				rem = geom.RectF(rem.Min.X, rem.Min.Y, rem.Max.X, rem.Max.Y-height)
			}
		}
	}
	return rects
}

func (p *dockPanel) Arrange(ctx Context, rect geom.RectangleF) {
	p.ContainerBase.SetRect(rect)
	var rects = p.arrangeChildren(ctx)
	for i, child := range p.children {
		Arrange(ctx, child, rects[i])
	}
}