tui/views/layout_flow.go

package views

import (
	"git.tordarus.net/Tordarus/tui"
)

// FlowLayout ia a tui.Layout which places its children in a linear layout
type FlowLayout struct {
	tui.ViewTmpl
	views           []tui.View
	lastLayoutPhase *LayoutResult

	// Orientation defines in which direction the children will be placed
	Orientation tui.Orientation
}

var _ tui.Layout = &FlowLayout{}

func NewFlowLayout(orientation tui.Orientation) *FlowLayout {
	return &FlowLayout{
		views:       make([]tui.View, 0),
		Orientation: orientation,
	}
}

func (g *FlowLayout) Views() []tui.View {
	return g.views
}

func (g *FlowLayout) AppendViews(v ...tui.View) {
	g.views = append(g.views, v...)
}

func (g *FlowLayout) PrependViews(v ...tui.View) {
	g.views = append(v, g.views...)
}

func (g *FlowLayout) InsertView(v tui.View, index int) {
	g.views = append(g.views[:index], append([]tui.View{v}, g.views[index:]...)...)
}

func (g *FlowLayout) removeView(v tui.View) {
	for index, view := range g.Views() {
		if v == view {
			g.views = append(g.views[:index], g.views[index+1:]...)
			return
		}
	}
}

func (g *FlowLayout) RemoveViews(v ...tui.View) {
	views := make([]tui.View, 0, len(v))
	for _, view := range v {
		views = append(views, view)
	}
	for _, view := range views {
		g.removeView(view)
	}
}

func (g *FlowLayout) Draw(buf *tui.ViewBuffer) {
	g.ViewTmpl.Draw(buf)

	if g.lastLayoutPhase == nil {
		g.Layout()
	}
	layout := g.lastLayoutPhase

	if g.Orientation == tui.Horizontal {
		remainingSpacePerView := buf.Width() - layout.Sum.Width
		if remainingSpacePerView < 0 {
			remainingSpacePerView = 0
		}
		if layout.HorizontalNegativeCount > 0 {
			remainingSpacePerView /= layout.HorizontalNegativeCount
		}

		x := 0
		for _, view := range g.views {
			size := layout.Sizes[view]

			size.Height = iff(size.Height < 0, buf.Height(), size.Height)
			if size.Width < 0 {
				size.Width = iff(layout.Sum.Width > buf.Width(), 0, remainingSpacePerView)
			}

			view.Draw(buf.Sub(x, 0, size.Width, size.Height))

			x += size.Width
			if x >= buf.Width() {
				break
			}
		}
	} else if g.Orientation == tui.Vertical {
		remainingSpacePerView := buf.Height() - layout.Sum.Height
		if remainingSpacePerView < 0 {
			remainingSpacePerView = 0
		}
		if layout.VerticalNegativeCount > 0 {
			remainingSpacePerView /= layout.VerticalNegativeCount
		}

		y := 0
		for _, view := range g.views {
			size := layout.Sizes[view]

			size.Width = iff(size.Width < 0, buf.Width(), size.Width)
			if size.Height < 0 {
				size.Height = iff(layout.Sum.Height > buf.Height(), 0, remainingSpacePerView)
			}

			view.Draw(buf.Sub(0, y, size.Width, size.Height))

			y += size.Height
			if y >= buf.Height() {
				break
			}
		}
	}

	g.lastLayoutPhase = nil
}

func (g *FlowLayout) Layout() (prefWidth, prefHeight int) {
	layout := CalculateLayoutResult(g.Views())
	g.lastLayoutPhase = layout

	if g.Orientation == tui.Horizontal {
		prefWidth = iff(layout.HorizontalNegativeCount == 0, layout.Sum.Width, -1)
		prefHeight = iff(layout.VerticalNegativeCount == 0, layout.Max.Height, -1)
	} else if g.Orientation == tui.Vertical {
		prefWidth = iff(layout.HorizontalNegativeCount == 0, layout.Max.Width, -1)
		prefHeight = iff(layout.VerticalNegativeCount == 0, layout.Sum.Height, -1)
	}

	layout.Pref = tui.Size{Width: prefWidth, Height: prefHeight}
	return
}

func (g *FlowLayout) OnKeyPressed(event *tui.KeyEvent) (consumed bool) {
	for _, view := range g.Views() {
		if view.OnKeyPressed(event) {
			return true
		}
	}
	return false
}