tui/views/view_border.go

package views

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

// BorderView is a tui.Wrapper which draws an ASCII border around its view.
// Be aware that box drawing characters must share the same tui.Style with the next character.
// This can lead to color artifacts when using BorderView with colored styles.
type BorderView struct {
	tui.WrapperTmpl
	Border BorderBox
}

var _ tui.Wrapper = &BorderView{}

func NewBorderView(view tui.View) *BorderView {
	v := new(BorderView)
	v.SetView(view)
	v.Border = ThinBorder()
	return v
}

func (g *BorderView) Draw(buf *tui.ViewBuffer) {
	g.View().Draw(buf.Sub(1, 1, buf.Width()-2, buf.Height()-2))

	buf.Set(0, 0, tui.Rune{Rn: g.Border.TopLeft, Style: g.Style()})
	buf.Set(buf.Width()-1, 0, tui.Rune{Rn: g.Border.TopRight, Style: g.Style()})

	buf.Set(0, buf.Height()-1, tui.Rune{Rn: g.Border.BottomLeft, Style: g.Style()})
	buf.Set(buf.Width()-1, buf.Height()-1, tui.Rune{Rn: g.Border.BottomRight, Style: g.Style()})

	for x := 1; x < buf.Width()-1; x++ {
		buf.Set(x, 0, tui.Rune{Rn: g.Border.Horizontal, Style: g.Style()})
		buf.Set(x, buf.Height()-1, tui.Rune{Rn: g.Border.Horizontal, Style: g.Style()})
	}

	for y := 1; y < buf.Height()-1; y++ {
		buf.Set(0, y, tui.Rune{Rn: g.Border.Vertical, Style: g.Style()})
		buf.Set(buf.Width()-1, y, tui.Rune{Rn: g.Border.Vertical, Style: g.Style()})
	}
}

func (v *BorderView) Layout() (prefWidth, prefHeight int) {
	w, h := v.View().Layout()
	w = iff(w > 0, w+2, w)
	h = iff(h > 0, h+2, h)
	return w, h
}

type BorderBox struct {
	TopLeft     rune
	TopRight    rune
	BottomLeft  rune
	BottomRight rune
	Horizontal  rune
	Vertical    rune
}

func ThickBorder() BorderBox {
	return BorderBox{
		TopLeft:     '┏',
		TopRight:    '┓',
		BottomLeft:  '┗',
		BottomRight: '┛',
		Horizontal:  '━',
		Vertical:    '┃',
	}
}

func ThinBorder() BorderBox {
	return BorderBox{
		TopLeft:     '┌',
		TopRight:    '┐',
		BottomLeft:  '└',
		BottomRight: '┘',
		Horizontal:  '─',
		Vertical:    '│',
	}
}

func DoubleBorder() BorderBox {
	return BorderBox{
		TopLeft:     '╔',
		TopRight:    '╗',
		BottomLeft:  '╚',
		BottomRight: '╝',
		Horizontal:  '═',
		Vertical:    '║',
	}
}