gocui/view.go

// Copyright 2014 The gocui Authors.  All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package gocui

import (
	"bufio"
	"bytes"
	"errors"

	"github.com/nsf/termbox-go"
)

type View struct {
	name                   string
	x0, y0, x1, y1         int
	ox, oy                 int
	cx, cy                 int
	lines                  [][]rune
	bgColor, fgColor       Attribute
	selBgColor, selFgColor Attribute

	Highlight bool
}

func newView(name string, x0, y0, x1, y1 int) *View {
	v := &View{
		name: name,
		x0:   x0,
		y0:   y0,
		x1:   x1,
		y1:   y1,
	}
	return v
}

func (v *View) Size() (x, y int) {
	return v.x1 - v.x0 - 1, v.y1 - v.y0 - 1
}

func (v *View) Name() string {
	return v.name
}

func (v *View) setRune(x, y int, ch rune) error {
	maxX, maxY := v.Size()
	if x < 0 || x >= maxX || y < 0 || y >= maxY {
		return errors.New("invalid point")
	}

	var fgColor, bgColor Attribute
	if v.Highlight && y == v.cy {
		fgColor = v.selFgColor
		bgColor = v.selBgColor
	} else {
		fgColor = v.fgColor
		bgColor = v.bgColor
	}
	termbox.SetCell(v.x0+x+1, v.y0+y+1, ch,
		termbox.Attribute(fgColor), termbox.Attribute(bgColor))
	return nil
}

func (v *View) SetCursor(x, y int) error {
	maxX, maxY := v.Size()
	if x < 0 || x >= maxX || y < 0 || y >= maxY {
		return errors.New("invalid point")
	}
	v.cx = x
	v.cy = y
	return nil
}

func (v *View) Cursor() (x, y int) {
	return v.cx, v.cy
}

func (v *View) SetOrigin(x, y int) error {
	if x < 0 || y < 0 {
		return errors.New("invalid point")
	}
	v.ox = x
	v.oy = y
	return nil
}

func (v *View) Origin() (x, y int) {
	return v.ox, v.oy
}

func (v *View) Write(p []byte) (n int, err error) {
	r := bytes.NewReader(p)
	s := bufio.NewScanner(r)
	for s.Scan() {
		line := bytes.Runes(s.Bytes())
		v.lines = append(v.lines, line)
	}
	if err := s.Err(); err != nil {
		return 0, err
	}
	return len(p), nil
}

func (v *View) draw() error {
	maxX, maxY := v.Size()
	y := 0
	for i, line := range v.lines {
		if i < v.oy {
			continue
		}
		x := 0
		for j, ch := range line {
			if j < v.ox {
				continue
			}
			if x >= 0 && x < maxX && y >= 0 && y < maxY {
				if err := v.setRune(x, y, ch); err != nil {
					return err
				}
			}
			x++
		}
		y++
	}
	return nil
}

func (v *View) Clear() {
	v.lines = nil
	v.clearRunes()
}

func (v *View) clearRunes() {
	maxX, maxY := v.Size()
	for x := 0; x < maxX; x++ {
		for y := 0; y < maxY; y++ {
			termbox.SetCell(v.x0+x+1, v.y0+y+1, 0,
				termbox.Attribute(v.fgColor), termbox.Attribute(v.bgColor))
		}
	}
}