go/src/github.com/jroimartin/gocui/view.go - third_party - Git at Google

 // 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 (
 	"bytes"
 	"errors"
 	"io"
 	"strings"

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

 // A View is a window. It maintains its own internal buffer and cursor
 // position.
 type View struct {
 	name           string
 	x0, y0, x1, y1 int
 	ox, oy         int
 	cx, cy         int
 	lines          [][]cell
 	readOffset     int
 	readCache      string

 	tainted   bool       // marks if the viewBuffer must be updated
 	viewLines []viewLine // internal representation of the view's buffer

 	ei *escapeInterpreter // used to decode ESC sequences on Write

 	// BgColor and FgColor allow to configure the background and foreground
 	// colors of the View.
 	BgColor, FgColor Attribute

 	// SelBgColor and SelFgColor are used to configure the background and
 	// foreground colors of the selected line, when it is highlighted.
 	SelBgColor, SelFgColor Attribute

 	// If Editable is true, keystrokes will be added to the view's internal
 	// buffer at the cursor position.
 	Editable bool

 	// Overwrite enables or disables the overwrite mode of the view.
 	Overwrite bool

 	// If Highlight is true, Sel{Bg,Fg}Colors will be used
 	// for the line under the cursor position.
 	Highlight bool

 	// If Frame is true, a border will be drawn around the view.
 	Frame bool

 	// If Wrap is true, the content that is written to this View is
 	// automatically wrapped when it is longer than its width. If true the
 	// view's x-origin will be ignored.
 	Wrap bool

 	// If Autoscroll is true, the View will automatically scroll down when the
 	// text overflows. If true the view's y-origin will be ignored.
 	Autoscroll bool

 	// If Frame is true, Title allows to configure a title for the view.
 	Title string

 	// If Mask is true, the View will display the mask instead of the real
 	// content
 	Mask rune
 }

 type viewLine struct {
 	linesX, linesY int // coordinates relative to v.lines
 	line           []cell
 }

 type cell struct {
 	chr              rune
 	bgColor, fgColor Attribute
 }

 type lineType []cell

 // String returns a string from a given cell slice.
 func (l lineType) String() string {
 	str := ""
 	for _, c := range l {
 		str += string(c.chr)
 	}
 	return str
 }

 // newView returns a new View object.
 func newView(name string, x0, y0, x1, y1 int) *View {
 	v := &View{
 		name:    name,
 		x0:      x0,
 		y0:      y0,
 		x1:      x1,
 		y1:      y1,
 		Frame:   true,
 		tainted: true,
 		ei:      newEscapeInterpreter(),
 	}
 	return v
 }

 // Size returns the number of visible columns and rows in the View.
 func (v *View) Size() (x, y int) {
 	return v.x1 - v.x0 - 1, v.y1 - v.y0 - 1
 }

 // Name returns the name of the view.
 func (v *View) Name() string {
 	return v.name
 }

 // setRune sets a rune at the given point relative to the view. It applies the
 // specified colors, taking into account if the cell must be highlighted. Also,
 // it checks if the position is valid.
 func (v *View) setRune(x, y int, ch rune, fgColor, bgColor Attribute) error {
 	maxX, maxY := v.Size()
 	if x < 0 || x >= maxX || y < 0 || y >= maxY {
 		return errors.New("invalid point")
 	}

 	var (
 		ry, rcy int
 		err     error
 	)
 	if v.Highlight {
 		_, ry, err = v.realPosition(x, y)
 		if err != nil {
 			return err
 		}
 		_, rcy, err = v.realPosition(v.cx, v.cy)
 		if err != nil {
 			return err
 		}
 	}

 	if v.Mask != 0 {
 		fgColor = v.FgColor
 		bgColor = v.BgColor
 		ch = v.Mask
 	} else if v.Highlight && ry == rcy {
 		fgColor = v.SelFgColor
 		bgColor = v.SelBgColor
 	}

 	termbox.SetCell(v.x0+x+1, v.y0+y+1, ch,
 		termbox.Attribute(fgColor), termbox.Attribute(bgColor))

 	return nil
 }

 // SetCursor sets the cursor position of the view at the given point,
 // relative to the view. It checks if the position is valid.
 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
 }

 // Cursor returns the cursor position of the view.
 func (v *View) Cursor() (x, y int) {
 	return v.cx, v.cy
 }

 // SetOrigin sets the origin position of the view's internal buffer,
 // so the buffer starts to be printed from this point, which means that
 // it is linked with the origin point of view. It can be used to
 // implement Horizontal and Vertical scrolling with just incrementing
 // or decrementing ox and oy.
 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
 }

 // Origin returns the origin position of the view.
 func (v *View) Origin() (x, y int) {
 	return v.ox, v.oy
 }

 // Write appends a byte slice into the view's internal buffer. Because
 // View implements the io.Writer interface, it can be passed as parameter
 // of functions like fmt.Fprintf, fmt.Fprintln, io.Copy, etc. Clear must
 // be called to clear the view's buffer.
 func (v *View) Write(p []byte) (n int, err error) {
 	v.tainted = true

 	for _, ch := range bytes.Runes(p) {
 		switch ch {
 		case '\n':
 			v.lines = append(v.lines, nil)
 		case '\r':
 			nl := len(v.lines)
 			if nl > 0 {
 				v.lines[nl-1] = nil
 			} else {
 				v.lines = make([][]cell, 1)
 			}
 		default:
 			cells := v.parseInput(ch)
 			if cells == nil {
 				continue
 			}

 			nl := len(v.lines)
 			if nl > 0 {
 				v.lines[nl-1] = append(v.lines[nl-1], cells...)
 			} else {
 				v.lines = append(v.lines, cells)
 			}
 		}
 	}
 	return len(p), nil
 }

 // parseInput parses char by char the input written to the View. It returns nil
 // while processing ESC sequences. Otherwise, it returns a cell slice that
 // contains the processed data.
 func (v *View) parseInput(ch rune) []cell {
 	cells := []cell{}

 	// ei's default colors must be updated, because they could have been
 	// changed
 	v.ei.defaultFgColor = v.FgColor
 	v.ei.defaultBgColor = v.BgColor

 	isEscape, err := v.ei.parseOne(ch)
 	if err != nil {
 		for _, r := range v.ei.runes() {
 			c := cell{
 				fgColor: v.FgColor,
 				bgColor: v.BgColor,
 				chr:     r,
 			}
 			cells = append(cells, c)
 		}
 		v.ei.reset()
 	} else {
 		if isEscape {
 			return nil
 		} else {
 			c := cell{
 				fgColor: v.ei.curFgColor,
 				bgColor: v.ei.curBgColor,
 				chr:     ch,
 			}
 			cells = append(cells, c)
 		}
 	}

 	return cells
 }

 // Read reads data into p. It returns the number of bytes read into p.
 // At EOF, err will be io.EOF. Calling Read() after Rewind() makes the
 // cache to be refreshed with the contents of the view.
 func (v *View) Read(p []byte) (n int, err error) {
 	if v.readOffset == 0 {
 		v.readCache = v.Buffer()
 	}
 	if v.readOffset < len(v.readCache) {
 		n = copy(p, v.readCache[v.readOffset:])
 		v.readOffset += n
 	} else {
 		err = io.EOF
 	}
 	return
 }

 // Rewind sets the offset for the next Read to 0, which also refresh the
 // read cache.
 func (v *View) Rewind() {
 	v.readOffset = 0
 }

 // draw re-draws the view's contents.
 func (v *View) draw() error {
 	maxX, maxY := v.Size()

 	if v.Wrap {
 		if maxX == 0 {
 			return errors.New("X size of the view cannot be 0")
 		}
 		v.ox = 0
 	}
 	if v.tainted {
 		v.viewLines = nil
 		for i, line := range v.lines {
 			if v.Wrap {
 				if len(line) <= maxX {
 					vline := viewLine{linesX: 0, linesY: i, line: line}
 					v.viewLines = append(v.viewLines, vline)
 					continue
 				} else {
 					vline := viewLine{linesX: 0, linesY: i, line: line[:maxX]}
 					v.viewLines = append(v.viewLines, vline)
 				}
 				// Append remaining lines
 				for n := maxX; n < len(line); n += maxX {
 					if len(line[n:]) <= maxX {
 						vline := viewLine{linesX: n, linesY: i, line: line[n:]}
 						v.viewLines = append(v.viewLines, vline)
 					} else {
 						vline := viewLine{linesX: n, linesY: i, line: line[n : n+maxX]}
 						v.viewLines = append(v.viewLines, vline)
 					}
 				}
 			} else {
 				vline := viewLine{linesX: 0, linesY: i, line: line}
 				v.viewLines = append(v.viewLines, vline)
 			}
 		}
 		v.tainted = false
 	}

 	if v.Autoscroll && len(v.viewLines) > maxY {
 		v.oy = len(v.viewLines) - maxY
 	}
 	y := 0
 	for i, vline := range v.viewLines {
 		if i < v.oy {
 			continue
 		}
 		if y >= maxY {
 			break
 		}
 		x := 0
 		for j, c := range vline.line {
 			if j < v.ox {
 				continue
 			}
 			if x >= maxX {
 				break
 			}
 			if err := v.setRune(x, y, c.chr, c.fgColor, c.bgColor); err != nil {
 				return err
 			}
 			x++
 		}
 		y++
 	}
 	return nil
 }

 // realPosition returns the position in the internal buffer corresponding to the
 // point (x, y) of the view.
 func (v *View) realPosition(vx, vy int) (x, y int, err error) {
 	vx = v.ox + vx
 	vy = v.oy + vy

 	if vx < 0 || vy < 0 {
 		return 0, 0, errors.New("invalid point")
 	}

 	if len(v.viewLines) == 0 {
 		return vx, vy, nil
 	}

 	if vy < len(v.viewLines) {
 		vline := v.viewLines[vy]
 		x = vline.linesX + vx
 		y = vline.linesY
 	} else {
 		vline := v.viewLines[len(v.viewLines)-1]
 		x = vx
 		y = vline.linesY + vy - len(v.viewLines) + 1
 	}

 	return x, y, nil
 }

 // Clear empties the view's internal buffer.
 func (v *View) Clear() {
 	v.tainted = true

 	v.lines = nil
 	v.clearRunes()
 }

 // clearRunes erases all the cells in the view.
 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, ' ',
 				termbox.Attribute(v.FgColor), termbox.Attribute(v.BgColor))
 		}
 	}
 }

 // writeRune writes a rune into the view's internal buffer, at the
 // position corresponding to the point (x, y). The length of the internal
 // buffer is increased if the point is out of bounds. Overwrite mode is
 // governed by the value of View.overwrite.
 func (v *View) writeRune(x, y int, ch rune) error {
 	v.tainted = true

 	x, y, err := v.realPosition(x, y)
 	if err != nil {
 		return err
 	}

 	if x < 0 || y < 0 {
 		return errors.New("invalid point")
 	}

 	if y >= len(v.lines) {
 		s := make([][]cell, y-len(v.lines)+1)
 		v.lines = append(v.lines, s...)
 	}

 	olen := len(v.lines[y])
 	if x >= len(v.lines[y]) {
 		s := make([]cell, x-len(v.lines[y])+1)
 		v.lines[y] = append(v.lines[y], s...)
 	}

 	c := cell{
 		fgColor: v.FgColor,
 		bgColor: v.BgColor,
 	}
 	if !v.Overwrite && x < olen {
 		c.chr = '\x00'
 		v.lines[y] = append(v.lines[y], c)
 		copy(v.lines[y][x+1:], v.lines[y][x:])
 	}
 	c.chr = ch
 	v.lines[y][x] = c
 	return nil
 }

 // deleteRune removes a rune from the view's internal buffer, at the
 // position corresponding to the point (x, y).
 func (v *View) deleteRune(x, y int) error {
 	v.tainted = true

 	x, y, err := v.realPosition(x, y)
 	if err != nil {
 		return err
 	}

 	if x < 0 || y < 0 || y >= len(v.lines) || x >= len(v.lines[y]) {
 		return errors.New("invalid point")
 	}
 	v.lines[y] = append(v.lines[y][:x], v.lines[y][x+1:]...)
 	return nil
 }

 // mergeLines merges the lines "y" and "y+1" if possible.
 func (v *View) mergeLines(y int) error {
 	v.tainted = true

 	_, y, err := v.realPosition(0, y)
 	if err != nil {
 		return err
 	}

 	if y < 0 || y >= len(v.lines) {
 		return errors.New("invalid point")
 	}

 	if y < len(v.lines)-1 { // otherwise we don't need to merge anything
 		v.lines[y] = append(v.lines[y], v.lines[y+1]...)
 		v.lines = append(v.lines[:y+1], v.lines[y+2:]...)
 	}
 	return nil
 }

 // breakLine breaks a line of the internal buffer at the position corresponding
 // to the point (x, y).
 func (v *View) breakLine(x, y int) error {
 	v.tainted = true

 	x, y, err := v.realPosition(x, y)
 	if err != nil {
 		return err
 	}

 	if y < 0 || y >= len(v.lines) {
 		return errors.New("invalid point")
 	}

 	var left, right []cell
 	if x < len(v.lines[y]) { // break line
 		left = make([]cell, len(v.lines[y][:x]))
 		copy(left, v.lines[y][:x])
 		right = make([]cell, len(v.lines[y][x:]))
 		copy(right, v.lines[y][x:])
 	} else { // new empty line
 		left = v.lines[y]
 	}

 	lines := make([][]cell, len(v.lines)+1)
 	lines[y] = left
 	lines[y+1] = right
 	copy(lines, v.lines[:y])
 	copy(lines[y+2:], v.lines[y+1:])
 	v.lines = lines
 	return nil
 }

 // Buffer returns a string with the contents of the view's internal
 // buffer.
 func (v *View) Buffer() string {
 	str := ""
 	for _, l := range v.lines {
 		str += lineType(l).String() + "\n"
 	}
 	return strings.Replace(str, "\x00", " ", -1)
 }

 // ViewBuffer returns a string with the contents of the view's buffer that is
 // shown to the user.
 func (v *View) ViewBuffer() string {
 	str := ""
 	for _, l := range v.viewLines {
 		str += lineType(l.line).String() + "\n"
 	}
 	return strings.Replace(str, "\x00", " ", -1)
 }

 // Line returns a string with the line of the view's internal buffer
 // at the position corresponding to the point (x, y).
 func (v *View) Line(y int) (string, error) {
 	_, y, err := v.realPosition(0, y)
 	if err != nil {
 		return "", err
 	}

 	if y < 0 || y >= len(v.lines) {
 		return "", errors.New("invalid point")
 	}

 	return lineType(v.lines[y]).String(), nil
 }

 // Word returns a string with the word of the view's internal buffer
 // at the position corresponding to the point (x, y).
 func (v *View) Word(x, y int) (string, error) {
 	x, y, err := v.realPosition(x, y)
 	if err != nil {
 		return "", err
 	}

 	if x < 0 || y < 0 || y >= len(v.lines) || x >= len(v.lines[y]) {
 		return "", errors.New("invalid point")
 	}

 	str := lineType(v.lines[y]).String()

 	nl := strings.LastIndexFunc(str[:x], indexFunc)
 	if nl == -1 {
 		nl = 0
 	} else {
 		nl = nl + 1
 	}
 	nr := strings.IndexFunc(str[x:], indexFunc)
 	if nr == -1 {
 		nr = len(str)
 	} else {
 		nr = nr + x
 	}
 	return string(str[nl:nr]), nil
 }

 // indexFunc allows to split lines by words taking into account spaces
 // and 0.
 func indexFunc(r rune) bool {
 	return r == ' ' || r == 0
 }
	// 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 (
	"bytes"
	"errors"
	"io"
	"strings"

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

	// A View is a window. It maintains its own internal buffer and cursor
	// position.
	type View struct {
	name string
	x0, y0, x1, y1 int
	ox, oy int
	cx, cy int
	lines [][]cell
	readOffset int
	readCache string

	tainted bool // marks if the viewBuffer must be updated
	viewLines []viewLine // internal representation of the view's buffer

	ei *escapeInterpreter // used to decode ESC sequences on Write

	// BgColor and FgColor allow to configure the background and foreground
	// colors of the View.
	BgColor, FgColor Attribute

	// SelBgColor and SelFgColor are used to configure the background and
	// foreground colors of the selected line, when it is highlighted.
	SelBgColor, SelFgColor Attribute

	// If Editable is true, keystrokes will be added to the view's internal
	// buffer at the cursor position.
	Editable bool

	// Overwrite enables or disables the overwrite mode of the view.
	Overwrite bool

	// If Highlight is true, Sel{Bg,Fg}Colors will be used
	// for the line under the cursor position.
	Highlight bool

	// If Frame is true, a border will be drawn around the view.
	Frame bool

	// If Wrap is true, the content that is written to this View is
	// automatically wrapped when it is longer than its width. If true the
	// view's x-origin will be ignored.
	Wrap bool

	// If Autoscroll is true, the View will automatically scroll down when the
	// text overflows. If true the view's y-origin will be ignored.
	Autoscroll bool

	// If Frame is true, Title allows to configure a title for the view.
	Title string

	// If Mask is true, the View will display the mask instead of the real
	// content
	Mask rune
	}

	type viewLine struct {
	linesX, linesY int // coordinates relative to v.lines
	line []cell
	}

	type cell struct {
	chr rune
	bgColor, fgColor Attribute
	}

	type lineType []cell

	// String returns a string from a given cell slice.
	func (l lineType) String() string {
	str := ""
	for _, c := range l {
	str += string(c.chr)
	}
	return str
	}

	// newView returns a new View object.
	func newView(name string, x0, y0, x1, y1 int) *View {
	v := &View{
	name: name,
	x0: x0,
	y0: y0,
	x1: x1,
	y1: y1,
	Frame: true,
	tainted: true,
	ei: newEscapeInterpreter(),
	}
	return v
	}

	// Size returns the number of visible columns and rows in the View.
	func (v *View) Size() (x, y int) {
	return v.x1 - v.x0 - 1, v.y1 - v.y0 - 1
	}

	// Name returns the name of the view.
	func (v *View) Name() string {
	return v.name
	}

	// setRune sets a rune at the given point relative to the view. It applies the
	// specified colors, taking into account if the cell must be highlighted. Also,
	// it checks if the position is valid.
	func (v *View) setRune(x, y int, ch rune, fgColor, bgColor Attribute) error {
	maxX, maxY := v.Size()
	if x < 0 \|\| x >= maxX \|\| y < 0 \|\| y >= maxY {
	return errors.New("invalid point")
	}

	var (
	ry, rcy int
	err error
	)
	if v.Highlight {
	_, ry, err = v.realPosition(x, y)
	if err != nil {
	return err
	}
	_, rcy, err = v.realPosition(v.cx, v.cy)
	if err != nil {
	return err
	}
	}

	if v.Mask != 0 {
	fgColor = v.FgColor
	bgColor = v.BgColor
	ch = v.Mask
	} else if v.Highlight && ry == rcy {
	fgColor = v.SelFgColor
	bgColor = v.SelBgColor
	}

	termbox.SetCell(v.x0+x+1, v.y0+y+1, ch,
	termbox.Attribute(fgColor), termbox.Attribute(bgColor))

	return nil
	}

	// SetCursor sets the cursor position of the view at the given point,
	// relative to the view. It checks if the position is valid.
	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
	}

	// Cursor returns the cursor position of the view.
	func (v *View) Cursor() (x, y int) {
	return v.cx, v.cy
	}

	// SetOrigin sets the origin position of the view's internal buffer,
	// so the buffer starts to be printed from this point, which means that
	// it is linked with the origin point of view. It can be used to
	// implement Horizontal and Vertical scrolling with just incrementing
	// or decrementing ox and oy.
	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
	}

	// Origin returns the origin position of the view.
	func (v *View) Origin() (x, y int) {
	return v.ox, v.oy
	}

	// Write appends a byte slice into the view's internal buffer. Because
	// View implements the io.Writer interface, it can be passed as parameter
	// of functions like fmt.Fprintf, fmt.Fprintln, io.Copy, etc. Clear must
	// be called to clear the view's buffer.
	func (v *View) Write(p []byte) (n int, err error) {
	v.tainted = true

	for _, ch := range bytes.Runes(p) {
	switch ch {
	case '\n':
	v.lines = append(v.lines, nil)
	case '\r':
	nl := len(v.lines)
	if nl > 0 {
	v.lines[nl-1] = nil
	} else {
	v.lines = make([][]cell, 1)
	}
	default:
	cells := v.parseInput(ch)
	if cells == nil {
	continue
	}

	nl := len(v.lines)
	if nl > 0 {
	v.lines[nl-1] = append(v.lines[nl-1], cells...)
	} else {
	v.lines = append(v.lines, cells)
	}
	}
	}
	return len(p), nil
	}

	// parseInput parses char by char the input written to the View. It returns nil
	// while processing ESC sequences. Otherwise, it returns a cell slice that
	// contains the processed data.
	func (v *View) parseInput(ch rune) []cell {
	cells := []cell{}

	// ei's default colors must be updated, because they could have been
	// changed
	v.ei.defaultFgColor = v.FgColor
	v.ei.defaultBgColor = v.BgColor

	isEscape, err := v.ei.parseOne(ch)
	if err != nil {
	for _, r := range v.ei.runes() {
	c := cell{
	fgColor: v.FgColor,
	bgColor: v.BgColor,
	chr: r,
	}
	cells = append(cells, c)
	}
	v.ei.reset()
	} else {
	if isEscape {
	return nil
	} else {
	c := cell{
	fgColor: v.ei.curFgColor,
	bgColor: v.ei.curBgColor,
	chr: ch,
	}
	cells = append(cells, c)
	}
	}

	return cells
	}

	// Read reads data into p. It returns the number of bytes read into p.
	// At EOF, err will be io.EOF. Calling Read() after Rewind() makes the
	// cache to be refreshed with the contents of the view.
	func (v *View) Read(p []byte) (n int, err error) {
	if v.readOffset == 0 {
	v.readCache = v.Buffer()
	}
	if v.readOffset < len(v.readCache) {
	n = copy(p, v.readCache[v.readOffset:])
	v.readOffset += n
	} else {
	err = io.EOF
	}
	return
	}

	// Rewind sets the offset for the next Read to 0, which also refresh the
	// read cache.
	func (v *View) Rewind() {
	v.readOffset = 0
	}

	// draw re-draws the view's contents.
	func (v *View) draw() error {
	maxX, maxY := v.Size()

	if v.Wrap {
	if maxX == 0 {
	return errors.New("X size of the view cannot be 0")
	}
	v.ox = 0
	}
	if v.tainted {
	v.viewLines = nil
	for i, line := range v.lines {
	if v.Wrap {
	if len(line) <= maxX {
	vline := viewLine{linesX: 0, linesY: i, line: line}
	v.viewLines = append(v.viewLines, vline)
	continue
	} else {
	vline := viewLine{linesX: 0, linesY: i, line: line[:maxX]}
	v.viewLines = append(v.viewLines, vline)
	}
	// Append remaining lines
	for n := maxX; n < len(line); n += maxX {
	if len(line[n:]) <= maxX {
	vline := viewLine{linesX: n, linesY: i, line: line[n:]}
	v.viewLines = append(v.viewLines, vline)
	} else {
	vline := viewLine{linesX: n, linesY: i, line: line[n : n+maxX]}
	v.viewLines = append(v.viewLines, vline)
	}
	}
	} else {
	vline := viewLine{linesX: 0, linesY: i, line: line}
	v.viewLines = append(v.viewLines, vline)
	}
	}
	v.tainted = false
	}

	if v.Autoscroll && len(v.viewLines) > maxY {
	v.oy = len(v.viewLines) - maxY
	}
	y := 0
	for i, vline := range v.viewLines {
	if i < v.oy {
	continue
	}
	if y >= maxY {
	break
	}
	x := 0
	for j, c := range vline.line {
	if j < v.ox {
	continue
	}
	if x >= maxX {
	break
	}
	if err := v.setRune(x, y, c.chr, c.fgColor, c.bgColor); err != nil {
	return err
	}
	x++
	}
	y++
	}
	return nil
	}

	// realPosition returns the position in the internal buffer corresponding to the
	// point (x, y) of the view.
	func (v *View) realPosition(vx, vy int) (x, y int, err error) {
	vx = v.ox + vx
	vy = v.oy + vy

	if vx < 0 \|\| vy < 0 {
	return 0, 0, errors.New("invalid point")
	}

	if len(v.viewLines) == 0 {
	return vx, vy, nil
	}

	if vy < len(v.viewLines) {
	vline := v.viewLines[vy]
	x = vline.linesX + vx
	y = vline.linesY
	} else {
	vline := v.viewLines[len(v.viewLines)-1]
	x = vx
	y = vline.linesY + vy - len(v.viewLines) + 1
	}

	return x, y, nil
	}

	// Clear empties the view's internal buffer.
	func (v *View) Clear() {
	v.tainted = true

	v.lines = nil
	v.clearRunes()
	}

	// clearRunes erases all the cells in the view.
	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, ' ',
	termbox.Attribute(v.FgColor), termbox.Attribute(v.BgColor))
	}
	}
	}

	// writeRune writes a rune into the view's internal buffer, at the
	// position corresponding to the point (x, y). The length of the internal
	// buffer is increased if the point is out of bounds. Overwrite mode is
	// governed by the value of View.overwrite.
	func (v *View) writeRune(x, y int, ch rune) error {
	v.tainted = true

	x, y, err := v.realPosition(x, y)
	if err != nil {
	return err
	}

	if x < 0 \|\| y < 0 {
	return errors.New("invalid point")
	}

	if y >= len(v.lines) {
	s := make([][]cell, y-len(v.lines)+1)
	v.lines = append(v.lines, s...)
	}

	olen := len(v.lines[y])
	if x >= len(v.lines[y]) {
	s := make([]cell, x-len(v.lines[y])+1)
	v.lines[y] = append(v.lines[y], s...)
	}

	c := cell{
	fgColor: v.FgColor,
	bgColor: v.BgColor,
	}
	if !v.Overwrite && x < olen {
	c.chr = '\x00'
	v.lines[y] = append(v.lines[y], c)
	copy(v.lines[y][x+1:], v.lines[y][x:])
	}
	c.chr = ch
	v.lines[y][x] = c
	return nil
	}

	// deleteRune removes a rune from the view's internal buffer, at the
	// position corresponding to the point (x, y).
	func (v *View) deleteRune(x, y int) error {
	v.tainted = true

	x, y, err := v.realPosition(x, y)
	if err != nil {
	return err
	}

	if x < 0 \|\| y < 0 \|\| y >= len(v.lines) \|\| x >= len(v.lines[y]) {
	return errors.New("invalid point")
	}
	v.lines[y] = append(v.lines[y][:x], v.lines[y][x+1:]...)
	return nil
	}

	// mergeLines merges the lines "y" and "y+1" if possible.
	func (v *View) mergeLines(y int) error {
	v.tainted = true

	_, y, err := v.realPosition(0, y)
	if err != nil {
	return err
	}

	if y < 0 \|\| y >= len(v.lines) {
	return errors.New("invalid point")
	}

	if y < len(v.lines)-1 { // otherwise we don't need to merge anything
	v.lines[y] = append(v.lines[y], v.lines[y+1]...)
	v.lines = append(v.lines[:y+1], v.lines[y+2:]...)
	}
	return nil
	}

	// breakLine breaks a line of the internal buffer at the position corresponding
	// to the point (x, y).
	func (v *View) breakLine(x, y int) error {
	v.tainted = true

	x, y, err := v.realPosition(x, y)
	if err != nil {
	return err
	}

	if y < 0 \|\| y >= len(v.lines) {
	return errors.New("invalid point")
	}

	var left, right []cell
	if x < len(v.lines[y]) { // break line
	left = make([]cell, len(v.lines[y][:x]))
	copy(left, v.lines[y][:x])
	right = make([]cell, len(v.lines[y][x:]))
	copy(right, v.lines[y][x:])
	} else { // new empty line
	left = v.lines[y]
	}

	lines := make([][]cell, len(v.lines)+1)
	lines[y] = left
	lines[y+1] = right
	copy(lines, v.lines[:y])
	copy(lines[y+2:], v.lines[y+1:])
	v.lines = lines
	return nil
	}

	// Buffer returns a string with the contents of the view's internal
	// buffer.
	func (v *View) Buffer() string {
	str := ""
	for _, l := range v.lines {
	str += lineType(l).String() + "\n"
	}
	return strings.Replace(str, "\x00", " ", -1)
	}

	// ViewBuffer returns a string with the contents of the view's buffer that is
	// shown to the user.
	func (v *View) ViewBuffer() string {
	str := ""
	for _, l := range v.viewLines {
	str += lineType(l.line).String() + "\n"
	}
	return strings.Replace(str, "\x00", " ", -1)
	}

	// Line returns a string with the line of the view's internal buffer
	// at the position corresponding to the point (x, y).
	func (v *View) Line(y int) (string, error) {
	_, y, err := v.realPosition(0, y)
	if err != nil {
	return "", err
	}

	if y < 0 \|\| y >= len(v.lines) {
	return "", errors.New("invalid point")
	}

	return lineType(v.lines[y]).String(), nil
	}

	// Word returns a string with the word of the view's internal buffer
	// at the position corresponding to the point (x, y).
	func (v *View) Word(x, y int) (string, error) {
	x, y, err := v.realPosition(x, y)
	if err != nil {
	return "", err
	}

	if x < 0 \|\| y < 0 \|\| y >= len(v.lines) \|\| x >= len(v.lines[y]) {
	return "", errors.New("invalid point")
	}

	str := lineType(v.lines[y]).String()

	nl := strings.LastIndexFunc(str[:x], indexFunc)
	if nl == -1 {
	nl = 0
	} else {
	nl = nl + 1
	}
	nr := strings.IndexFunc(str[x:], indexFunc)
	if nr == -1 {
	nr = len(str)
	} else {
	nr = nr + x
	}
	return string(str[nl:nr]), nil
	}

	// indexFunc allows to split lines by words taking into account spaces
	// and 0.
	func indexFunc(r rune) bool {
	return r == ' ' \|\| r == 0
	}