// 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
// Editor allows to define the editor that manages the edition mode,
// including keybindings or cursor behaviour. DefaultEditor is used by
// default.
Editor Editor
// 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, mode OutputMode) *View {
v := &View{
name: name,
x0: x0,
y0: y0,
x1: x1,
y1: y1,
Frame: true,
Editor: DefaultEditor,
tainted: true,
ei: newEscapeInterpreter(mode),
}
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{}
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
}
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 {
for n := 0; 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
}
fgColor := c.fgColor
if fgColor == ColorDefault {
fgColor = v.FgColor
}
bgColor := c.bgColor
if bgColor == ColorDefault {
bgColor = v.BgColor
}
if err := v.setRune(x, y, c.chr, fgColor, 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.viewLines = nil
v.readOffset = 0
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))
}
}
}
// BufferLines returns the lines in the view's internal
// buffer.
func (v *View) BufferLines() []string {
lines := make([]string, len(v.lines))
for i, l := range v.lines {
str := lineType(l).String()
str = strings.Replace(str, "\x00", " ", -1)
lines[i] = str
}
return lines
}
// 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)
}
// ViewBufferLines returns the lines in the view's internal
// buffer that is shown to the user.
func (v *View) ViewBufferLines() []string {
lines := make([]string, len(v.viewLines))
for i, l := range v.viewLines {
str := lineType(l.line).String()
str = strings.Replace(str, "\x00", " ", -1)
lines[i] = str
}
return lines
}
// 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
}
