forked from jroimartin/gocui
/
view.go
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/
view.go
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// 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"
"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 [][]rune
bgColor, fgColor Attribute
selBgColor, selFgColor Attribute
overwrite bool // overwrite in edit mode
// If Editable is true, keystrokes will be added to the view's internal
// buffer at the cursor position.
Editable bool
// If Highlight is true, Sel{Bg,Fg}Colors will be used
// for the line under the cursor position.
Highlight bool
}
// 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,
}
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 writes a rune at the given point, relative to the view. It
// checks if the position is valid and applies the view's colors, taking
// into account if the cell must be highlighted.
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
}
// 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) {
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
}
// draw re-draws the view's contents.
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
}
// Clear empties the view's internal buffer.
func (v *View) Clear() {
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 {
x = v.ox + x
y = v.oy + y
if x < 0 || y < 0 {
return errors.New("invalid point")
}
if y >= len(v.lines) {
if y >= cap(v.lines) {
s := make([][]rune, y+1, (y+1)*2)
copy(s, v.lines)
v.lines = s
} else {
v.lines = v.lines[:y+1]
}
}
if v.lines[y] == nil {
v.lines[y] = make([]rune, x+1, (x+1)*2)
} else if x >= len(v.lines[y]) {
if x >= cap(v.lines[y]) {
s := make([]rune, x+1, (x+1)*2)
copy(s, v.lines[y])
v.lines[y] = s
} else {
v.lines[y] = v.lines[y][:x+1]
}
}
if !v.overwrite {
v.lines[y] = append(v.lines[y], ' ')
copy(v.lines[y][x+1:], v.lines[y][x:])
}
v.lines[y][x] = ch
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 {
x = v.ox + x
y = v.oy + y
if x < 0 || y < 0 || y >= len(v.lines) || v.lines[y] == nil || x >= len(v.lines[y]) {
return errors.New("invalid point")
}
copy(v.lines[y][x:], v.lines[y][x+1:])
v.lines[y][len(v.lines[y])-1] = ' '
return nil
}
// addLine adds a line into the view's internal buffer at the position
// corresponding to the point (x, y).
func (v *View) addLine(y int) error {
y = v.oy + y
if y < 0 || y >= len(v.lines) {
return errors.New("invalid point")
}
v.lines = append(v.lines, nil)
copy(v.lines[y+1:], v.lines[y:])
v.lines[y] = nil
return nil
}
// 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 = v.oy + y
if y < 0 || y >= len(v.lines) {
return "", errors.New("invalid point")
}
return string(v.lines[y]), 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 = v.ox + x
y = v.oy + y
if y < 0 || y >= len(v.lines) || x >= len(v.lines[y]) {
return "", errors.New("invalid point")
}
l := string(v.lines[y])
nl := strings.LastIndexFunc(l[:x], indexFunc)
if nl == -1 {
nl = 0
} else {
nl = nl + 1
}
nr := strings.IndexFunc(l[x:], indexFunc)
if nr == -1 {
nr = len(l)
} else {
nr = nr + x
}
return string(l[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
}