File: cell.go

package info (click to toggle)
golang-github-gdamore-tcell 1.1.0-1
  • links: PTS, VCS
  • area: main
  • in suites: buster, sid
  • size: 11,676 kB
  • sloc: makefile: 2
file content (186 lines) | stat: -rw-r--r-- 4,884 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
// Copyright 2015 The TCell Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use file except in compliance with the License.
// You may obtain a copy of the license at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package tcell

import (
	"github.com/mattn/go-runewidth"
)

type cell struct {
	currMain  rune
	currComb  []rune
	currStyle Style
	lastMain  rune
	lastStyle Style
	lastComb  []rune
	width     int
}

// CellBuffer represents a two dimensional array of character cells.
// This is primarily intended for use by Screen implementors; it
// contains much of the common code they need.  To create one, just
// declare a variable of its type; no explicit initialization is necessary.
//
// CellBuffer is not thread safe.
type CellBuffer struct {
	w     int
	h     int
	cells []cell
}

// SetContent sets the contents (primary rune, combining runes,
// and style) for a cell at a given location.
func (cb *CellBuffer) SetContent(x int, y int,
	mainc rune, combc []rune, style Style) {

	if x >= 0 && y >= 0 && x < cb.w && y < cb.h {
		c := &cb.cells[(y*cb.w)+x]

		c.currComb = append([]rune{}, combc...)
		i := 0
		for i < len(c.currComb) {
			r := c.currComb[i]
			if runewidth.RuneWidth(r) != 0 {
				// not a combining character, yank it
				c.currComb = append(c.currComb[:i-1], c.currComb[i+1:]...)
				continue
			}
			i++
		}

		if c.currMain != mainc {
			c.width = runewidth.RuneWidth(mainc)
		}
		c.currMain = mainc
		c.currStyle = style
	}
}

// GetContent returns the contents of a character cell, including the
// primary rune, any combining character runes (which will usually be
// nil), the style, and the display width in cells.  (The width can be
// either 1, normally, or 2 for East Asian full-width characters.)
func (cb *CellBuffer) GetContent(x, y int) (rune, []rune, Style, int) {
	var mainc rune
	var combc []rune
	var style Style
	var width int
	if x >= 0 && y >= 0 && x < cb.w && y < cb.h {
		c := &cb.cells[(y*cb.w)+x]
		mainc, combc, style = c.currMain, c.currComb, c.currStyle
		if width = c.width; width == 0 || mainc < ' ' {
			width = 1
			mainc = ' '
		}
	}
	return mainc, combc, style, width
}

// Size returns the (width, height) in cells of the buffer.
func (cb *CellBuffer) Size() (int, int) {
	return cb.w, cb.h
}

// Invalidate marks all characters within the buffer as dirty.
func (cb *CellBuffer) Invalidate() {
	for i := range cb.cells {
		cb.cells[i].lastMain = rune(0)
	}
}

// Dirty checks if a character at the given location needs an
// to be refreshed on the physical display.  This returns true
// if the cell content is different since the last time it was
// marked clean.
func (cb *CellBuffer) Dirty(x, y int) bool {
	if x >= 0 && y >= 0 && x < cb.w && y < cb.h {
		c := &cb.cells[(y*cb.w)+x]
		if c.lastMain == rune(0) {
			return true
		}
		if c.lastMain != c.currMain {
			return true
		}
		if c.lastStyle != c.currStyle {
			return true
		}
		if len(c.lastComb) != len(c.currComb) {
			return true
		}
		for i := range c.lastComb {
			if c.lastComb[i] != c.currComb[i] {
				return true
			}
		}
	}
	return false
}

// SetDirty is normally used to indicate that a cell has
// been displayed (in which case dirty is false), or to manually
// force a cell to be marked dirty.
func (cb *CellBuffer) SetDirty(x, y int, dirty bool) {
	if x >= 0 && y >= 0 && x < cb.w && y < cb.h {
		c := &cb.cells[(y*cb.w)+x]
		if dirty {
			c.lastMain = rune(0)
		} else {
			if c.currMain == rune(0) {
				c.currMain = ' '
			}
			c.lastMain = c.currMain
			c.lastComb = c.currComb
			c.lastStyle = c.currStyle
		}
	}
}

// Resize is used to resize the cells array, with different dimensions,
// while preserving the original contents.  The cells will be invalidated
// so that they can be redrawn.
func (cb *CellBuffer) Resize(w, h int) {

	if cb.h == h && cb.w == w {
		return
	}

	newc := make([]cell, w*h)
	for y := 0; y < h && y < cb.h; y++ {
		for x := 0; x < w && x < cb.w; x++ {
			oc := &cb.cells[(y*cb.w)+x]
			nc := &newc[(y*w)+x]
			nc.currMain = oc.currMain
			nc.currComb = oc.currComb
			nc.currStyle = oc.currStyle
			nc.width = oc.width
			nc.lastMain = rune(0)
		}
	}
	cb.cells = newc
	cb.h = h
	cb.w = w
}

// Fill fills the entire cell buffer array with the specified character
// and style.  Normally choose ' ' to clear the screen.  This API doesn't
// support combining characters.
func (cb *CellBuffer) Fill(r rune, style Style) {
	for i := range cb.cells {
		c := &cb.cells[i]
		c.currMain = r
		c.currComb = nil
		c.currStyle = style
	}
}