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tview
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Rewrote TextView's reindex() and Draw() to introduce text alignment and 

word wrapping
This commit is contained in:
Oliver 2018-01-13 14:16:49 +01:00
parent 38d663c267
commit 1e78c506cb
3 changed files with 226 additions and 107 deletions
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2
README.md
View File

@ -62,6 +62,8 @@ Add your issue here on GitHub. Feel free to get in touch if you have any questio
## Releases
- v0.5 (2018-01-13)
- `TextView` now has word wrapping and text alignment
- v0.4 (2018-01-12)
- `TextView` now accepts color tags with any W3C color (including RGB hex values).
- Support for wide unicode characters.

1
demos/textview/main.go
View File

@ -24,6 +24,7 @@ func main() {
textView := tview.NewTextView().
SetDynamicColors(true).
SetRegions(true).
SetWordWrap(true).
SetChangedFunc(func() {
app.Draw()
})

330
textview.go
View File

@ -2,7 +2,6 @@ package tview
import (
"bytes"
"math"
"regexp"
"sync"
"unicode/utf8"
@ -13,20 +12,24 @@ import (
// Regular expressions commonly used throughout the TextView class.
var (
colorPattern = regexp.MustCompile(`\[([a-zA-Z]+|#[0-9a-zA-Z]{6})\]`)
regionPattern = regexp.MustCompile(`\["([a-zA-Z0-9_,;: \-\.]*)"\]`)
colorPattern = regexp.MustCompile(`\[([a-zA-Z]+|#[0-9a-zA-Z]{6})\]`)
regionPattern = regexp.MustCompile(`\["([a-zA-Z0-9_,;: \-\.]*)"\]`)
boundaryPattern = regexp.MustCompile("([[:punct:]]\\s*|\\s+)")
spacePattern = regexp.MustCompile(`\s+`)
)
// TabSize is the number of spaces to be drawn for a tab character.
// TabSize is the number of spaces with which a tab character will be replaced.
var TabSize = 4
// textViewIndex contains information about each line displayed in the text
// view.
type textViewIndex struct {
Line int // The index into the "buffer" variable.
Pos int // The index into the "buffer" string.
Color tcell.Color // The starting color.
Region string // The starting region ID.
Line int // The index into the "buffer" variable.
Pos int // The index into the "buffer" string (byte position).
NextPos int // The (byte) index of the next character in this buffer line.
Width int // The screen width of this line.
Color tcell.Color // The starting color.
Region string // The starting region ID.
}
// TextView is a box which displays text. It implements the io.Writer interface
@ -103,6 +106,9 @@ type TextView struct {
// to be re-indexed.
index []*textViewIndex
// The text alignment, one of AlignLeft, AlignCenter, or AlignRight.
align int
// Indices into the "index" slice which correspond to the first line of the
// first highlight and the last line of the last highlight. This is calculated
// during re-indexing. Set to -1 if there is no current highlight.
@ -111,10 +117,10 @@ type TextView struct {
// A set of region IDs that are currently highlighted.
highlights map[string]struct{}
// The display width for which the index is created.
indexWidth int
// The last width for which the current table is drawn.
lastWidth int
// The width of the longest line in the index (not the buffer).
// The screen width of the longest line in the index (not the buffer).
longestLine int
// The index of the first line shown in the text view.
@ -138,6 +144,10 @@ type TextView struct {
// width are discarded.
wrap bool
// If set to true and if wrap is also true, lines are split at spaces or
// after punctuation characters.
wordWrap bool
// The (starting) color of the text.
textColor tcell.Color
@ -172,6 +182,7 @@ func NewTextView() *TextView {
highlights: make(map[string]struct{}),
lineOffset: -1,
scrollable: true,
align: AlignLeft,
wrap: true,
textColor: Styles.PrimaryTextColor,
dynamicColors: false,
@ -199,6 +210,29 @@ func (t *TextView) SetWrap(wrap bool) *TextView {
return t
}
// SetWordWrap sets the flag that, if true and if the "wrap" flag is also true
// (see SetWrap()), wraps the line at spaces or after punctuation marks. Note
// that trailing spaces will not be printed.
//
// This flag is ignored if the "wrap" flag is false.
func (t *TextView) SetWordWrap(wrapOnWords bool) *TextView {
if t.wordWrap != wrapOnWords {
t.index = nil
}
t.wordWrap = wrapOnWords
return t
}
// SetTextAlign sets the text alignment within the text view. This must be
// either AlignLeft, AlignCenter, or AlignRight.
func (t *TextView) SetTextAlign(align int) *TextView {
if t.align != align {
t.index = nil
}
t.align = align
return t
}
// SetTextColor sets the initial color of the text (which can be changed
// dynamically by sending color strings in square brackets to the text view if
// dynamic colors are enabled).
@ -220,6 +254,9 @@ func (t *TextView) SetDynamicColors(dynamic bool) *TextView {
// SetRegions sets the flag that allows to define regions in the text. See class
// description for details.
func (t *TextView) SetRegions(regions bool) *TextView {
if t.regions != regions {
t.index = nil
}
t.regions = regions
return t
}
@ -273,6 +310,7 @@ func (t *TextView) Highlight(regionIDs ...string) *TextView {
}
t.highlights[id] = struct{}{}
}
t.index = nil
return t
}
@ -374,7 +412,9 @@ func (t *TextView) GetRegionText(regionID string) string {
return buffer.String()
}
// Write lets us implement the io.Writer interface.
// Write lets us implement the io.Writer interface. Tab characters will be
// replaced with TabSize space characters. A "\n" or "\r\n" will be interpreted
// as a new line.
func (t *TextView) Write(p []byte) (n int, err error) {
// Notify at the end.
if t.changed != nil {
@ -396,7 +436,7 @@ func (t *TextView) Write(p []byte) (n int, err error) {
// If we have a trailing open dynamic color, exclude it.
if t.dynamicColors {
openColor := regexp.MustCompile(`\[[a-z]+$`)
openColor := regexp.MustCompile(`\[([a-zA-Z]*|#[0-9a-zA-Z]*)$`)
location := openColor.FindIndex(newBytes)
if location != nil {
t.recentBytes = newBytes[location[0]:]
@ -404,8 +444,19 @@ func (t *TextView) Write(p []byte) (n int, err error) {
}
}
// If we have a trailing open region, exclude it.
if t.regions {
openRegion := regexp.MustCompile(`\["[a-zA-Z0-9_,;: \-\.]*"?$`)
location := openRegion.FindIndex(newBytes)
if location != nil {
t.recentBytes = newBytes[location[0]:]
newBytes = newBytes[:location[0]]
}
}
// Transform the new bytes into strings.
newLine := regexp.MustCompile(`\r?\n`)
newBytes = bytes.Replace(newBytes, []byte{'\t'}, bytes.Repeat([]byte{' '}, TabSize), -1)
for index, line := range newLine.Split(string(newBytes), -1) {
if index == 0 {
if len(t.buffer) == 0 {
@ -429,23 +480,25 @@ func (t *TextView) Write(p []byte) (n int, err error) {
// into the buffer from which on we will print text. It will also contain the
// color with which the line starts.
func (t *TextView) reindexBuffer(width int) {
if t.index != nil && width == t.indexWidth {
if t.index != nil {
return // Nothing has changed. We can still use the current index.
}
t.index = nil
t.fromHighlight, t.toHighlight = -1, -1
var (
regionID string
highlighted bool
)
t.longestLine = 0
color := t.textColor
if !t.wrap {
width = math.MaxInt32
// If there's no space, there's no index.
if width < 1 {
return
}
for index, str := range t.buffer {
// Find all color tags in this line.
// Initial states.
regionID := ""
var highlighted bool
color := t.textColor
// Go through each line in the buffer.
for bufferIndex, str := range t.buffer {
// Find all color tags in this line. Then remove them.
var (
colorTagIndices [][]int
colorTags [][]string
@ -453,9 +506,10 @@ func (t *TextView) reindexBuffer(width int) {
if t.dynamicColors {
colorTagIndices = colorPattern.FindAllStringIndex(str, -1)
colorTags = colorPattern.FindAllStringSubmatch(str, -1)
str = colorPattern.ReplaceAllString(str, "")
}
// Find all regions in this line.
// Find all regions in this line. Then remove them.
var (
regionIndices [][]int
regions [][]string
@ -463,89 +517,109 @@ func (t *TextView) reindexBuffer(width int) {
if t.regions {
regionIndices = regionPattern.FindAllStringIndex(str, -1)
regions = regionPattern.FindAllStringSubmatch(str, -1)
str = regionPattern.ReplaceAllString(str, "")
}
// We also keep a reference to empty lines.
if len(str) == 0 {
t.index = append(t.index, &textViewIndex{
Line: index,
Pos: 0,
// Split the line if required.
var splitLines []string
if t.wrap && len(str) > 0 {
for len(str) > 0 {
extract := runewidth.Truncate(str, width, "")
if t.wordWrap && len(extract) < len(str) {
// Add any spaces from the next line.
if spaces := spacePattern.FindStringIndex(str[len(extract):]); spaces != nil && spaces[0] == 0 {
extract = str[:len(extract)+spaces[1]]
}
// Can we split before the mandatory end?
matches := boundaryPattern.FindAllStringIndex(extract, -1)
if len(matches) > 0 {
// Yes. Let's split there.
extract = extract[:matches[len(matches)-1][1]]
}
}
splitLines = append(splitLines, extract)
str = str[len(extract):]
}
} else {
// No need to split the line.
splitLines = []string{str}
}
// Create index from split lines.
var startPos, originalPos, colorPos, regionPos int
for _, splitLine := range splitLines {
line := &textViewIndex{
Line: bufferIndex,
Pos: originalPos,
Color: color,
Region: regionID,
})
}
// Break down the line.
var currentTag, currentRegion, currentWidth int
for pos, ch := range str {
// Skip any color tags.
if currentTag < len(colorTags) && pos >= colorTagIndices[currentTag][0] && pos < colorTagIndices[currentTag][1] {
if pos == colorTagIndices[currentTag][1]-1 {
color = tcell.GetColor(colorTags[currentTag][1])
currentTag++
}
continue
}
// Check regions.
if currentRegion < len(regionIndices) && pos >= regionIndices[currentRegion][0] && pos < regionIndices[currentRegion][1] {
if pos == regionIndices[currentRegion][1]-1 {
// We're done with this region.
regionID = regions[currentRegion][1]
// Shift original position with tags.
lineWidth := 0
for index, ch := range splitLine {
// Get the width of the current rune.
lineWidth += runewidth.RuneWidth(ch)
// Is this region highlighted?
// Process color tags.
for colorPos < len(colorTagIndices) && colorTagIndices[colorPos][0] <= originalPos+index {
originalPos += colorTagIndices[colorPos][1] - colorTagIndices[colorPos][0]
color = tcell.GetColor(colorTags[colorPos][1])
colorPos++
}
// Process region tags.
for regionPos < len(regionIndices) && regionIndices[regionPos][0] <= originalPos+index {
originalPos += regionIndices[regionPos][1] - regionIndices[regionPos][0]
regionID = regions[regionPos][1]
_, highlighted = t.highlights[regionID]
currentRegion++
}
continue
}
// Update highlight range.
if highlighted {
line := len(t.index)
if t.fromHighlight < 0 {
t.fromHighlight, t.toHighlight = line, line
} else if line > t.toHighlight {
t.toHighlight = line
}
}
// Get the width of the current rune.
chWidth := runewidth.RuneWidth(ch)
if ch == '\t' {
chWidth = TabSize
}
if chWidth == 0 {
continue // Skip width-less runes.
}
// Add this line.
if currentWidth == 0 {
t.index = append(t.index, &textViewIndex{
Line: index,
Pos: pos,
Color: color,
Region: regionID,
})
}
// Update highlight range.
if highlighted {
line := len(t.index) - 1
if t.fromHighlight < 0 {
t.fromHighlight, t.toHighlight = line, line
} else if line > t.toHighlight {
t.toHighlight = line
regionPos++
}
}
// Proceed.
currentWidth += chWidth
// Advance to next line.
startPos += len(splitLine)
originalPos += len(splitLine)
// Have we crossed the width?
if t.wrap && currentWidth >= width {
currentWidth = 0
}
// Append this line.
line.NextPos = originalPos
line.Width = lineWidth
t.index = append(t.index, line)
}
// Do we have a new maximum width?
if currentWidth > t.longestLine {
t.longestLine = currentWidth
// Word-wrapped lines may have trailing whitespace. Remove it.
if t.wrap && t.wordWrap {
for _, line := range t.index {
str := t.buffer[line.Line][line.Pos:line.NextPos]
spaces := spacePattern.FindAllStringIndex(str, -1)
if spaces != nil && spaces[len(spaces)-1][1] == len(str) {
oldNextPos := line.NextPos
line.NextPos -= spaces[len(spaces)-1][1] - spaces[len(spaces)-1][0]
line.Width -= runewidth.StringWidth(t.buffer[line.Line][line.NextPos:oldNextPos])
}
}
}
}
t.indexWidth = width
// Calculate longest line.
t.longestLine = 0
for _, line := range t.index {
if line.Width > t.longestLine {
t.longestLine = line.Width
}
}
}
// Draw draws this primitive onto the screen.
@ -558,9 +632,20 @@ func (t *TextView) Draw(screen tcell.Screen) {
x, y, width, height := t.GetInnerRect()
t.pageSize = height
// If the width has changed, we need to reindex.
if width != t.lastWidth {
t.index = nil
}
t.lastWidth = width
// Re-index.
t.reindexBuffer(width)
// If we don't have an index, there's nothing to draw.
if t.index == nil {
return
}
// Move to highlighted regions.
if t.regions && t.scrollToHighlights && t.fromHighlight >= 0 {
// Do we fit the entire height?
@ -586,11 +671,32 @@ func (t *TextView) Draw(screen tcell.Screen) {
}
// Adjust column offset.
if t.columnOffset+width > t.longestLine {
t.columnOffset = t.longestLine - width
}
if t.columnOffset < 0 {
t.columnOffset = 0
if t.align == AlignLeft {
if t.columnOffset+width > t.longestLine {
t.columnOffset = t.longestLine - width
}
if t.columnOffset < 0 {
t.columnOffset = 0
}
} else if t.align == AlignRight {
if t.columnOffset-width < -t.longestLine {
t.columnOffset = width - t.longestLine
}
if t.columnOffset > 0 {
t.columnOffset = 0
}
} else { // AlignCenter.
half := (t.longestLine - width) / 2
if half > 0 {
if t.columnOffset > half {
t.columnOffset = half
}
if t.columnOffset < -half {
t.columnOffset = -half
}
} else {
t.columnOffset = 0
}
}
// Draw the buffer.
@ -602,7 +708,7 @@ func (t *TextView) Draw(screen tcell.Screen) {
// Get the text for this line.
index := t.index[line]
text := t.buffer[index.Line][index.Pos:]
text := t.buffer[index.Line][index.Pos:index.NextPos]
color := index.Color
regionID := index.Region
@ -626,8 +732,22 @@ func (t *TextView) Draw(screen tcell.Screen) {
regions = regionPattern.FindAllStringSubmatch(text, -1)
}
// Print one line.
var currentTag, currentRegion, skip, posX int
// Calculate the position of the line.
var skip, posX int
if t.align == AlignLeft {
posX = -t.columnOffset
} else if t.align == AlignRight {
posX = width - index.Width - t.columnOffset
} else { // AlignCenter.
posX = (width-index.Width)/2 - t.columnOffset
}
if posX < 0 {
skip = -posX
posX = 0
}
// Print the line.
var currentTag, currentRegion, skipped int
for pos, ch := range text {
// Get the color.
if currentTag < len(colorTags) && pos >= colorTagIndices[currentTag][0] && pos < colorTagIndices[currentTag][1] {
@ -647,19 +767,15 @@ func (t *TextView) Draw(screen tcell.Screen) {
continue
}
// Skip to the right.
if !t.wrap && skip < t.columnOffset {
skip++
// Determine the width of this rune.
chWidth := runewidth.RuneWidth(ch)
if chWidth == 0 {
continue
}
// Determine the width of this rune.
chWidth := runewidth.RuneWidth(ch)
if ch == '\t' {
chWidth = TabSize
ch = ' '
}
if chWidth == 0 {
// Skip to the right.
if !t.wrap && skipped < skip {
skipped += chWidth
continue
}