package tview import ( "bytes" "fmt" "regexp" "strings" "sync" "unicode/utf8" "github.com/gdamore/tcell" colorful "github.com/lucasb-eyer/go-colorful" runewidth "github.com/mattn/go-runewidth" "github.com/rivo/uniseg" ) var ( openColorRegex = regexp.MustCompile(`\[([a-zA-Z]*|#[0-9a-zA-Z]*)$`) openRegionRegex = regexp.MustCompile(`\["[a-zA-Z0-9_,;: \-\.]*"?$`) newLineRegex = regexp.MustCompile(`\r?\n`) // TabSize is the number of spaces with which a tab character will be replaced. 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 (byte position). NextPos int // The (byte) index of the next character in this buffer line. Width int // The screen width of this line. ForegroundColor string // The starting foreground color ("" = don't change, "-" = reset). BackgroundColor string // The starting background color ("" = don't change, "-" = reset). Attributes string // The starting attributes ("" = don't change, "-" = reset). Region string // The starting region ID. } // textViewRegion contains information about a region. type textViewRegion struct { // The region ID. ID string // The starting and end screen position of the region as determined the last // time Draw() was called. A negative value indicates out-of-rect positions. FromX, FromY, ToX, ToY int } // TextView is a box which displays text. It implements the io.Writer interface // so you can stream text to it. This does not trigger a redraw automatically // but if a handler is installed via SetChangedFunc(), you can cause it to be // redrawn. (See SetChangedFunc() for more details.) // // Navigation // // If the text view is scrollable (the default), text is kept in a buffer which // may be larger than the screen and can be navigated similarly to Vim: // // - h, left arrow: Move left. // - l, right arrow: Move right. // - j, down arrow: Move down. // - k, up arrow: Move up. // - g, home: Move to the top. // - G, end: Move to the bottom. // - Ctrl-F, page down: Move down by one page. // - Ctrl-B, page up: Move up by one page. // // If the text is not scrollable, any text above the top visible line is // discarded. // // Use SetInputCapture() to override or modify keyboard input. // // Colors // // If dynamic colors are enabled via SetDynamicColors(), text color can be // changed dynamically by embedding color strings in square brackets. This works // the same way as anywhere else. Please see the package documentation for more // information. // // Regions and Highlights // // If regions are enabled via SetRegions(), you can define text regions within // the text and assign region IDs to them. Text regions start with region tags. // Region tags are square brackets that contain a region ID in double quotes, // for example: // // We define a ["rg"]region[""] here. // // A text region ends with the next region tag. Tags with no region ID ([""]) // don't start new regions. They can therefore be used to mark the end of a // region. Region IDs must satisfy the following regular expression: // // [a-zA-Z0-9_,;: \-\.]+ // // Regions can be highlighted by calling the Highlight() function with one or // more region IDs. This can be used to display search results, for example. // // The ScrollToHighlight() function can be used to jump to the currently // highlighted region once when the text view is drawn the next time. // // See https://github.com/rivo/tview/wiki/TextView for an example. type TextView struct { sync.Mutex *Box // The text buffer. buffer []string // The last bytes that have been received but are not part of the buffer yet. recentBytes []byte // The processed line index. This is nil if the buffer has changed and needs // to be re-indexed. index []*textViewIndex // The text alignment, one of AlignLeft, AlignCenter, or AlignRight. align int // Information about visible regions as of the last call to Draw(). regionInfos []*textViewRegion // 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. fromHighlight, toHighlight int // The screen space column of the highlight in its first line. Set to -1 if // there is no current highlight. posHighlight int // A set of region IDs that are currently highlighted. highlights map[string]struct{} // The last width for which the current table is drawn. lastWidth int // 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. lineOffset int // If set to true, the text view will always remain at the end of the content. trackEnd bool // The number of characters to be skipped on each line (not in wrap mode). columnOffset int // The height of the content the last time the text view was drawn. pageSize int // If set to true, the text view will keep a buffer of text which can be // navigated when the text is longer than what fits into the box. scrollable bool // If set to true, lines that are longer than the available width are wrapped // onto the next line. If set to false, any characters beyond the available // 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 // If set to true, the text color can be changed dynamically by piping color // strings in square brackets to the text view. dynamicColors bool // If set to true, region tags can be used to define regions. regions bool // A temporary flag which, when true, will automatically bring the current // highlight(s) into the visible screen. scrollToHighlights bool // If true, setting new highlights will be a XOR instead of an overwrite // operation. toggleHighlights bool // An optional function which is called when the content of the text view has // changed. changed func() // An optional function which is called when the user presses one of the // following keys: Escape, Enter, Tab, Backtab. done func(tcell.Key) // An optional function which is called when one or more regions were // highlighted. highlighted func(added, removed, remaining []string) } // NewTextView returns a new text view. func NewTextView() *TextView { return &TextView{ Box: NewBox(), highlights: make(map[string]struct{}), lineOffset: -1, scrollable: true, align: AlignLeft, wrap: true, textColor: Styles.PrimaryTextColor, regions: false, dynamicColors: false, } } // SetScrollable sets the flag that decides whether or not the text view is // scrollable. If true, text is kept in a buffer and can be navigated. If false, // the last line will always be visible. func (t *TextView) SetScrollable(scrollable bool) *TextView { t.scrollable = scrollable if !scrollable { t.trackEnd = true } return t } // SetWrap sets the flag that, if true, leads to lines that are longer than the // available width being wrapped onto the next line. If false, any characters // beyond the available width are not displayed. func (t *TextView) SetWrap(wrap bool) *TextView { if t.wrap != wrap { t.index = nil } t.wrap = wrap 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). func (t *TextView) SetTextColor(color tcell.Color) *TextView { t.textColor = color return t } // SetText sets the text of this text view to the provided string. Previously // contained text will be removed. func (t *TextView) SetText(text string) *TextView { t.Clear() fmt.Fprint(t, text) return t } // GetText returns the current text of this text view. If "stripTags" is set // to true, any region/color tags are stripped from the text. func (t *TextView) GetText(stripTags bool) string { // Get the buffer. buffer := t.buffer if !stripTags { buffer = append(buffer, string(t.recentBytes)) } // Add newlines again. text := strings.Join(buffer, "\n") // Strip from tags if required. if stripTags { if t.regions { text = regionPattern.ReplaceAllString(text, "") } if t.dynamicColors { text = colorPattern.ReplaceAllStringFunc(text, func(match string) string { if len(match) > 2 { return "" } return match }) } if t.regions || t.dynamicColors { text = escapePattern.ReplaceAllString(text, `[$1$2]`) } } return text } // SetDynamicColors sets the flag that allows the text color to be changed // dynamically. See class description for details. func (t *TextView) SetDynamicColors(dynamic bool) *TextView { if t.dynamicColors != dynamic { t.index = nil } t.dynamicColors = dynamic return t } // 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 } // SetChangedFunc sets a handler function which is called when the text of the // text view has changed. This is useful when text is written to this io.Writer // in a separate goroutine. Doing so does not automatically cause the screen to // be refreshed so you may want to use the "changed" handler to redraw the // screen. // // Note that to avoid race conditions or deadlocks, there are a few rules you // should follow: // // - You can call Application.Draw() from this handler. // - You can call TextView.HasFocus() from this handler. // - During the execution of this handler, access to any other variables from // this primitive or any other primitive must be queued using // Application.QueueUpdate(). // // See package description for details on dealing with concurrency. func (t *TextView) SetChangedFunc(handler func()) *TextView { t.changed = handler return t } // SetDoneFunc sets a handler which is called when the user presses on the // following keys: Escape, Enter, Tab, Backtab. The key is passed to the // handler. func (t *TextView) SetDoneFunc(handler func(key tcell.Key)) *TextView { t.done = handler return t } // SetHighlightedFunc sets a handler which is called when the list of currently // highlighted regions change. It receives a list of region IDs which were newly // highlighted, those that are not highlighted anymore, and those that remain // highlighted. // // Note that because regions are only determined during drawing, this function // can only fire for regions that have existed during the last call to Draw(). func (t *TextView) SetHighlightedFunc(handler func(added, removed, remaining []string)) *TextView { t.highlighted = handler return t } // ScrollTo scrolls to the specified row and column (both starting with 0). func (t *TextView) ScrollTo(row, column int) *TextView { if !t.scrollable { return t } t.lineOffset = row t.columnOffset = column t.trackEnd = false return t } // ScrollToBeginning scrolls to the top left corner of the text if the text view // is scrollable. func (t *TextView) ScrollToBeginning() *TextView { if !t.scrollable { return t } t.trackEnd = false t.lineOffset = 0 t.columnOffset = 0 return t } // ScrollToEnd scrolls to the bottom left corner of the text if the text view // is scrollable. Adding new rows to the end of the text view will cause it to // scroll with the new data. func (t *TextView) ScrollToEnd() *TextView { if !t.scrollable { return t } t.trackEnd = true t.columnOffset = 0 return t } // GetScrollOffset returns the number of rows and columns that are skipped at // the top left corner when the text view has been scrolled. func (t *TextView) GetScrollOffset() (row, column int) { return t.lineOffset, t.columnOffset } // Clear removes all text from the buffer. func (t *TextView) Clear() *TextView { t.buffer = nil t.recentBytes = nil t.index = nil return t } // Highlight specifies which regions should be highlighted. If highlight // toggling is set to true (see SetToggleHighlights()), the highlight of the // provided regions is toggled (highlighted regions are un-highlighted and vice // versa). If toggling is set to false, the provided regions are highlighted and // all other regions will not be highlighted (you may also provide nil to turn // off all highlights). // // For more information on regions, see class description. Empty region strings // are ignored. // // Text in highlighted regions will be drawn inverted, i.e. with their // background and foreground colors swapped. func (t *TextView) Highlight(regionIDs ...string) *TextView { // Toggle highlights. if t.toggleHighlights { var newIDs []string HighlightLoop: for regionID := range t.highlights { for _, id := range regionIDs { if regionID == id { continue HighlightLoop } } newIDs = append(newIDs, regionID) } for _, regionID := range regionIDs { if _, ok := t.highlights[regionID]; !ok { newIDs = append(newIDs, regionID) } } regionIDs = newIDs } // Now we have a list of region IDs that end up being highlighted. // Determine added and removed regions. var added, removed, remaining []string if t.highlighted != nil { for _, regionID := range regionIDs { if _, ok := t.highlights[regionID]; ok { remaining = append(remaining, regionID) delete(t.highlights, regionID) } else { added = append(added, regionID) } } for regionID := range t.highlights { removed = append(removed, regionID) } } // Make new selection. t.highlights = make(map[string]struct{}) for _, id := range regionIDs { if id == "" { continue } t.highlights[id] = struct{}{} } t.index = nil // Notify. if t.highlighted != nil && len(added) > 0 || len(removed) > 0 { t.highlighted(added, removed, remaining) } return t } // GetHighlights returns the IDs of all currently highlighted regions. func (t *TextView) GetHighlights() (regionIDs []string) { for id := range t.highlights { regionIDs = append(regionIDs, id) } return } // SetToggleHighlights sets a flag to determine how regions are highlighted. // When set to true, the Highlight() function (or a mouse click) will toggle the // provided/selected regions. When set to false, Highlight() (or a mouse click) // will simply highlight the provided regions. func (t *TextView) SetToggleHighlights(toggle bool) *TextView { t.toggleHighlights = toggle return t } // ScrollToHighlight will cause the visible area to be scrolled so that the // highlighted regions appear in the visible area of the text view. This // repositioning happens the next time the text view is drawn. It happens only // once so you will need to call this function repeatedly to always keep // highlighted regions in view. // // Nothing happens if there are no highlighted regions or if the text view is // not scrollable. func (t *TextView) ScrollToHighlight() *TextView { if len(t.highlights) == 0 || !t.scrollable || !t.regions { return t } t.index = nil t.scrollToHighlights = true t.trackEnd = false return t } // GetRegionText returns the text of the region with the given ID. If dynamic // colors are enabled, color tags are stripped from the text. Newlines are // always returned as '\n' runes. // // If the region does not exist or if regions are turned off, an empty string // is returned. func (t *TextView) GetRegionText(regionID string) string { if !t.regions || regionID == "" { return "" } var ( buffer bytes.Buffer currentRegionID string ) for _, str := range t.buffer { // Find all color tags in this line. var colorTagIndices [][]int if t.dynamicColors { colorTagIndices = colorPattern.FindAllStringIndex(str, -1) } // Find all regions in this line. var ( regionIndices [][]int regions [][]string ) if t.regions { regionIndices = regionPattern.FindAllStringIndex(str, -1) regions = regionPattern.FindAllStringSubmatch(str, -1) } // Analyze this line. var currentTag, currentRegion int for pos, ch := range str { // Skip any color tags. if currentTag < len(colorTagIndices) && pos >= colorTagIndices[currentTag][0] && pos < colorTagIndices[currentTag][1] { if pos == colorTagIndices[currentTag][1]-1 { currentTag++ } if colorTagIndices[currentTag][1]-colorTagIndices[currentTag][0] > 2 { continue } } // Skip any regions. if currentRegion < len(regionIndices) && pos >= regionIndices[currentRegion][0] && pos < regionIndices[currentRegion][1] { if pos == regionIndices[currentRegion][1]-1 { if currentRegionID == regionID { // This is the end of the requested region. We're done. return buffer.String() } currentRegionID = regions[currentRegion][1] currentRegion++ } continue } // Add this rune. if currentRegionID == regionID { buffer.WriteRune(ch) } } // Add newline. if currentRegionID == regionID { buffer.WriteRune('\n') } } return escapePattern.ReplaceAllString(buffer.String(), `[$1$2]`) } // Focus is called when this primitive receives focus. func (t *TextView) Focus(delegate func(p Primitive)) { // Implemented here with locking because this is used by layout primitives. t.Lock() defer t.Unlock() t.hasFocus = true } // HasFocus returns whether or not this primitive has focus. func (t *TextView) HasFocus() bool { // Implemented here with locking because this may be used in the "changed" // callback. t.Lock() defer t.Unlock() return t.hasFocus } // 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. t.Lock() changed := t.changed t.Unlock() if changed != nil { defer func() { // We always call the "changed" function in a separate goroutine to avoid // deadlocks. go changed() }() } t.Lock() defer t.Unlock() // Copy data over. newBytes := append(t.recentBytes, p...) t.recentBytes = nil // If we have a trailing invalid UTF-8 byte, we'll wait. if r, _ := utf8.DecodeLastRune(p); r == utf8.RuneError { t.recentBytes = newBytes return len(p), nil } // If we have a trailing open dynamic color, exclude it. if t.dynamicColors { location := openColorRegex.FindIndex(newBytes) if location != nil { t.recentBytes = newBytes[location[0]:] newBytes = newBytes[:location[0]] } } // If we have a trailing open region, exclude it. if t.regions { location := openRegionRegex.FindIndex(newBytes) if location != nil { t.recentBytes = newBytes[location[0]:] newBytes = newBytes[:location[0]] } } // Transform the new bytes into strings. newBytes = bytes.Replace(newBytes, []byte{'\t'}, bytes.Repeat([]byte{' '}, TabSize), -1) for index, line := range newLineRegex.Split(string(newBytes), -1) { if index == 0 { if len(t.buffer) == 0 { t.buffer = []string{line} } else { t.buffer[len(t.buffer)-1] += line } } else { t.buffer = append(t.buffer, line) } } // Reset the index. t.index = nil return len(p), nil } // reindexBuffer re-indexes the buffer such that we can use it to easily draw // the buffer onto the screen. Each line in the index will contain a pointer // 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 { return // Nothing has changed. We can still use the current index. } t.index = nil t.fromHighlight, t.toHighlight, t.posHighlight = -1, -1, -1 // If there's no space, there's no index. if width < 1 { return } // Initial states. regionID := "" var ( highlighted bool foregroundColor, backgroundColor, attributes string ) // Go through each line in the buffer. for bufferIndex, str := range t.buffer { colorTagIndices, colorTags, regionIndices, regions, escapeIndices, strippedStr, _ := decomposeString(str, t.dynamicColors, t.regions) // Split the line if required. var splitLines []string str = strippedStr if t.wrap && len(str) > 0 { for len(str) > 0 { extract := runewidth.Truncate(str, width, "") if len(extract) == 0 { // We'll extract at least one grapheme cluster. gr := uniseg.NewGraphemes(str) gr.Next() _, to := gr.Positions() extract = str[:to] } 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 originalPos, colorPos, regionPos, escapePos int for _, splitLine := range splitLines { line := &textViewIndex{ Line: bufferIndex, Pos: originalPos, ForegroundColor: foregroundColor, BackgroundColor: backgroundColor, Attributes: attributes, Region: regionID, } // Shift original position with tags. lineLength := len(splitLine) remainingLength := lineLength tagEnd := originalPos totalTagLength := 0 for { // Which tag comes next? nextTag := make([][3]int, 0, 3) if colorPos < len(colorTagIndices) { nextTag = append(nextTag, [3]int{colorTagIndices[colorPos][0], colorTagIndices[colorPos][1], 0}) // 0 = color tag. } if regionPos < len(regionIndices) { nextTag = append(nextTag, [3]int{regionIndices[regionPos][0], regionIndices[regionPos][1], 1}) // 1 = region tag. } if escapePos < len(escapeIndices) { nextTag = append(nextTag, [3]int{escapeIndices[escapePos][0], escapeIndices[escapePos][1], 2}) // 2 = escape tag. } minPos := -1 tagIndex := -1 for index, pair := range nextTag { if minPos < 0 || pair[0] < minPos { minPos = pair[0] tagIndex = index } } // Is the next tag in range? if tagIndex < 0 || minPos > tagEnd+remainingLength { break // No. We're done with this line. } // Advance. strippedTagStart := nextTag[tagIndex][0] - originalPos - totalTagLength tagEnd = nextTag[tagIndex][1] tagLength := tagEnd - nextTag[tagIndex][0] if nextTag[tagIndex][2] == 2 { tagLength = 1 } totalTagLength += tagLength remainingLength = lineLength - (tagEnd - originalPos - totalTagLength) // Process the tag. switch nextTag[tagIndex][2] { case 0: // Process color tags. foregroundColor, backgroundColor, attributes = styleFromTag(foregroundColor, backgroundColor, attributes, colorTags[colorPos]) colorPos++ case 1: // Process region tags. regionID = regions[regionPos][1] _, highlighted = t.highlights[regionID] // Update highlight range. if highlighted { line := len(t.index) if t.fromHighlight < 0 { t.fromHighlight, t.toHighlight = line, line t.posHighlight = stringWidth(splitLine[:strippedTagStart]) } else if line > t.toHighlight { t.toHighlight = line } } regionPos++ case 2: // Process escape tags. escapePos++ } } // Advance to next line. originalPos += lineLength + totalTagLength // Append this line. line.NextPos = originalPos line.Width = stringWidth(splitLine) t.index = append(t.index, line) } // 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 -= stringWidth(t.buffer[line.Line][line.NextPos:oldNextPos]) } } } } // 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. func (t *TextView) Draw(screen tcell.Screen) { t.Lock() defer t.Unlock() t.Box.Draw(screen) totalWidth, totalHeight := screen.Size() // Get the available size. x, y, width, height := t.GetInnerRect() t.pageSize = height // If the width has changed, we need to reindex. if width != t.lastWidth && t.wrap { t.index = nil } t.lastWidth = width // Re-index. t.reindexBuffer(width) if t.regions { t.regionInfos = nil } // 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? if t.toHighlight-t.fromHighlight+1 < height { // Yes, let's center the highlights. t.lineOffset = (t.fromHighlight + t.toHighlight - height) / 2 } else { // No, let's move to the start of the highlights. t.lineOffset = t.fromHighlight } // If the highlight is too far to the right, move it to the middle. if t.posHighlight-t.columnOffset > 3*width/4 { t.columnOffset = t.posHighlight - width/2 } // If the highlight is off-screen on the left, move it on-screen. if t.posHighlight-t.columnOffset < 0 { t.columnOffset = t.posHighlight - width/4 } } t.scrollToHighlights = false // Adjust line offset. if t.lineOffset+height > len(t.index) { t.trackEnd = true } if t.trackEnd { t.lineOffset = len(t.index) - height } if t.lineOffset < 0 { t.lineOffset = 0 } // Adjust column offset. 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. defaultStyle := tcell.StyleDefault.Foreground(t.textColor) for line := t.lineOffset; line < len(t.index); line++ { // Are we done? if line-t.lineOffset >= height || y+line-t.lineOffset >= totalHeight { break } // Get the text for this line. index := t.index[line] text := t.buffer[index.Line][index.Pos:index.NextPos] foregroundColor := index.ForegroundColor backgroundColor := index.BackgroundColor attributes := index.Attributes regionID := index.Region if t.regions && regionID != "" && (len(t.regionInfos) == 0 || t.regionInfos[len(t.regionInfos)-1].ID != regionID) { t.regionInfos = append(t.regionInfos, &textViewRegion{ ID: regionID, FromX: x, FromY: y + line - t.lineOffset, ToX: -1, ToY: -1, }) } // Process tags. colorTagIndices, colorTags, regionIndices, regions, escapeIndices, strippedText, _ := decomposeString(text, t.dynamicColors, t.regions) // 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. if y+line-t.lineOffset >= 0 { var colorPos, regionPos, escapePos, tagOffset, skipped int iterateString(strippedText, func(main rune, comb []rune, textPos, textWidth, screenPos, screenWidth int) bool { // Process tags. for { if colorPos < len(colorTags) && textPos+tagOffset >= colorTagIndices[colorPos][0] && textPos+tagOffset < colorTagIndices[colorPos][1] { // Get the color. foregroundColor, backgroundColor, attributes = styleFromTag(foregroundColor, backgroundColor, attributes, colorTags[colorPos]) tagOffset += colorTagIndices[colorPos][1] - colorTagIndices[colorPos][0] colorPos++ } else if regionPos < len(regionIndices) && textPos+tagOffset >= regionIndices[regionPos][0] && textPos+tagOffset < regionIndices[regionPos][1] { // Get the region. if regionID != "" && len(t.regionInfos) > 0 && t.regionInfos[len(t.regionInfos)-1].ID == regionID { // End last region. t.regionInfos[len(t.regionInfos)-1].ToX = x + posX t.regionInfos[len(t.regionInfos)-1].ToY = y + line - t.lineOffset } regionID = regions[regionPos][1] if regionID != "" { // Start new region. t.regionInfos = append(t.regionInfos, &textViewRegion{ ID: regionID, FromX: x + posX, FromY: y + line - t.lineOffset, ToX: -1, ToY: -1, }) } tagOffset += regionIndices[regionPos][1] - regionIndices[regionPos][0] regionPos++ } else { break } } // Skip the second-to-last character of an escape tag. if escapePos < len(escapeIndices) && textPos+tagOffset == escapeIndices[escapePos][1]-2 { tagOffset++ escapePos++ } // Mix the existing style with the new style. _, _, existingStyle, _ := screen.GetContent(x+posX, y+line-t.lineOffset) _, background, _ := existingStyle.Decompose() style := overlayStyle(background, defaultStyle, foregroundColor, backgroundColor, attributes) // Do we highlight this character? var highlighted bool if regionID != "" { if _, ok := t.highlights[regionID]; ok { highlighted = true } } if highlighted { fg, bg, _ := style.Decompose() if bg == tcell.ColorDefault { r, g, b := fg.RGB() c := colorful.Color{R: float64(r) / 255, G: float64(g) / 255, B: float64(b) / 255} _, _, li := c.Hcl() if li < .5 { bg = tcell.ColorWhite } else { bg = tcell.ColorBlack } } style = style.Background(fg).Foreground(bg) } // Skip to the right. if !t.wrap && skipped < skip { skipped += screenWidth return false } // Stop at the right border. if posX+screenWidth > width || x+posX >= totalWidth { return true } // Draw the character. for offset := screenWidth - 1; offset >= 0; offset-- { if offset == 0 { screen.SetContent(x+posX+offset, y+line-t.lineOffset, main, comb, style) } else { screen.SetContent(x+posX+offset, y+line-t.lineOffset, ' ', nil, style) } } // Advance. posX += screenWidth return false }) } } // If this view is not scrollable, we'll purge the buffer of lines that have // scrolled out of view. if !t.scrollable && t.lineOffset > 0 { if t.lineOffset >= len(t.index) { t.buffer = nil } else { t.buffer = t.buffer[t.index[t.lineOffset].Line:] } t.index = nil t.lineOffset = 0 } } // InputHandler returns the handler for this primitive. func (t *TextView) InputHandler() func(event *tcell.EventKey, setFocus func(p Primitive)) { return t.WrapInputHandler(func(event *tcell.EventKey, setFocus func(p Primitive)) { key := event.Key() if key == tcell.KeyEscape || key == tcell.KeyEnter || key == tcell.KeyTab || key == tcell.KeyBacktab { if t.done != nil { t.done(key) } return } if !t.scrollable { return } switch key { case tcell.KeyRune: switch event.Rune() { case 'g': // Home. t.trackEnd = false t.lineOffset = 0 t.columnOffset = 0 case 'G': // End. t.trackEnd = true t.columnOffset = 0 case 'j': // Down. t.lineOffset++ case 'k': // Up. t.trackEnd = false t.lineOffset-- case 'h': // Left. t.columnOffset-- case 'l': // Right. t.columnOffset++ } case tcell.KeyHome: t.trackEnd = false t.lineOffset = 0 t.columnOffset = 0 case tcell.KeyEnd: t.trackEnd = true t.columnOffset = 0 case tcell.KeyUp: t.trackEnd = false t.lineOffset-- case tcell.KeyDown: t.lineOffset++ case tcell.KeyLeft: t.columnOffset-- case tcell.KeyRight: t.columnOffset++ case tcell.KeyPgDn, tcell.KeyCtrlF: t.lineOffset += t.pageSize case tcell.KeyPgUp, tcell.KeyCtrlB: t.trackEnd = false t.lineOffset -= t.pageSize } }) } // MouseHandler returns the mouse handler for this primitive. func (t *TextView) MouseHandler() func(action MouseAction, event *tcell.EventMouse, setFocus func(p Primitive)) (consumed bool, capture Primitive) { return t.WrapMouseHandler(func(action MouseAction, event *tcell.EventMouse, setFocus func(p Primitive)) (consumed bool, capture Primitive) { x, y := event.Position() if !t.InRect(x, y) { return false, nil } switch action { case MouseLeftClick: if t.regions { // Find a region to highlight. for _, region := range t.regionInfos { if y == region.FromY && x < region.FromX || y == region.ToY && x >= region.ToX || region.FromY >= 0 && y < region.FromY || region.ToY >= 0 && y > region.ToY { continue } t.Highlight(region.ID) break } } setFocus(t) consumed = true case MouseScrollUp: t.trackEnd = false t.lineOffset-- consumed = true case MouseScrollDown: t.lineOffset++ consumed = true } return }) }