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Implemented selections.

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pull/759/head
Oliver 2 years ago
parent 6680aa9dbe
commit 8b7b755a7f
1 changed files with 180 additions and 54 deletions
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234
textarea.go
Unescape Escape View File

@ -117,7 +117,7 @@ type textAreaSpan struct {
//
// - Entering a character (rune) will replace the selected text with the new
// character.
// - Backspace, delete: Delete the selected text.
// - Backspace, delete, Ctrl-H, Ctrl-D: Delete the selected text.
// - Ctrl-Q: Copy the selected text into the clipboard, unselect the text.
// - Ctrl-X: Copy the selected text into the clipboard and delete it.
// - Ctrl-V: Replace the selected text with the clipboard text. If no text is
@ -159,6 +159,9 @@ type TextArea struct {
// background color may lead to unwanted artefacts.
textStyle tcell.Style
// The style of the selected text.
selectedStyle tcell.Style
// The style of the placeholder text.
placeholderStyle tcell.Style
@ -221,8 +224,10 @@ type TextArea struct {
lineStarts [][3]int
// The cursor always points to the next position where a new character would
// be placed.
cursor struct {
// be placed. The selection start is the same as cursor as long as there is
// no selection. When there is one, the selection is between selectionStart
// and cursor.
cursor, selectionStart struct {
// The row and column in screen space but relative to the start of the
// text which may be outside the text area's box. The column value may
// be larger than where the cursor actually is if the line the cursor
@ -233,30 +238,53 @@ type TextArea struct {
// The textAreaSpan position with state for the actual next character.
pos [3]int
// If set to true, [Draw] will attempt to keep the cursor in the
// viewport. If you set this to true, you should make sure the cursor
// position is known or else finding it will be expensive.
clamp bool
}
}
// NewTextArea returns a new text area. For an empty text area, provide an empty
// string.
func NewTextArea(text string) *TextArea {
// NewTextArea returns a new text area. Use [TextArea.SetText] to set the
// initial text.
func NewTextArea() *TextArea {
t := &TextArea{
Box: NewBox(),
wrap: true,
wordWrap: true,
placeholderStyle: tcell.StyleDefault.Background(Styles.PrimitiveBackgroundColor).Foreground(Styles.TertiaryTextColor),
textStyle: tcell.StyleDefault.Background(Styles.PrimitiveBackgroundColor).Foreground(Styles.PrimaryTextColor),
initialText: text,
selectedStyle: tcell.StyleDefault.Background(Styles.PrimaryTextColor).Foreground(Styles.PrimitiveBackgroundColor),
spans: make([]textAreaSpan, 2, pieceChainMinCap), // We reserve some space to avoid reallocations right when editing starts.
}
t.editText.Grow(editBufferMinCap)
t.spans[0] = textAreaSpan{previous: -1, next: 1}
t.spans[1] = textAreaSpan{previous: 0, next: -1}
t.cursor.pos = [3]int{1, 0, -1}
t.selectionStart = t.cursor
return t
}
// SetText sets the text of the text area. All text is deleted and replaced with
// the new text. Any edits are discarded, no undos are available. This function
// is typically only used to initialize the text area with a text after it has
// been created. To clear the text area's text (again, no undos), provide an
// empty string.
//
// If cursorAtTheEnd is false, the cursor is placed at the start of the text. If
// it is true, it is placed at the end of the text. For very long texts, placing
// the cursor at the end can be an expensive operation because the entire text
// needs to be parsed and laid out.
func (t *TextArea) SetText(text string, cursorAtTheEnd bool) *TextArea {
t.spans = t.spans[:2]
t.initialText = text
t.editText.Reset()
t.lineStarts = nil
t.length = len(text)
t.rowOffset = 0
t.columnOffset = 0
t.resetLines()
t.cursor.column = 0
t.cursor.pos = [3]int{1, 0, -1}
//TODO: Reset undo.
if len(text) > 0 {
t.spans = append(t.spans, textAreaSpan{
previous: 0,
@ -266,10 +294,16 @@ func NewTextArea(text string) *TextArea {
})
t.spans[0].next = 2
t.spans[1].previous = 2
t.length = len(text)
t.cursor.row = -1
t.cursor.clamp = true
if !cursorAtTheEnd {
t.cursor.row = 0
}
} else {
t.spans[0].next = 1
t.spans[1].previous = 0
t.cursor.row, t.cursor.actualColumn = 0, 0
}
t.selectionStart = t.cursor
return t
}
@ -317,6 +351,12 @@ func (t *TextArea) SetTextStyle(style tcell.Style) *TextArea {
return t
}
// SetSelectedStyle sets the style of the selected text.
func (t *TextArea) SetSelectedStyle(style tcell.Style) *TextArea {
t.selectedStyle = style
return t
}
// SetPlaceholderStyle sets the style of the placeholder text.
func (t *TextArea) SetPlaceholderStyle(style tcell.Style) *TextArea {
t.placeholderStyle = style
@ -530,6 +570,23 @@ func (t *TextArea) Draw(screen tcell.Screen) {
if width == 0 || height == 0 {
return // We have no space for anything.
}
columnOffset := t.columnOffset
if t.wrap {
columnOffset = 0
}
// Show/hide the cursor at the end.
defer func() {
if t.HasFocus() {
if t.cursor.row >= 0 &&
t.cursor.row-t.rowOffset >= 0 && t.cursor.row-t.rowOffset < height &&
t.cursor.actualColumn-columnOffset >= 0 && t.cursor.actualColumn-columnOffset < width {
screen.ShowCursor(x+t.cursor.actualColumn-columnOffset, y+t.cursor.row-t.rowOffset)
} else {
screen.HideCursor()
}
}
}()
// Placeholder.
if t.length == 0 && len(t.placeholder) > 0 {
@ -547,21 +604,13 @@ func (t *TextArea) Draw(screen tcell.Screen) {
return // It's scrolled out of view.
}
// Helper function which completes missing cursor information.
var cursorVisible bool
columnOffset := t.columnOffset
if t.wrap {
columnOffset = 0
}
updateCursor := func(row, column int, pos [3]int) {
if t.cursor.row < 0 && t.cursor.pos == pos {
// The screen location is unknown but we've hit the span position.
t.cursor.row, t.cursor.column, t.cursor.actualColumn = row, column, column
t.cursor.pos = pos
// If the cursor position is unknown, find it. This usually only happens
// before the screen is drawn for the first time.
if t.cursor.row < 0 {
t.clampToCursor(0)
if t.selectionStart.row < 0 {
t.selectionStart = t.cursor
}
cursorVisible = t.cursor.row >= 0 &&
t.cursor.row-t.rowOffset >= 0 && t.cursor.row-t.rowOffset < height &&
t.cursor.actualColumn-columnOffset >= 0 && t.cursor.actualColumn-columnOffset < width
}
// Print the text.
@ -570,14 +619,31 @@ func (t *TextArea) Draw(screen tcell.Screen) {
pos := t.lineStarts[line]
endPos := pos
posX, posY := 0, 0
updateCursor(line, columnOffset, pos)
for pos[0] != 1 {
cluster, text, _, pos, endPos = t.step(text, pos, endPos)
// Prepare drawing.
clusterWidth := stringWidth(cluster)
runes := []rune(cluster)
style := t.selectedStyle
fromRow, fromColumn := t.cursor.row, t.cursor.actualColumn
toRow, toColumn := t.selectionStart.row, t.selectionStart.actualColumn
if fromRow > toRow || fromRow == toRow && fromColumn > toColumn {
fromRow, fromColumn, toRow, toColumn = toRow, toColumn, fromRow, fromColumn
}
if toRow < line ||
toRow == line && toColumn <= posX ||
fromRow > line ||
fromRow == line && fromColumn > posX {
style = t.textStyle
}
// Draw character.
if posX+clusterWidth-columnOffset <= width && posX-columnOffset >= 0 && clusterWidth > 0 {
screen.SetContent(x+posX-columnOffset, y+posY, runes[0], runes[1:], t.textStyle)
screen.SetContent(x+posX-columnOffset, y+posY, runes[0], runes[1:], style)
}
// Advance.
posX += clusterWidth
if line+1 < len(t.lineStarts) && t.lineStarts[line+1] == pos {
// We must break over.
@ -588,22 +654,6 @@ func (t *TextArea) Draw(screen tcell.Screen) {
posX = 0
line++
}
updateCursor(posY+t.rowOffset, posX, pos)
}
// Make cursor visible.
if t.HasFocus() {
if cursorVisible {
screen.ShowCursor(x+t.cursor.actualColumn-columnOffset, y+t.cursor.row-t.rowOffset)
} else {
// Are we required to make the cursor visible?
if t.cursor.clamp {
t.clampToCursor(0)
t.Draw(screen) // Draw again.
return
}
screen.HideCursor()
}
}
}
@ -773,8 +823,6 @@ func (t *TextArea) truncateLines(fromLine int) {
// is expensive for long texts). This function also sets the cursor clamp flag
// to false.
func (t *TextArea) clampToCursor(startRow int) {
t.cursor.clamp = false
if t.cursor.row >= 0 {
// This is the simple case because the current cursor position is known.
if t.cursor.row < t.rowOffset {
@ -973,11 +1021,14 @@ func (t *TextArea) moveCursor(row, column int) {
// No. Extent the line buffer.
t.extendLines(t.lastWidth, row)
}
if len(t.lineStarts) == 0 {
return // No lines. Nothing to do.
}
if row < 0 {
// We're at the start of the text.
row = 0
column = 0
} else if row >= len(t.lineStarts) || row < 0 {
} else if row >= len(t.lineStarts) {
// We're already past the end.
row = len(t.lineStarts) - 1
column = -1
@ -1009,7 +1060,7 @@ func (t *TextArea) moveCursor(row, column int) {
t.cursor.column = column
}
t.cursor.pos = pos
t.cursor.clamp = true
t.clampToCursor(row)
}
// moveWordRight moves the cursor to the end of the current or next word. The
@ -1169,6 +1220,22 @@ func (t *TextArea) deleteLine() {
t.clampToCursor(startRow)
}
// getSelection returns the current selection as span locations where the first
// returned location is always before or the same as the second returned
// location. This assumes that the cursor and selection positions are known. The
// third return value is the starting row of the selection.
func (t *TextArea) getSelection() ([3]int, [3]int, int) {
from := t.selectionStart.pos
to := t.cursor.pos
row := t.selectionStart.row
if t.cursor.row < t.selectionStart.row ||
(t.cursor.row == t.selectionStart.row && t.cursor.column < t.selectionStart.column) {
from, to = to, from
row = t.cursor.row
}
return from, to, row
}
// InputHandler returns the handler for this primitive.
func (t *TextArea) InputHandler() func(event *tcell.EventKey, setFocus func(p Primitive)) {
return t.WrapInputHandler(func(event *tcell.EventKey, setFocus func(p Primitive)) {
@ -1185,6 +1252,9 @@ func (t *TextArea) InputHandler() func(event *tcell.EventKey, setFocus func(p Pr
// Move one grapheme cluster to the left.
t.moveCursor(t.cursor.row, t.cursor.actualColumn-1)
}
if event.Modifiers()&tcell.ModShift == 0 {
t.selectionStart = t.cursor
}
} else if !t.wrap {
// Just scroll.
t.columnOffset--
@ -1206,12 +1276,15 @@ func (t *TextArea) InputHandler() func(event *tcell.EventKey, setFocus func(p Pr
t.cursor.row++
t.cursor.actualColumn = 0
t.cursor.column = 0
t.cursor.clamp = true
t.clampToCursor(t.cursor.row)
} else {
// Move one character to the right.
t.moveCursor(t.cursor.row, t.cursor.actualColumn+stringWidth(cluster))
}
}
if event.Modifiers()&tcell.ModShift == 0 {
t.selectionStart = t.cursor
}
} else if !t.wrap {
// Just scroll.
t.columnOffset++
@ -1226,6 +1299,9 @@ func (t *TextArea) InputHandler() func(event *tcell.EventKey, setFocus func(p Pr
if event.Modifiers()&tcell.ModAlt == 0 {
// Regular movement.
t.moveCursor(t.cursor.row+1, t.cursor.column)
if event.Modifiers()&tcell.ModShift == 0 {
t.selectionStart = t.cursor
}
} else {
// Just scroll.
t.rowOffset++
@ -1243,6 +1319,9 @@ func (t *TextArea) InputHandler() func(event *tcell.EventKey, setFocus func(p Pr
if event.Modifiers()&tcell.ModAlt == 0 {
// Regular movement.
t.moveCursor(t.cursor.row-1, t.cursor.column)
if event.Modifiers()&tcell.ModShift == 0 {
t.selectionStart = t.cursor
}
} else {
// Just scroll.
t.rowOffset--
@ -1252,14 +1331,27 @@ func (t *TextArea) InputHandler() func(event *tcell.EventKey, setFocus func(p Pr
}
case tcell.KeyHome, tcell.KeyCtrlA: // Move to the start of the line.
t.moveCursor(t.cursor.row, 0)
if event.Modifiers()&tcell.ModShift == 0 {
t.selectionStart = t.cursor
}
case tcell.KeyEnd, tcell.KeyCtrlE: // Move to the end of the line.
t.moveCursor(t.cursor.row, -1)
if event.Modifiers()&tcell.ModShift == 0 {
t.selectionStart = t.cursor
}
case tcell.KeyPgDn, tcell.KeyCtrlF: // Move one page down.
t.moveCursor(t.cursor.row+t.lastHeight, t.cursor.column)
if event.Modifiers()&tcell.ModShift == 0 {
t.selectionStart = t.cursor
}
case tcell.KeyPgUp, tcell.KeyCtrlB: // Move one page up.
t.moveCursor(t.cursor.row-t.lastHeight, t.cursor.column)
if event.Modifiers()&tcell.ModShift == 0 {
t.selectionStart = t.cursor
}
case tcell.KeyEnter: // Insert a newline.
t.cursor.pos = t.replace(t.cursor.pos, t.cursor.pos, NewLine)
from, to, _ := t.getSelection()
t.cursor.pos = t.replace(from, to, NewLine)
row := t.cursor.row
t.cursor.row = -1
t.truncateLines(row - 1)
@ -1270,18 +1362,36 @@ func (t *TextArea) InputHandler() func(event *tcell.EventKey, setFocus func(p Pr
switch event.Rune() {
case 'f':
t.moveWordRight()
if event.Modifiers()&tcell.ModShift == 0 {
t.selectionStart = t.cursor
}
case 'b':
t.moveWordLeft()
if event.Modifiers()&tcell.ModShift == 0 {
t.selectionStart = t.cursor
}
}
} else {
// Other keys are simply accepted as regular characters.
t.cursor.pos = t.replace(t.cursor.pos, t.cursor.pos, string(event.Rune()))
from, to, _ := t.getSelection()
t.cursor.pos = t.replace(from, to, string(event.Rune()))
row := t.cursor.row
t.cursor.row = -1
t.truncateLines(row - 1)
t.clampToCursor(row)
}
case tcell.KeyBackspace, tcell.KeyBackspace2: // Delete backwards. tcell.KeyBackspace is the same as tcell.CtrlH.
from, to, row := t.getSelection()
if from != to {
// Simply delete the current selection.
t.cursor.pos = t.replace(from, to, "")
t.cursor.row = -1
t.truncateLines(row - 1)
t.clampToCursor(row)
t.selectionStart = t.cursor
break
}
// Move the cursor back by one grapheme cluster.
endPos := t.cursor.pos
if t.cursor.actualColumn == 0 {
@ -1299,7 +1409,19 @@ func (t *TextArea) InputHandler() func(event *tcell.EventKey, setFocus func(p Pr
t.truncateLines(t.cursor.row - 1)
t.clampToCursor(t.cursor.row)
}
t.selectionStart = t.cursor
case tcell.KeyDelete, tcell.KeyCtrlD: // Delete forward.
from, to, row := t.getSelection()
if from != to {
// Simply delete the current selection.
t.cursor.pos = t.replace(from, to, "")
t.cursor.row = -1
t.truncateLines(row - 1)
t.clampToCursor(row)
t.selectionStart = t.cursor
break
}
if t.cursor.pos[0] != 1 {
_, _, _, endPos, _ := t.step("", t.cursor.pos, t.cursor.pos)
t.cursor.pos = t.replace(t.cursor.pos, endPos, "")
@ -1307,6 +1429,7 @@ func (t *TextArea) InputHandler() func(event *tcell.EventKey, setFocus func(p Pr
t.truncateLines(t.cursor.row - 1)
t.clampToCursor(t.cursor.row)
}
t.selectionStart = t.cursor
case tcell.KeyCtrlK: // Delete everything under and to the right of the cursor until before the next newline character.
pos := t.cursor.pos
endPos := pos
@ -1327,6 +1450,7 @@ func (t *TextArea) InputHandler() func(event *tcell.EventKey, setFocus func(p Pr
t.cursor.row = -1
t.truncateLines(row - 1)
t.clampToCursor(row)
t.selectionStart = t.cursor
case tcell.KeyCtrlW: // Delete from the start of the current word to the left of the cursor.
pos := t.cursor.pos
t.moveWordLeft()
@ -1335,8 +1459,10 @@ func (t *TextArea) InputHandler() func(event *tcell.EventKey, setFocus func(p Pr
t.cursor.row = -1
t.truncateLines(row)
t.clampToCursor(row)
t.selectionStart = t.cursor
case tcell.KeyCtrlU: // Delete the current line.
t.deleteLine()
t.selectionStart = t.cursor
}
})
}

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