cview/inputfield.go

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package cview
import (
"bytes"
"math"
"regexp"
"sync"
"unicode/utf8"
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"github.com/gdamore/tcell/v2"
"github.com/mattn/go-runewidth"
)
// InputField is a one-line box (three lines if there is a title) where the
// user can enter text. Use SetAcceptanceFunc() to accept or reject input,
// SetChangedFunc() to listen for changes, and SetMaskCharacter() to hide input
// from onlookers (e.g. for password input).
//
// The following keys can be used for navigation and editing:
//
// - Left arrow: Move left by one character.
// - Right arrow: Move right by one character.
// - Home, Ctrl-A, Alt-a: Move to the beginning of the line.
// - End, Ctrl-E, Alt-e: Move to the end of the line.
// - Alt-left, Alt-b: Move left by one word.
// - Alt-right, Alt-f: Move right by one word.
// - Backspace: Delete the character before the cursor.
// - Delete: Delete the character after the cursor.
// - Ctrl-K: Delete from the cursor to the end of the line.
// - Ctrl-W: Delete the last word before the cursor.
// - Ctrl-U: Delete the entire line.
type InputField struct {
*Box
// The text that was entered.
text []byte
// The text to be displayed before the input area.
label []byte
// The text to be displayed in the input area when "text" is empty.
placeholder []byte
// The label color.
labelColor tcell.Color
// The label color when focused.
labelColorFocused tcell.Color
// The background color of the input area.
fieldBackgroundColor tcell.Color
// The background color of the input area when focused.
fieldBackgroundColorFocused tcell.Color
// The text color of the input area.
fieldTextColor tcell.Color
// The text color of the input area when focused.
fieldTextColorFocused tcell.Color
// The text color of the placeholder.
placeholderTextColor tcell.Color
// The text color of the placeholder when focused.
placeholderTextColorFocused tcell.Color
// The text color of the list items.
autocompleteListTextColor tcell.Color
// The background color of the autocomplete list.
autocompleteListBackgroundColor tcell.Color
// The text color of the selected ListItem.
autocompleteListSelectedTextColor tcell.Color
// The background color of the selected ListItem.
autocompleteListSelectedBackgroundColor tcell.Color
// The text color of the suggestion.
autocompleteSuggestionTextColor tcell.Color
// The text color of the note below the input field.
fieldNoteTextColor tcell.Color
// The note to show below the input field.
fieldNote []byte
// The screen width of the label area. A value of 0 means use the width of
// the label text.
labelWidth int
// The screen width of the input area. A value of 0 means extend as much as
// possible.
fieldWidth int
// A character to mask entered text (useful for password fields). A value of 0
// disables masking.
maskCharacter rune
// The cursor position as a byte index into the text string.
cursorPos int
// An optional autocomplete function which receives the current text of the
// input field and returns a slice of ListItems to be displayed in a drop-down
// selection. Items' main text is displayed in the autocomplete list. When
// set, items' secondary text is used as the selection value. Otherwise,
// the main text is used.
autocomplete func(text string) []*ListItem
// The List object which shows the selectable autocomplete entries. If not
// nil, the list's main texts represent the current autocomplete entries.
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autocompleteList *List
// The suggested completion of the current autocomplete ListItem.
autocompleteListSuggestion []byte
// An optional function which may reject the last character that was entered.
accept func(text string, ch rune) bool
// An optional function which is called when the input has changed.
changed func(text string)
// An optional function which is called when the user indicated that they
// are done entering text. The key which was pressed is provided (tab,
// shift-tab, enter, or escape).
done func(tcell.Key)
// A callback function set by the Form class and called when the user leaves
// this form item.
finished func(tcell.Key)
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// The x-coordinate of the input field as determined during the last call to Draw().
fieldX int
// The number of bytes of the text string skipped ahead while drawing.
offset int
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sync.RWMutex
}
// NewInputField returns a new input field.
func NewInputField() *InputField {
return &InputField{
Box: NewBox(),
labelColor: Styles.SecondaryTextColor,
fieldBackgroundColor: Styles.ContrastBackgroundColor,
fieldTextColor: Styles.PrimaryTextColor,
placeholderTextColor: Styles.ContrastSecondaryTextColor,
autocompleteListTextColor: Styles.PrimitiveBackgroundColor,
autocompleteListBackgroundColor: Styles.MoreContrastBackgroundColor,
autocompleteListSelectedTextColor: Styles.PrimitiveBackgroundColor,
autocompleteListSelectedBackgroundColor: Styles.PrimaryTextColor,
autocompleteSuggestionTextColor: Styles.ContrastPrimaryTextColor,
fieldNoteTextColor: Styles.SecondaryTextColor,
labelColorFocused: ColorUnset,
fieldBackgroundColorFocused: ColorUnset,
fieldTextColorFocused: ColorUnset,
placeholderTextColorFocused: ColorUnset,
}
}
// SetText sets the current text of the input field.
func (i *InputField) SetText(text string) {
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i.Lock()
i.text = []byte(text)
i.cursorPos = len(text)
if i.changed != nil {
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i.Unlock()
i.changed(text)
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} else {
i.Unlock()
}
}
// GetText returns the current text of the input field.
func (i *InputField) GetText() string {
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i.RLock()
defer i.RUnlock()
return string(i.text)
}
// SetLabel sets the text to be displayed before the input area.
func (i *InputField) SetLabel(label string) {
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i.Lock()
defer i.Unlock()
i.label = []byte(label)
}
// GetLabel returns the text to be displayed before the input area.
func (i *InputField) GetLabel() string {
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i.RLock()
defer i.RUnlock()
return string(i.label)
}
// SetLabelWidth sets the screen width of the label. A value of 0 will cause the
// primitive to use the width of the label string.
func (i *InputField) SetLabelWidth(width int) {
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i.Lock()
defer i.Unlock()
i.labelWidth = width
}
// SetPlaceholder sets the text to be displayed when the input text is empty.
func (i *InputField) SetPlaceholder(text string) {
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i.Lock()
defer i.Unlock()
i.placeholder = []byte(text)
}
// SetLabelColor sets the color of the label.
func (i *InputField) SetLabelColor(color tcell.Color) {
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i.Lock()
defer i.Unlock()
i.labelColor = color
}
// SetLabelColorFocused sets the color of the label when focused.
func (i *InputField) SetLabelColorFocused(color tcell.Color) {
i.Lock()
defer i.Unlock()
i.labelColorFocused = color
}
// SetFieldBackgroundColor sets the background color of the input area.
func (i *InputField) SetFieldBackgroundColor(color tcell.Color) {
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i.Lock()
defer i.Unlock()
i.fieldBackgroundColor = color
}
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// SetFieldBackgroundColorFocused sets the background color of the input area
// when focused.
func (i *InputField) SetFieldBackgroundColorFocused(color tcell.Color) {
i.Lock()
defer i.Unlock()
i.fieldBackgroundColorFocused = color
}
// SetFieldTextColor sets the text color of the input area.
func (i *InputField) SetFieldTextColor(color tcell.Color) {
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i.Lock()
defer i.Unlock()
i.fieldTextColor = color
}
// SetFieldTextColorFocused sets the text color of the input area when focused.
func (i *InputField) SetFieldTextColorFocused(color tcell.Color) {
i.Lock()
defer i.Unlock()
i.fieldTextColorFocused = color
}
// SetPlaceholderTextColor sets the text color of placeholder text.
func (i *InputField) SetPlaceholderTextColor(color tcell.Color) {
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i.Lock()
defer i.Unlock()
i.placeholderTextColor = color
}
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// SetPlaceholderTextColorFocused sets the text color of placeholder text when
// focused.
func (i *InputField) SetPlaceholderTextColorFocused(color tcell.Color) {
i.Lock()
defer i.Unlock()
i.placeholderTextColorFocused = color
}
// SetAutocompleteListTextColor sets the text color of the ListItems.
func (i *InputField) SetAutocompleteListTextColor(color tcell.Color) {
i.Lock()
defer i.Unlock()
i.autocompleteListTextColor = color
}
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// SetAutocompleteListBackgroundColor sets the background color of the
// autocomplete list.
func (i *InputField) SetAutocompleteListBackgroundColor(color tcell.Color) {
i.Lock()
defer i.Unlock()
i.autocompleteListBackgroundColor = color
}
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// SetAutocompleteListSelectedTextColor sets the text color of the selected
// ListItem.
func (i *InputField) SetAutocompleteListSelectedTextColor(color tcell.Color) {
i.Lock()
defer i.Unlock()
i.autocompleteListSelectedTextColor = color
}
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// SetAutocompleteListSelectedBackgroundColor sets the background of the
// selected ListItem.
func (i *InputField) SetAutocompleteListSelectedBackgroundColor(color tcell.Color) {
i.Lock()
defer i.Unlock()
i.autocompleteListSelectedBackgroundColor = color
}
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// SetAutocompleteSuggestionTextColor sets the text color of the autocomplete
// suggestion in the input field.
func (i *InputField) SetAutocompleteSuggestionTextColor(color tcell.Color) {
i.Lock()
defer i.Unlock()
i.autocompleteSuggestionTextColor = color
}
// SetFieldNoteTextColor sets the text color of the note.
func (i *InputField) SetFieldNoteTextColor(color tcell.Color) {
i.Lock()
defer i.Unlock()
i.fieldNoteTextColor = color
}
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// SetFieldNote sets the text to show below the input field, e.g. when the
// input is invalid.
func (i *InputField) SetFieldNote(note string) {
i.Lock()
defer i.Unlock()
i.fieldNote = []byte(note)
}
// ResetFieldNote sets the note to an empty string.
func (i *InputField) ResetFieldNote() {
i.Lock()
defer i.Unlock()
i.fieldNote = nil
}
// SetFieldWidth sets the screen width of the input area. A value of 0 means
// extend as much as possible.
func (i *InputField) SetFieldWidth(width int) {
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i.Lock()
defer i.Unlock()
i.fieldWidth = width
}
// GetFieldWidth returns this primitive's field width.
func (i *InputField) GetFieldWidth() int {
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i.RLock()
defer i.RUnlock()
return i.fieldWidth
}
// GetFieldHeight returns the height of the field.
func (i *InputField) GetFieldHeight() int {
i.RLock()
defer i.RUnlock()
if len(i.fieldNote) == 0 {
return 1
}
return 2
}
// GetCursorPosition returns the cursor position.
func (i *InputField) GetCursorPosition() int {
i.RLock()
defer i.RUnlock()
return i.cursorPos
}
// SetCursorPosition sets the cursor position.
func (i *InputField) SetCursorPosition(cursorPos int) {
i.Lock()
defer i.Unlock()
i.cursorPos = cursorPos
}
// SetMaskCharacter sets a character that masks user input on a screen. A value
// of 0 disables masking.
func (i *InputField) SetMaskCharacter(mask rune) {
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i.Lock()
defer i.Unlock()
i.maskCharacter = mask
}
// SetAutocompleteFunc sets an autocomplete callback function which may return
// ListItems to be selected from a drop-down based on the current text of the
// input field. The drop-down appears only if len(entries) > 0. The callback is
// invoked in this function and whenever the current text changes or when
// Autocomplete() is called. Entries are cleared when the user selects an entry
// or presses Escape.
func (i *InputField) SetAutocompleteFunc(callback func(currentText string) (entries []*ListItem)) {
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i.Lock()
i.autocomplete = callback
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i.Unlock()
i.Autocomplete()
}
// Autocomplete invokes the autocomplete callback (if there is one). If the
// length of the returned autocomplete entries slice is greater than 0, the
// input field will present the user with a corresponding drop-down list the
// next time the input field is drawn.
//
// It is safe to call this function from any goroutine. Note that the input
// field is not redrawn automatically unless called from the main goroutine
// (e.g. in response to events).
func (i *InputField) Autocomplete() {
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i.Lock()
if i.autocomplete == nil {
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i.Unlock()
return
}
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i.Unlock()
// Do we have any autocomplete entries?
entries := i.autocomplete(string(i.text))
if len(entries) == 0 {
// No entries, no list.
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i.Lock()
i.autocompleteList = nil
i.autocompleteListSuggestion = nil
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i.Unlock()
return
}
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i.Lock()
// Make a list if we have none.
if i.autocompleteList == nil {
l := NewList()
l.SetChangedFunc(i.autocompleteChanged)
l.ShowSecondaryText(false)
l.SetMainTextColor(i.autocompleteListTextColor)
l.SetSelectedTextColor(i.autocompleteListSelectedTextColor)
l.SetSelectedBackgroundColor(i.autocompleteListSelectedBackgroundColor)
l.SetHighlightFullLine(true)
l.SetBackgroundColor(i.autocompleteListBackgroundColor)
i.autocompleteList = l
}
// Fill it with the entries.
currentEntry := -1
i.autocompleteList.Clear()
for index, entry := range entries {
i.autocompleteList.AddItem(entry)
if currentEntry < 0 && entry.GetMainText() == string(i.text) {
currentEntry = index
}
}
// Set the selection if we have one.
if currentEntry >= 0 {
i.autocompleteList.SetCurrentItem(currentEntry)
}
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i.Unlock()
}
// autocompleteChanged gets called when another item in the
// autocomplete list has been selected.
func (i *InputField) autocompleteChanged(_ int, item *ListItem) {
mainText := item.GetMainBytes()
secondaryText := item.GetSecondaryBytes()
if len(i.text) < len(secondaryText) {
i.autocompleteListSuggestion = secondaryText[len(i.text):]
} else if len(i.text) < len(mainText) {
i.autocompleteListSuggestion = mainText[len(i.text):]
} else {
i.autocompleteListSuggestion = nil
}
}
// SetAcceptanceFunc sets a handler which may reject the last character that was
// entered (by returning false).
//
// This package defines a number of variables prefixed with InputField which may
// be used for common input (e.g. numbers, maximum text length).
func (i *InputField) SetAcceptanceFunc(handler func(textToCheck string, lastChar rune) bool) {
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i.Lock()
defer i.Unlock()
i.accept = handler
}
// SetChangedFunc sets a handler which is called whenever the text of the input
// field has changed. It receives the current text (after the change).
func (i *InputField) SetChangedFunc(handler func(text string)) {
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i.Lock()
defer i.Unlock()
i.changed = handler
}
// SetDoneFunc sets a handler which is called when the user is done entering
// text. The callback function is provided with the key that was pressed, which
// is one of the following:
//
// - KeyEnter: Done entering text.
// - KeyEscape: Abort text input.
// - KeyTab: Move to the next field.
// - KeyBacktab: Move to the previous field.
func (i *InputField) SetDoneFunc(handler func(key tcell.Key)) {
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i.Lock()
defer i.Unlock()
i.done = handler
}
// SetFinishedFunc sets a callback invoked when the user leaves this form item.
func (i *InputField) SetFinishedFunc(handler func(key tcell.Key)) {
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i.Lock()
defer i.Unlock()
i.finished = handler
}
// Draw draws this primitive onto the screen.
func (i *InputField) Draw(screen tcell.Screen) {
if !i.GetVisible() {
return
}
i.Box.Draw(screen)
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i.Lock()
defer i.Unlock()
// Select colors
labelColor := i.labelColor
fieldBackgroundColor := i.fieldBackgroundColor
fieldTextColor := i.fieldTextColor
if i.GetFocusable().HasFocus() {
if i.labelColorFocused != ColorUnset {
labelColor = i.labelColorFocused
}
if i.fieldBackgroundColorFocused != ColorUnset {
fieldBackgroundColor = i.fieldBackgroundColorFocused
}
if i.fieldTextColorFocused != ColorUnset {
fieldTextColor = i.fieldTextColorFocused
}
}
// Prepare
x, y, width, height := i.GetInnerRect()
rightLimit := x + width
if height < 1 || rightLimit <= x {
return
}
// Draw label.
if i.labelWidth > 0 {
labelWidth := i.labelWidth
if labelWidth > rightLimit-x {
labelWidth = rightLimit - x
}
Print(screen, i.label, x, y, labelWidth, AlignLeft, labelColor)
x += labelWidth
} else {
_, drawnWidth := Print(screen, i.label, x, y, rightLimit-x, AlignLeft, labelColor)
x += drawnWidth
}
// Draw input area.
i.fieldX = x
fieldWidth := i.fieldWidth
if fieldWidth == 0 {
fieldWidth = math.MaxInt32
}
if rightLimit-x < fieldWidth {
fieldWidth = rightLimit - x
}
fieldStyle := tcell.StyleDefault.Background(fieldBackgroundColor)
for index := 0; index < fieldWidth; index++ {
screen.SetContent(x+index, y, ' ', nil, fieldStyle)
}
// Text.
var cursorScreenPos int
text := i.text
if len(text) == 0 && len(i.placeholder) > 0 {
// Draw placeholder text.
placeholderTextColor := i.placeholderTextColor
if i.GetFocusable().HasFocus() && i.placeholderTextColorFocused != ColorUnset {
placeholderTextColor = i.placeholderTextColorFocused
}
Print(screen, EscapeBytes(i.placeholder), x, y, fieldWidth, AlignLeft, placeholderTextColor)
i.offset = 0
} else {
// Draw entered text.
if i.maskCharacter > 0 {
text = bytes.Repeat([]byte(string(i.maskCharacter)), utf8.RuneCount(i.text))
}
var drawnText []byte
if fieldWidth >= runewidth.StringWidth(string(text)) {
// We have enough space for the full text.
drawnText = EscapeBytes(text)
Print(screen, drawnText, x, y, fieldWidth, AlignLeft, fieldTextColor)
i.offset = 0
iterateString(string(text), func(main rune, comb []rune, textPos, textWidth, screenPos, screenWidth int) bool {
if textPos >= i.cursorPos {
return true
}
cursorScreenPos += screenWidth
return false
})
} else {
// The text doesn't fit. Where is the cursor?
if i.cursorPos < 0 {
i.cursorPos = 0
} else if i.cursorPos > len(text) {
i.cursorPos = len(text)
}
// Shift the text so the cursor is inside the field.
var shiftLeft int
if i.offset > i.cursorPos {
i.offset = i.cursorPos
} else if subWidth := runewidth.StringWidth(string(text[i.offset:i.cursorPos])); subWidth > fieldWidth-1 {
shiftLeft = subWidth - fieldWidth + 1
}
currentOffset := i.offset
iterateString(string(text), func(main rune, comb []rune, textPos, textWidth, screenPos, screenWidth int) bool {
if textPos >= currentOffset {
if shiftLeft > 0 {
i.offset = textPos + textWidth
shiftLeft -= screenWidth
} else {
if textPos+textWidth > i.cursorPos {
return true
}
cursorScreenPos += screenWidth
}
}
return false
})
drawnText = EscapeBytes(text[i.offset:])
Print(screen, drawnText, x, y, fieldWidth, AlignLeft, fieldTextColor)
}
// Draw suggestion
if i.maskCharacter == 0 && len(i.autocompleteListSuggestion) > 0 {
Print(screen, i.autocompleteListSuggestion, x+runewidth.StringWidth(string(drawnText)), y, fieldWidth-runewidth.StringWidth(string(drawnText)), AlignLeft, i.autocompleteSuggestionTextColor)
}
}
// Draw field note
if len(i.fieldNote) > 0 {
Print(screen, i.fieldNote, x, y+1, fieldWidth, AlignLeft, i.fieldNoteTextColor)
}
// Draw autocomplete list.
if i.autocompleteList != nil {
// How much space do we need?
lheight := i.autocompleteList.GetItemCount()
lwidth := 0
for index := 0; index < lheight; index++ {
entry, _ := i.autocompleteList.GetItemText(index)
width := TaggedStringWidth(entry)
if width > lwidth {
lwidth = width
}
}
// We prefer to drop down but if there is no space, maybe drop up?
lx := x
ly := y + 1
_, sheight := screen.Size()
if ly+lheight >= sheight && ly-2 > lheight-ly {
ly = y - lheight
if ly < 0 {
ly = 0
}
}
if ly+lheight >= sheight {
lheight = sheight - ly
}
if i.autocompleteList.scrollBarVisibility == ScrollBarAlways || (i.autocompleteList.scrollBarVisibility == ScrollBarAuto && i.autocompleteList.GetItemCount() > lheight) {
lwidth++ // Add space for scroll bar
}
i.autocompleteList.SetRect(lx, ly, lwidth, lheight)
i.autocompleteList.Draw(screen)
}
// Set cursor.
if i.focus.HasFocus() {
screen.ShowCursor(x+cursorScreenPos, y)
}
}
// InputHandler returns the handler for this primitive.
func (i *InputField) InputHandler() func(event *tcell.EventKey, setFocus func(p Primitive)) {
return i.WrapInputHandler(func(event *tcell.EventKey, setFocus func(p Primitive)) {
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i.Lock()
// Trigger changed events.
currentText := i.text
defer func() {
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i.Lock()
newText := i.text
i.Unlock()