forked from fyne-io/fyne
/
text.go
302 lines (254 loc) · 7.59 KB
/
text.go
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package widget
import (
"image/color"
"strings"
"fyne.io/fyne"
"fyne.io/fyne/canvas"
"fyne.io/fyne/theme"
)
const (
passwordChar = "*"
)
// textPresenter provides the widget specific information to a generic text provider
type textPresenter interface {
textAlign() fyne.TextAlign
textStyle() fyne.TextStyle
textColor() color.Color
password() bool
object() fyne.Widget
}
// textProvider represents the base element for text based widget.
type textProvider struct {
baseWidget
presenter textPresenter
buffer []rune
rowBounds [][2]int
}
// newTextProvider returns a new textProvider with the given text and settings from the passed textPresenter.
func newTextProvider(text string, pres textPresenter) textProvider {
if pres == nil {
panic("textProvider requires a presenter")
}
t := textProvider{
buffer: []rune(text),
presenter: pres,
}
t.updateRowBounds()
return t
}
// Resize sets a new size for a widget.
// Note this should not be used if the widget is being managed by a Layout within a Container.
func (t *textProvider) Resize(size fyne.Size) {
t.resize(size, t)
}
// Move the widget to a new position, relative to it's parent.
// Note this should not be used if the widget is being managed by a Layout within a Container.
func (t *textProvider) Move(pos fyne.Position) {
t.move(pos, t)
}
// MinSize returns the smallest size this widget can shrink to
func (t *textProvider) MinSize() fyne.Size {
return t.minSize(t)
}
// Show this widget, if it was previously hidden
func (t *textProvider) Show() {
t.show(t)
}
// Hide this widget, if it was previously visible
func (t *textProvider) Hide() {
t.hide(t)
}
// CreateRenderer is a private method to Fyne which links this widget to it's renderer
func (t *textProvider) CreateRenderer() fyne.WidgetRenderer {
if t.presenter == nil {
panic("Cannot render a textProvider without a presenter")
}
r := &textRenderer{provider: t}
t.updateRowBounds() // set up the initial text layout etc
r.Refresh()
return r
}
// updateRowBounds updates the row bounds used to render properly the text widget.
// updateRowBounds should be invoked every time t.buffer changes.
func (t *textProvider) updateRowBounds() {
var lowBound, highBound int
t.rowBounds = [][2]int{}
if len(t.buffer) == 0 {
t.rowBounds = append(t.rowBounds, [2]int{lowBound, highBound})
return
}
for i, r := range t.buffer {
highBound = i
if r != '\n' {
continue
}
t.rowBounds = append(t.rowBounds, [2]int{lowBound, highBound})
lowBound = i + 1
}
//first or last line, increase the highBound index to include the last char
highBound++
t.rowBounds = append(t.rowBounds, [2]int{lowBound, highBound})
}
// refreshTextRenderer refresh the textRenderer canvas objects
// this method should be invoked every time the t.buffer changes
// example:
// t.buffer = []rune("new text")
// t.updateRowBounds()
// t.refreshTextRenderer()
func (t *textProvider) refreshTextRenderer() {
obj := t.presenter.object()
if obj == nil {
obj = t
}
Refresh(obj)
}
// SetText sets the text of the widget
func (t *textProvider) SetText(text string) {
t.buffer = []rune(text)
t.updateRowBounds()
t.refreshTextRenderer()
}
// String returns the text widget buffer as string
func (t *textProvider) String() string {
return string(t.buffer)
}
// Len returns the text widget buffer length
func (t *textProvider) len() int {
return len(t.buffer)
}
// insertAt inserts the text at the specified position
func (t *textProvider) insertAt(pos int, runes []rune) {
t.buffer = append(t.buffer[:pos], append(runes, t.buffer[pos:]...)...)
t.updateRowBounds()
t.refreshTextRenderer()
}
// deleteFromTo removes the text between the specified positions
func (t *textProvider) deleteFromTo(lowBound int, highBound int) []rune {
deleted := make([]rune, highBound-lowBound)
copy(deleted, t.buffer[lowBound:highBound])
t.buffer = append(t.buffer[:lowBound], t.buffer[highBound:]...)
t.updateRowBounds()
t.refreshTextRenderer()
return deleted
}
// rows returns the number of text rows in this text entry.
// The entry may be longer than required to show this amount of content.
func (t *textProvider) rows() int {
return len(t.rowBounds)
}
// Row returns the characters in the row specified.
// The row parameter should be between 0 and t.Rows()-1.
func (t *textProvider) row(row int) []rune {
bounds := t.rowBounds[row]
return t.buffer[bounds[0]:bounds[1]]
}
// RowLength returns the number of visible characters in the row specified.
// The row parameter should be between 0 and t.Rows()-1.
func (t *textProvider) rowLength(row int) int {
return len(t.row(row))
}
// CharMinSize returns the average char size to use for internal computation
func (t *textProvider) charMinSize() fyne.Size {
defaultChar := "M"
if t.presenter.password() {
defaultChar = passwordChar
}
return textMinSize(defaultChar, theme.TextSize(), t.presenter.textStyle())
}
// Renderer
type textRenderer struct {
objects []fyne.CanvasObject
texts []*canvas.Text
provider *textProvider
}
// MinSize calculates the minimum size of a label.
// This is based on the contained text with a standard amount of padding added.
func (r *textRenderer) MinSize() fyne.Size {
height := 0
width := 0
for i := 0; i < len(r.texts); i++ {
min := r.texts[i].MinSize()
if r.texts[i].Text == "" {
min = r.provider.charMinSize()
}
height += min.Height
width = fyne.Max(width, min.Width)
}
return fyne.NewSize(width, height).Add(fyne.NewSize(theme.Padding()*2, theme.Padding()*2))
}
func (r *textRenderer) Layout(size fyne.Size) {
yPos := theme.Padding()
lineHeight := r.provider.charMinSize().Height
lineSize := fyne.NewSize(size.Width-theme.Padding()*2, lineHeight)
for i := 0; i < len(r.texts); i++ {
text := r.texts[i]
text.Resize(lineSize)
text.Move(fyne.NewPos(theme.Padding(), yPos))
yPos += lineHeight
}
}
func (r *textRenderer) Objects() []fyne.CanvasObject {
return r.objects
}
// ApplyTheme is called when the Label may need to update it's look
func (r *textRenderer) ApplyTheme() {
c := theme.TextColor()
if r.provider.presenter.textColor() != nil {
c = r.provider.presenter.textColor()
}
for _, text := range r.texts {
text.Color = c
}
}
func (r *textRenderer) Refresh() {
r.texts = []*canvas.Text{}
r.objects = []fyne.CanvasObject{}
for index := 0; index < r.provider.rows(); index++ {
var line string
row := r.provider.row(index)
if r.provider.presenter.password() {
line = strings.Repeat(passwordChar, len(row))
} else {
line = string(row)
}
textCanvas := canvas.NewText(line, theme.TextColor())
textCanvas.Alignment = r.provider.presenter.textAlign()
textCanvas.TextStyle = r.provider.presenter.textStyle()
textCanvas.Hidden = r.provider.Hidden
r.texts = append(r.texts, textCanvas)
r.objects = append(r.objects, textCanvas)
}
r.ApplyTheme()
r.Layout(r.provider.Size())
if r.provider.presenter.object() == nil {
canvas.Refresh(r.provider)
} else {
canvas.Refresh(r.provider.presenter.object())
}
}
func (r *textRenderer) BackgroundColor() color.Color {
return color.Transparent
}
// lineSize returns the rendered size for the line specified by col and row
func (r *textRenderer) lineSize(col, row int) (size fyne.Size) {
text := r.provider
line := text.row(row)
if col >= len(line) {
col = len(line)
}
lineCopy := *r.texts[row]
if r.provider.presenter.password() {
lineCopy.Text = strings.Repeat(passwordChar, col)
} else {
lineCopy.Text = string(line[0:col])
}
return lineCopy.MinSize()
}
func (r *textRenderer) Destroy() {
}
func textMinSize(text string, size int, style fyne.TextStyle) fyne.Size {
t := canvas.NewText(text, color.Black)
t.TextSize = size
t.TextStyle = style
return t.MinSize()
}