Move termgridrenderer to its own file

Author: mgazza

internal/widget/renderer.go

@@ -0,0 +1,285 @@
+package widget
+
+import (
+	"context"
+	"image/color"
+	"math"
+	"strconv"
+	"time"
+
+	"fyne.io/fyne/v2"
+	"fyne.io/fyne/v2/canvas"
+	"fyne.io/fyne/v2/theme"
+	"fyne.io/fyne/v2/widget"
+)
+
+type termGridRenderer struct {
+	text *TermGrid
+
+	cols, rows int
+
+	cellSize     fyne.Size
+	objects      []fyne.CanvasObject
+	current      fyne.Canvas
+	blink        bool
+	shouldBlink  bool
+	tickerCancel context.CancelFunc
+}
+
+func (t *termGridRenderer) appendTextCell(str rune) {
+	text := canvas.NewText(string(str), theme.ForegroundColor())
+	text.TextStyle.Monospace = true
+
+	bg := canvas.NewRectangle(color.Transparent)
+	t.objects = append(t.objects, bg, text)
+}
+
+func (t *termGridRenderer) setCellRune(str rune, pos int, style widget.TextGridStyle) {
+	if str == 0 {
+		str = ' '
+	}
+	fg := theme.ForegroundColor()
+	if style != nil && style.TextColor() != nil {
+		fg = style.TextColor()
+	}
+	bg := color.Color(color.Transparent)
+	if style != nil && style.BackgroundColor() != nil {
+		bg = style.BackgroundColor()
+	}
+
+	if s, ok := style.(*TermTextGridStyle); ok && s != nil && s.BlinkEnabled {
+		t.shouldBlink = true
+		if t.blink {
+			fg = bg
+		}
+	}
+
+	text := t.objects[pos*2+1].(*canvas.Text)
+	text.TextSize = theme.TextSize()
+
+	newStr := string(str)
+	if text.Text != newStr || text.Color != fg {
+		text.Text = newStr
+		text.Color = fg
+		t.refresh(text)
+	}
+
+	rect := t.objects[pos*2].(*canvas.Rectangle)
+	if rect.FillColor != bg {
+		rect.FillColor = bg
+		t.refresh(rect)
+	}
+}
+
+func (t *termGridRenderer) addCellsIfRequired() {
+	cellCount := t.cols * t.rows
+	if len(t.objects) == cellCount*2 {
+		return
+	}
+	for i := len(t.objects); i < cellCount*2; i += 2 {
+		t.appendTextCell(' ')
+	}
+}
+
+func (t *termGridRenderer) refreshGrid() {
+	line := 1
+	x := 0
+	// reset shouldBlink which can be set by setCellRune if a cell with BlinkEnabled is found
+	t.shouldBlink = false
+
+	for rowIndex, row := range t.text.Rows {
+		i := 0
+		if t.text.ShowLineNumbers {
+			lineStr := []rune(strconv.Itoa(line))
+			pad := t.lineNumberWidth() - len(lineStr)
+			for ; i < pad; i++ {
+				t.setCellRune(' ', x, widget.TextGridStyleWhitespace) // padding space
+				x++
+			}
+			for c := 0; c < len(lineStr); c++ {
+				t.setCellRune(lineStr[c], x, widget.TextGridStyleDefault) // line numbers
+				i++
+				x++
+			}
+
+			t.setCellRune('|', x, widget.TextGridStyleWhitespace) // last space
+			i++
+			x++
+		}
+		for _, r := range row.Cells {
+			if i >= t.cols { // would be an overflow - bad
+				continue
+			}
+			if t.text.ShowWhitespace && (r.Rune == ' ' || r.Rune == '\t') {
+				sym := textAreaSpaceSymbol
+				if r.Rune == '\t' {
+					sym = textAreaTabSymbol
+				}
+
+				if r.Style != nil && r.Style.BackgroundColor() != nil {
+					whitespaceBG := &widget.CustomTextGridStyle{FGColor: widget.TextGridStyleWhitespace.TextColor(),
+						BGColor: r.Style.BackgroundColor()}
+					t.setCellRune(sym, x, whitespaceBG) // whitespace char
+				} else {
+					t.setCellRune(sym, x, widget.TextGridStyleWhitespace) // whitespace char
+				}
+			} else {
+				t.setCellRune(r.Rune, x, r.Style) // regular char
+			}
+			i++
+			x++
+		}
+		if t.text.ShowWhitespace && i < t.cols && rowIndex < len(t.text.Rows)-1 {
+			t.setCellRune(textAreaNewLineSymbol, x, widget.TextGridStyleWhitespace) // newline
+			i++
+			x++
+		}
+		for ; i < t.cols; i++ {
+			t.setCellRune(' ', x, widget.TextGridStyleDefault) // blanks
+			x++
+		}
+
+		line++
+	}
+	for ; x < len(t.objects)/2; x++ {
+		t.setCellRune(' ', x, widget.TextGridStyleDefault) // trailing cells and blank lines
+	}
+
+	switch {
+	case t.shouldBlink && t.tickerCancel == nil:
+		t.runBlink()
+	case !t.shouldBlink && t.tickerCancel != nil:
+		t.tickerCancel()
+		t.tickerCancel = nil
+	}
+}
+
+func (t *termGridRenderer) runBlink() {
+	if t.tickerCancel != nil {
+		t.tickerCancel()
+		t.tickerCancel = nil
+	}
+	var tickerContext context.Context
+	tickerContext, t.tickerCancel = context.WithCancel(context.Background())
+	ticker := time.NewTicker(blinkingInterval)
+	blinking := false
+	go func() {
+		for {
+			select {
+			case <-tickerContext.Done():
+				return
+			case <-ticker.C:
+				t.SetBlink(blinking)
+				blinking = !blinking
+				t.refreshGrid()
+			}
+		}
+	}()
+}
+
+func (t *termGridRenderer) lineNumberWidth() int {
+	return len(strconv.Itoa(t.rows + 1))
+}
+
+func (t *termGridRenderer) updateGridSize(size fyne.Size) {
+	bufRows := len(t.text.Rows)
+	bufCols := 0
+	for _, row := range t.text.Rows {
+		bufCols = int(math.Max(float64(bufCols), float64(len(row.Cells))))
+	}
+	sizeCols := math.Floor(float64(size.Width) / float64(t.cellSize.Width))
+	sizeRows := math.Floor(float64(size.Height) / float64(t.cellSize.Height))
+
+	if t.text.ShowWhitespace {
+		bufCols++
+	}
+	if t.text.ShowLineNumbers {
+		bufCols += t.lineNumberWidth()
+	}
+
+	t.cols = int(math.Max(sizeCols, float64(bufCols)))
+	t.rows = int(math.Max(sizeRows, float64(bufRows)))
+	t.addCellsIfRequired()
+}
+
+func (t *termGridRenderer) Layout(size fyne.Size) {
+	t.updateGridSize(size)
+
+	i := 0
+	cellPos := fyne.NewPos(0, 0)
+	for y := 0; y < t.rows; y++ {
+		for x := 0; x < t.cols; x++ {
+			t.objects[i*2+1].Move(cellPos)
+
+			t.objects[i*2].Resize(t.cellSize)
+			t.objects[i*2].Move(cellPos)
+			cellPos.X += t.cellSize.Width
+			i++
+		}
+
+		cellPos.X = 0
+		cellPos.Y += t.cellSize.Height
+	}
+}
+
+func (t *termGridRenderer) MinSize() fyne.Size {
+	longestRow := float32(0)
+	for _, row := range t.text.Rows {
+		longestRow = fyne.Max(longestRow, float32(len(row.Cells)))
+	}
+	return fyne.NewSize(t.cellSize.Width*longestRow,
+		t.cellSize.Height*float32(len(t.text.Rows)))
+}
+
+func (t *termGridRenderer) Refresh() {
+	// we may be on a new canvas, so just update it to be sure
+	if fyne.CurrentApp() != nil && fyne.CurrentApp().Driver() != nil {
+		t.current = fyne.CurrentApp().Driver().CanvasForObject(t.text)
+	}
+
+	// theme could change text size
+	t.updateCellSize()
+
+	widget.TextGridStyleWhitespace = &widget.CustomTextGridStyle{FGColor: theme.DisabledColor()}
+	t.updateGridSize(t.text.Size())
+	t.refreshGrid()
+}
+
+func (t *termGridRenderer) ApplyTheme() {
+}
+
+func (t *termGridRenderer) Objects() []fyne.CanvasObject {
+	return t.objects
+}
+
+func (t *termGridRenderer) Destroy() {
+}
+
+func (t *termGridRenderer) refresh(obj fyne.CanvasObject) {
+	if t.current == nil {
+		if fyne.CurrentApp() != nil && fyne.CurrentApp().Driver() != nil {
+			// cache canvas for this widget, so we don't look it up many times for every cell/row refresh!
+			t.current = fyne.CurrentApp().Driver().CanvasForObject(t.text)
+		}
+
+		if t.current == nil {
+			return // not yet set up perhaps?
+		}
+	}
+
+	t.current.Refresh(obj)
+}
+
+func (t *termGridRenderer) updateCellSize() {
+	size := fyne.MeasureText("M", theme.TextSize(), fyne.TextStyle{Monospace: true})
+
+	// round it for seamless background
+	size.Width = float32(math.Round(float64((size.Width))))
+	size.Height = float32(math.Round(float64((size.Height))))
+
+	t.cellSize = size
+}
+
+func (t *termGridRenderer) SetBlink(b bool) {
+	t.blink = b
+}