Merge pull request fyne-io#4021 from andydotxyz/fix/slowtextgrid

widget/textgrid.go

@@ -337,6 +337,7 @@ type textGridRenderer struct {
 
 	cellSize fyne.Size
 	objects  []fyne.CanvasObject
+	current  fyne.Canvas
 }
 
 func (t *textGridRenderer) appendTextCell(str rune) {
@@ -369,9 +370,12 @@ func (t *textGridRenderer) setCellRune(str rune, pos int, style, rowStyle TextGr
 	} else if rowStyle != nil && rowStyle.TextColor() != nil {
 		fg = rowStyle.TextColor()
 	}
-	text.Text = string(str)
-	text.Color = fg
-	canvas.Refresh(text)
+	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)
 	bg := color.Color(color.Transparent)
@@ -380,8 +384,10 @@ func (t *textGridRenderer) setCellRune(str rune, pos int, style, rowStyle TextGr
 	} else if rowStyle != nil && rowStyle.BackgroundColor() != nil {
 		bg = rowStyle.BackgroundColor()
 	}
-	rect.FillColor = bg
-	canvas.Refresh(rect)
+	if rect.FillColor != bg {
+		rect.FillColor = bg
+		t.refresh(rect)
+	}
 }
 
 func (t *textGridRenderer) addCellsIfRequired() {
@@ -521,6 +527,11 @@ func (t *textGridRenderer) MinSize() fyne.Size {
 }
 
 func (t *textGridRenderer) 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()
 
@@ -539,6 +550,21 @@ func (t *textGridRenderer) Objects() []fyne.CanvasObject {
 func (t *textGridRenderer) Destroy() {
 }
 
+func (t *textGridRenderer) 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 *textGridRenderer) updateCellSize() {
 	size := fyne.MeasureText("M", theme.TextSize(), fyne.TextStyle{Monospace: true})