no-wrap option; pivoted exponential zoom

client/canvas.go

@@ -11,12 +11,13 @@ import (
 type interactiveRaster struct {
 	widget.BaseWidget
 
-	edit      *editor
-	min       fyne.Size
-	raster    *canvas.Raster
-	onLayout  func(fyne.Size)
-	onDragged func(*fyne.DragEvent)
-	onDragEnd func()
+	edit       *editor
+	min        fyne.Size
+	raster     *canvas.Raster
+	onLayout   func(fyne.Size)
+	onScrolled func(*fyne.ScrollEvent)
+	onDragged  func(*fyne.DragEvent)
+	onDragEnd  func()
 }
 
 func (r *interactiveRaster) SetMinSize(size fyne.Size) {
@@ -48,14 +49,15 @@ func (r *interactiveRaster) Tapped(ev *fyne.PointEvent) {
 // TappedSecondary is a right-click event
 func (r *interactiveRaster) TappedSecondary(*fyne.PointEvent) {}
 
-func newInteractiveRaster(edit *editor, raster *canvas.Raster, onLayout func(fyne.Size), onDragged func(*fyne.DragEvent), onDragEnd func()) *interactiveRaster {
+func newInteractiveRaster(edit *editor, raster *canvas.Raster, onLayout func(fyne.Size), onScrolled func(*fyne.ScrollEvent), onDragged func(*fyne.DragEvent), onDragEnd func()) *interactiveRaster {
 	r := &interactiveRaster{
 		// raster:    canvas.NewRaster(edit.draw),
-		raster:    raster,
-		edit:      edit,
-		onLayout:  onLayout,
-		onDragged: onDragged,
-		onDragEnd: onDragEnd,
+		raster:     raster,
+		edit:       edit,
+		onLayout:   onLayout,
+		onScrolled: onScrolled,
+		onDragged:  onDragged,
+		onDragEnd:  onDragEnd,
 	}
 	r.ExtendBaseWidget(r)
 	return r
@@ -71,6 +73,13 @@ func bgPattern(x, y, _, _ int) color.Color {
 	return color.Gray{Y: 84}
 }
 
+func (r *interactiveRaster) Scrolled(e *fyne.ScrollEvent) {
+	if r.onScrolled == nil {
+		return
+	}
+	r.onScrolled(e)
+}
+
 func (r *interactiveRaster) Dragged(e *fyne.DragEvent) {
 	if r.onDragged == nil {
 		return