ui: basic map scroller

client/canvas.go

@@ -0,0 +1,87 @@
+package client
+
+import (
+	"image/color"
+
+	"fyne.io/fyne/v2"
+	"fyne.io/fyne/v2/canvas"
+	"fyne.io/fyne/v2/widget"
+)
+
+type interactiveRaster struct {
+	widget.BaseWidget
+
+	edit      *editor
+	min       fyne.Size
+	raster    *canvas.Raster
+	onLayout  func(fyne.Size)
+	onDragged func(*fyne.DragEvent)
+	onDragEnd func()
+}
+
+func (r *interactiveRaster) SetMinSize(size fyne.Size) {
+	r.min = size
+	r.Resize(size)
+}
+
+func (r *interactiveRaster) MinSize() fyne.Size {
+	return r.min
+}
+
+func (r *interactiveRaster) CreateRenderer() fyne.WidgetRenderer {
+	return &rasterWidgetRender{
+		canvas:   r,
+		bg:       canvas.NewRasterWithPixels(bgPattern),
+		onLayout: r.onLayout,
+	}
+}
+
+// Tapped is a left-click event
+func (r *interactiveRaster) Tapped(ev *fyne.PointEvent) {
+	x, y := int(ev.Position.X), int(ev.Position.Y)
+	size := r.raster.Size()
+	if x >= int(size.Width) || y >= int(size.Height) {
+		return
+	}
+}
+
+// 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 {
+	r := &interactiveRaster{
+		// raster:    canvas.NewRaster(edit.draw),
+		raster:    raster,
+		edit:      edit,
+		onLayout:  onLayout,
+		onDragged: onDragged,
+		onDragEnd: onDragEnd,
+	}
+	r.ExtendBaseWidget(r)
+	return r
+}
+
+func bgPattern(x, y, _, _ int) color.Color {
+	const boxSize = 25
+
+	if (x/boxSize)%2 == (y/boxSize)%2 {
+		return color.Gray{Y: 58}
+	}
+
+	return color.Gray{Y: 84}
+}
+
+func (r *interactiveRaster) Dragged(e *fyne.DragEvent) {
+	if r.onDragged == nil {
+		return
+	}
+
+	r.onDragged(e)
+}
+
+func (r *interactiveRaster) DragEnd() {
+	if r.onDragEnd == nil {
+		return
+	}
+	r.onDragEnd()
+}