Reimplement cursor as a query operation

internal/ui/driver.go

@@ -90,7 +90,8 @@ func registerBuilder(t menus.MenuType, f builderFunc) {
 type Driver struct {
 	Name string
 
-	menu *assetstore.Menu
+	assets *assetstore.AssetStore
+	menu   *assetstore.Menu
 
 	// UI elements we need to drive
 	clickables []clickable
@@ -100,6 +101,8 @@ type Driver struct {
 	paintables []paintable
 	valueables []valueable
 
+	cursor assetstore.CursorName
+
 	// The cursor in two different coordinate spaces: original, and screen-scaled
 	cursorOrig   image.Point
 	cursorScaled image.Point
@@ -112,10 +115,12 @@ type Driver struct {
 	tooltip string
 }
 
-func NewDriver(menu *assetstore.Menu) (*Driver, error) {
+func NewDriver(assets *assetstore.AssetStore, menu *assetstore.Menu) (*Driver, error) {
 	driver := &Driver{
 		Name: menu.Name,
-		menu: menu,
+
+		assets: assets,
+		menu:   menu,
 	}
 
 	for _, record := range menu.Records() {
@@ -307,6 +312,20 @@ func (d *Driver) Draw(screen *ebiten.Image) error {
 	return nil
 }
 
+func (d *Driver) Cursor() (*ebiten.Image, *ebiten.DrawImageOptions, error) {
+	cursor, err := d.assets.Cursor(d.cursor)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	op := &ebiten.DrawImageOptions{}
+	op.GeoM.Translate(float64(d.cursorOrig.X), float64(d.cursorOrig.Y))
+	op.GeoM.Concat(d.orig2native)
+	op.GeoM.Translate(float64(-cursor.Hotspot.X), float64(-cursor.Hotspot.Y))
+
+	return cursor.Image, op, nil
+}
+
 func (d *Driver) addRecord(record *menus.Record) error {
 	//log.Printf("Adding record: %#+v", record)
 	children := record.Children