Added simple pointer tool

src/components/map/MapPointer.js

@@ -0,0 +1,81 @@
+import React, { useContext, useEffect } from "react";
+import { Group, Circle } from "react-konva";
+
+import MapInteractionContext from "../../contexts/MapInteractionContext";
+import MapStageContext from "../../contexts/MapStageContext";
+
+import { getStrokeWidth } from "../../helpers/drawing";
+import { getRelativePointerPositionNormalized } from "../../helpers/konva";
+
+import colors from "../../helpers/colors";
+
+function MapPointer({
+  gridSize,
+  active,
+  position,
+  onPointerDown,
+  onPointerMove,
+  onPointerUp,
+  visible,
+}) {
+  const { mapWidth, mapHeight, interactionEmitter } = useContext(
+    MapInteractionContext
+  );
+  const mapStageRef = useContext(MapStageContext);
+
+  // const [isBrushDown, setIsBrushDown] = useState(false);
+  // const [brushPosition, setBrushPosition] = useState({ x: 0, y: 0 });
+
+  useEffect(() => {
+    if (!active) {
+      return;
+    }
+
+    const mapStage = mapStageRef.current;
+
+    function getBrushPosition() {
+      const mapImage = mapStage.findOne("#mapImage");
+      return getRelativePointerPositionNormalized(mapImage);
+    }
+
+    function handleBrushDown() {
+      onPointerDown && onPointerDown(getBrushPosition());
+    }
+
+    function handleBrushMove() {
+      onPointerMove && onPointerMove(getBrushPosition());
+    }
+
+    function handleBrushUp() {
+      onPointerMove && onPointerUp({ x: 0, y: 0 });
+    }
+
+    interactionEmitter.on("dragStart", handleBrushDown);
+    interactionEmitter.on("drag", handleBrushMove);
+    interactionEmitter.on("dragEnd", handleBrushUp);
+
+    return () => {
+      interactionEmitter.off("dragStart", handleBrushDown);
+      interactionEmitter.off("drag", handleBrushMove);
+      interactionEmitter.off("dragEnd", handleBrushUp);
+    };
+  });
+
+  const size = getStrokeWidth(2, gridSize, mapWidth, mapHeight);
+
+  return (
+    <Group>
+      {visible && (
+        <Circle
+          x={position.x * mapWidth}
+          y={position.y * mapHeight}
+          fill={colors.red}
+          width={size}
+          height={size}
+        />
+      )}
+    </Group>
+  );
+}
+
+export default MapPointer;