add Drawer class that manages the shapes wich extends Canvas (javafx class)

src/main/java/shape/tp5/Drawer.java

+package shape.tp5;
+
+import javafx.scene.canvas.Canvas;
+import javafx.scene.canvas.GraphicsContext;
+import java.util.ArrayList;
+import java.util.List;
+
+public class Drawer extends Canvas {
+    private List<Shape> shapes;
+
+    public Drawer(double width, double height) {
+        super(width, height);
+        shapes = new ArrayList<>();
+    }
+
+    public void add(Shape shape) {
+        shapes.add(shape);
+        repaint();
+    }
+
+    public void repaint() {
+        GraphicsContext gc = getGraphicsContext2D();
+        gc.clearRect(0, 0, getWidth(), getHeight());
+        for (Shape shape : shapes) {
+            shape.paint(gc);
+        }
+    }
+
+    public Shape shapeContaining(double x, double y) {
+        for (Shape shape : shapes) {
+            if (shape.contains(x, y)) {
+                return shape;
+            }
+        }
+        return null;
+    }
+}