import java.util.ArrayList;

import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;

public class MyCanvas extends Canvas {
    
    private double width, height;  // Canvas has them, as private
    private GraphicsContext gc;    // Canvas has it, as private
    
    private ArrayList<Stroke> strokes;
    
    public MyCanvas(double w, double h) {
        super(w, h);
        
        width  = w;
        height = h;
        
        gc = super.getGraphicsContext2D();
        
        strokes = new ArrayList<>();
    }
    
    public void addStroke(Stroke s) {
        strokes.add(s);
        
        // must repaint
        paint();
    }
    
    public void clearCanvas() {
        strokes.clear();
        
        paint();
    }
    
    public void paint() {
        // clear canvas
        gc.clearRect(0, 0, width, height);
        
        // draw all strokes in the arraylist
        for (Stroke s : strokes) {
            s.draw(gc);
        }
    }
    
}