JavaFX - draw line with arrow (Canvas)
<p>I have problem with rewrite this code to JavaFX:</p>

<pre><code>private final int ARR_SIZE = 8;

void drawArrow(Graphics g1, int x1, int y1, int x2, int y2) {
    Graphics2D g = (Graphics2D) g1.create();
    g.setPaint(Color.BLACK);

    double dx = x2 - x1, dy = y2 - y1;
    double angle = Math.atan2(dy, dx);
    int len = (int) Math.sqrt(dx * dx + dy * dy);
    AffineTransform at = AffineTransform.getTranslateInstance(x1, y1);
    at.concatenate(AffineTransform.getRotateInstance(angle));
    g.transform(at);

    g.drawLine(0, 0, len, 0);
    g.fillPolygon(new int[] { len, len - ARR_SIZE, len - ARR_SIZE, len }, new int[] { 0, -ARR_SIZE, ARR_SIZE, 0 },
            4);
}
</code></pre>

<p>my solution is not working correctly because the result of code: </p>

<pre><code>drawArrow(gc, 200, 50, 50, 50);
</code></pre>

<p>is</p>

<p><a href="https://i.stack.imgur.com/v9bDW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/v9bDW.png" alt="arrow"></a>.</p>

<p>Expected result is</p>

<p><a href="https://i.stack.imgur.com/lS5Js.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/lS5Js.png" alt="arrow2"></a>.</p>

<pre><code>private final int ARR_SIZE = 8;

void drawArrow(GraphicsContext gc, int x1, int y1, int x2, int y2) {

    gc.setFill(Color.BLACK);

    double dx = x2 - x1, dy = y2 - y1;
    double angle = Math.atan2(dy, dx);
    int len = (int) Math.sqrt(dx * dx + dy * dy);

    Affine affine = new Affine(Affine.translate(x1, y1));
    affine.createConcatenation(Affine.rotate(angle, 0, 0));
    gc.setTransform(affine);

    gc.strokeLine(0, 0, len, 0);
    gc.fillPolygon(new double[]{len, len - ARR_SIZE, len - ARR_SIZE, len}, new double[]{0, -ARR_SIZE, ARR_SIZE, 0},
            4);

}
</code></pre>

<p>can you help me pls ?</p>