Fill arrow head goes off in line in canvas Android

Question

The arrow head with stroke working fine in canvas, but the filled arrow head is not drawing at the right position ,Here is my code for draw arrow.

 private void drawArrow(Point startPoint, Point endPoint, Paint paint, Canvas mCanvas) {
        Path mPath = new Path();
        float deltaX = endPoint.x - startPoint.x;
        float deltaY = endPoint.y - startPoint.y;
        //float frac = (float) 0.1;
        int ARROWHEAD_LENGTH = 15;
        float sideZ = (float) Math.sqrt(deltaX * deltaX + deltaY * deltaY);
        float frac = ARROWHEAD_LENGTH < sideZ ? ARROWHEAD_LENGTH / sideZ : 1.0f;
        float point_x_1 = startPoint.x + (float) ((1 - frac) * deltaX + frac * deltaY);
        float point_y_1 = startPoint.y + (float) ((1 - frac) * deltaY - frac * deltaX);
        float point_x_2 = endPoint.x;
        float point_y_2 = endPoint.y;
        float point_x_3 = startPoint.x + (float) ((1 - frac) * deltaX - frac * deltaY);
        float point_y_3 = startPoint.y + (float) ((1 - frac) * deltaY + frac * deltaX);
        mPath.moveTo(point_x_1, point_y_1);
        mPath.lineTo(point_x_2, point_y_2);
        mPath.lineTo(point_x_3, point_y_3);
        //mPath.lineTo(point_x_1, point_y_1);
        //mPath.lineTo(point_x_1, point_y_1);
        mCanvas.drawPath(mPath, paint);
        invalidate();
    }

Answer 1

to resolve this issue, I have placed the end line to the center of triangle.

You can do it with this formula :

float endLineX = (point_x_1 + point_x_2 + point_x_3) / 3;
float endLineY = (point_y_1 + point_y_2 + point_y_3) / 3;

Voilà