title: Drawing a circle with Pythagorean equation
body: <p>I HAVE to draw a circle with the following code 
  (check if point is on the circle). </p>
  
  <pre><code>int rad=10;
  // i=x,j=y
  for (int j=ymid-rad;j&lt;=ymid+rad;j++){
     for (int i=xmid-rad;i&lt;=xmid+rad;i++){
        if (((i-xmid)*(i-xmid)+(j-ymid)*(j-ymid)) == rad*rad)
           Image1-&gt;Canvas-&gt;Pixels[i][j]=clRed;
     }
  }
  </code></pre>
  
  <p>However it only draws a few points of the circle.
  What am I doing wrong?</p>
  
  <p>Thank you.</p>