I was referring example of Imagick::distortImage
Now look at Example 1 which generates following image
I got confused while looking at below part of code.
/* Control points for the distortion */
$controlPoints = array( 10, 10,
10, 5,
10, $im->getImageHeight() - 20,
10, $im->getImageHeight() - 5,
$im->getImageWidth() - 10, 10,
$im->getImageWidth() - 10, 20,
$im->getImageWidth() - 10, $im->getImageHeight() - 10,
$im->getImageWidth() - 10, $im->getImageHeight() - 30);
Now can anybody tell me what this 16 points exactly means ?