Imagick::contrastImage

Both xyking and quickshiftin include errors in their comments. xyking's error is in looping through negative numbers. quickshifting is incorrect in stating that 0 *increases* contrast (it does not - it decreases it).Here is a (tested, working) method to increment or decrement contrast:<?phpclass Images {public function contrastImage($contrast, $imagePath){$this->image = new Imagick();$this->image->readImage($imagePath);                      if ($contrast > 0){                for ($i = 1; $i < $contrast; $i++){                    $this->image->contrastImage(1);                }            }else if ($contrast <= 0) {                for ($i = 0; $i > $contrast; $i--) {                    $this->image->contrastImage(0);                }            }     }}?>

Tip: <?php$image->contrastImage(1); //Increase contrast once$image->contrastImage(1); //Increase contrast more$image->contrastImage(1); //Increase contrast even more$image->contrastImage(0); //Decrease contrast once$image->contrastImage(0); //Decrease contrast more$image->contrastImage(0); //Decrease contrast even more//This could be made into a function like this:public function contrast($level) {        $level = (int)$level;        if ($level < -10) {            $level = -10;        } else if ($level > 10) {            $level = 10;        }        if ($level > 0) {            for ($i = 0; $i < $level; $i++) {                $this->image->contrastImage(1);            }        } else if ($level < 0) {            for ($i = $level; $i > 0; $i--) {                $this->image->contrastImage(0);            }        }    }?>

xyking's comment is wrong so be careful if you read it. You pass a value of 0 to *increase* the contrast.