/**
* 裁剪函数，两个参数表示需要的长宽，可以为百分比，表示目标大小为现在的百分之多少
* @param number $width
* @param number $height
* @return GdImage
*/
public function crop($width, $height)
{
$sourceWidth = $this->image->getWidth();
$sourceHeight = $this->image->getHeight();
if ($width < 1) {
$width = $sourceWidth * $width;
}
if ($height < 1) {
$height = $sourceHeight * $height;
}
$sourceHWRatio = $sourceHeight / $sourceWidth;
$targetHWRatio = $height / $width;
if ($sourceHWRatio > $targetHWRatio) {
$ratio = 1.0 * $width / $sourceWidth;
} else {
$ratio = 1.0 * $height / $sourceHeight;
}
$tmp_w = (int) ($width / $ratio);
$tmp_h = (int) ($height / $ratio);
$tmp_x = (int) ($sourceWidth - $tmp_w) / 2;
$tmp_y = (int) ($sourceHeight - $tmp_h) / 2;
$targetImage = $this->image->initNew($width, $height);
imagecopyresampled($targetImage->getImage(), $this->image->getImage(), 0, 0, $tmp_x, $tmp_y, $width, $height, $tmp_w, $tmp_h);
return $targetImage;
}