最终决定基本使用这个：http://shiftingpixel.com/2008/03/03/smart-image-resizer/。它可以处理一切，我已经关闭了缓存并在管理控制器中执行此操作：
$image = file_get_contents(SITE_ADMIN_IMAGE.'/SmartImage.php?width='.$this->thumb_width.'&height='.$this->thumb_height.'&image=/images/'.$this->image_directory.'/'.$formData['image_url'].'');
file_put_contents(ROOT_PATH.'/public/images/'.$this->image_directory.'/thumb/'.$formData['image_url'], $image);
编辑：我发现这个方法可行，但是它会产生非常锐利的边缘，看起来不太自然。
imagecolortransparent($dstImage, $background);
imagealphablending($dstImage, false);
$colorTransparent = imagecolorallocatealpha($dstImage, 0, 0, 0, 127);
imagefill($dstImage, 0, 0, $colorTransparent);
imagesavealpha($dstImage, true);
imagepng($dstImage, $toWhere);
有什么想法吗？
你好，
我的课程有两个问题，基本上jpeg图像的质量相当差，但我不确定是否是由于我的比例调整造成的。理想情况下，我希望这个类在图像大小方面非常严格，并对它们进行裁剪，但我无法理解。
我主要的问题是png总是有黑色背景，有人遇到过这种情况吗？
<?php
class OpenSource_ImageResize {
function __construct($theFile, $toWhere, $mime, $extension, $newWidth, $newHeight) {
if ($mime == NULL) {
$mime = getimagesize($theFile);
$mime = $mime['mime'];
}
if ($mime == 'image/jpeg') {
$size = getimagesize($theFile);
if ($size[0] > $newWidth || $size[1] > $newHeight) {
$sourceImage = imagecreatefromjpeg($theFile);
} else {
return copy($theFile, $toWhere);
throw new exception('Could not create jpeg');
return false;
}
} else if ($mime == 'image/png') {
$size = getimagesize($theFile);
if ($size[0] > $newWidth || $size[1] > $newHeight) {
$sourceImage = imagecreatefrompng($theFile);
} else {
return copy($theFile, $toWhere);
//throw new exception('Could not create png');
return false;
}
} else if ($mime == 'image/gif') {
$size = getimagesize($theFile);
if ($size[0] > $newWidth || $size[1] > $newHeight) {
$sourceImage = imagecreatefromgif ($theFile);
} else {
return copy($theFile, $toWhere);
//throw new exception('Could not create gif');
return false;
}
} else {
throw new exception('Not a valid mime type');
return false;
}
$oldX = imageSX($sourceImage);
$oldY = imageSY($sourceImage);
if ($newWidth == NULL) {
$thumbHeight = $newHeight;
$thumbWidth = round($newHeight/($oldY/$oldX));
} else
if ($oldX > $oldY) {
$thumbWidth = $newWidth;
$thumbHeight = $oldY * ($newHeight/$oldX);
}
if ($oldX < $oldY) {
$thumbWidth = round($newHeight/($oldY/$oldX));
$thumbHeight = $newHeight;
}
if ($oldX == $oldY) {
$thumbWidth = $newWidth;
$thumbHeight = $newHeight;
}
if (!gd_info()) {
$dstImage = ImageCreate($thumbWidth, $thumbHeight);
imagecopyresized($dstImage, $sourceImage, 0, 0, 0, 0, $thumbWidth, $thumbHeight, $oldX, $oldY);
} else {
$dstImage = ImageCreateTrueColor($thumbWidth, $thumbHeight);
imagecopyresampled($dstImage, $sourceImage, 0, 0, 0, 0, $thumbWidth, $thumbHeight, $oldX, $oldY);
}
if ($mime == 'image/png') {
$xparent = imagecolorresolvealpha($dstImage, 255,2,240, 0) ;
imagecolortransparent($dstImage,$xparent);
imagealphablending($dstImage,true);
imagepng($dstImage, $toWhere);
} else if ($mime == 'image/jpeg') {
imagejpeg($dstImage, $toWhere);
} else if ($mime == 'image/gif') {
imagegif ($dstImage, $toWhere);
}
imagedestroy($dstImage);
imagedestroy($sourceImage);
return true;
}
}