我正在使用 ImageMagick 获取上传图片的 3 个版本。
问题是这 3 张新图片没有针对 Web 进行优化，例如Photoshop 中的“保存为 Web 和设备”。差别很大。ImageMagick 生成的文件比 Photoshop 中的网络优化图片大 5 倍。
你能帮我改善这个问题吗？
这是 ImageMagick 部分：
exec($imageMagickPath." uploads/foto.jpg -resize 514x uploads/fl-foto.jpg");
exec($imageMagickPath." uploads/fl-foto.jpg -resize 320x320 uploads/hl-foto.jpg");
exec($imageMagickPath." uploads/fl-foto.jpg -resize x96 -gravity center -crop 96x96+0+0 +repage uploads/th-foto.jpg");
当然，我想在前端使用这 3 个图像，但它们会变大并减慢整个页面的速度。
有什么建议么？
你能试试这个代码。
$im = new Imagick('Penguins.jpg');
$im->cropImage(300, 300, 0, 0);
header("Content-Type: image/png");
echo $im;
如果它不工作。你介意我给你的phpinfo吗？
<?php phpinfo(); ?>
Imagemagick 使用该参数-quality #设置所需的质量，通过该参数您可以通过增加压缩来减小图像大小。您可以在他们的文档中阅读更多相关信息。关于 jpeg 的部分是这样说的：
对于 JPEG 和 MPEG 图像格式，质量为 1（最低图像质量和最高压缩）到 100（最佳质量但最不有效的压缩）。如果可以确定，默认使用输入图像的估计质量，否则使用 92。当质量大于 90 时，色度通道不会下采样。使用 -sampling-factor 选项指定色度下采样的因子。
在您的情况下，这将变为：
exec($imageMagickPath." uploads/foto.jpg -resize 514x -quality 60 uploads/fl-foto.jpg");
<p>
//Function for image re-size and cropping//
if(isset($_POST))
{
//Some Settings
$ThumbSquareSize = 200; //Thumbnail will be 200x200
$BigImageMaxSize = 500; //Image Maximum height or width
$ThumbPrefix = "thumb_"; //Normal thumb Prefix
$DestinationDirectory = 'uploads/'; //Upload Directory ends with / (slash)
$Quality = 90;
// check $_FILES['ImageFile'] array is not empty
// "is_uploaded_file" Tells whether the file was uploaded via HTTP POST
if(!isset($_FILES['ImageFile']) || !is_uploaded_file($_FILES['ImageFile']['tmp_name']))
{
die('Something went wrong with Upload!'); // output error when above checks fail.
}
// Random number for both file, will be added after image name
$RandomNumber = rand(0, 9999999999);
// Elements (values) of $_FILES['ImageFile'] array
//let's access these values by using their index position
$ImageName = str_replace(' ','-',strtolower($_FILES['ImageFile']['name']));
$ImageSize = $_FILES['ImageFile']['size']; // Obtain original image size
$TempSrc = $_FILES['ImageFile']['tmp_name']; // Tmp name of image file stored in PHP tmp folder
$ImageType = $_FILES['ImageFile']['type']; //Obtain file type, returns "image/png", image/jpeg, text/plain etc.
switch(strtolower($ImageType))
{
case 'image/png':
$CreatedImage = imagecreatefrompng($_FILES['ImageFile']['tmp_name']);
break;
case 'image/gif':
$CreatedImage = imagecreatefromgif($_FILES['ImageFile']['tmp_name']);
break;
case 'image/jpeg':
case 'image/pjpeg':
$CreatedImage = imagecreatefromjpeg($_FILES['ImageFile']['tmp_name']);
break;
default:
die('Unsupported File!'); //output error and exit
}
//PHP getimagesize() function returns height-width from image file stored in PHP tmp folder.
//Let's get first two values from image, width and height. list assign values to $CurWidth,$CurHeight
list($CurWidth,$CurHeight)=getimagesize($TempSrc);
//Get file extension from Image name, this will be re-added after random name
$ImageExt = substr($ImageName, strrpos($ImageName, '.'));
$ImageExt = str_replace('.','',$ImageExt);
//remove extension from filename
$ImageName = preg_replace("/\\.[^.\\s]{3,4}$/", "", $ImageName);
//Construct a new image name (with random number added) for our new image.
$NewImageName = $ImageName.'-'.$RandomNumber.'.'.$ImageExt;
//set the Destination Image
$thumb_DestRandImageName = $DestinationDirectory.$ThumbPrefix.$NewImageName; //Thumb name
$DestRandImageName = $DestinationDirectory.$NewImageName; //Name for Big Image
//Resize image to our Specified Size by calling resizeImage function.
if(resizeImage($CurWidth,$CurHeight,$BigImageMaxSize,$DestRandImageName,$CreatedImage,$Quality,$ImageType))
{
//Create a square Thumbnail right after, this time we are using cropImage() function
if(!cropImage($CurWidth,$CurHeight,$ThumbSquareSize,$thumb_DestRandImageName,$CreatedImage,$Quality,$ImageType))
{
echo 'Error Creating thumbnail';
}
/*
At this point we have succesfully resized and created thumbnail image
We can render image to user's browser or store information in the database
For demo, we are going to output results on browser.
*/
echo '<table width="100%" border="0" cellpadding="4" cellspacing="0">';
echo '<tr>';
echo '<td align="center"><img src="uploads/'.$ThumbPrefix.$NewImageName.'" alt="Thumbnail"></td>';
echo '</tr><tr>';
echo '<td align="center"><img src="uploads/'.$NewImageName.'" alt="Resized Image"></td>';
echo '</tr>';
echo '</table>';
/*
// Insert info into database table!
mysql_query("INSERT INTO myImageTable (ImageName, ThumbName, ImgPath)
VALUES ($DestRandImageName, $thumb_DestRandImageName, 'uploads/')");
*/
}else{
die('Resize Error'); //output error
}
}
// This function will proportionally resize image
function resizeImage($CurWidth,$CurHeight,$MaxSize,$DestFolder,$SrcImage,$Quality,$ImageType)
{
//Check Image size is not 0
if($CurWidth <= 0 || $CurHeight <= 0)
{
return false;
}
//Construct a proportional size of new image
$ImageScale = min($MaxSize/$CurWidth, $MaxSize/$CurHeight);
$NewWidth = ceil($ImageScale*$CurWidth);
$NewHeight = ceil($ImageScale*$CurHeight);
$NewCanves = imagecreatetruecolor($NewWidth, $NewHeight);
// Resize Image
if(imagecopyresampled($NewCanves, $SrcImage,0, 0, 0, 0, $NewWidth, $NewHeight, $CurWidth, $CurHeight))
{
switch(strtolower($ImageType))
{
case 'image/png':
imagepng($NewCanves,$DestFolder);
break;
case 'image/gif':
imagegif($NewCanves,$DestFolder);
break;
case 'image/jpeg':
case 'image/pjpeg':
imagejpeg($NewCanves,$DestFolder,$Quality);
break;
default:
return false;
}
//Destroy image, frees memory
if(is_resource($NewCanves)) {imagedestroy($NewCanves);}
return true;
}
}
//This function corps image to create exact square images, no matter what its original size!
function cropImage($CurWidth,$CurHeight,$iSize,$DestFolder,$SrcImage,$Quality,$ImageType)
{
//Check Image size is not 0
if($CurWidth <= 0 || $CurHeight <= 0)
{
return false;
}
if($CurWidth>$CurHeight)
{
$y_offset = 0;
$x_offset = ($CurWidth - $CurHeight) / 2;
$square_size = $CurWidth - ($x_offset * 2);
}else{
$x_offset = 0;
$y_offset = ($CurHeight - $CurWidth) / 2;
$square_size = $CurHeight - ($y_offset * 2);
}
$NewCanves = imagecreatetruecolor($iSize, $iSize);
if(imagecopyresampled($NewCanves, $SrcImage,0, 0, $x_offset, $y_offset, $iSize, $iSize, $square_size, $square_size))
{
switch(strtolower($ImageType))
{
case 'image/png':
imagepng($NewCanves,$DestFolder);
break;
case 'image/gif':
imagegif($NewCanves,$DestFolder);
break;
case 'image/jpeg':
case 'image/pjpeg':
imagejpeg($NewCanves,$DestFolder,$Quality);
break;
default:
return false;
}
//Destroy image, frees memory
if(is_resource($NewCanves)) {imagedestroy($NewCanves);}
return true;
}
}
</p>