Question

如果Facebook上传的图片高于2 megapixels，则会调整其大小。例如我的图片是3264x1832，Facebook会将其调整为2048x1529。因此，如果长的是哪条边，则图像会缩小到边缘为2048px。测量到另一边缘减少的减少量。之后，压缩图像尺寸的图像较小。该方法在大图像中很小心。我将做我的mvc 5项目的方法，如何找到一个c＃，jquery，javascrip，php插件或api这样的方法？

Answer 1

这需要在您的php服务器上安装GD，并期望path/to/temp/image.jpg是上传图像的位置。如果上传不受支持的文件类型或损坏的图片，您可能需要使用try/catch。

以下是主程序代码：

$maxWidth = 2048;
$maxHeight = 2048;
$compression = 75;

//Create an image object out of the uploaded file
$sourceImage = imagecreatefromjpeg('path/to/temp/image.jpg'); 

//Resize the image
$resizedImage = ImageSizeDown($sourceImage, $maxWidth, $maxHeight);

//Save the image as a jpeg to it's new home
imagejpeg($resizedImage, 'path/to/permanent/image.jpg', $compression);

这些是其他必要的功能：

//Function for resizing an image if it's larger than a certain resolution
function ImageSizeDown($image, $maxWidth, $maxHeight) {
    $maxAspect = $maxWidth / $maxHeight;
    $sourceWidth = imagesx($image);
    $sourceHeight = imagesy($image);
    $sourceAspect = $sourceWidth / $sourceHeight;
    if($sourceWidth > $maxWidth || $sourceHeight > $maxHeight) {
        if($maxAspect > $sourceAspect) {
            $newWidth = (int)$maxWidth;
            $newHeight = (int)($maxWidth / $sourceWidth * $sourceHeight);
        }
        else { 
            $newHeight = (int)$maxHeight;
            $newWidth = (int)($maxHeight / $sourceHeight * $sourceWidth);
        }
        $result = TransparentImage($newWidth, $newHeight);
        imagesavealpha($image, true);
        imagealphablending($image, false);
        imagecopyresampled($result, $image, 0, 0, 0, 0, $newWidth, $newHeight, $sourceWidth, $sourceHeight);
        return $result;
    }
    else return $image; //Image is already small enough
}

//Handy function for creating a base for most any image stuff, especially PNG
function TransparentImage($x, $y) { 
    $image = imagecreatetruecolor($x, $y);
    imagesavealpha($image, true);
    imagealphablending($image, false);
    $transparent = imagecolorallocatealpha($image, 200, 200, 200, 127);
    imagefill($image, 0, 0, $transparent);
    return $image;
}

我现在不能在任何地方测试这个，所以我的纵横比数学可能会转换。

Facebook风格上传图像调整大小和压缩

1 个答案: