php - imagecopyresampled

Question

我正在尝试使用jcrop来允许用户创建其图片的缩略图，它将是190x190 pixels。

jcrop似乎正在工作并向我发送正确的坐标。然而，imagecopyresampled似乎行为非常不可预测，并没有给我我期望的东西。这是我的代码：

$destWidth = $destHeight = 190;
$jpeg_quality = 90;
$path = Yii::app()->basePath."/../images/user/";
$src = $path.$model->image;

$img_src = imagecreatefromjpeg($src);
$img_dest = ImageCreateTrueColor( $destWidth, $destHeight );

imagecopyresampled(
$img_dest, //destination image
$img_src, //source image
0, //top left coordinate of the destination image in x direction
0, //top left coordinate of the destination image in y direction
$_POST['x'], //top left coordinate in x direction of source image that I want copying to start at
$_POST['y'], //top left coordinate in y direction of source image that I want copying to start at
$destWidth, //190, thumbnail width
$destHeight, //190, thumbnail height
$_POST['w'], //how wide the rectangle from the source image we want thumbnailed is
$_POST['h'] //how high the rectangle from the source image we want thumbnailed is
);

imagejpeg($img_dest,$path."thumbs/test.jpg",$jpeg_quality);

我真的很茫然，我已经检查过这四个$_POST变量都是正确的，但由于某些原因我无法得到一个合适的缩略图。我可以肯定的是，缩略图通常放大太多，我希望它从左上角开始没有被使用。

Answer 1

这是我的最终源代码。我发现我的CSS与我的代码冲突，因为它允许最大高度为550px，最大宽度为700px。这导致图像变大以具有不正确的宽度和/或高度。因此，在这些情况下，我必须根据图像的宽高比添加乘数，以及CSS如何调整它的大小。

        $destWidth = $destHeight = 190;
        $jpeg_quality = 90;

        $path = Yii::app()->basePath."/../images/user/";
        $src = $path.$model->image;
        $img_src = imagecreatefromjpeg($src);
        $img_dest = ImageCreateTrueColor( $destWidth, $destHeight );

        //
        // IMPORTANT!! 
        // If you change the max-width or max-height in the css, you MUST change them here too!!
        //
        $maxWidth = 700;
        $maxHeight = 550;

        $srcWidth = imagesx($img_src);
        $srcHeight = imagesy($img_src);
        $srcRatio = $srcWidth/$srcHeight;
        $mult = 1;

        //if the image is wider than the max allowed width AND has a wider aspect ratio than a max height + max width image
        if ($srcWidth > $maxWidth && $srcRatio > $maxWidth/$maxHeight) {
            $mult = $srcWidth/$maxWidth;
        //else if the image is taller than the max height
        } else if ($srcHeight > $maxHeight) {
            $mult = $srcHeight/$maxHeight;
        }

        imagecopyresampled(
            $img_dest, //destination image
            $img_src, //source image
            0, //top left coordinate of the destination image in x direction
            0, //top left coordinate of the destination image in y direction
            $_POST['x']*$mult, //top left coordinate in x direction of source image that I want copying to start at
            $_POST['y']*$mult, //top left coordinate in y direction of source image that I want copying to start at
            $destWidth, //190, thumbnail width
            $destHeight, //190, thumbnail height
            $_POST['w']*$mult, //how wide the rectangle from the source image we want thumbnailed is
            $_POST['h']*$mult //how high the rectangle from the source image we want thumbnailed is
        );

        imagejpeg($img_dest,$path."thumbs/$model->image",$jpeg_quality);