PHP 图像复制重新采样问题 - php imagecopyresampled issue

php imagecopyresampled issue

我在图像复制重新采样时遇到了一些问题，主要是图像缩放不正确，图像的位置错误并且边缘周围有黑色边框。

我设置了以下变量

    $tW = $width; // Original width of image
    $tH = $height; // Orignal height of image
    $w = postvar; // New width
    $h = postvar; // New height
    $x = postvar; // New X pos
    $y = postvar; // New Y pos

然后运行以下命令

    $tn = imagecreatetruecolor($w, $h);
    $image = imagecreatefromjpeg('filepathhere.jpeg');
    imagecopyresampled($tn, $image, 0, 0, $x, $y, $w, $h, $tW, $tH);

如果有人有任何线索，那将是很大的帮助！谢谢

这里有几个问题。首先，您不应使用指定的新高度和宽度创建新图像，而应根据原始图像的比例计算它们应该是什么，否则缩放的图像将失真。例如，下面的代码将创建一个适当调整大小的图像，该图像将适合给定的$w x $h矩形：

$tW = $width;    //original width
$tH = $height;   //original height
$w = postvar;
$h = postvar;
if($w == 0 || $h == 0) {
    //error...
    exit;
}
if($tW / $tH > $w / $h) {
    // specified height is too big for the specified width
    $h = $w * $tH / $tW;
}
elseif($tW / $tH < $w / $h) {
    // specified width is too big for the specified height
    $w = $h * $tW / $tH;
}
$tn = imagecreatetruecolor($w, $h);  //this will create it with black background
imagefill($tn, 0, 0, imagecolorallocate($tn, 255, 255, 255));    //fill it with white;
//now you can copy the original image:
$image = imagecreatefromjpeg('filepathhere.jpeg');
//next line will just create a scaled-down image
imagecopyresampled($tn, $image, 0, 0, 0, 0, $w, $h, $tW, $tH);

现在，如果您只想复制原始图像的某个部分，例如从坐标($x, $y)复制到右上角，那么您需要将其包含在计算中：

$tW = $width - $x;    //original width
$tH = $height - $y;   //original height
$w = postvar;
$h = postvar;
if($w == 0 || $h == 0) {
    //error...
    exit;
}
if($tW / $tH > $w / $h) {
    // specified height is too big for the specified width
    $h = $w * $tH / $tW;
}
elseif($tW / $tH < $w / h) {
    // specified width is too big for the specified height
    $w = $h * $tW / $tH;
}
$tn = imagecreatetruecolor($w, $h);  //this will create it with black background
imagefill($tn, 0, 0, imagecolorallocate($tn, 255, 255, 255));    //fill it with white;
//now you can copy the original image:
$image = imagecreatefromjpeg('filepathhere.jpeg');
//next line will create a scaled-down portion of the original image from coordinates ($x, $y) to the lower-right corner
imagecopyresampled($tn, $image, 0, 0, $x, $y, $w, $h, $tW, $tH);

如果您提供有关您要实现的目标的更多详细信息，我可能会进一步提供帮助。