我正在尝试将上传的图像缩小到固定的高度和高度,例如:宽度= 200px和高度200px 。我试图用固定的宽度缩小图像的宽度,并用新的宽度计算新的高度。现在我想要实现的是将宽度和高度缩小到固定尺寸宽度= 200px&身高= 200px
我的HTML:
<form action="do_upload.php" method="post" enctype="multipart/form-data">
<input type="file" name="upload_image">
<br/>
<br/>
<input type="submit" value="submit">
</form>
do_upload.php:
<?php
move_uploaded_file($_FILES["upload_image"]["tmp_name"], "uploads/" . $_FILES["upload_image"]["name"]);
$image_path = "uploads/" . $_FILES["upload_image"]["name"];
$src = imagecreatefromjpeg($image_path);
list($width, $height) = getimagesize($image_path);
$newwidth = 200;
$newheight = ($height / $width) * $newwidth;
$tmp = imagecreatetruecolor($newwidth, $newheight);
imagecopyresampled($tmp, $src, 0, 0,0,0,$newwidth,$newheight, $width, $height);
imagejpeg($tmp, "uploads/small.jpeg", 100);
imagedestroy($src);
imagedestroy($tmp);
?>
这对我来说很好,缩小了图像。请指导我如何缩小所有图像(jpeg,png,gif等)到固定的宽度和高度。只是引导我朝着我将要做的方向。如果有人能够通过示例解释或为我编辑代码,那将会非常棒。提前致谢
答案 0 :(得分:0)
您可以看到上面的评论来回答关于如何处理小于200的维度和宽高比的问题。话虽如此,我可以继续回答关于如何扩展任何一个维度的问题。基本上问题很简单。
首先确定现有图像的宽度或高度是否为更大的尺寸。在此基础上,您可以确定图像的缩放系数,然后将该缩放系数应用于这两个维度。
在代码中可能看起来像:
$src = imagecreatefromjpeg($image_path);
list($width, $height) = getimagesize($image_path);
$max_dimension = 200;
if($width >= $height) {
// scale on width
$scaling_factor = $width / $max_dimension;
} else {
// scale on height
$scaling_factor = $height / $max_dimension;
}
$new_width = $width / $scaling_factor;
$new_height = $height / $scaling_factor;
一个更通用的解决方案,可以让你指定任何可以缩放的矩形(即不同的最大高度和宽度)。
$max_width = 200;
$max_height = 150;
// determine which dimension must be scaled to fit target size
$width_scaling_factor = $width / $max_width;
$height_scaling_factor = $height / $max_height;
if($width_scaling_factor >= $height_scaling_factor) {
$scaling_factor = $width_scaling_factor;
} else {
$scaling_factor = $height_scaling factor;
}
$new_width = $width / $scaling_factor;
$new_height = $height / $scaling_factor;