图片缩放

最新推荐文章于 2024-04-01 16:42:05 发布

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最新推荐文章于 2024-04-01 16:42:05 发布

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CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/xuehouxt/p/6039913.html

本文介绍了一段PHP代码，用于实现图片的自动缩放功能，并可根据指定的最大宽度和高度进行调整。此外，还展示了如何为图片添加水印。

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//缩放图片
function resizeImage($im, $maxwidth, $maxheight, $name, $filetype)
{
    $pic_width = imagesx($im);
    $pic_height = imagesy($im);

if (($maxwidth && $pic_width > $maxwidth) || ($maxheight && $pic_height > $maxheight)) {
if ($maxwidth && $pic_width > $maxwidth) {
            $widthratio = $maxwidth / $pic_width;
            $resizewidth_tag = true;
        }

if ($maxheight && $pic_height > $maxheight) {
            $heightratio = $maxheight / $pic_height;
            $resizeheight_tag = true;
        }

if ($resizewidth_tag && $resizeheight_tag) {
if ($widthratio < $heightratio)
                $ratio = $widthratio;
else
                $ratio = $heightratio;
        }

if ($resizewidth_tag && !$resizeheight_tag)
            $ratio = $widthratio;
if ($resizeheight_tag && !$resizewidth_tag)
            $ratio = $heightratio;

        $newwidth = $pic_width * $ratio;
        $newheight = $pic_height * $ratio;

if (function_exists("imagecopyresampled")) {
            $newim = imagecreatetruecolor($newwidth, $newheight);
imagecopyresampled($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $pic_width, $pic_height);
        } else {
            $newim = imagecreate($newwidth, $newheight);
imagecopyresized($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $pic_width, $pic_height);
        }

$name = $name . $filetype;
imagejpeg($newim, $name);
imagedestroy($newim);
    } else {
$name = $name . $filetype;
imagejpeg($im, $name);
    }
}


用法如下
$img=imagecreatefromjpeg('./uploads/1.jpg');

//生成缩放图片的名字
$imgname = md5(time());
resizeImage($im, 560, 996, $imgname, '.jpg');
$logo = imagecreatefromjpeg('./' . $imgname . '.jpg');

ImageCopy($img, $logo, 40, 40, 0, 0, 560, 560);

转载于:https://www.cnblogs.com/xuehouxt/p/6039913.html