php怎么将图片压缩成指定大小

2020-11-13 10:39 PHP在线

1、按照指定的尺寸压缩图片

/**     * 按照指定的尺寸压缩图片     * @param $source_path  原图路径     * @param $target_path  保存路径     * @param $imgWidth     目标宽度     * @param $imgHeight    目标高度     * @return bool|string     */    function resize_image($source_path,$target_path,$imgWidth,$imgHeight){        $source_info = getimagesize($source_path);        $source_mime = $source_info['mime'];        switch ($source_mime)        {            case 'image/gif':                $source_image = imagecreatefromgif($source_path);                break;
case 'image/jpeg': $source_image = imagecreatefromjpeg($source_path); break;
case 'image/png': $source_image = imagecreatefrompng($source_path); break;
default: return false; break; } $target_image = imagecreatetruecolor($imgWidth, $imgHeight); //创建一个彩色的底图 imagecopyresampled($target_image, $source_image, 0, 0, 0, 0, $imgWidth, $imgHeight, $source_info[0], $source_info[1]); //保存图片到本地 $dir = '../'.$target_path. '/'. date("Ymd") . '/'; if (!is_dir($dir)) { mkdir($dir, 0777); }
$fileName = $dir.date("YmdHis").uniqid().'.jpg'; if(!imagejpeg($target_image,'./'.$fileName)){ $fileName = ''; } imagedestroy($target_image); return $fileName; }

2、按照比例裁剪图片

/**     * 图像裁剪     * @param $title string 原图路径     * @param $content string 需要裁剪的宽     * @param $encode string 需要裁剪的高     * @param $target_path string 需要保存的路径     */    function image_cropper($source_path, $target_width, $target_height, $target_path){        $source_info     = getimagesize($source_path);        $source_width     = $source_info[0];        $source_height     = $source_info[1];        $source_mime     = $source_info['mime'];        $source_ratio     = $source_height / $source_width;        $target_ratio     = $target_height / $target_width;

if ($source_ratio > $target_ratio) // 源图过高 { $cropped_width = $source_width; $cropped_height = $source_width * $target_ratio; $source_x = 0; $source_y = ($source_height - $cropped_height) / 2;
}elseif ($source_ratio < $target_ratio){ // 源图过宽
$cropped_width = $source_height / $target_ratio; $cropped_height = $source_height; $source_x = ($source_width - $cropped_width) / 2; $source_y = 0; }else{ // 源图适中
$cropped_width = $source_width; $cropped_height = $source_height; $source_x = 0; $source_y = 0; }
switch ($source_mime) { case 'image/gif': $source_image = imagecreatefromgif($source_path); break;
case 'image/jpeg': $source_image = imagecreatefromjpeg($source_path); break;
case 'image/png': $source_image = imagecreatefrompng($source_path); break;
default: return false; break; }
$target_image = imagecreatetruecolor($target_width, $target_height); $cropped_image = imagecreatetruecolor($cropped_width, $cropped_height);
// 裁剪 imagecopy($cropped_image, $source_image, 0, 0, $source_x, $source_y, $cropped_width, $cropped_height); // 缩放 imagecopyresampled($target_image, $cropped_image, 0, 0, 0, 0, $target_width, $target_height, $cropped_width, $cropped_height);
//保存图片到本地(两者选一) $dir = '../../'.$target_path. '/'. date("Ymd") . '/'; if (!is_dir($dir)) { mkdir($dir, 0777); }
$fileName = $dir.date("YmdHis").uniqid().'.jpg'; if(!imagejpeg($target_image,'./'.$fileName)){ $fileName = ''; } imagedestroy($target_image); return $fileName; }

3. 图片上添加二维码图片

$a = picMerge('./bb.jpg','./dd.jpg',$top,$left,$qrwidth,$qrheight,$pct,'ee.jpg');var_dump($a);
function picMerge($dstPath,$srcPath,$dstX=0,$dstY=0,$srcX=0,$srcY=0,$pct=100,$filename=''){ //创建图片的实例 $dst = imagecreatefromstring(file_get_contents($dstPath)); $src = imagecreatefromstring(file_get_contents($srcPath)); //获取水印图片的宽高 list($src_w, $src_h) = getimagesize($srcPath); //将水印图片复制到目标图片上,最后个参数50是设置透明度,这里实现半透明效果 imagecopymerge($dst, $src, $dstX, $dstY, 0, 0, $src_w, $src_h, $pct); //如果水印图片本身带透明色,则使用imagecopy方法 //imagecopy($dst, $src, 10, 10, 0, 0, $src_w, $src_h); //输出图片 list($dst_w, $dst_h, $dst_type) = getimagesize($dstPath); switch ($dst_type) { case 1://GIF if(!$filename){ header('Content-Type: image/gif'); imagegif($dst); }else{ imagegif($dst,$filename); } break; case 2://JPG if(!$filename){ header('Content-Type: image/jpeg'); imagejpeg($dst); }else{ imagejpeg($dst,$filename); } break; case 3://PNG if(!$filename){ header('Content-Type: image/png'); imagepng($dst); }else{ imagepng($dst,$filename); } break; default: break; } imagedestroy($dst); imagedestroy($src); return $filename;}

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