PHP uses GD to create thumbnails that maintain aspect ratios

/** * Create a thumbnail image from $inputFileName no taller or wider than * $maxSize. Returns the new image resource or false on error. * Author:mthorn.net */ function thumbnail ($inputFileName, $maxSize = 100) { $info = getimagesize ($inputFileName); $type = Isset ($info [' type '])? $info [' type ']: $info [2]; Check support of file type if (! ( Imagetypes () & $type)) { Server does not support file type return false; } $width = Isset ($info [' width '])? $info [' width ']: $info [0]; $height = Isset ($info [' height '])? $info [' Height ']: $info [1]; Calculate aspect ratio $wRatio = $maxSize/$width; $hRatio = $maxSize/$height; Using imagecreatefromstring would automatically detect the file type $sourceImage = imagecreatefromstring (file_get_contents ($inputFileName)); Calculate a proportional width and height no larger than the max size. if ($width <= $maxSize) && ($height <= $maxSize)) { Input is smaller than thumbnail return $sourceImage; } ElseIf (($wRatio * $height) < $maxSize) { Image is Horizontal $tHeight = Ceil ($wRatio * $height); $tWidth = $maxSize; } Else { Image is vertical $tWidth = Ceil ($hRatio * $width); $tHeight = $maxSize; } $thumb = Imagecreatetruecolor ($tWidth, $tHeight); if ($sourceImage = = = False) { Could Not load image return false; } Copy resampled makes a smooth thumbnail Imagecopyresampled ($thumb, $sourceImage, 0, 0, 0, 0, $tWidth, $tHeight, $width, $height); Imagedestroy ($sourceImage); return $thumb; } /** * Save the image to a file. Type is determined from the extension. * $quality is only used for JPEGs. * Author:mthorn.net */ function Imagetofile ($im, $fileName, $quality = 80) { if (! $im | | file_exists ($FILENAME)) { return false; } $ext = Strtolower (substr ($fileName, Strrpos ($fileName, '. '))); Switch ($ext) { Case '. gif ': Imagegif ($im, $fileName); Break Case '. jpg ': Case '. JPEG ': Imagejpeg ($im, $fileName, $quality); Break Case '. png ': Imagepng ($im, $fileName); Break Case '. bmp ': Imagewbmp ($im, $fileName); Break Default return false; } return true; } $im = Thumbnail (' temp.jpg ', 100); Imagetofile ($im, ' temp-thumbnail.jpg '); Copy Code

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