Posted in PHP onMay 06, 2014
把下面的代码直接复制,新建一个文件叫做 thumbnailimage.php ,文件名最好不要用大写,把以下代码复制进去:
<?php define ( 'MAX_IMG_SIZE', 100000 ); // Supported image types define ( 'THUMB_JPEG', 'image/jpeg' ); define ( 'THUMB_PNG', 'image/png' ); define ( 'THUMB_GIF', 'image/gif' ); // Interlacing modes define ( 'INTERLACE_OFF', 0 ); define ( 'INTERLACE_ON', 1 ); // Output modes define ( 'STDOUT', '' ); // Empty constants define ( 'NO_LOGO', '' ); define ( 'NO_LABEL', '' ); // Logo and label positioning define ( 'POS_LEFT', 0 ); define ( 'POS_RIGHT', 1 ); define ( 'POS_CENTER', 2 ); define ( 'POS_TOP', 3 ); define ( 'POS_BOTTOM', 4 ); // Error messages define ( 'E_001', 'File <b>%s</b> do not exist' ); define ( 'E_002', 'Failed reading image data from <b>%s</b>' ); define ( 'E_003', 'Cannot create the copy of <b>%s</b>' ); define ( 'E_004', 'Cannot copy the logo image' ); define ( 'E_005', 'Cannot create final image' ); // **************************************************************************** // CLASS DEFINITION // **************************************************************************** class ThumbnailImage { // **************************************************************************** // PUBLIC PROPERTIES // **************************************************************************** var $src_file; // source image file var $dest_file; // destination image file var $dest_type; // destination image type var $interlace; // destination image interlacing mode var $jpeg_quality; // quality of resulting JPEG var $max_width; // maximal thumbnail width var $max_height; // maximal thumbnail height var $fit_to_max; // enlarge small images? var $logo; // array of logo parameters var $label; // array of label parameters // **************************************************************************** // CLASS CONSTRUCTOR // **************************************************************************** /* Description: Defines default values for properties. Prototype: void ThumbImg ( string src_file = '' ) Parameters: src_file - source image filename */ function ThumbnailImage ( $src_file = '' ) { $this->src_file = $src_file; $this->dest_file = STDOUT; $this->dest_type = THUMB_JPEG; $this->interlace = INTERLACE_OFF; $this->jpeg_quality = -1; $this->max_width = 100; $this->max_height = 90; $this->fit_to_max = FALSE; $this->logo['file'] = NO_LOGO; $this->logo['vert_pos'] = POS_TOP; $this->logo['horz_pos'] = POS_LEFT; $this->label['text'] = NO_LABEL; $this->label['vert_pos'] = POS_BOTTOM; $this->label['horz_pos'] = POS_RIGHT; $this->label['font'] = ''; $this->label['size'] = 20; $this->label['color'] = '#000000'; $this->label['angle'] = 0; } // **************************************************************************** // PRIVATE METHODS // **************************************************************************** /* Description: Extracts decimal color components from hex color string. Prototype: array ParseColor ( string hex_color ) Parameters: hex_color - color in '#rrggbb' format Return: Decimal values for red, green and blue color components. */ function ParseColor ( $hex_color ) { if ( strpos ( $hex_color, '#' ) === 0 ) $hex_color = substr ( $hex_color, 1 ); $r = hexdec ( substr ( $hex_color, 0, 2 ) ); $g = hexdec ( substr ( $hex_color, 2, 2 ) ); $b = hexdec ( substr ( $hex_color, 4, 2 ) ); return array ( $r, $g, $b ); } /* Description: Retrives image data as a string. Thanks to Luis Larrateguy for the idea of this function. Prototype: string GetImageStr ( string image_file ) Parameters: image_file - filename of image Return: Image file contents string. */ function GetImageStr ( $image_file ) { if ( function_exists ( 'file_get_contents' ) ) { $str = @file_get_contents ( $image_file ); if ( ! $str ) { $err = sprintf( E_002, $image_file ); trigger_error( $err, E_USER_ERROR ); } return $str; } $f = fopen ( $image_file, 'rb' ); if ( ! $f ) { $err = sprintf( E_002, $image_file ); trigger_error( $err, E_USER_ERROR ); } $fsz = @filesize ( $image_file ); if ( ! $fsz ) $fsz = MAX_IMG_SIZE; $str = fread ( $f, $fsz ); fclose ( $f ); return $str; } /* Description: Loads image from file. Prototype: resource LoadImage ( string image_file, int &image_width, int &image_height ) Parameters: image_file - filename of image image_width - width of loaded image image_height - height of loaded image Return: Image identifier representing the image obtained from the given file. */ function LoadImage ( $image_file, &$image_width, &$image_height ) { $image_width = 0; $image_height = 0; $image_data = $this->GetImageStr( $image_file ); $image = imagecreatefromstring ( $image_data ); if ( ! $image ) { $err = sprintf( E_003, $image_file ); trigger_error( $err, E_USER_ERROR ); } $image_width = imagesx ( $image ); $image_height = imagesy ( $image ); return $image; } /* Description: Calculates thumbnail image sizes from source image width and height. Prototype: array GetThumbSize ( int src_width, int src_height ) Parameters: src_width - width of source image src_height - height of source image Return: An array with 2 elements. Index 0 contains the width of thumbnail image and index 1 contains the height. */ function GetThumbSize ( $src_width, $src_height ) { $max_width = $this->max_width; $max_height = $this->max_height; $x_ratio = $max_width / $src_width; $y_ratio = $max_height / $src_height; $is_small = ( $src_width <= $max_width && $src_height <= $max_height ); if ( ! $this->fit_to_max && $is_small ) { $dest_width = $src_width; $dest_height = $src_height; } elseif ( $x_ratio * $src_height < $max_height ) { $dest_width = $max_width; $dest_height = ceil ( $x_ratio * $src_height ); } else { $dest_width = ceil ( $y_ratio * $src_width ); $dest_height = $max_height; } return array ( $dest_width, $dest_height ); } /* Description: Adds logo image to thumbnail. Prototype: void AddLogo ( int thumb_width, int thumb_height, resource &thumb_img ) Parameters: thumb_width - width of thumbnail image thumb_height - height of thumbnail image thumb_img - thumbnail image identifier */ function AddLogo ( $thumb_width, $thumb_height, &$thumb_img ) { extract ( $this->logo ); $logo_image = $this->LoadImage ( $file, $logo_width, $logo_height ); if ( $vert_pos == POS_CENTER ) $y_pos = ceil ( $thumb_height / 2 - $logo_height / 2 ); elseif ($vert_pos == POS_BOTTOM) $y_pos = $thumb_height - $logo_height; else $y_pos = 0; if ( $horz_pos == POS_CENTER ) $x_pos = ceil ( $thumb_width / 2 - $logo_width / 2 ); elseif ( $horz_pos == POS_RIGHT ) $x_pos = $thumb_width - $logo_width; else $x_pos = 0; if ( ! imagecopy ( $thumb_img, $logo_image, $x_pos, $y_pos, 0, 0, $logo_width, $logo_height ) ) trigger_error( E_004, E_USER_ERROR ); } /* Description: Adds label text to thumbnail. Prototype: void AddLabel ( int thumb_width, int thumb_height, resource &thumb_img ) Parameters: thumb_width - width of thumbnail image thumb_height - height of thumbnail image thumb_img - thumbnail image identifier */ function AddLabel ( $thumb_width, $thumb_height, &$thumb_img ) { extract ( $this->label ); list( $r, $g, $b ) = $this->ParseColor ( $color ); $color_id = imagecolorallocate ( $thumb_img, $r, $g, $b ); $text_box = imagettfbbox ( $size, $angle, $font, $text ); $text_width = $text_box [ 2 ] - $text_box [ 0 ]; $text_height = abs ( $text_box [ 1 ] - $text_box [ 7 ] ); if ( $vert_pos == POS_TOP ) $y_pos = 5 + $text_height; elseif ( $vert_pos == POS_CENTER ) $y_pos = ceil( $thumb_height / 2 - $text_height / 2 ); elseif ( $vert_pos == POS_BOTTOM ) $y_pos = $thumb_height - $text_height; if ( $horz_pos == POS_LEFT ) $x_pos = 5; elseif ( $horz_pos == POS_CENTER ) $x_pos = ceil( $thumb_width / 2 - $text_width / 2 ); elseif ( $horz_pos == POS_RIGHT ) $x_pos = $thumb_width - $text_width -5; imagettftext ( $thumb_img, $size, $angle, $x_pos, $y_pos, $color_id, $font, $text ); } /* Description: Output thumbnail image into the browser. Prototype: void OutputThumbImage ( resource dest_image ) Parameters: dest_img - thumbnail image identifier */ function OutputThumbImage ( $dest_image ) { imageinterlace ( $dest_image, $this->interlace ); header ( 'Content-type: ' . $this->dest_type ); if ( $this->dest_type == THUMB_JPEG ) imagejpeg ( $dest_image, '', $this->jpeg_quality ); elseif ( $this->dest_type == THUMB_GIF ) imagegif($dest_image); elseif ( $this->dest_type == THUMB_PNG ) imagepng ( $dest_image ); } /* Description: Save thumbnail image into the disc file. Prototype: void SaveThumbImage ( string image_file, resource dest_image ) Parameters: image_file - destination file name dest_img - thumbnail image identifier */ function SaveThumbImage ( $image_file, $dest_image ) { imageinterlace ( $dest_image, $this->interlace ); if ( $this->dest_type == THUMB_JPEG ) imagejpeg ( $dest_image, $this->dest_file, $this->jpeg_quality ); elseif ( $this->dest_type == THUMB_GIF ) imagegif ( $dest_image, $this->dest_file ); elseif ( $this->dest_type == THUMB_PNG ) imagepng ( $dest_image, $this->dest_file ); } // **************************************************************************** // PUBLIC METHODS // **************************************************************************** /* Description: Output thumbnail image into the browser or disc file according to the values of parameters. Prototype: void Output ( ) */ function Output() { $src_image = $this->LoadImage($this->src_file, $src_width, $src_height); $dest_size = $this->GetThumbSize($src_width, $src_height); $dest_width=$dest_size[0]; $dest_height=$dest_size[1]; $dest_image=imagecreatetruecolor($dest_width, $dest_height); if (!$dest_image) trigger_error(E_005, E_USER_ERROR); imagecopyresampled( $dest_image, $src_image, 0, 0, 0, 0, $dest_width, $dest_height, $src_width, $src_height ); if ($this->logo['file'] != NO_LOGO) $this->AddLogo($dest_width, $dest_height, $dest_image); if ($this->label['text'] != NO_LABEL) $this->AddLabel($dest_width, $dest_height, $dest_image); if ($this->dest_file == STDOUT) $this->OutputThumbImage ( $dest_image ); else $this->SaveThumbImage ( $this->dest_file, $dest_image ); imagedestroy ( $src_image ); imagedestroy ( $dest_image ); } } // End of class definition ?>
使用方法:
1、首先引用该php文件(不要告诉我不会)
2、调用代码
$tis = new ThumbnailImage(); $tis->src_file = "这里写源文件的路径" $tis->dest_type = THUMB_JPEG;//生成图片的类型是 jpg $tis->dest_file = '这里写目标文件的路径'; $tis->max_width = 120;//自适应大小,但是最大宽度为120 $tis->max_height = 4000; //自适应大小,但是最大高度为4000 $tis->Output();
代码关键在于 max_width 和max_height,填多少,就会帮你生成一个 差不多大小的文件,一般来说除非你的图片很有个性,譬如很长,否则缩略图生成的还是很体贴的。
PHP生成自适应大小的缩略图类及使用方法分享
声明:登载此文出于传递更多信息之目的,并不意味着赞同其观点或证实其描述。
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