wordpress从顶部开始裁剪图片的方法

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wordpress默认情况下,裁剪的图片会直接裁剪图片的中间部分,例如你上传了一张美女图片上传上去由于图片的尺寸超出了内部规定的尺寸,wordpress会对其进行裁剪,按照规定的尺寸裁剪好后生成另外一张图片进行保存,可惜的是,当你调用这张图片的时候发现,美女的头被卡擦了,这样的缩略图完全失去了吸引读者的功效,下面我们就来解决这个问题

PHPcode4"> absint( $width ),'height' => absint( $height ),'crop' => $crop );} /** * Returning no sizes (an empty array) will force * wp_generate_attachment_Metadata to skip creating intermediate image sizes on * upload,then we can run our own resizing functions by hooking into the * 'wp_generate_attachment_Metadata' filter */function bt_intermediate_image_sizes_advanced( $sizes ) { return array();} function bt_generate_attachment_Metadata( $Metadata,$attachment_id ) { $attachment = get_post( $attachment_id ); $uploadPath = wp_upload_dir(); $file = path_join($uploadPath['basedir'],$Metadata['file']); if ( !preg_match('!^image/!',get_post_mime_type( $attachment )) || !file_is_displayable_image( $file ) ) return $Metadata; global $_wp_additional_image_sizes; foreach ( get_intermediate_image_sizes() as $s ) { $sizes[$s] = array( 'width' => '','height' => '','crop' => FALSE ); if ( isset( $_wp_additional_image_sizes[$s]['width'] ) ) $sizes[$s]['width'] = intval( $_wp_additional_image_sizes[$s]['width'] ); // For theme-added sizes else $sizes[$s]['width'] = get_option( "{$s}_size_w" ); // For default sizes set in options if ( isset( $_wp_additional_image_sizes[$s]['height'] ) ) $sizes[$s]['height'] = intval( $_wp_additional_image_sizes[$s]['height'] ); // For theme-added sizes else $sizes[$s]['height'] = get_option( "{$s}_size_h" ); // For default sizes set in options if ( isset( $_wp_additional_image_sizes[$s]['crop'] ) ) $sizes[$s]['crop'] = $_wp_additional_image_sizes[$s]['crop']; else $sizes[$s]['crop'] = get_option( "{$s}_crop" ); } foreach ( $sizes as $size => $size_data ) { $resized = bt_image_make_intermediate_size( $file,$size_data['width'],$size_data['height'],$size_data['crop'] ); if ( $resized ) $Metadata['sizes'][$size] = $resized; } return $Metadata;} /** * Resize an image to make a thumbnail or intermediate size. * * The returned array has the file size,the image width,and image height. The * filter 'image_make_intermediate_size' can be used to hook in and change the * values of the returned array. The only parameter is the resized file path. * * @param string $file File path. * @param int $width Image width. * @param int $height Image height. * @param bool|array $crop Optional,if no image was created. Metadata array on success. */function bt_image_make_intermediate_size( $file,$width,$height,$crop = false ) { if ( $width || $height ) { $resized_file = bt_image_resize( $file,$crop,null,90 ); if ( !is_wp_error( $resized_file ) && $resized_file && $info = getimagesize( $resized_file ) ) { $resized_file = apply_filters('image_make_intermediate_size',$resized_file); return array( 'file' => wp_basename( $resized_file ), 'width' => $info[0], 'height' => $info[1], ); } } return false;} /** * Retrieve calculated resized dimensions for use in imagecopyresampled(). * * Calculate dimensions and coordinates for a resized image that fits within a * specified width and height. If $crop is true,the largest matching central * portion of the image will be cropped out and resized to the required size. * * @param int $orig_w Original width. * @param int $orig_h Original height. * @param int $dest_w New width. * @param int $dest_h New height. * @param bool $crop Optional,default is false. Whether to crop image or resize. * @return bool|array False,on failure. Returned array matches parameters for imagecopyresampled() PHP function. */function bt_image_resize_dimensions($orig_w,$orig_h,$dest_w,$dest_h,$crop = false) { if ($orig_w <= 0 || $orig_h <= 0) return false; // at least one of dest_w or dest_h must be specific if ($dest_w <= 0 && $dest_h <= 0) return false; if ( $crop ) { // crop the largest possible portion of the original image that we can size to $dest_w x $dest_h $aspect_ratio = $orig_w / $orig_h; $new_w = min($dest_w,$orig_w); $new_h = min($dest_h,$orig_h); if ( !$new_w ) { $new_w = intval($new_h * $aspect_ratio); } if ( !$new_h ) { $new_h = intval($new_w / $aspect_ratio); } $size_ratio = max($new_w / $orig_w,$new_h / $orig_h); $crop_w = round($new_w / $size_ratio); $crop_h = round($new_h / $size_ratio); if ( !is_array( $crop ) || count( $crop ) != 2 ) { $crop = apply_filters( 'image_resize_crop_default','center' ) ); } switch ( $crop[0] ) { case 'left': $s_x = 0; break; case 'right': $s_x = $orig_w - $crop_w; break; default: $s_x = floor( ( $orig_w - $crop_w ) / 2 ); } switch ( $crop[1] ) { case 'top': $s_y = 0; break; case 'bottom': $s_y = $orig_h - $crop_h; break; default: $s_y = floor( ( $orig_h - $crop_h ) / 2 ); } } else { // don't crop,just resize using $dest_w x $dest_h as a maximum bounding box $crop_w = $orig_w; $crop_h = $orig_h; $s_x = 0; $s_y = 0; list( $new_w,$new_h ) = wp_constrain_dimensions( $orig_w,$dest_h ); } // if the resulting image would be the same size or larger we don't want to resize it if ( $new_w >= $orig_w && $new_h >= $orig_h ) return false; // the return array matches the parameters to imagecopyresampled() // int dst_x,int dst_y,int src_x,int src_y,int dst_w,int dst_h,int src_w,int src_h return array( 0,(int) $s_x,(int) $s_y,(int) $new_w,(int) $new_h,(int) $crop_w,(int) $crop_h ); } /** * Scale down an image to fit a particular size and save a new copy of the image. * * The PNG transparency will be preserved using the function,as well as the * image type. If the file going in is PNG,then the resized image is going to * be PNG. The only supported image types are PNG,GIF,and JPEG. * * Some functionality requires API to exist,so some PHP version may lose out * support. This is not the fault of wordpress (where functionality is * downgraded,not actual defects),but of your PHP version. * * @since 2.5.0 * * @param string $file Image file path. * @param int $max_w Maximum width to resize to. * @param int $max_h Maximum height to resize to. * @param bool $crop Optional. Whether to crop image or resize. * @param string $suffix Optional. File Suffix. * @param string $dest_path Optional. New image file path. * @param int $jpeg_quality Optional,default is 90. Image quality percentage. * @return mixed WP_Error on failure. String with new destination path. */function bt_image_resize( $file,$max_w,$max_h,$crop = false,$suffix = null,$dest_path = null,$jpeg_quality = 90 ) { $image = wp_load_image( $file ); if ( !is_resource( $image ) ) return new WP_Error( 'error_loading_image',$image,$file ); $size = @getimagesize( $file ); if ( !$size ) return new WP_Error('invalid_image',__('Could not read image size'),$file); list($orig_w,$orig_type) = $size; // Rotate if EXIF 'Orientation' is set // This code is from the reverted patch at // wordpress.org/changeset/11746/trunk/wp-includes/media.PHP">http://core.trac.wordpress.org/changeset/11746/trunk/wp-includes/media.PHP $rotate = false; if ( is_callable( 'exif_read_data' ) && in_array( $orig_type,apply_filters( 'wp_read_image_Metadata_types',array( IMAGETYPE_JPEG,IMAGETYPE_TIFF_II,IMAGETYPE_TIFF_MM ) ) ) ) { $exif = @exif_read_data( $file,true ); if ( $exif && isset( $exif['IFD0'] ) && is_array( $exif['IFD0'] ) && isset( $exif['IFD0']['Orientation'] ) ) { if ( 6 == $exif['IFD0']['Orientation'] ) $rotate = 90; elseif ( 8 == $exif['IFD0']['Orientation'] ) $rotate = 270; } } if ( $rotate ) list($max_h,$max_w) = array($max_w,$max_h); $dims = bt_image_resize_dimensions($orig_w,$crop); if ( !$dims ) return new WP_Error( 'error_getting_dimensions',__('Could not calculate resized image dimensions') ); list($dst_x,$dst_y,$src_x,$src_y,$dst_w,$dst_h,$src_w,$src_h) = $dims; $newimage = wp_imagecreatetruecolor( $dst_w,$dst_h ); if ( $rotate ) list($src_y,$src_x) = array($src_x,$src_y); imagecopyresampled( $newimage,$dst_x,$src_h); // convert from full colors to index colors,like original PNG. if ( IMAGETYPE_PNG == $orig_type && function_exists('imageistruecolor') && !imageistruecolor( $image ) ) imagetruecolortopalette( $newimage,false,imagecolorstotal( $image ) ); // we don't need the original in memory anymore imagedestroy( $image ); // $suffix will be appended to the destination filename,just before the extension if ( !$suffix ) { if ( $rotate ) $suffix = "{$dst_h}x{$dst_w}"; else $suffix = "{$dst_w}x{$dst_h}"; } $info = pathinfo($file); $dir = $info['dirname']; $ext = $info['extension']; $name = wp_basename($file,".$ext"); if ( !is_null($dest_path) and $_dest_path = realpath($dest_path) ) $dir = $_dest_path; $destfilename = "{$dir}/{$name}-{$suffix}.{$ext}"; if ( IMAGETYPE_GIF == $orig_type ) { if ( !imagegif( $newimage,$destfilename ) ) return new WP_Error('resize_path_invalid',__( 'Resize path invalid' )); } elseif ( IMAGETYPE_PNG == $orig_type ) { if ( !imagepng( $newimage,__( 'Resize path invalid' )); } else { if ( $rotate ) { $newimage = _rotate_image_resource( $newimage,360 - $rotate ); } // all other formats are converted to jpg $destfilename = "{$dir}/{$name}-{$suffix}.jpg"; $return = imagejpeg( $newimage,$destfilename,apply_filters( 'jpeg_quality',$jpeg_quality,'image_resize' ) ); if ( !$return ) return new WP_Error('resize_path_invalid',__( 'Resize path invalid' )); } imagedestroy( $newimage ); // Set correct file permissions $stat = stat( dirname( $destfilename )); $perms = $stat['mode'] & 0000666; //same permissions as parent folder,strip off the executable bits @ chmod( $destfilename,$perms ); return $destfilename;} 原文链接:https://www.f2er.com/wordpress/15303.html

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