http://www.zorba-xquery.com/modules/image/basic

import module namespace basic = "http://www.zorba-xquery.com/modules/image/basic";

This module provides function to do the following basic image operations:

• create empty images
• compare images
• compress image
• convert an image one format to another
• retrieve with, height, format, and exif information from an image

• GIF
• JPEG
• PNG
• TIFF
• BMP

The errors raised by functions of this module have the namespace http://www.zorba-xquery.com/modules/image/error (associated with prefix ierr).

Daniel Thomas

xquery version "3.0" encoding "utf-8";

• the XQuery module can be found here.

Imported schemas:

• http://www.zorba-xquery.com/modules/image/image

External C++ library dependencies:

• Magick++ C++ Library

	compress ( $image as xs:base64Binary, $quality as xs:unsignedInt ) as xs:base64Binary external Compresses the passed image.
	convert ( $image as xs:base64Binary, $format as xs:string ) as xs:base64Binary Converts an image to another format.
	convert-svg ( $svg as xs:base64Binary, $format as xs:string ) as xs:base64Binary Converts an SVG image to a supported image format.
	create ( $width as xs:unsignedInt, $height as xs:unsignedInt, $format as xs:string ) as xs:base64Binary Creates an empty image with background color white.
	equals ( $image1 as xs:base64Binary, $image2 as xs:base64Binary ) as xs:boolean external Compares two images.
	exif ( $image as xs:base64Binary, $tag as xs:string ) as xs:string? external Reads exif information from an image.
	format ( $image as xs:base64Binary ) as xs:string external Returns the format of the passed image.
	height ( $image as xs:base64Binary ) as xs:unsignedInt external Returns the height of the passed image.
	width ( $image as xs:base64Binary ) as xs:unsignedInt external Returns the width of the passed image.

compress

declare function basic:compress (
            $image as xs:base64Binary, 
            $quality as xs:unsignedInt 
 ) as xs:base64Binary external

Compresses the passed image. Compressing means lowering the quality and reducing the size.

• $image the image
• $quality compression level, 0 to 100

• the compressed image

• ierr:IM001 the passed image is invalid.

• basic_compress.xq

convert

declare function basic:convert (
            $image as xs:base64Binary, 
            $format as xs:string 
 ) as xs:base64Binary

Converts an image to another format.

• $image the source image
• $format the format (see supported formats above) of the resulting image.

• A new image with the same content as the passed image but with the specified file format.

• ierr:IM001 the passed image is invalid.
• err:FORG0001 unsupported image format

• basic_convert.xq

convert-svg

declare function basic:convert-svg (
            $svg as xs:base64Binary, 
            $format as xs:string 
 ) as xs:base64Binary

Converts an SVG image to a supported image format.

• $svg the image to convert
• $format target format

• the resulting image

• ierr:IM001 the passed SVG is invalid.

• basic_svg.xq

create

declare function basic:create (
            $width as xs:unsignedInt, 
            $height as xs:unsignedInt, 
            $format as xs:string 
 ) as xs:base64Binary

Creates an empty image with background color white.

• $width the width of the new image
• $height the height of the new image
• $format the format of the new image

• newly created image

• err:FORG0001 unsupported image format

• basic_create.xq

equals

declare function basic:equals (
            $image1 as xs:base64Binary, 
            $image2 as xs:base64Binary 
 ) as xs:boolean external

Compares two images.

• $image1 first image
• $image2 second image

• True if the images are equal.

• ierr:IM001 one of the passed images is invalid.

• basic_equals.xq

exif

declare function basic:exif (
            $image as xs:base64Binary, 
            $tag as xs:string 
 ) as xs:string? external

Reads exif information from an image. This function works for JPEG and TIFF images only. It returns empty sequence if no exif information matching the passed tag is found.

• $image the image
• $tag the field name we want read (e.g. DateTime).

• exif field content

• ierr:IM001 the passed image is invalid.

• basic_exif.xq

format

declare function basic:format (
            $image as xs:base64Binary 
 ) as xs:string external

Returns the format of the passed image.

• $image the image

• the format

• ierr:IM001 the passed image is invalid.

• basic_type.xq

height

declare function basic:height (
            $image as xs:base64Binary 
 ) as xs:unsignedInt external

Returns the height of the passed image.

• $image the image

• the height in pixels

• ierr:IM001 the passed image is invalid.

• basic_height.xq

width

declare function basic:width (
            $image as xs:base64Binary 
 ) as xs:unsignedInt external

Returns the width of the passed image.

• $image the image

• the width in pixels

• ierr:IM001 the passed image is invalid.

• basic_width.xq