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OpenOffice::OODoc::Image
Image manipulation methods

OpenOffice::OODoc::Image - Image manipulation methods


NAME

OpenOffice::OODoc::Image - Image manipulation methods


DESCRIPTION

The OpenOffice::OODoc::Image class is a derivative of OpenOffice::OODoc::XPath designed for the manipulation of graphics objects contained in documents. It mainly allows you to modify the size and position of an image and exchange its content outside the document.

This class should not be explictly used in an ordinary application, because all its features are available in the OpenOffice::OODoc::Document class, in combination with other features. So, each time an application needs to get an image-focused access to a document, it should use the general ooDocument() constructor instead of the ooImage() one.

Practically, the present manual is provided to describe the image-container processing features of OpenOffice::OODoc::Document (knowing that these features are technically supported by the OpenOffice::OODoc::Image component of the API).

Knowing that an image is displayed or printed according to a style, the OpenOffice::OODoc::Image features should be used in conjunction with the OpenOffice::OODoc::Styles ones. The OpenOffice::OODoc::Document class allows the user to invoke text-, style- and image-focused methods from the same object.

All the methods described here can equally be used with images contained in style sheets (headers, footers) as with images contained in the body of a document. It can therefore be associated just as well with a ``styles.xml'' member as with a ``content.xml'' member of an OpenOffice.org file.

This class works with all types of document (text, presentation, etc.).

For all methods where the first argument is given below as ``image'', it is (unless otherwise stated) either the name of an image as it appears to the end user when editing its properties in OpenOffice.org or StarOffice or the image's element reference obtained previously by the program. All these methods fail and return a null value (or in some cases produce an error message) if the argument does not correspond to a known image contained in the document.

Note: This module is not an image-processing tool. It can insert or remove images, and control the way the images are displayed in the documents. But it can't process the images themselves.

Methods

Constructor : OpenOffice::OODoc::Image->new(<parameters>)


        Short Form: ooImage(<parameters>)

        See OpenOffice::OODoc::XPath->new.

        The XML member loaded by default is 'content.xml', but only member

        => 'styles' is required if you want to work with page background

        images. Example:

                my $doc = ooImage

                        (

                        file    => 'my_presentation.odp',

                        member  => 'styles.xml'

                        );

        Real applications should not expressly use this constructor,

        knowing that the compound OpenOffice::OODoc::Document (whose

        usual constructor is ooDocument) inherits all the features

        of OpenOffice::OODoc::Image.

                        

=head3  createImageElement(name [, options])

        Creates an element which represents an image and inserts it into the

        document according to given parameters. The image element created is

        only an anchor. It then needs to have a graphical content loaded

        into it and, if needed, be given parameters using other methods.

        Example:

                $doc->createImageElement("Logo");

        inserts a default image element called "Logo".

        Normally, the image name is unique in an OpenOffice.org document but

        no checking of its uniqueness is performed here. Things you should

        know, however, are:

            - if several images have the same name, one only of them can be

            retrieved and handled by methods which use the name to identify

            them. It is almost impossible to know which of them it will be,

            without a thorough knowledge of the OpenOffice.org format and

            the internal logic of OODoc.

            - if the document is subsequently read and saved by

            OpenOffice.org (which controls the uniqueness of image names),

            sequential numbers will be given to all but one of the repeated

            names in order to make them unique.

        Attributes can be passed in pairs [parameter => value]. Such as:

                style           => image style name

        It should be noted that an image should normally be associated with

        a graphic style. The presence of a style is not obligatory when

        calling createImageElement (and this is not checked), but the image

        should preferably be actually linked to an existing style before

        displaying or printing the document. See OpenOffice::OODoc::Styles

        for style creation or, better, OpenOffice::OODoc::Document for image

        styles.

                attachment      => anchor element

        indicates if the image is attached to a text element (for ex. a

        paragraph), and which one. This parameter must be an existing

        element reference (obtained, for example, using getElement or

        selectElementxxx). It is useless if the image is linked to a page.

        The OASIS OpenDocument specification doesn't provide the list of

        possible attachments for an image, and OpenOffice.org make some

        differences in this area between the different document classes.

        For example, OOo Writer doesn't display images which are directly

        attached to table cells, while OOo Calc does (in text documents,

        an image which appears in a table cell is attached to a paragraph,

        possibly empty, belonging to the cell; see the example below).

                page            => anchor page

        If this parameter is used, it indicates that the image will be

        anchored to a page, and the given value is a page number. It does

        not matter if, when createImageElement is called, this number is

        beyond the end of the document or not. If the content class of the

        document is "presentation" (Impress) or "drawing" (Draw), then the

        page option is mandatory and must be either the visible name or the

        element reference of an existing draw page. In a "text" content,

        all that matters is that the particular page exists when it is opened

        by OpenOffice.org and if this parameter is absent, the image is

        anchored to a paragraph.

                position        => coordinates

        This parameter indicates the x,y coordinates of the image in

        relation to its anchor point. By default and generally, if the page

        parameter is given, the origin (0,0) is the top left corner of the

        physical page. When attached to a text element, if there is no given

        position, the image is appended to the text.

        Coordinates go from left to right and top to bottom, however

        everything really depends on the image style. Coordinates should be

        given here in the form of a string "x,y", and the default unit is

        centimeters. You can choose millimeters instead by attaching the

        usual abbreviation, such as "12.5cm, 35mm" which is the same as

        "125mm, 3.5cm" or "12.5,3.5", etc. The point ("pt") unit is allowed

        as well.

                size            => size

        The image's size (width, height) is given here in the same syntax as

        for position. Caution: if no size is given, you must not assume that

        the image will be spontaneously displayed in the document in a

        convenient size. Remember that the "original" size of the image is

        not automatically selected by default; the application must provide

        a display size. If an image is to be displayed according to its

        original size which is not known in advance, you can get it using,

        for example, the imgsize() function of Image::Size (this function

        returns the size in points, so the "pt" unit must be expressly

        selected unless you convert the size in centimeters).

                description     => label

        This optional parameter gives the descriptive text (long label) for

        the image as it will appear to the end user when editing the image's

        properties.

                link            => link

        The link parameter contains a reference to the image's physical

        content which can be inserted into an OpenOffice.org file (internal

        link) or a reference to an external file or even the URL of an image

        accessible using a communication protocol supported by the

        OpenOffice.org suite.

        

        Remember that, with OpenOffice.org, physical images are "referenced",

        and not "loaded" into XML elements. The reverse of course would not

        only be against "good practice" but would result in outrageously

        large documents. According to the OpenDocument specification, the

        conforming applications could embed base-64-encoded graphics in the

        XML elements, but this option is not used when you insert an image

        in a document through the OOo GUI.

        

        If the target link is unavailable when the document is displayed,

        an error message is displayed in place of the image. (See imageLink

        about links.) This parameter is useless if import is given.

        

        Relative paths in the local filesystem are allowed, but should be

        used with care, due to differences between operating systems... and

        between editing applications (for example, in a Unix environment,

        OOo 2.x requires "../image.jpg" while OOo 1.x allows "image.jpg" for

        a link to an image file in the current directory).

                import          => image file

        The presence of this parameter indicates that the image content

        should be imported from an external file and, implicitly, that the

        image link (which it is useless to give here) points to the image

        imported into the OpenOffice.org file. The import will only be made

        when all the updates are validated by a save(). See importImage

        about importing images. An imported image is *not* embedded in the

        XML image element; it's always referred to through a link, and stored

        in a separate, non-XML member of the ODF archive. However, with the

        "import" option, the appropriate internal link is automatically

        created and the new member, containing the image, is automatically

        built later, when the save() method is executed from the current

        document (provided that the image file is available).

        For those who know the appropriate XML vocabulary, there are other

        parameters you can pass. Parameters other than those described above

        are written to the image's XML element as is and without any checks.

        All of these attributes, and others, can be read or modified later

        by other methods.

        We would discourage you from relying on the default choices in a

        serious application, but it is still a possibility. With no

        parameters (other than mandatory image name), the createImageElement

        method chooses its own often arbitrary course according to the

        following circumstances:

            - if the OODoc::Image object is associated with a document body

            (document-content) then a new paragraph is created at the end of

            the document and the image is inserted into this paragraph

            (appears at the end of the text). Repeated image creations

            without parameters will therefore add images one after the other

            at the end of the document.

            - if the OODoc::Image object is associated with a background

            (document-styles) then it tries to create a paragraph in the

            first available header and insert the image into it. If no page

            style contains a header, the same is attempted in the first

            available footer. If there is no footer either, the creation

            fails with the message "No valid attachment".

        This method otherwise tries to be "intelligent" whenever the set of

        parameters is incomplete. If the results are useful, then the rest

        is up to you...

        The method returns the new image element's reference (undef if it

        fails).

        The following example attaches an image to a paragraph, gives it a

        size, loads its content into it from an external file and attributes

        a style to it which has been defined elsewhere. You will note that

        this example combines an OODoc::Image method (createImageElement)

        with an OODoc::Text method (getParagraph). This means that, here,

        the $doc object is a OODoc::Document class. See also

        createImageStyle in OODoc::Document.

                $doc->createImageElement

                        (

                        "Landscape",

                        description     => "Kilimanjaro in winter",

                        attachment      => $doc->getParagraph(4),

                        size            => "5cm, 3.5cm",

                        style           => "gr1",

                        import          => "C:\Images\Landscape.jpg"

                        );

                        

        The same image element could be inserted in a table cell. To do

        so, in a spreadsheet document, the "attachment" option could be

        set with a $doc->getCell($table, $row, $column) value. But the

        present version of OpenOffice.org doesn't allow direct cell

        attachments in text documents; the image element must be attached

        to a paragraph which is in turn attached to the target cell. So

        a possible approach consists of 1) issuing a setText($cell, "") in

        order to ensure the target cell contains an empty text paragraph

        and 2) provide an "attachment" option set to

        $doc->getCellParagraph($cell) in order to anchor the image to this

        paragraph.

        Remember: creating an image element will only make that image appear

        in the document if 1) the image has a valid link which points to a

        valid image, 2) the corresponding graphics file exists (loaded

        possibly using importImage) in the archive if it is an internal

        link, and 3) the image has a style actually defined elsewhere

        (either pre-existing, created using the createStyle method of

        OODoc::Styles, copied from another document using replicateElement,

        or coming from another source).

exportImage(image [, destination])


        Exports the content of an image contained in a document if the

        OODoc::Image object was linked to a file when it was created (with

        file or archive parameters passed to the new constructor).

        The first argument is either the name of the image (as it would

        appear to the end user in the image's properties in OpenOffice.org),

        or the image element's reference if the program already has it.

        The second optional argument is the destination file. Example:

                $doc->exportImage("Logo1", "C:\My Documents\logo.jpg");

        It is up to the application to choose an appropriate extension for

        the exported file (.jpg, .gif, .png, etc.). You can easily find out

        which extension using the imageLink accessor.

        Without the second argument, the image file is created in the

        current directory, and its name is the name of the image in the

        document, with an extension depending on the format (.jpg, .png,

        etc), according to the information stored in the document (but

        the format is not checked). Be careful, the export fails unless 

        such a construct provides a valid file name for the operating system.

        If the image is unnamed in the document, exportImage() tries to

        build a path/name which replicates the internal path/name of the

        image in the archive and to use it under the current directory

        (this path normally begins with "Pictures/").

        Caution: this method only exports what is exportable i.e. internal

        images (physically contained in the file). It has no effect if used

        with an image inserted by an external link into the document.

exportImages([options])


        Exports all or part of the images contained in a document.

        By default, and with no parameters, each internal image is exported

        to a file whose access path is the same as it would be if using

        exportImage. This behaviour can be changed by parameters passed

        in hash form (parameter => value).

        

        Possible parameters are as follows:

                selection       => filtering of image names (regex)

                filter          => filtering of image names (regex)

                name            => filtering of image names (regex)

                target          => path and/or basic filename

                path            => path and/or basic filename

                suffix          => extension to be given to filenames

                extension       => extension to be given to filenames

                start_count     => begin count indicator

        The "filter", "selection" or "name" parameters allow you to export

        only those images whose names match the given regular expression.

        Such filtering works on the name as the document "knows" it, i.e. as

        it appears to the end user in the image's properties within the

        document. It is not a technical filter and does not allow, for

        example, selection of images according to their file type.

        The "target" or "path" parameters allow you to choose the access

        path and basic filename for exported files (e.g.

        "/usr/local/images/img"). If given, a sequential number will

        automatically be added to the basic filename to identify each file.

        The "suffix" or "extension" parameters allow the application to

        force a common extension for each file instead of leaving the

        extension as it existed in the archive (which normally identifies the

        physical image type).

        By default, the sequential numbers given to filenames (between basic

        name and extension) are reset to zero each time exportImages is

        called. An application can however force the numbering to start at a

        different value using the "start_count" parameter.

        In a list context, this method returns a list of exported files

        which the application can use later. In a scalar context, it returns

        the number of exported files.

getImageElementList()


        Returns the list of all image elements in the active context. If the

        current OODoc::Image object is associated with document-content,

        this will be the images contained in the body of the document. If

        associated with document-styles, this will be the images linked to

        headers and footers.

getImageElement(image)

getImageElement(element)


        Returns the element which corresponds to the image whose name is

        given as an argument. This name is usually unique as OpenOffice.org

        does not allow the user to give two files the same name in a

        document. It is the name which appears in the "Options" tab when

        editing the object's properties in OpenOffice.org Writer, or in the

        "Name object" dialog box when you right-click an image in

        OpenOffice.org Impress. Returns undef if the image is not found.

        Can also be used as a check method by specifying an element as the

        argument instead of a name. In this case, the given element is

        simply returned without modification if it is indeed an image or

        undef if not.

        Caution: images do not always have names. OpenOffice.org Writer gives

        default names to images (e.g. Image1, Image2, ...) if the user does

        not deliberately name them. This is not the case in Impress.

getInternalImagePath(image)


        This method returns the given image's link (see definition of "link"

        in the section on imageLink), but only if it is an internal link in

        a form which is directly usable by a zip archive management tool

        (without the initial "#").

imageAttribute(image, attribute [, value])


        Accessor which allows you to check or modify (even create) an

        image's XML attributes directly. The attribute is modified or

        created if a value is given as the third argument. If not, it

        returns the current value of the attribute if found, or undef if

        not. The name and value of the attribute must be given according to

        the OpenOffice.org vocabulary.

        This generic accessor remains invisible to most applications as

        specialist accessors are available for the most useful attributes

        (e.g. imageLink, imageName, etc.).

imageDescription(image [, text])


        Returns an image's description, or if the "text" argument is given,

        replaces it. This description corresponds to the optional text which

        appears in the Options tab when editing the image's properties in

        OpenOffice.org. It is not used in Impress or Draw documents.

imageLink(image [, link])


        Reads or modifies an image's link. A link is the address of the file

        which physically contains the image.

        If working with an image loaded into the document (often but not

        always the case), the link is internal and the file is physically

        stored in the zip archive containing the document. In this case, the

        link is written as "#Pictures/xxxx". It corresponds to what the user

        would see if opening the file using a zip archive tool instead of

        opening it in OpenOffice.org.

        If working with an external image, the link is then the URL of the

        image.

        The same method allows you to read and modify the link. If a second

        argument is given, it cancels and replaces the existing link, or

        creates a link if the image was still "empty".

        Example:

                $doc->imageLink("Logo", "http://www.mysite.com/logo.png";);

        Caution: the actual physical existence of a valid image which

        corresponds to the link is not checked.

imageName(image [, name])


        Reads an image's name, or if the second argument is given, replaces

        it.

        Returns undef if the first argument (name or reference) is not an

        image.

imagePosition(image [, x, y])


        Allows you to read or modify the coordinates of an image in relation

        to its anchor point. Coordinates are returned in the form of a pair

        of values.

        Example:

                my ($x, $y) = $doc->imagePosition("Landscape");

        If the coordinate arguments are given, they replace the image's old

        coordinates.

        Caution: coordinates are not numeric values in the classic sense of

        the word. They are character strings starting with numeric values

        and ending with units of measure (normally "cm" or "mm"). If an

        application passes only numeric arguments without giving a unit of

        measure, the default unit is assumed to be the centimetre.

        Example:

                $doc->imagePosition("Landscape", "2.5cm", "5.125cm");

        Normally, coordinates are measured from left to right and from top

        to bottom starting from the point of reference. The point of

        reference is normally the top left corner of the page or paragraph

        to which it is anchored (depending on the type of anchorage). All

        this can depend on the page style.

imageSize(image [, height, width])


        Allows you to read or modify the display size of an image. Returns

        the height and width as a pair of values. If height and width

        arguments are provided, they replace the image's old size. Caution:

        it is up to the application to maintain the proportions of an image

        if needed.

        See imagePosition about measure formats.

imageStyle(image [, style])


        Returns the name of the image's current style, or changes this style

        if the second argument "style" is given. In the second case, the

        presence or pertinence of the called style is not checked. This can

        otherwise be created or imported later.

importImage(image, filename)


        Loads an image's content from an external file.

        Example:

                $doc->importImage("Image1", "C:\Images\Portrait.jpg");

        This import cancels and replaces any previous image content.

        The first argument is either the image's name (as the user would see

        it) or the image's corresponding element reference. In any case, the

        image must already exist, created if necessary using

        insertImageElement. Obviously, the imported file should preferably

        be in a graphics format supported by OpenOffice.org, but this method

        actually allows you to import anything, including data which could

        not be displayed in an OpenOffice.org document.

        Caution: this method does not carry out the import immediately and

        does not check for the presence of the file to be imported. It only

        sends the request to the associated OODoc::File object (via its

        raw_import method) which performs the operation at the next save

        call.

insertImageElement(name [, options])


        See createImageElement.

isImage


        Method added to OpenOffice::OODoc::Element class objects by the

        OODoc::Image package and is an element method rather than a document

        method. Allows you to "ask" an element if it is an image.

        Example:

                print "This is an image" if $element->isImage;

removeImageDescription(image)


        Deletes an image's optional image description.

selectImageElementByDescription(expression)


        Returns the first (or only) image (if found) which has an image

        description and which matches the regular expression.

selectImageElementByLink(link)


        Allows you to select an image element by its link (as in imageLink)

        instead of by its name. The link can be an approximation and

        represented in this case by a regular expression.

        It should only be used if you are sure that the link is unique in

        the document. This is not normally the case, as many images can

        share the same content. Conversely, the returned element is the

        first image, in the physical XML order, which has the given link

        (and not necessarily in the logical order of the document).

        Returns undef if no image has the given link and therefore allows

        you to find out if a particular target (e.g. URL) is used in the

        document.

        Note: if an application needs to get a list of individual or

        multiple images which share the same target, the easiest way is to

        loop through the list returned by getImageElementList and perform an

        imageLink on each element.

selectImageElementsByDescription(expression)


        Returns a list of images whose image descriptions match the given

        regular expression.

selectImageElementsByLink(expression)


        Returns a list of images whose internal or external links match the

        given regular expression.

        Allows you, for example, to get a list of image elements which share

        the same physical image file or even those which use a particular

        transport protocol to access these images.

        Example:

                my @webimages = $doc->selectImageElementsByLink("^http:";);

        allows you to get a list of images which will not be visible if the

        user's machine is not connected to the internet.

selectImageElementsByName(expression)


        Returns a list of images whose names match the given regular

        expression.

Properties


        No variable is exported.

        There is a static class variable which contains the description of a

        default image style (in hash form):

                %OpenOffice::OODoc::Image::DEFAULT_IMAGE_STYLE

        This hash is not used directly by the module itself (which offers no

        styles functions), but it is available to any application which

        needs to create image styles using either XPath base methods or the

        Styles module. Its structure is exactly the same as the parameters

        hash expected by the createStyle method. By default, it is

        automatically used by the createImageStyle method of the Document

        module.


AUTHOR/COPYRIGHT

Developer/Maintainer: Jean-Marie Gouarne http://jean.marie.gouarne.online.fr

Contact: jmgdoc@cpan.org

Copyright 2004-2006 by Genicorp, S.A. http://www.genicorp.com

Initial English version of the reference manual by Graeme A. Hunter (graeme.hunter@zen.co.uk)

License:


        - Licence Publique Generale Genicorp v1.0

        - GNU Lesser General Public License v2.1
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