~centralelyon2010/inkscape/imagelinks2

/*

 * Inkscape::SelectionDescriber - shows messages describing selection

 *

 * Authors:

 *   MenTaLguY <mental@rydia.net>

 *   Jon A. Cruz <jon@joncruz.org>

 *

 * Copyright (C) 2004 MenTaLguY

 *

 * Released under GNU GPL, read the file 'COPYING' for more information

 */

#ifdef HAVE_CONFIG_H

# include "config.h"

#endif

#include "document.h"

#include "sp-item-group.h"

#include "xml/repr.h"

#include "util/find-last-if.h"

#include "layer-fns.h"

// TODO move the documentation comments into the .h file

namespace Inkscape {

namespace {

bool is_layer(SPObject &object) {

    return SP_IS_GROUP(&object) &&

           SP_GROUP(&object)->layerMode() == SPGroup::LAYER;

}

/** Finds the next sibling layer for a \a layer

 *

 *  @returns NULL if there are no further layers under a parent

 */

SPObject *next_sibling_layer(SPObject *layer) {

    using std::find_if;

    return find_if<SPObject::SiblingIterator>(

        layer->getNext(), NULL, &is_layer

    );

}

/** Finds the previous sibling layer for a \a layer

 *

 *  @returns NULL if there are no further layers under a parent

 */

SPObject *previous_sibling_layer(SPObject *layer) {

    using Inkscape::Algorithms::find_last_if;

    SPObject *sibling(find_last_if<SPObject::SiblingIterator>(

        layer->parent->firstChild(), layer, &is_layer

    ));

    return ( sibling != layer ) ? sibling : NULL;

}

/** Finds the first child of a \a layer

 *

 *  @returns NULL if layer has no sublayers

 */

SPObject *first_descendant_layer(SPObject *layer) {

    using std::find_if;

    SPObject *first_descendant=NULL;

    while (layer) {

        layer = find_if<SPObject::SiblingIterator>(

            layer->firstChild(), NULL, &is_layer

        );

        if (layer) {

            first_descendant = layer;

        }

    }

    return first_descendant;

}

/** Finds the last (topmost) child of a \a layer

 *

 *  @returns NULL if layer has no sublayers

 */

SPObject *last_child_layer(SPObject *layer) {

    using Inkscape::Algorithms::find_last_if;

    return find_last_if<SPObject::SiblingIterator>(

        layer->firstChild(), NULL, &is_layer

    );

}

SPObject *last_elder_layer(SPObject *root, SPObject *layer) {

    using Inkscape::Algorithms::find_last_if;

    SPObject *result = 0;

    while ( layer != root ) {

        SPObject *sibling(previous_sibling_layer(layer));

        if (sibling) {

            result = sibling;

            break;

        }

        layer = layer->parent;

    }

    return result;

}

}

/** Finds the next layer under \a root, relative to \a layer in

 *  depth-first order.

 *

 *  @returns NULL if there are no further layers under \a root

 */

SPObject *next_layer(SPObject *root, SPObject *layer) {

    using std::find_if;

    g_return_val_if_fail(layer != NULL, NULL);

    SPObject *result = 0;

    SPObject *sibling = next_sibling_layer(layer);

    if (sibling) {

        SPObject *descendant(first_descendant_layer(sibling));

        if (descendant) {

            result = descendant;

        } else {

            result = sibling;

        }

    } else if ( layer->parent != root ) {

        result = layer->parent;

    }

    return result;

}

/** Finds the previous layer under \a root, relative to \a layer in

 *  depth-first order.

 *

 *  @returns NULL if there are no prior layers under \a root.

 */

SPObject *previous_layer(SPObject *root, SPObject *layer) {

    using Inkscape::Algorithms::find_last_if;

    g_return_val_if_fail(layer != NULL, NULL);

    SPObject *result = 0;

    SPObject *child = last_child_layer(layer);

    if (child) {

        result = child;

    } else if ( layer != root ) {

        SPObject *sibling = previous_sibling_layer(layer);

        if (sibling) {

            result = sibling;

        } else {

            result = last_elder_layer(root, layer->parent);

        }

    }

    return result;

}

/**

*  Creates a new layer.  Advances to the next layer id indicated

 *  by the string "layerNN", then creates a new group object of

 *  that id with attribute inkscape:groupmode='layer', and finally

 *  appends the new group object to \a root after object \a layer.

 *

 *  \pre \a root should be either \a layer or an ancestor of it

 */

SPObject *create_layer(SPObject *root, SPObject *layer, LayerRelativePosition position) {

    SPDocument *document = root->document;

    static int layer_suffix=1;

    gchar *id=NULL;

    do {

        g_free(id);

        id = g_strdup_printf("layer%d", layer_suffix++);

    } while (document->getObjectById(id));

    Inkscape::XML::Document *xml_doc = document->getReprDoc();

    Inkscape::XML::Node *repr = xml_doc->createElement("svg:g");

    repr->setAttribute("inkscape:groupmode", "layer");

    repr->setAttribute("id", id);

    g_free(id);

    if ( LPOS_CHILD == position ) {

        root = layer;

        SPObject *child_layer = Inkscape::last_child_layer(layer);

        if ( NULL != child_layer ) {

            layer = child_layer;

        }

    }

    if ( root == layer ) {

        root->getRepr()->appendChild(repr);

    } else {

        Inkscape::XML::Node *layer_repr = layer->getRepr();

        sp_repr_parent(layer_repr)->addChild(repr, layer_repr);

        if ( LPOS_BELOW == position ) {

            SP_ITEM(document->getObjectByRepr(repr))->lowerOne();

        }

    }

    return document->getObjectByRepr(repr);

}

}

/*

  Local Variables:

  mode:c++

  c-file-style:"stroustrup"

  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))

  indent-tabs-mode:nil

  fill-column:99

  End:

*/

// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :