system clipboard support (bug #170185) from Chris Kosiński

(bzr r5190)

1 files changed, 1137 insertions, 0 deletions

diff --git a/src/ui/clipboard.cpp b/src/ui/clipboard.cpp
new file mode 100644
index 000000000..0f9223054
--- /dev/null
+++ b/src/ui/clipboard.cpp
@@ -0,0 +1,1137 @@
+/** @file
+ * @brief System-wide clipboard management - implementation
+ */
+/* Authors:
+ *   Krzysztof Kosiński <tweenk@o2.pl>
+ *   Incorporates some code from selection-chemistry.cpp, see that file for more credits.
+ *
+ * Copyright (C) 2008 authors
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * See the file COPYING for details.
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+#include "path-prefix.h"
+
+#include "ui/clipboard.h"
+
+// TODO: reduce header bloat if possible
+
+#include <list>
+#include <algorithm>
+#include <gtkmm/clipboard.h>
+#include <glibmm/ustring.h>
+#include <glibmm/i18n.h>
+#include <glib/gstdio.h> // for g_file_set_contents etc., used in _onGet and paste
+#include "gc-core.h"
+#include "xml/repr.h"
+#include "inkscape.h"
+#include "io/stringstream.h"
+#include "desktop.h"
+#include "desktop-handles.h"
+#include "desktop-style.h" // for sp_desktop_set_style, used in _pasteStyle
+#include "document.h"
+#include "document-private.h"
+#include "selection.h"
+#include "message-stack.h"
+#include "context-fns.h"
+#include "dropper-context.h" // used in copy()
+#include "style.h"
+#include "extension/db.h" // extension database
+#include "extension/input.h"
+#include "extension/output.h"
+#include "selection-chemistry.h"
+#include "libnr/nr-rect.h"
+#include "box3d.h"
+#include "gradient-drag.h"
+#include "sp-item.h"
+#include "sp-item-transform.h" // for sp_item_scale_rel, used in _pasteSize
+#include "sp-path.h"
+#include "sp-pattern.h"
+#include "sp-shape.h"
+#include "sp-gradient.h"
+#include "sp-gradient-reference.h"
+#include "sp-gradient-fns.h"
+#include "sp-linear-gradient-fns.h"
+#include "sp-radial-gradient-fns.h"
+#include "sp-clippath.h"
+#include "sp-mask.h"
+#include "sp-textpath.h"
+#include "live_effects/lpeobject.h"
+#include "live_effects/parameter/path.h"
+#include "svg/svg.h" // for sp_svg_transform_write, used in _copySelection
+#include "svg/css-ostringstream.h" // used in _parseColor
+#include "file.h" // for file_import, used in _pasteImage
+#include "prefs-utils.h" // for prefs_get_string_attribute, used in _pasteImage
+#include "text-context.h"
+#include "text-editing.h"
+#include "tools-switch.h"
+
+/// @brief Made up mimetype to represent Gdk::Pixbuf clipboard contents
+#define CLIPBOARD_GDK_PIXBUF_TARGET "image/x-gdk-pixbuf"
+
+#define CLIPBOARD_TEXT_TARGET "text/plain"
+
+namespace Inkscape {
+namespace UI {
+
+
+/**
+ * @brief Default implementation of the clipboard manager
+ */
+class ClipboardManagerImpl : public ClipboardManager {
+public:
+    virtual void copy();
+    virtual void copyPathParameter(Inkscape::LivePathEffect::PathParam *);
+    virtual bool paste(bool in_place);
+    virtual bool pasteStyle();
+    virtual bool pasteSize(bool, bool, bool);
+    virtual bool pastePathEffect();
+    virtual Glib::ustring getPathParameter();
+    
+    ClipboardManagerImpl();
+    ~ClipboardManagerImpl();
+    
+private:
+    void _copySelection(Inkscape::Selection *);
+    void _copyUsedDefs(SPItem *);
+    void _copyGradient(SPGradient *);
+    void _copyPattern(SPPattern *);
+    void _copyTextPath(SPTextPath *);
+    Inkscape::XML::Node *_copyNode(Inkscape::XML::Node *, Inkscape::XML::Document *, Inkscape::XML::Node *);
+    
+    void _pasteDocument(SPDocument *, bool in_place);
+    void _pasteDefs(SPDocument *);
+    bool _pasteImage();
+    bool _pasteText();
+    SPCSSAttr *_parseColor(const Glib::ustring &);
+    void _applyPathEffect(SPItem *, gchar const *);
+    SPDocument *_retrieveClipboard(Glib::ustring = "");
+    
+    // clipboard callbacks
+    void _onGet(Gtk::SelectionData &, guint);
+    void _onClear();
+    
+    // various helpers
+    void _createInternalClipboard();
+    void _discardInternalClipboard();
+    Inkscape::XML::Node *_createClipNode();
+    NR::scale _getScale(Geom::Point &, Geom::Point &, NR::Rect &, bool, bool);
+    Glib::ustring _getBestTarget();
+    void _setClipboardTargets();
+    void _setClipboardColor(guint32);
+    void _userWarn(SPDesktop *, char const *);
+
+    // private properites
+    SPDocument *_clipboardSPDoc; ///< Document that stores the clipboard until someone requests it
+    Inkscape::XML::Node *_defs; ///< Reference to the clipboard document's defs node
+    Inkscape::XML::Node *_root; ///< Reference to the clipboard's root node
+    Inkscape::XML::Node *_clipnode; ///< The node that holds extra information
+    Inkscape::XML::Document *_doc; ///< Reference to the clipboard's Inkscape::XML::Document
+    
+    Glib::RefPtr<Gtk::Clipboard> _clipboard; ///< Handle to the system wide clipboard - for convenience
+    std::list<Glib::ustring> _preferred_targets; ///< List of supported clipboard targets
+};
+
+
+ClipboardManagerImpl::ClipboardManagerImpl()
+    : _clipboardSPDoc(NULL),
+      _defs(NULL),
+      _root(NULL),
+      _clipnode(NULL),
+      _doc(NULL),
+      _clipboard( Gtk::Clipboard::get() )
+{
+    // push supported clipboard targets, in order of preference
+    _preferred_targets.push_back("image/x-inkscape-svg");
+    _preferred_targets.push_back("image/svg+xml");
+    _preferred_targets.push_back("image/svg+xml-compressed");
+#ifdef WIN32
+    _preferred_targets.push_back("image/x-emf");
+#endif
+    _preferred_targets.push_back("application/pdf");
+    _preferred_targets.push_back("image/x-adobe-illustrator");
+}
+
+
+ClipboardManagerImpl::~ClipboardManagerImpl() {}
+
+
+/**
+ * @brief Copy selection contents to the clipboard
+ */
+void ClipboardManagerImpl::copy()
+{
+    SPDesktop *desktop = SP_ACTIVE_DESKTOP;
+    if ( desktop == NULL ) return;
+    Inkscape::Selection *selection = sp_desktop_selection(desktop);
+    
+    // Special case for when the gradient dragger is active - copies gradient color
+    if (desktop->event_context->get_drag()) {
+        GrDrag *drag = desktop->event_context->get_drag();
+        if (drag->hasSelection()) {
+            _setClipboardColor(drag->getColor());
+            _discardInternalClipboard();
+            return;
+        }
+    }
+    
+    // Special case for when the color picker ("dropper") is active - copies color under cursor
+    if (tools_isactive(desktop, TOOLS_DROPPER)) {
+        _setClipboardColor(sp_dropper_context_get_color(desktop->event_context));
+        _discardInternalClipboard();
+        return;
+    }
+    
+    // Special case for when the text tool is active - if some text is selected, copy plain text,
+    // not the object that holds it
+    if (tools_isactive(desktop, TOOLS_TEXT)) {
+        Glib::ustring selected_text = sp_text_get_selected_text(desktop->event_context);
+        if (!selected_text.empty()) {
+            _clipboard->set_text(selected_text);
+            _discardInternalClipboard();
+            return;
+        }
+    }
+    
+    if (selection->isEmpty()) {  // check whether something is selected
+        _userWarn(desktop, _("Nothing was copied."));
+        return;
+    }
+    _discardInternalClipboard();
+    
+    _createInternalClipboard();   // construct a new clipboard document
+    _copySelection(selection);   // copy all items in the selection to the internal clipboard
+    fit_canvas_to_drawing(_clipboardSPDoc);
+    
+    _setClipboardTargets();
+}
+
+
+/**
+ * @brief Copy a Live Path Effect path parameter to the clipboard
+ * @param pp The path parameter to store in the clipboard
+ */
+void ClipboardManagerImpl::copyPathParameter(Inkscape::LivePathEffect::PathParam *pp)
+{
+    if ( pp == NULL ) return;
+    gchar *svgd = pp->param_writeSVGValue();
+    if ( svgd == NULL || *svgd == '\0' ) return;
+    
+    _discardInternalClipboard();
+    _createInternalClipboard();
+    
+    Inkscape::XML::Node *pathnode = _doc->createElement("svg:path");
+    pathnode->setAttribute("d", svgd);
+    g_free(svgd);
+    _root->appendChild(pathnode);
+    Inkscape::GC::release(pathnode);
+    
+    fit_canvas_to_drawing(_clipboardSPDoc);
+    _setClipboardTargets();
+}
+
+/**
+ * @brief Paste from the system clipboard into the active desktop
+ * @param in_place Whether to put the contents where they were when copied
+ */
+bool ClipboardManagerImpl::paste(bool in_place)
+{
+    // do any checking whether we really are able to paste before requesting the contents
+    SPDesktop *desktop = SP_ACTIVE_DESKTOP;
+    if ( desktop == NULL ) return false;
+    if ( Inkscape::have_viable_layer(desktop, desktop->messageStack()) == false ) return false;
+    
+    Glib::ustring target = _getBestTarget();
+    
+    // Special cases of clipboard content handling go here 00ff00
+    // Note that target priority is determined in _getBestTarget.
+    // TODO: Handle x-special/gnome-copied-files and text/uri-list to support pasting files
+    
+    // if there is an image on the clipboard, paste it
+    if ( target == CLIPBOARD_GDK_PIXBUF_TARGET ) return _pasteImage();
+    // if there's only text, paste it into a selected text object or create a new one
+    if ( target == CLIPBOARD_TEXT_TARGET ) return _pasteText();
+    
+    // otherwise, use the import extensions
+    SPDocument *tempdoc = _retrieveClipboard(target);
+    if ( tempdoc == NULL ) {
+        _userWarn(desktop, _("Nothing on the clipboard."));
+        return false;
+    }
+    
+    _pasteDocument(tempdoc, in_place);
+    sp_document_unref(tempdoc);
+    
+    return true;
+}
+
+
+/**
+ * @brief Implements the Paste Style action
+ */
+bool ClipboardManagerImpl::pasteStyle()
+{
+    SPDesktop *desktop = SP_ACTIVE_DESKTOP;
+    if (desktop == NULL) return false;
+
+    // check whether something is selected
+    Inkscape::Selection *selection = sp_desktop_selection(desktop);
+    if (selection->isEmpty()) {
+        _userWarn(desktop, _("Select <b>object(s)</b> to paste style to."));
+        return false;
+    }
+    
+    SPDocument *tempdoc = _retrieveClipboard("image/x-inkscape-svg");
+    if ( tempdoc == NULL ) {
+        _userWarn(desktop, _("No style on the clipboard."));
+        return false;
+    }
+    
+    Inkscape::XML::Node
+        *root = sp_document_repr_root(tempdoc),
+        *clipnode = sp_repr_lookup_name(root, "inkscape:clipboard", 1);
+    
+    bool pasted = false;
+    
+    if (clipnode) {
+        _pasteDefs(tempdoc);
+        SPCSSAttr *style = sp_repr_css_attr(clipnode, "style");
+        sp_desktop_set_style(desktop, style);
+        pasted = true;
+    }
+    else {
+        _userWarn(desktop, _("No style on the clipboard."));
+    }
+
+    sp_document_unref(tempdoc);
+    return pasted;
+}
+
+
+/**
+ * @brief Resize the selection or each object in the selection to match the clipboard's size
+ * @param separately Whether to scale each object in the selection separately
+ * @param apply_x Whether to scale the width of objects / selection
+ * @param apply_y Whether to scale the height of objects / selection
+ */
+bool ClipboardManagerImpl::pasteSize(bool separately, bool apply_x, bool apply_y)
+{
+    if(!apply_x && !apply_y) return false; // pointless parameters
+    
+    SPDesktop *desktop = SP_ACTIVE_DESKTOP;
+    if ( desktop == NULL ) return false;
+    Inkscape::Selection *selection = sp_desktop_selection(desktop);
+    if (selection->isEmpty()) {
+        _userWarn(desktop, _("Select <b>object(s)</b> to paste size to."));
+        return false;
+    }
+    
+    // FIXME: actually, this should accept arbitrary documents
+    SPDocument *tempdoc = _retrieveClipboard("image/x-inkscape-svg");
+    if ( tempdoc == NULL ) {
+        _userWarn(desktop, _("No size on the clipboard."));
+        return false;
+    }
+    
+    // retrieve size ifomration from the clipboard
+    Inkscape::XML::Node *root = sp_document_repr_root(tempdoc);
+    Inkscape::XML::Node *clipnode = sp_repr_lookup_name(root, "inkscape:clipboard", 1);
+    bool pasted = false;
+    if (clipnode) {
+        Geom::Point min, max;
+        sp_repr_get_point(clipnode, "min", &min);
+        sp_repr_get_point(clipnode, "max", &max);
+        
+        // resize each object in the selection
+        if (separately) {
+            for (GSList *i = const_cast<GSList*>(selection->itemList()) ; i ; i = i->next) {
+                SPItem *item = SP_ITEM(i->data);
+                NR::Maybe<NR::Rect> obj_size = sp_item_bbox_desktop(item);
+                if ( !obj_size || obj_size->isEmpty() ) continue;
+                sp_item_scale_rel(item, _getScale(min, max, *obj_size, apply_x, apply_y));
+            }
+        }
+        // resize the selection as a whole
+        else {
+            NR::Maybe<NR::Rect> sel_size = selection->bounds();
+            if ( sel_size && !sel_size->isEmpty() ) {
+                sp_selection_scale_relative(selection, sel_size->midpoint(),
+                    _getScale(min, max, *sel_size, apply_x, apply_y));
+            }
+        }
+        pasted = true;
+    }
+    sp_document_unref(tempdoc);
+    return pasted;
+}
+
+
+/**
+ * @brief Applies a path effect from the clipboard to the selected path
+ */
+bool ClipboardManagerImpl::pastePathEffect()
+{
+    /** @todo FIXME: pastePathEffect crashes when moving the path with the applied effect,
+        segfaulting in fork_private_if_necessary(). */
+    
+    SPDesktop *desktop = SP_ACTIVE_DESKTOP;
+    if ( desktop == NULL ) return false;
+    Inkscape::Selection *selection = sp_desktop_selection(desktop);
+    if (selection->isEmpty()) {
+        _userWarn(desktop, _("Select <b>object(s)</b> to paste live path effect to."));
+        return false;
+    }
+    
+    Inkscape::XML::Node *root, *clipnode;
+    gchar const *effect;
+    SPDocument *tempdoc = _retrieveClipboard("image/x-inkscape-svg");
+    if ( tempdoc == NULL ) goto no_effect;
+    
+    root = sp_document_repr_root(tempdoc),
+    clipnode = sp_repr_lookup_name(root, "inkscape:clipboard", 1);
+    if ( clipnode == NULL ) goto no_effect;
+    effect = clipnode->attribute("inkscape:path-effect");
+    if ( effect == NULL ) goto no_effect;
+    
+    _pasteDefs(tempdoc);
+    for (GSList *item = const_cast<GSList *>(selection->itemList()) ; item ; item = item->next) {
+        _applyPathEffect(reinterpret_cast<SPItem*>(item->data), effect);
+    }
+    return true;
+    
+    no_effect:
+    _userWarn(desktop, _("No effect on the clipboard."));
+    return false;
+}
+
+
+/**
+ * @brief Get LPE path data from the clipboard
+ * @return The retrieved path data (contents of the d attribute), or "" if no path was found
+ */
+Glib::ustring ClipboardManagerImpl::getPathParameter()
+{
+    SPDocument *tempdoc = _retrieveClipboard(); // any target will do here
+    if ( tempdoc == NULL ) {
+        _userWarn(SP_ACTIVE_DESKTOP, _("Nothing on the clipboard."));
+        return "";
+    }
+    Inkscape::XML::Node
+        *root = sp_document_repr_root(tempdoc),
+        *path = sp_repr_lookup_name(root, "svg:path", -1); // unlimited search depth
+    if ( path == NULL ) {
+        _userWarn(SP_ACTIVE_DESKTOP, _("Clipboard does not contain a path."));
+        sp_document_unref(tempdoc);
+        return "";
+    }
+    gchar const *svgd = path->attribute("d");
+    return svgd;
+}
+
+
+/**
+ * @brief Iterate over a list of items and copy them to the clipboard.
+ */
+void ClipboardManagerImpl::_copySelection(Inkscape::Selection *selection)
+{
+    GSList const *items = selection->itemList();
+    // copy the defs used by all items
+    for (GSList *i = const_cast<GSList *>(items) ; i != NULL ; i = i->next) {
+        _copyUsedDefs(SP_ITEM (i->data));
+    }
+    
+    // copy the representation of the items
+    GSList *sorted_items = g_slist_copy(const_cast<GSList *>(items));
+    sorted_items = g_slist_sort(sorted_items, (GCompareFunc) sp_object_compare_position);
+    
+    for (GSList *i = sorted_items ; i ; i = i->next) {
+        if (!SP_IS_ITEM(i->data)) continue;
+        Inkscape::XML::Node *obj = SP_OBJECT_REPR(i->data);
+        Inkscape::XML::Node *obj_copy = _copyNode(obj, _doc, _root);
+
+        // copy complete inherited style
+        SPCSSAttr *css = sp_repr_css_attr_inherited(obj, "style");
+        sp_repr_css_set(obj_copy, css, "style");
+        sp_repr_css_attr_unref(css);
+
+        // write the complete accumulated transform passed to us
+        // (we're dealing with unattached representations, so we write to their attributes
+        // instead of using sp_item_set_transform)
+        gchar *transform_str = sp_svg_transform_write(sp_item_i2doc_affine(SP_ITEM(i->data)));
+        obj_copy->setAttribute("transform", transform_str);
+        g_free(transform_str);
+    }
+    
+    // copy style for Paste Style action
+    if (sorted_items) {
+        if(SP_IS_ITEM(sorted_items->data)) {
+            SPCSSAttr *style = take_style_from_item((SPItem *) sorted_items->data);
+            sp_repr_css_set(_clipnode, style, "style");
+            sp_repr_css_attr_unref(style);
+        }
+        
+        // copy path effect from the first path
+        if (SP_IS_OBJECT(sorted_items->data)) {
+            gchar const *effect = SP_OBJECT_REPR(sorted_items->data)->attribute("inkscape:path-effect");
+            if (effect) {
+                _clipnode->setAttribute("inkscape:path-effect", effect);
+            }
+        }
+    }
+    
+    NR::Maybe<NR::Rect> size = selection->bounds();
+    if (size) {
+        sp_repr_set_point(_clipnode, "min", size->min().to_2geom());
+        sp_repr_set_point(_clipnode, "max", size->max().to_2geom());
+    }
+    
+    g_slist_free(sorted_items);
+}
+
+
+/**
+ * @brief Recursively copy all the definitions used by a given item to the clipboard defs
+ */
+void ClipboardManagerImpl::_copyUsedDefs(SPItem *item)
+{
+    // copy fill and stroke styles (patterns and gradients)
+    SPStyle *style = SP_OBJECT_STYLE(item);
+    
+    if (style && (style->fill.isPaintserver())) {
+        SPObject *server = SP_OBJECT_STYLE_FILL_SERVER(item);
+        if (SP_IS_LINEARGRADIENT(server) || SP_IS_RADIALGRADIENT(server))
+            _copyGradient(SP_GRADIENT(server));
+        if (SP_IS_PATTERN(server))
+            _copyPattern(SP_PATTERN(server));
+    }
+    if (style && (style->stroke.isPaintserver())) {
+        SPObject *server = SP_OBJECT_STYLE_STROKE_SERVER(item);
+        if (SP_IS_LINEARGRADIENT(server) || SP_IS_RADIALGRADIENT(server))
+            _copyGradient(SP_GRADIENT(server));
+        if (SP_IS_PATTERN(server))
+            _copyPattern(SP_PATTERN(server));
+    }
+    
+    // For shapes, copy all of the shape's markers
+    if (SP_IS_SHAPE(item)) {
+        SPShape *shape = SP_SHAPE (item);
+        for (int i = 0 ; i < SP_MARKER_LOC_QTY ; i++) {
+            if (shape->marker[i]) {
+                _copyNode(SP_OBJECT_REPR(SP_OBJECT(shape->marker[i])), _doc, _defs);
+            }
+        }
+        // Also copy live effects if applicable
+        if (sp_shape_has_path_effect(shape)) {
+            _copyNode(SP_OBJECT_REPR(SP_OBJECT(sp_shape_get_livepatheffectobject(shape))), _doc, _defs);
+        }
+    }
+    // For 3D boxes, copy perspectives
+    if (SP_IS_BOX3D(item)) {
+        _copyNode(SP_OBJECT_REPR(SP_OBJECT(box3d_get_perspective(SP_BOX3D(item)))), _doc, _defs);
+    }
+    // Copy text paths
+    if (SP_IS_TEXT_TEXTPATH(item)) {
+        _copyTextPath(SP_TEXTPATH(sp_object_first_child(SP_OBJECT(item))));
+    }
+    // Copy clipping objects
+    if (item->clip_ref->getObject()) {
+        _copyNode(SP_OBJECT_REPR(item->clip_ref->getObject()), _doc, _defs);
+    }
+    // Copy mask objects
+    if (item->mask_ref->getObject()) {
+        SPObject *mask = item->mask_ref->getObject();
+        _copyNode(SP_OBJECT_REPR(mask), _doc, _defs);
+        // recurse into the mask for its gradients etc.
+        for (SPObject *o = SP_OBJECT(mask)->children ; o != NULL ; o = o->next) {
+            if (SP_IS_ITEM(o))
+                _copyUsedDefs(SP_ITEM(o));
+        }
+    }
+    // Copy filters
+    if (style->getFilter()) {
+        SPObject *filter = style->getFilter();
+        if (SP_IS_FILTER(filter)) {
+            _copyNode(SP_OBJECT_REPR(filter), _doc, _defs);
+        }
+    }
+
+    // recurse
+    for (SPObject *o = SP_OBJECT(item)->children ; o != NULL ; o = o->next) {
+        if (SP_IS_ITEM(o))
+            _copyUsedDefs(SP_ITEM(o));
+    }
+}
+
+
+/**
+ * @brief Copy a single gradient to the clipboard's defs element
+ */
+void ClipboardManagerImpl::_copyGradient(SPGradient *gradient)
+{
+    while (gradient) {
+        // climb up the refs, copying each one in the chain
+        _copyNode(SP_OBJECT_REPR(gradient), _doc, _defs);
+        gradient = gradient->ref->getObject();
+    }
+}
+
+
+/**
+ * @brief Copy a single pattern to the clipboard document's defs element
+ */
+void ClipboardManagerImpl::_copyPattern(SPPattern *pattern)
+{
+    // climb up the references, copying each one in the chain
+    while (pattern) {
+        _copyNode(SP_OBJECT_REPR(pattern), _doc, _defs);
+
+        // items in the pattern may also use gradients and other patterns, so recurse
+        for (SPObject *child = sp_object_first_child(SP_OBJECT(pattern)) ; child != NULL ; child = SP_OBJECT_NEXT(child) ) {
+            if (!SP_IS_ITEM (child)) continue;
+            _copyUsedDefs(SP_ITEM(child));
+        }
+        pattern = pattern->ref->getObject();
+    }
+}
+
+
+/**
+ * @brief Copy a text path to the clipboard's defs element
+ */
+void ClipboardManagerImpl::_copyTextPath(SPTextPath *tp)
+{
+    SPItem *path = sp_textpath_get_path_item(tp);
+    if(!path) return;
+    Inkscape::XML::Node *path_node = SP_OBJECT_REPR(path);
+    
+    // Do not copy the text path to defs if it's already copied
+    if(sp_repr_lookup_child(_root, "id", path_node->attribute("id"))) return;
+    _copyNode(path_node, _doc, _defs);
+}
+
+
+/**
+ * @brief Copy a single XML node from one document to another
+ * @param node The node to be copied
+ * @param target_doc The document to which the node is to be copied
+ * @param parent The node in the target document which will become the parent of the copied node
+ * @return Pointer to the copied node
+ */
+Inkscape::XML::Node *ClipboardManagerImpl::_copyNode(Inkscape::XML::Node *node, Inkscape::XML::Document *target_doc, Inkscape::XML::Node *parent)
+{
+    Inkscape::XML::Node *dup = node->duplicate(target_doc);
+    parent->appendChild(dup);
+    Inkscape::GC::release(dup);
+    return dup;
+}
+
+
+/**
+ * @brief Paste the contents of a document into the active desktop
+ * @param clipdoc The document to paste
+ * @param in_place Whether to paste the selection where it was when copied
+ * @pre @c clipdoc is not empty and items can be added to the current layer
+ */
+void ClipboardManagerImpl::_pasteDocument(SPDocument *clipdoc, bool in_place)
+{
+    SPDesktop *desktop = SP_ACTIVE_DESKTOP;
+    SPDocument *target_document = sp_desktop_document(desktop);
+    Inkscape::XML::Node
+        *root = sp_document_repr_root(clipdoc),
+        *target_parent = SP_OBJECT_REPR(desktop->currentLayer());
+    Inkscape::XML::Document *target_xmldoc = sp_document_repr_doc(target_document);
+    
+    // copy definitions
+    _pasteDefs(clipdoc);
+    
+    // copy objects
+    GSList *pasted_objects = NULL;
+    for (Inkscape::XML::Node *obj = root->firstChild() ; obj ; obj = obj->next()) {
+        // Don't copy metadata, defs, named views and internal clipboard contents to the document
+        if (!strcmp(obj->name(), "svg:defs")) continue;
+        if (!strcmp(obj->name(), "svg:metadata")) continue;
+        if (!strcmp(obj->name(), "sodipodi:namedview")) continue;
+        if (!strcmp(obj->name(), "inkscape:clipboard")) continue;
+        Inkscape::XML::Node *obj_copy = _copyNode(obj, target_xmldoc, target_parent);
+        pasted_objects = g_slist_prepend(pasted_objects, (gpointer) obj_copy);
+    }
+    
+    Inkscape::Selection *selection = sp_desktop_selection(desktop);
+    selection->setReprList(pasted_objects);
+    
+    // move the selection to the right position
+    if(in_place)
+    {
+        Inkscape::XML::Node *clipnode = sp_repr_lookup_name(root, "inkscape:clipboard", 1);
+        if (clipnode) {
+            Geom::Point min, max;
+            sp_repr_get_point(clipnode, "min", &min);
+            sp_repr_get_point(clipnode, "max", &max);
+            
+            // this formula was discovered empyrically
+            min[Geom::Y] += ((max[Geom::Y] - min[Geom::Y]) - sp_document_height(target_document));
+            sp_selection_move_relative(selection, NR::Point(min));
+        }
+    }
+    // copied from former sp_selection_paste in selection-chemistry.cpp
+    else {
+        sp_document_ensure_up_to_date(target_document);
+        NR::Maybe<NR::Rect> sel_size = selection->bounds();
+
+        NR::Point m( desktop->point() );
+        if (sel_size) {
+            m -= sel_size->midpoint();
+        }
+        sp_selection_move_relative(selection, m);
+    }
+    
+    g_slist_free(pasted_objects);
+}
+
+
+/**
+ * @brief Paste SVG defs from the document retrieved from the clipboard into the active document
+ * @param clipdoc The document to paste
+ * @pre @c clipdoc != NULL and pasting into the active document is possible
+ */
+void ClipboardManagerImpl::_pasteDefs(SPDocument *clipdoc)
+{
+    // boilerplate vars copied from _pasteDocument
+    SPDesktop *desktop = SP_ACTIVE_DESKTOP;
+    SPDocument *target_document = sp_desktop_document(desktop);
+    Inkscape::XML::Node
+        *root = sp_document_repr_root(clipdoc),
+        *defs = sp_repr_lookup_name(root, "svg:defs", 1),
+        *target_defs = SP_OBJECT_REPR(SP_DOCUMENT_DEFS(target_document));
+    Inkscape::XML::Document *target_xmldoc = sp_document_repr_doc(target_document);
+        
+    for (Inkscape::XML::Node *def = defs->firstChild() ; def ; def = def->next()) {
+        /// @todo TODO: implement def id collision resolution in ClipboardManagerImpl::_pasteDefs()
+        
+        /*
+        // simplistic solution: when a collision occurs, add "a" to id until it's unique
+        Glib::ustring pasted_id = def->attribute("id");
+        if ( pasted_id.empty() ) continue; // defs without id are useless
+        Glib::ustring pasted_id_original = pasted_id;
+        
+        while(sp_repr_lookup_child(target_defs, "id", pasted_id.data())) {
+            pasted_id.append("a");
+        }
+        
+        if ( pasted_id != pasted_id_original ) {
+            def->setAttribute("id", pasted_id.data());
+            // Update the id in the rest of the document so there are no dangling references
+            // How to do that?
+            _changeIdReferences(clipdoc, pasted_id_original, pasted_id);
+        }
+        */
+        if (sp_repr_lookup_child(target_defs, "id", def->attribute("id")))
+            continue; // skip duplicate defs - temporary non-solution
+        
+        _copyNode(def, target_xmldoc, target_defs);
+    }
+}
+
+
+/**
+ * @brief Retrieve a bitmap image from the clipboard and paste it into the active document
+ */
+bool ClipboardManagerImpl::_pasteImage()
+{
+    SPDocument *doc = SP_ACTIVE_DOCUMENT;
+    if ( doc == NULL ) return false;
+    
+    // retrieve image data
+    Glib::RefPtr<Gdk::Pixbuf> img = _clipboard->wait_for_image();
+    if (!img) return false;
+
+    // Very stupid hack: Write into a file, then import the file into the document.
+    // To avoid using tmpfile and POSIX file handles, make the filename based on current time.
+    // This wasn't my idea, I just copied this from selection-chemistry.cpp
+    // and just can't think of something saner at the moment. Pasting more than
+    // one image per second will overwrite the image.
+    // However, I don't think anyone is able to copy a _different_ image into inkscape
+    // in 1 second.
+    time_t rawtime;
+    char image_filename[128];
+    gchar const *save_folder;
+
+    time(&rawtime);
+    strftime(image_filename, 128, "inkscape_pasted_image_%Y%m%d_%H%M%S.png", localtime( &rawtime ));
+    save_folder = (gchar const *) prefs_get_string_attribute("dialogs.save_as", "path");
+    
+    gchar *image_path = g_build_filename(save_folder, image_filename, NULL);
+    img->save(image_path, "png");
+    file_import(doc, image_path, NULL);
+    g_free(image_path);
+
+    return true;
+}
+
+/**
+ * @brief Paste text into the selected text object or create a new one to hold it
+ */
+bool ClipboardManagerImpl::_pasteText()
+{
+    SPDesktop *desktop = SP_ACTIVE_DESKTOP;
+    if ( desktop == NULL ) return false;
+    
+    // if the text editing tool is active, paste the text into the active text object
+    if (tools_isactive(desktop, TOOLS_TEXT))
+        return sp_text_paste_inline(desktop->event_context);
+    
+    // try to parse the text as a color and, if successful, apply it as the current style
+    SPCSSAttr *css = _parseColor(_clipboard->wait_for_text());
+    if (css) {
+        sp_desktop_set_style(desktop, css);
+        return true;
+    }
+    
+    return false;
+}
+
+
+/**
+ * @brief Attempt to parse the passed string as a hexadecimal RGB or RGBA color
+ * @param text The Glib::ustring to parse
+ * @return New CSS style representation if the parsing was successful, NULL otherwise
+ */
+SPCSSAttr *ClipboardManagerImpl::_parseColor(const Glib::ustring &text)
+{
+    Glib::ustring::size_type len = text.bytes();
+    char *str = const_cast<char *>(text.data());
+    bool attempt_alpha = false;
+    if ( !str || ( *str == '\0' ) ) return NULL; // this is OK due to boolean short-circuit
+    
+    // those conditionals guard against parsing e.g. the string "fab" as "fab000"
+    // (incomplete color) and "45fab71" as "45fab710" (incomplete alpha)
+    if ( *str == '#' ) {
+        if ( len < 7 ) return NULL;
+        if ( len >= 9 ) attempt_alpha = true;
+    } else {
+        if ( len < 6 ) return NULL;
+        if ( len >= 8 ) attempt_alpha = true;
+    }
+    
+    unsigned int color = 0, alpha = 0xff;
+    
+    // skip a leading #, if present
+    if ( *str == '#' ) ++str;
+    
+    // try to parse first 6 digits
+    int res = sscanf(str, "%6x", &color);
+    if ( res && ( res != EOF ) ) {
+        if (attempt_alpha) {// try to parse alpha if there's enough characters
+            sscanf(str + 6, "%2x", &alpha);
+            if ( !res || res == EOF ) alpha = 0xff;
+        }
+
+        SPCSSAttr *color_css = sp_repr_css_attr_new();
+        
+        // print and set properties
+        gchar color_str[16];
+        g_snprintf(color_str, 16, "#%06x", color);
+        sp_repr_css_set_property(color_css, "fill", color_str);
+        
+        float opacity = static_cast<float>(alpha)/static_cast<float>(0xff);
+        if (opacity > 1.0) opacity = 1.0; // safeguard
+        Inkscape::CSSOStringStream opcss;
+        opcss << opacity;
+        sp_repr_css_set_property(color_css, "fill-opacity", opcss.str().data());
+        return color_css;
+    }
+    return NULL;
+}
+
+
+/**
+ * @brief Applies a pasted path effect to a given item
+ */
+void ClipboardManagerImpl::_applyPathEffect(SPItem *item, gchar const *effect)
+{
+    if ( item == NULL ) return;
+    
+    if (SP_IS_SHAPE(item))
+    {
+        SPShape *shape = SP_SHAPE(item);
+        SPObject *obj = sp_uri_reference_resolve(_clipboardSPDoc, effect);
+        if (!obj) return;
+        // if the effect is not used by anyone, we might as well take it
+        LivePathEffectObject *lpeobj = LIVEPATHEFFECT(obj)->fork_private_if_necessary(1);
+        sp_shape_set_path_effect(shape, lpeobj);
+
+        // set inkscape:original-d for paths. the other shapes don't need this
+        if (SP_IS_PATH(item)) {
+            Inkscape::XML::Node *pathrepr = SP_OBJECT_REPR(item);
+            if (!pathrepr->attribute("inkscape:original-d")) {
+                pathrepr->setAttribute("inkscape:original-d", pathrepr->attribute("d"));
+            }
+        }
+    }
+    else if (SP_IS_GROUP(item))
+    {
+        for (SPObject *child = sp_object_first_child(SP_OBJECT(item)) ;
+            child != NULL ; child = SP_OBJECT_NEXT(child))
+        {
+            if (!SP_IS_ITEM(child)) continue;
+            _applyPathEffect(SP_ITEM(child), effect);
+        }
+    }
+}
+
+
+/**
+ * @brief Retrieve the clipboard contents as a document
+ * @return Clipboard contents converted to SPDocument, or NULL if no suitable content was present
+ */
+SPDocument *ClipboardManagerImpl::_retrieveClipboard(Glib::ustring required_target)
+{
+    Glib::ustring best_target;
+    if ( required_target == "" ) best_target = _getBestTarget();
+    else best_target = required_target;
+
+    if ( best_target == "" ) {
+        return NULL;
+    }
+    
+    // doing this synchronously makes better sense
+    Gtk::SelectionData sel = _clipboard->wait_for_contents(best_target);
+    
+    Glib::ustring target = sel.get_target();
+    
+    // there is no specific plain SVG input extension, so if we can paste the Inkscape SVG format,
+    // we use the image/svg+xml mimetype to look up the input extension
+    if(target == "image/x-inkscape-svg")
+        target = "image/svg+xml";
+    
+    Inkscape::Extension::DB::InputList inlist;
+    Inkscape::Extension::db.get_input_list(inlist);
+    Inkscape::Extension::DB::InputList::const_iterator in = inlist.begin();
+    for (; in != inlist.end() && target != (*in)->get_mimetype() ; ++in);
+    if ( in == inlist.end() ) return NULL; // this shouldn't happen unless _getBestTarget returns something bogus
+    
+    // FIXME: Temporary hack until we add memory input.
+    // Save the clipboard contents to some file, then read it
+    gchar *filename = g_build_filename( g_get_tmp_dir(), "inkscape-clipboard-import", NULL );
+    g_file_set_contents(filename, (const gchar *) sel.get_data(), sel.get_length(), NULL);
+    
+    SPDocument *tempdoc = (*in)->open(filename);
+    g_unlink(filename);
+    g_free(filename);
+    
+    return tempdoc;
+}
+
+
+/**
+ * @brief Callback called when some other application requests data from Inkscape
+ *
+ * Finds a suitable output extension to save the internal clipboard document,
+ * then saves it to memory and sets the clipboard contents.
+ */
+void ClipboardManagerImpl::_onGet(Gtk::SelectionData &sel, guint info)
+{
+    g_assert( _clipboardSPDoc != NULL );
+    
+    const Glib::ustring target = sel.get_target();
+    if(target == "") return; // this shouldn't happen
+    
+    Inkscape::Extension::DB::OutputList outlist;
+    Inkscape::Extension::db.get_output_list(outlist);
+    Inkscape::Extension::DB::OutputList::const_iterator out = outlist.begin();
+    for ( ; out != outlist.end() && target != (*out)->get_mimetype() ; ++out);
+    if ( out == outlist.end() ) return; // this also shouldn't happen
+    
+    // FIXME: Temporary hack until we add support for memory output.
+    // Save to a temporary file, read it back and then set the clipboard contents
+    gchar *filename = g_build_filename( g_get_tmp_dir(), "inkscape-clipboard-export", NULL );
+    gsize len; gchar *data;
+    
+    (*out)->save(_clipboardSPDoc, filename);
+    g_file_get_contents(filename, &data, &len, NULL);
+    g_unlink(filename); // delete the temporary file
+    g_free(filename);
+    
+    sel.set(8, (guint8 const *) data, len);
+}
+
+
+/**
+ * @brief Callback when someone else takes the clipboard
+ *
+ * When the clipboard owner changes, this callback clears the internal clipboard document
+ * to reduce memory usage.
+ */
+void ClipboardManagerImpl::_onClear()
+{
+    // why is this called before _onGet???
+    //_discardInternalClipboard();
+}
+
+
+/**
+ * @brief Creates an internal clipboard document from scratch
+ */
+void ClipboardManagerImpl::_createInternalClipboard()
+{
+    if ( _clipboardSPDoc == NULL ) {
+        _clipboardSPDoc = sp_document_new(NULL, false, true);
+        //g_assert( _clipboardSPDoc != NULL );
+        _defs = SP_OBJECT_REPR(SP_DOCUMENT_DEFS(_clipboardSPDoc));
+        _doc = sp_document_repr_doc(_clipboardSPDoc);
+        _root = sp_document_repr_root(_clipboardSPDoc);
+        
+        _clipnode = _doc->createElement("inkscape:clipboard");
+        _root->appendChild(_clipnode);
+        Inkscape::GC::release(_clipnode);
+    }
+}
+
+
+/**
+ * @brief Deletes the internal clipboard document
+ */
+void ClipboardManagerImpl::_discardInternalClipboard()
+{
+    if ( _clipboardSPDoc != NULL ) {
+        sp_document_unref(_clipboardSPDoc);
+        _clipboardSPDoc = NULL;
+        _defs = NULL;
+        _doc = NULL;
+        _root = NULL;
+        _clipnode = NULL;
+    }
+}
+
+
+/**
+ * @brief Get the scale to resize an item, based on the command and desktop state
+ */
+NR::scale ClipboardManagerImpl::_getScale(Geom::Point &min, Geom::Point &max, NR::Rect &obj_rect, bool apply_x, bool apply_y)
+{
+    SPDesktop *desktop = SP_ACTIVE_DESKTOP;
+    double scale_x = 1.0;
+    double scale_y = 1.0;
+    
+    if (apply_x) {
+        scale_x = (max[Geom::X] - min[Geom::X]) / obj_rect.extent(NR::X);
+    }
+    if (apply_y) {
+        scale_y = (max[Geom::Y] - min[Geom::Y]) / obj_rect.extent(NR::Y);
+    }
+    // If the "lock aspect ratio" button is pressed and we paste only a single coordinate,
+    // resize the second one by the same ratio too
+    if (desktop->isToolboxButtonActive("lock")) {
+        if (apply_x && !apply_y) scale_y = scale_x;
+        if (apply_y && !apply_x) scale_x = scale_y;
+    }
+    
+    return NR::scale(scale_x, scale_y);
+}
+
+
+/**
+ * @brief Find the most suitable clipboard target
+ */
+Glib::ustring ClipboardManagerImpl::_getBestTarget()
+{
+    std::list<Glib::ustring> targets = _clipboard->wait_for_targets();
+    
+    // clipboard target debugging snippet
+    /*
+    g_debug("Begin clipboard targets");
+    for ( std::list<Glib::ustring>::iterator x = targets.begin() ; x != targets.end(); ++x )
+        g_debug("Clipboard target: %s", (*x).data());
+    g_debug("End clipboard targets\n");
+    //*/
+    
+    for(std::list<Glib::ustring>::iterator i = _preferred_targets.begin() ;
+        i != _preferred_targets.end() ; ++i)
+    {
+        if ( std::find(targets.begin(), targets.end(), *i) != targets.end() )
+            return *i;
+    }
+    if (_clipboard->wait_is_image_available())
+        return CLIPBOARD_GDK_PIXBUF_TARGET;
+    if (_clipboard->wait_is_text_available())
+        return CLIPBOARD_TEXT_TARGET;
+    
+    return "";
+}
+
+
+/**
+ * @brief Set the clipboard targets to reflect the mimetypes Inkscape can output
+ */
+void ClipboardManagerImpl::_setClipboardTargets()
+{   
+    Inkscape::Extension::DB::OutputList outlist;
+    Inkscape::Extension::db.get_output_list(outlist);
+    std::list<Gtk::TargetEntry> target_list;
+    for (Inkscape::Extension::DB::OutputList::const_iterator out = outlist.begin() ; out != outlist.end() ; ++out) {
+        target_list.push_back(Gtk::TargetEntry( (*out)->get_mimetype() ));
+    }
+    
+    _clipboard->set(target_list,
+        sigc::mem_fun(*this, &ClipboardManagerImpl::_onGet),
+        sigc::mem_fun(*this, &ClipboardManagerImpl::_onClear));
+}
+
+
+/**
+ * @brief Set the string representation of a 32-bit RGBA color as the clipboard contents
+ */
+void ClipboardManagerImpl::_setClipboardColor(guint32 color)
+{
+    gchar colorstr[16];
+    g_snprintf(colorstr, 16, "%08x", color);
+    _clipboard->set_text(colorstr);
+}
+
+
+/**
+ * @brief Put a notification on the mesage stack
+ */
+void ClipboardManagerImpl::_userWarn(SPDesktop *desktop, char const *msg)
+{
+    desktop->messageStack()->flash(Inkscape::WARNING_MESSAGE, msg);
+}
+
+
+
+/* #######################################
+          ClipboardManager class
+   ####################################### */
+
+ClipboardManager *ClipboardManager::_instance = NULL;
+
+ClipboardManager::ClipboardManager() {}
+ClipboardManager::~ClipboardManager() {}
+ClipboardManager *ClipboardManager::get()
+{
+    if ( _instance == NULL )
+        _instance = new ClipboardManagerImpl;
+    return _instance;
+}
+
+} // namespace Inkscape
+} // namespace IO
+
+/*
+  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:encoding=utf-8:textwidth=99 :