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// SPDX-License-Identifier: GPL-2.0-or-later
#ifndef SEEN_SP_PAINT_SERVER_H
#define SEEN_SP_PAINT_SERVER_H
/*
* Base class for gradients and patterns
*
* Author:
* Lauris Kaplinski <lauris@kaplinski.com>
* Jon A. Cruz <jon@joncruz.org>
*
* Copyright (C) 1999-2002 Lauris Kaplinski
* Copyright (C) 2000-2001 Ximian, Inc.
* Copyright (C) 2010 Authors
*
* Released under GNU GPL v2+, read the file 'COPYING' for more information.
*/
#include <memory>
#include <cairo.h>
#include <2geom/rect.h>
#include <sigc++/slot.h>
#include "sp-object.h"
namespace Inkscape {
class Drawing;
class DrawingPattern;
class DrawingPaintServer;
} // namespace Inkscape
class SPPaintServer
: public SPObject
{
public:
SPPaintServer();
~SPPaintServer() override;
int tag() const override { return tag_of<decltype(*this)>; }
bool isSwatch() const;
virtual bool isValid() const;
/*
* There are two ways to implement a paint server:
*
* 1. Simple paint servers (solid colors and gradients) implement the create_drawing_paintserver() method.
* This returns a DrawingPaintServer instance holding a copy of the paint server's resources which is
* used to produce a pattern on-demand using create_pattern().
*
* 2. The other paint servers (patterns and hatches) implement show(), hide() and setBBox().
* The drawing item subtree returned by show() is attached as a fill/stroke child of the
* drawing item the paint server is applied to, and used directly when rendering.
*
* Paint servers only need to implement one method. If both are implemented, then option 2 is used.
*/
virtual std::unique_ptr<Inkscape::DrawingPaintServer> create_drawing_paintserver();
virtual Inkscape::DrawingPattern *show(Inkscape::Drawing &drawing, unsigned key, Geom::OptRect const &bbox);
virtual void hide(unsigned key);
virtual void setBBox(unsigned key, Geom::OptRect const &bbox);
protected:
bool swatch = false;
};
/**
* Returns the first of {src, src-\>ref-\>getObject(),
* src-\>ref-\>getObject()-\>ref-\>getObject(),...}
* for which \a match is true, or NULL if none found.
*
* The raison d'être of this routine is that it correctly handles cycles in the href chain (e.g., if
* a gradient gives itself as its href, or if each of two gradients gives the other as its href).
*
* \pre is<SPGradient>(src).
*/
template <class PaintServer>
PaintServer *chase_hrefs(PaintServer *src, sigc::slot<bool (PaintServer const *)> match) {
/* Use a pair of pointers for detecting loops: p1 advances half as fast as p2. If there is a
loop, then once p1 has entered the loop, we'll detect it the next time the distance between
p1 and p2 is a multiple of the loop size. */
PaintServer *p1 = src, *p2 = src;
bool do1 = false;
for (;;) {
if (match(p2)) {
return p2;
}
p2 = p2->ref->getObject();
if (!p2) {
return p2;
}
if (do1) {
p1 = p1->ref->getObject();
}
do1 = !do1;
if ( p2 == p1 ) {
/* We've been here before, so return NULL to indicate that no matching gradient found
* in the chain. */
return nullptr;
}
}
}
#endif // SEEN_SP_PAINT_SERVER_H
/*
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 :
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