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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 <cairo.h>
#include <2geom/rect.h>
#include <sigc++/slot.h>
#include "sp-object.h"
namespace Inkscape {
class Drawing;
class DrawingPattern;
}
class SPPaintServer : public SPObject {
public:
SPPaintServer();
~SPPaintServer() override;
bool isSwatch() const;
virtual bool isValid() const;
//There are two ways to render a paint. The simple one is to create cairo_pattern_t structure
//on demand by pattern_new method. It is used for gradients. The other one is to add elements
//representing PaintServer in NR tree. It is used by hatches and patterns.
//Either pattern new or all three methods show, hide, setBBox need to be implemented
virtual Inkscape::DrawingPattern *show(Inkscape::Drawing &drawing, unsigned int key, Geom::OptRect bbox); // TODO check passing bbox by value. Looks suspicious.
virtual void hide(unsigned int key);
virtual void setBBox(unsigned int key, Geom::OptRect const &bbox);
virtual cairo_pattern_t* pattern_new(cairo_t *ct, Geom::OptRect const &bbox, double opacity);
protected:
bool swatch;
};
/**
* 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 SP_IS_GRADIENT(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;
}
}
}
MAKE_SP_OBJECT_TYPECHECK_FUNCTIONS(SP_IS_PAINT_SERVER, SPPaintServer)
#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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