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56 lines
1.9 KiB
56 lines
1.9 KiB
15 years ago
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/*
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* Copyright (c) 2003 Patrick Julien <freak@codepimps.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#ifndef KIS_CANVAS_OBSERVER_H_
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#define KIS_CANVAS_OBSERVER_H_
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class KisCanvasSubject;
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/**
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* This is the base interface plugins use to implement the Observer
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* design pattern. Observer can register themselves with an implementation
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* of KisCanvasSubject. The KisCanvasSubject will then call update()
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* on all registered observers whenever something interesting has happened.
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*
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* (This is something my predecessor should have done with signals and slots,
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* I think...)
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*/
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class KisCanvasObserver {
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public:
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KisCanvasObserver() {};
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virtual ~KisCanvasObserver() {};
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public:
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/**
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* Implement this function to query the KisCanvasSubject implementation
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* about state that may be interesting, such as current paint color and
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* so on.
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*
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* @param subject the KisCanvasSubject that may know something that's
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* interesting for us.
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*/
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virtual void update(KisCanvasSubject *subject) = 0;
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private:
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KisCanvasObserver(const KisCanvasObserver&);
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KisCanvasObserver& operator=(const KisCanvasObserver&);
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};
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#endif // KIS_CANVAS_OBSERVER_H_
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