forked from openkylin/kolourpaint
108 lines
3.5 KiB
C++
108 lines
3.5 KiB
C++
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/*
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Copyright (c) 2003-2007 Clarence Dang <dang@kde.org>
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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1. Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef kpSetOverrideCursorSaver_H
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#define kpSetOverrideCursorSaver_H
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class QCursor;
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//
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// A less error-prone way of setting the override cursor, compared to
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// the QApplication::{set,restore}OverrideCursor() pair.
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//
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// To use this class, allocate it on the stack with the desired cursor.
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//
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// This class sets the application's override cursor to <cursor> on
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// construction. It restores the cursor on destruction.
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//
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// Example Usage 1 - Cursor active during the entire method:
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//
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// void method ()
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// {
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// kpSetOverrideCursorSaver cursorSaver (Qt::WaitCursor);
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//
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// <potentially time-consuming operation>
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//
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// } // Stack unwinds, calling cursorSaver's destructor,
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// // which restores the cursor
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//
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// Example Usage 2 - Cursor active during part of the method:
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//
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// void method ()
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// {
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// <some code>
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//
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// {
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// kpSetOverrideCursorSaver cursorSaver (Qt::WaitCursor);
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//
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// <potentially time-consuming operation>
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//
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// } // Stack unwinds, calling cursorSaver's destructor,
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// // which restores the cursor
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//
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// // (cursor is restored before this code executes)
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// <more code>
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// }
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//
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// Note that the kpSetOverrideCursorSaver must be defined as a local
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// variable inside -- not outside --- the braces containing the code the
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// cursor can be active over, else the destruction and cursor restoration
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// might not occur at the right time. In other words, the following usage
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// is wrong:
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//
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// INCORRECT Example Usage 2:
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//
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// void method ()
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// {
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// <some code>
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//
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// kpSetOverrideCursorSaver cursorSaver (Qt::WaitCursor);
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// // BUG: These braces do nothing to limit the effect of cursorSaver.
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// {
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// <potentially time-consuming operation>
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// }
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//
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// // BUG: cursorSaver has not yet restored the cursor before this
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// // code executes.
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// <more code>
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//
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// } // Stack unwinds, calling cursorSaver's destructor,
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// // which restores the cursor
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//
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class kpSetOverrideCursorSaver
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{
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public:
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kpSetOverrideCursorSaver (const QCursor &cursor);
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~kpSetOverrideCursorSaver ();
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};
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#endif // kpSetOverrideCursorSaver_H
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