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1 /**************************************************************************** |
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2 ** |
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3 ** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies). |
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4 ** All rights reserved. |
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7 ** This file is part of the documentation of the Qt Toolkit. |
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24 ** In addition, as a special exception, Nokia gives you certain additional |
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38 ** $QT_END_LICENSE$ |
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39 ** |
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40 ****************************************************************************/ |
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41 |
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42 /*! |
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43 \page restoring-geometry.html |
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44 \title Restoring a Window's Geometry |
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45 |
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46 \ingroup best-practices |
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47 |
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48 This document describes how to save and restore a \l{Window |
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49 Geometry}{window's geometry} using the geometry properties. On |
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50 Windows, this is basically storing the result of |
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51 QWidget::geometry() and calling QWidget::setGeometry() in the next |
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52 session before calling \l{QWidget::show()}{show()}. |
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53 |
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54 On X11, this might not work because an invisible window does not |
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55 have a frame yet. The window manager will decorate the window |
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56 later. When this happens, the window shifts towards the |
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57 bottom/right corner of the screen depending on the size of the |
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58 decoration frame. Although X provides a way to avoid this shift, |
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59 some window managers fail to implement this feature. |
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60 |
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61 Since version 4.2, Qt provides functions that saves and restores a |
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62 window's geometry and state for you. QWidget::saveGeometry() |
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63 saves the window geometry and maximized/fullscreen state, while |
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64 QWidget::restoreGeometry() restores it. The restore function also |
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65 checks if the restored geometry is outside the available screen |
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66 geometry, and modifies it as appropriate if it is: |
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67 |
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68 \snippet doc/src/snippets/code/src_gui_widgets_qmainwindow.cpp 0 |
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69 \snippet doc/src/snippets/code/src_gui_widgets_qmainwindow.cpp 1 |
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70 |
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71 If those functions are not available or cannot be used, then a |
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72 workaround is to call \l{QWidget::setGeometry()}{setGeometry()} |
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73 after \l{QWidget::show()}{show()}. This has the two disadvantages |
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74 that the widget appears at a wrong place for a millisecond |
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75 (results in flashing) and that currently only every second window |
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76 manager gets it right. A safer solution is to store both |
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77 \l{QWidget::pos()}{pos()} and \l{QWidget::size()}{size()} and to |
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78 restore the geometry using \l{QWidget::resize()} and |
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79 \l{QWidget::move()}{move()} before calling |
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80 \l{QWidget::show()}{show()}, as demonstrated in the |
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81 \l{mainwindows/application}{Application} example. |
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82 */ |