edbcb09440
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@57056 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
102 lines
5.0 KiB
C
102 lines
5.0 KiB
C
/////////////////////////////////////////////////////////////////////////////
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// Name: windowsizing.h
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// Purpose: topic overview
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// Author: wxWidgets team
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// RCS-ID: $Id$
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// Licence: wxWindows license
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/////////////////////////////////////////////////////////////////////////////
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/**
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@page overview_windowsizing Window Sizing Overview
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It can sometimes be confusing to keep track of the various size-related
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attributes of a wxWindow, how they relate to each other, and how they interact
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with sizers. This document will attempt to clear the fog a little, and give
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some simple explanations of things.
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@li @ref overview_windowsizing_glossary
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@li @ref overview_windowsizing_func
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<hr>
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@section overview_windowsizing_glossary Glossary
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@li @b "Best Size": the best size of a widget depends on what kind of widget it is,
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and usually also on the contents of the widget. For example a wxListBox's best
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size will be calculated based on how many items it has, up to a certain limit,
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or a wxButton's best size will be calculated based on its label size, but
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normally won't be smaller than the platform default button size (unless a style
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flag overrides that).
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There is a special virtual method in the C++ window classes called
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wxWindow::DoGetBestSize() that a class needs to override if it wants to calculate
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its own best size based on its content.
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@li @b "Min Size": the minimal size of a widget is a size that is normally explicitly set
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by the programmer either with the wxWindow::SetMinSize() method or with the
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wxWindow::SetSizeHints() method.
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Most controls will also set the min size to the size given in the control's
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constructor if a non-default value is passed.
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Top-level windows such as wxFrame will not allow the user to resize the frame below
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the minimal size.
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@li @b "Size": the size of a widget can be explicitly set or fetched with the
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wxWindow::SetSize() or wxWindow::GetSize() methods.
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This size value is the size that the widget is currently using on screen and is
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the way to change the size of something that is not being managed by a sizer.
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@li @b "Client Size": the client size represents the widget's area inside of any
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borders belonging to the widget and is the area that can be drawn upon in a
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@c EVT_PAINT event. If a widget doesn't have a border then its client size is
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the same as its size.
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@li @b "Initial Size": the initial size of a widget is the size given to the
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constructor of the widget, if any.
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As mentioned above most controls will also set this size value as the control's
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minimal size. If the size passed to the constructor is the default ::wxDefaultSize,
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or if the size is not fully specified (such as wxSize(150,-1)) then most controls
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will fill in the missing size components using the best size and will set the
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initial size of the control to the resulting size.
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@section overview_windowsizing_func Functions related to sizing
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@li wxWindow::GetEffectiveMinSize(): returns a blending of the widget's minimal size
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and best size, giving precedence to the minimal size.
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For example, if a widget's min size is set to (150, -1) and the best size is
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(80, 22) then the best fitting size is (150, 22). If the min size is (50, 20)
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then the best fitting size is (50, 20). This method is what is called by the
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sizers when determining what the requirements of each item in the sizer is,
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and is used for calculating the overall minimum needs of the sizer.
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@li wxWindow::SetInitialSize(): this is a little different than the typical size
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setters. Rather than just setting an "initial size" attribute it actually sets
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the minimal size to the value passed in, blends that value with the best size,
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and then sets the size of the widget to be the result.
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So you can consider this method to be a "Smart SetSize". This method is what is
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called by the constructor of most controls to set the minimal size and the initial
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size of the control.
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@li wxWindow::Fit(): this method sets the size of a window to fit around its children.
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If it has no children then nothing is done, if it does have children then the size
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of the window is set to the window's best size.
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@li wxSizer::Fit(): this sets the size of the window to be large enough to
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accommodate the minimum size needed by the sizer, (along with a few other
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constraints...). If the sizer is the one that is assigned to the window then
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this should be equivalent to wxWindow::Fit().
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@li wxSizer::Layout(): recalculates the minimum space needed by each item in the
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sizer, and then lays out the items within the space currently allotted to the sizer.
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@li wxWindow::Layout(): if the window has a sizer then it sets the space given to
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the sizer to the current size of the window, which results in a call to
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wxSizer::Layout(). If the window has layout constraints instead of a sizer then
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the constraints algorithm is run. The @c Layout() method is what is called by
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the default @c EVT_SIZE handler for container windows.
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*/
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