3863c5ebd9
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@52244 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
101 lines
5.1 KiB
C
101 lines
5.1 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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@b BestSize: 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). Get the picture? There is a special virtual method in the
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C++ window classes called @c DoGetBestSize() that a class needs to override if
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it wants to calculate its own best size based on its content. The default
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@c DoGetBestSize() is designed for use in container windows, such as wxPanel,
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and works something like this:
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-# If the window has a sizer then it is used to calculate the best size.
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-# Otherwise if the window has layout constraints then that is used to
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calculate the best size.
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-# Otherwise if the window has children then the best size is set to be large
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enough to show all the children.
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-# Otherwise if there are no children then the window's min size will be used
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for the best size.
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-# Otherwise if there is no min size set, then the current size is used for the
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best size.
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@b MinSize: The min size of a widget is a size that is normally explicitly set
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by the programmer either with the @c SetMinSize() method or the
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@c SetSizeHints() method. Most controls will also set the min size to the size
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given in the control's constructor if a non-default value is passed. Top-level
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windows such as wxFrame will not allow the user to resize the frame below the
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min size.
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@b Size: The size of a widget can be explicitly set or fetched with the
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@c SetSize() or @c GetSize() methods. This size value is the size that the
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widget is currently using on screen and is the way to change the size of
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something that is not being managed by a sizer.
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@b ClientSize: 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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@b InitialSize: The initial size of a widget is the size given to the
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constructor of the widget, if any. As mentioned above most controls will also
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set this size value as the control's min size. If the size passed to the
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constructor is the default @c wxDefaultSize, or if the size is not fully
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specified (such as wxSize(150,-1)) then most controls will fill in the missing
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size components using the best size and will set the initial size of the
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control to the resulting size.
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@b GetEffectiveMinSize(): (formerly @c GetBestFittingSize) A blending of the
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widget's min size and best size, giving precedence to the min size. For
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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, and
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is used for calculating the overall minimum needs of the sizer.
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@b SetInitialSize(size): (formerly @c SetBestFittingSize) This is a little
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different than the typical size setters. Rather than just setting an
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"initial size" attribute it actually sets the minsize to the value passed in,
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blends that value with the best size, and then sets the size of the widget to
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be the result. So you can consider this method to be a "Smart SetSize". This
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method is what is called by the constructor of most controls to set the minsize
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and initial size of the control.
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@b window.Fit(): The @c Fit() method sets the size of a window to fit around
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its children. If it has no children then nothing is done, if it does have
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children then the size of the window is set to the window's best size.
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@b sizer.Fit(window): 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 @c window.Fit().
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@b sizer.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
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sizer.
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@b window.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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@c sizer.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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