672fc8ada4
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@52052 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
110 lines
5.2 KiB
C
110 lines
5.2 KiB
C
/////////////////////////////////////////////////////////////////////////////
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// Name: windowsizing
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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
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size-related attributes of a #wxWindow, how they
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relate to each other, and how they interact with sizers. This document
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will attempt to clear the fog a little, and give some simple
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explanations of things.
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@b BestSize: The best size of a widget depends on what kind of widget it
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is, and usually also on the contents of the widget. For example a
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#wxListBox's best size will be calculated based on
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how many items it has, up to a certain limit, or a
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#wxButton's best size will be calculated based on
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its label size, but normally won't be smaller than the platform
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default button size (unless a style flag overrides that). Get the
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picture? There is a special virtual method in the C++ window classes
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called @c DoGetBestSize() that a class needs to override if it
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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,
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such as #wxPanel, 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 calculate the best size.
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-# Otherwise if the window has children then the best size is set to be large 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 for the best size.
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-# Otherwise if there is no min size set, then the current size is used for the best size.
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@b MinSize: The min size of a widget is a size that is normally
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explicitly set by the programmer either with the @c SetMinSize()
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method or the @c SetSizeHints() method. Most controls will also
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set the min size to the size given in the control's constructor if a
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non-default value is passed. Top-level windows such as
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#wxFrame will not allow the user to resize the frame
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below the min size.
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@b Size: The size of a widget can be explicitly set or fetched with
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the @c SetSize() or @c GetSize() methods. This size value
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is the size that the widget is currently using on screen and is the
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way to change the size of something that is not being managed by a
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sizer.
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@b ClientSize: The client size represents the widget's area inside
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of any borders belonging to the widget and is the area that can be
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drawn upon in a @c EVT_PAINT event. If a widget doesn't have a
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border then its client size is the same as its size.
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@b InitialSize: The initial size of a widget is the size given to
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the constructor of the widget, if any. As mentioned above most
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controls will also set this size value as the control's min size. If
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the size passed to the constructor is the default
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@c wxDefaultSize, or if the size is not fully specified (such as
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@c 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
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the control to the resulting size.
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@b GetEffectiveMinSize(): (formerly @c GetBestFittingSize) A
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blending of the widget's min size and best size, giving precedence to
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the min size. For example, if a widget's min size is set to (150, -1)
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and the best size is (80, 22) then the best fitting size is (150,
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22). If the min size is (50, 20) then the best fitting size is (50,
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20). This method is what is called by the sizers when determining what
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the requirements of each item in the sizer is, and is used for
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calculating the overall minimum needs of the sizer.
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@b SetInitialSize(size): (formerly @c SetBestFittingSize)
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This is a little different than the typical size setters. Rather than
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just setting an "initial size" attribute it actually sets the minsize
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to the value passed in, blends that value with the best size, and then
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sets the size of the widget to be the result. So you can consider this
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method to be a "Smart SetSize". This method is what is called by the
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constructor of most controls to set the minsize and initial size of
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the control.
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@b window.Fit(): The @c Fit() method sets the size of a
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window to fit around its children. If it has no children then nothing
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is done, if it does have children then the size of the window is set
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to the window's best size.
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@b sizer.Fit(window): This sets the size of the window to be large
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enough to accommodate the minimum size needed by the sizer, (along with
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a few other constraints...) If the sizer is the one that is assigned
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to the window then this should be equivalent to @c window.Fit().
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@b sizer.Layout(): Recalculates the minimum space needed by each
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item in the sizer, and then lays out the items within the space
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currently allotted to the sizer.
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@b window.Layout(): If the window has a sizer then it sets the
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space given to the sizer to the current size of the window, which
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results in a call to @c sizer.Layout(). If the window has layout
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constraints instead of a sizer then the constraints algorithm is
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run. The @c Layout() method is what is called by the default
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@c EVT_SIZE handler for container windows.
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*/
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