/////////////////////////////////////////////////////////////////////////////
-// Name: sizer
+// Name: sizer.h
// Purpose: topic overview
// Author: wxWidgets team
// RCS-ID: $Id$
// Licence: wxWindows license
/////////////////////////////////////////////////////////////////////////////
-/*!
-
- @page sizer_overview Sizer overview
-
- Classes: #wxSizer, #wxGridSizer,
- #wxFlexGridSizer, #wxBoxSizer,
- #wxStaticBoxSizer,
- #CreateButtonSizer
- Sizers, as represented by the wxSizer class and its descendants in
- the wxWidgets class hierarchy, have become the method of choice to
- define the layout of controls in dialogs in wxWidgets because of
- their ability to create visually appealing dialogs independent of the
- platform, taking into account the differences in size and style of
- the individual controls. Unlike the original wxWidgets Dialog Editor,
- editors such as wxDesigner, DialogBlocks, XRCed and wxWorkshop create dialogs based exclusively on sizers,
- practically forcing the user to create platform independent layouts without compromises.
- The next section describes and shows what can be done with sizers.
- The following sections briefly describe how to program with individual sizer classes.
- For information about the new wxWidgets resource system, which can describe
- sizer-based dialogs, see the @ref xrc_overview.
- @ref ideabehindsizers_overview
- @ref boxsizerprogramming_overview
- @ref gridsizerprogramming_overview
- @ref flexgridsizerprogramming_overview
- @ref staticboxsizerprogramming_overview
- #CreateButtonSizer
-
-
- @section ideabehindsizers The idea behind sizers
-
- The layout algorithm used by sizers in wxWidgets is closely related to layout
- systems in other GUI toolkits, such as Java's AWT, the GTK toolkit or the Qt toolkit. It is
- based upon the idea of individual subwindows reporting their minimal required
- size and their ability to get stretched if the size of the parent window has changed.
- This will most often mean that the programmer does not set the start-up size of
- a dialog, the dialog will rather be assigned a sizer and this sizer
- will be queried about the recommended size. This sizer in turn will query its
- children (which can be normal windows, empty space or other sizers) so that
- a hierarchy of sizers can be constructed. Note that wxSizer does not derive from wxWindow
- and thus does not interfere with tab ordering and requires very few resources compared
- to a real window on screen.
- What makes sizers so well fitted for use in wxWidgets is the fact that every control
- reports its own minimal size and the algorithm can handle differences in font sizes
- or different window (dialog item) sizes on different platforms without problems. For example, if
- the standard font as well as the overall design of Linux/GTK widgets requires more space than
- on Windows, the initial dialog size will automatically be bigger on Linux/GTK than on Windows.
- There are currently five different kinds of sizers available in wxWidgets. Each represents
- either a certain way to lay out dialog items in a dialog or it fulfills a special task
- such as wrapping a static box around a dialog item (or another sizer). These sizers will
- be discussed one by one in the text below. For more detailed information on how to use sizers
- programmatically, please refer to the section @ref boxsizerprogramming_overview.
-
- @section sizerscommonfeatures Common features
-
- All sizers are containers, that is, they are used to lay out one dialog item (or several
- dialog items), which they contain. Such items are sometimes referred to as the children
- of the sizer. Independent of how the individual sizers lay out their children, all children
- have certain features in common:
- @b A minimal size: This minimal size is usually identical to
- the initial size of the controls and may either be set explicitly in the wxSize field
- of the control constructor or may be calculated by wxWidgets, typically by setting
- the height and/or the width of the item to -1. Note that only some controls can
- calculate their size (such as a checkbox) whereas others (such as a listbox)
- don't have any natural width or height and thus require an explicit size. Some controls
- can calculate their height, but not their width (e.g. a single line text control):
-
-
-
-
-
-
-
-
- @b A border: The border is just empty space and is used to separate dialog items
- in a dialog. This border can either be all around, or at any combination of sides
- such as only above and below the control. The thickness of this border must be set
- explicitly, typically 5 points. The following samples show dialogs with only one
- dialog item (a button) and a border of 0, 5, and 10 pixels around the button:
-
-
-
-
-
-
-
- @b An alignment: Often, a dialog item is given more space than its minimal size
- plus its border. Depending on what flags are used for the respective dialog
- item, the dialog item can be made to fill out the available space entirely, i.e.
- it will grow to a size larger than the minimal size, or it will be moved to either
- the centre of the available space or to either side of the space. The following
- sample shows a listbox and three buttons in a horizontal box sizer; one button
- is centred, one is aligned at the top, one is aligned at the bottom:
-
-
-
- @b A stretch factor: If a sizer contains more than one child and it is offered
- more space than its children and their borders need, the question arises how to
- distribute the surplus space among the children. For this purpose, a stretch
- factor may be assigned to each child, where the default value of 0 indicates that the child
- will not get more space than its requested minimum size. A value of more than zero
- is interpreted in relation to the sum of all stretch factors in the children
- of the respective sizer, i.e. if two children get a stretch factor of 1, they will
- get half the extra space each @e independent of whether one control has a minimal
- sizer inferior to the other or not. The following sample shows a dialog with
- three buttons, the first one has a stretch factor of 1 and thus gets stretched,
- whereas the other two buttons have a stretch factor of zero and keep their
- initial width:
-
-
-
- Within wxDesigner, this stretch factor gets set from the @e Option menu.
-
- @section sizershiding Hiding controls using sizers
-
- You can hide controls contained in sizers the same way you would hide any control,
- using the wxWindow::Show method.
- However, wxSizer also offers a separate method which can tell the sizer not to
- consider that control in its size calculations. To hide a window using the sizer,
- call wxSizer::Show. You must then call Layout on the sizer
- to force an update.
- This is useful when hiding parts of the interface, since you can avoid removing
- the controls from the sizer and having to add them back later.
- Note: This is supported only by wxBoxSizer and wxFlexGridSizer.
- @b wxBoxSizer
- #wxBoxSizer can lay out its children either vertically
- or horizontally, depending on what flag is being used in its constructor.
- When using a vertical sizer, each child can be centered, aligned to the
- right or aligned to the left. Correspondingly, when using a horizontal
- sizer, each child can be centered, aligned at the bottom or aligned at
- the top. The stretch factor described in the last paragraph is used
- for the main orientation, i.e. when using a horizontal box sizer, the
- stretch factor determines how much the child can be stretched horizontally.
- The following sample shows the same dialog as in the last sample,
- only the box sizer is a vertical box sizer now:
-
-
-
- @b wxStaticBoxSizer
- #wxStaticBoxSixer is the same as a wxBoxSizer, but surrounded by a
- static box. Here is a sample:
-
-
-
- @b wxGridSizer
- #wxGridSizer is a two-dimensional sizer. All children are given the
- same size, which is the minimal size required by the biggest child, in
- this case the text control in the left bottom border. Either the number
- of columns or the number or rows is fixed and the grid sizer will grow
- in the respectively other orientation if new children are added:
-
-
-
- For programming information, see #wxGridSizer.
- @b wxFlexGridSizer
- Another two-dimensional sizer derived from
- wxGridSizer. The width of each column and the height of each row
- are calculated individually according to the minimal requirements
- from the respectively biggest child. Additionally, columns and
- rows can be declared to be stretchable if the sizer is assigned
- a size different from the one it requested. The following sample shows
- the same dialog as the one above, but using a flex grid sizer:
-
-
-
-
- @section boxsizerprogramming Programming with wxBoxSizer
-
- The basic idea behind a #wxBoxSizer is that windows will most often be laid out in rather
- simple basic geometry, typically in a row or a column or several hierarchies of either.
- As an example, we will construct a dialog that will contain a text field at the top and
- two buttons at the bottom. This can be seen as a top-hierarchy column with the text at
- the top and buttons at the bottom and a low-hierarchy row with an OK button to the left
- and a Cancel button to the right. In many cases (particularly dialogs under Unix and
- normal frames) the main window will be resizable by the user and this change of size
- will have to get propagated to its children. In our case, we want the text area to grow
- with the dialog, whereas the button shall have a fixed size. In addition, there will be
- a thin border around all controls to make the dialog look nice and - to make matter worse -
- the buttons shall be centred as the width of the dialog changes.
- It is the unique feature of a box sizer, that it can grow in both directions (height and
- width) but can distribute its growth in the main direction (horizontal for a row) @e unevenly
- among its children. In our example case, the vertical sizer is supposed to propagate all its
- height changes to only the text area, not to the button area. This is determined by the @e proportion parameter
- when adding a window (or another sizer) to a sizer. It is interpreted
- as a weight factor, i.e. it can be zero, indicating that the window may not be resized
- at all, or above zero. If several windows have a value above zero, the value is interpreted
- relative to the sum of all weight factors of the sizer, so when adding two windows with
- a value of 1, they will both get resized equally much and each half as much as the sizer
- owning them. Then what do we do when a column sizer changes its width? This behaviour is
- controlled by @e flags (the second parameter of the Add() function): Zero or no flag
- indicates that the window will preserve it is original size, wxGROW flag (same as wxEXPAND)
- forces the window to grow with the sizer, and wxSHAPED flag tells the window to change it is
- size proportionally, preserving original aspect ratio. When wxGROW flag is not used,
- the item can be aligned within available space. wxALIGN_LEFT, wxALIGN_TOP, wxALIGN_RIGHT,
- wxALIGN_BOTTOM, wxALIGN_CENTER_HORIZONTAL and wxALIGN_CENTER_VERTICAL do what they say.
- wxALIGN_CENTRE (same as wxALIGN_CENTER) is defined as (wxALIGN_CENTER_HORIZONTAL |
- wxALIGN_CENTER_VERTICAL). Default alignment is wxALIGN_LEFT | wxALIGN_TOP.
- As mentioned above, any window belonging to a sizer may have a border, and it can be specified
- which of the four sides may have this border, using the wxTOP, wxLEFT, wxRIGHT and wxBOTTOM
- constants or wxALL for all directions (and you may also use wxNORTH, wxWEST etc instead). These
- flags can be used in combination with the alignment flags above as the second parameter of the
- Add() method using the binary or operator |. The sizer of the border also must be made known,
- and it is the third parameter in the Add() method. This means, that the entire behaviour of
- a sizer and its children can be controlled by the three parameters of the Add() method.
-
- @code
- // we want to get a dialog that is stretchable because it
- // has a text ctrl at the top and two buttons at the bottom
-
- MyDialog::MyDialog(wxFrame *parent, wxWindowID id, const wxString )
- : wxDialog(parent, id, title, wxDefaultPosition, wxDefaultSize,
- wxDEFAULT_DIALOG_STYLE | wxRESIZE_BORDER)
- {
- wxBoxSizer *topsizer = new wxBoxSizer( wxVERTICAL );
-
- // create text ctrl with minimal size 100x60
- topsizer-Add(
- new wxTextCtrl( this, -1, "My text.", wxDefaultPosition, wxSize(100,60), wxTE_MULTILINE),
- 1, // make vertically stretchable
- wxEXPAND | // make horizontally stretchable
- wxALL, // and make border all around
- 10 ); // set border width to 10
-
-
- wxBoxSizer *button_sizer = new wxBoxSizer( wxHORIZONTAL );
- button_sizer-Add(
- new wxButton( this, wxID_OK, "OK" ),
- 0, // make horizontally unstretchable
- wxALL, // make border all around (implicit top alignment)
- 10 ); // set border width to 10
- button_sizer-Add(
- new wxButton( this, wxID_CANCEL, "Cancel" ),
- 0, // make horizontally unstretchable
- wxALL, // make border all around (implicit top alignment)
- 10 ); // set border width to 10
-
- topsizer-Add(
- button_sizer,
- 0, // make vertically unstretchable
- wxALIGN_CENTER ); // no border and centre horizontally
-
- SetSizerAndFit(topsizer); // use the sizer for layout and size window
- // accordingly and prevent it from being resized
- // to smaller size
- }
- @endcode
-
- Note that the new way of specifying flags to wxSizer is via #wxSizerFlags. This class greatly eases the burden of passing flags to a wxSizer.
- Here's how you'd do the previous example with wxSizerFlags:
-
- @code
- // we want to get a dialog that is stretchable because it
- // has a text ctrl at the top and two buttons at the bottom
-
- MyDialog::MyDialog(wxFrame *parent, wxWindowID id, const wxString )
- : wxDialog(parent, id, title, wxDefaultPosition, wxDefaultSize,
- wxDEFAULT_DIALOG_STYLE | wxRESIZE_BORDER)
- {
- wxBoxSizer *topsizer = new wxBoxSizer( wxVERTICAL );
-
- // create text ctrl with minimal size 100x60 that is horizontally and
- // vertically stretchable with a border width of 10
- topsizer-Add(
- new wxTextCtrl( this, -1, "My text.", wxDefaultPosition, wxSize(100,60), wxTE_MULTILINE),
- wxSizerFlags(1).Align().Expand().Border(wxALL, 10));
-
- wxBoxSizer *button_sizer = new wxBoxSizer( wxHORIZONTAL );
-
- //create two buttons that are horizontally unstretchable,
- // with an all-around border with a width of 10 and implicit top alignment
- button_sizer-Add(
- new wxButton( this, wxID_OK, "OK" ),
- wxSizerFlags(0).Align().Border(wxALL, 10));
-
- button_sizer-Add(
- new wxButton( this, wxID_CANCEL, "Cancel" ),
- wxSizerFlags(0).Align().Border(wxALL, 10));
-
- //create a sizer with no border and centered horizontally
- topsizer-Add(
- button_sizer,
- wxSizerFlags(0).Center() );
-
- SetSizerAndFit(topsizer); // use the sizer for layout and set size and hints
- }
- @endcode
-
-
-
- @section gridsizerprogramming Programming with wxGridSizer
-
- #wxGridSizer is a sizer which lays out its children in a two-dimensional
- table with all table fields having the same size,
- i.e. the width of each field is the width of the widest child,
- the height of each field is the height of the tallest child.
-
- @section flexgridsizerprogramming Programming with wxFlexGridSizer
-
- #wxFlexGridSizer is a sizer which lays out its children in a two-dimensional
- table with all table fields in one row having the same
- height and all fields in one column having the same width, but all
- rows or all columns are not necessarily the same height or width as in
- the #wxGridSizer.
-
- @section staticboxsizerprogramming Programming with wxStaticBoxSizer
-
- #wxStaticBoxSizer is a sizer derived from wxBoxSizer but adds a static
- box around the sizer. Note that this static box has to be created
- separately.
-
- @section createbuttonsizer CreateButtonSizer
-
- As a convenience, CreateButtonSizer ( long flags ) can be used to create a standard button sizer
- in which standard buttons are displayed. The following flags can be passed to this function:
-
-
- @code
- wxYES_NO // Add Yes/No subpanel
- wxYES // return wxID_YES
- wxNO // return wxID_NO
- wxNO_DEFAULT // make the wxNO button the default, otherwise wxYES or wxOK button will be default
-
- wxOK // return wxID_OK
- wxCANCEL // return wxID_CANCEL
- wxHELP // return wxID_HELP
-
- wxFORWARD // return wxID_FORWARD
- wxBACKWARD // return wxID_BACKWARD
- wxSETUP // return wxID_SETUP
- wxMORE // return wxID_MORE
- @endcode
-
- */
-
-
+/**
+
+@page overview_sizer Sizers Overview
+
+Classes: wxSizer, wxBoxSizer, wxStaticBoxSizer, wxGridSizer, wxFlexGridSizer,
+ wxGridBagSizer
+
+Sizers, as represented by the wxSizer class and its descendants in the
+wxWidgets class hierarchy, have become the method of choice to define the
+layout of controls in dialogs in wxWidgets because of their ability to create
+visually appealing dialogs independent of the platform, taking into account
+the differences in size and style of the individual controls. Unlike the
+original wxWidgets Dialog Editor, editors such as wxDesigner, DialogBlocks,
+XRCed and wxWorkshop create dialogs based exclusively on sizers, practically
+forcing the user to create platform independent layouts without compromises.
+
+The next section describes and shows what can be done with sizers. The
+following sections briefly describe how to program with individual sizer
+classes.
+
+For information about the wxWidgets resource system, which can describe
+sizer-based dialogs, see the @ref overview_xrc.
+
+@li @ref overview_sizer_idea
+@li @ref overview_sizer_features
+@li @ref overview_sizer_hiding
+@li @ref overview_sizer_box
+@li @ref overview_sizer_types
+@li @ref overview_sizer_button
+
+
+<hr>
+
+
+@section overview_sizer_idea The Idea Behind Sizers
+
+The layout algorithm used by sizers in wxWidgets is closely related to layout
+systems in other GUI toolkits, such as Java's AWT, the GTK toolkit or the Qt
+toolkit. It is based upon the idea of individual subwindows reporting their
+minimal required size and their ability to get stretched if the size of the
+parent window has changed. This will most often mean that the programmer does
+not set the start-up size of a dialog, the dialog will rather be assigned a
+sizer and this sizer will be queried about the recommended size. This sizer in
+turn will query its children (which can be normal windows, empty space or other
+sizers) so that a hierarchy of sizers can be constructed. Note that wxSizer
+does not derive from wxWindow and thus does not interfere with tab ordering and
+requires very few resources compared to a real window on screen.
+
+What makes sizers so well fitted for use in wxWidgets is the fact that every
+control reports its own minimal size and the algorithm can handle differences
+in font sizes or different window (dialog item) sizes on different platforms
+without problems. For example, if the standard font as well as the overall
+design of Linux/GTK widgets requires more space than on Windows, the initial
+dialog size will automatically be bigger on Linux/GTK than on Windows.
+
+There are currently five different kinds of sizers available in wxWidgets. Each
+represents either a certain way to lay out dialog items in a dialog or it
+fulfills a special task such as wrapping a static box around a dialog item (or
+another sizer). These sizers will be discussed one by one in the text below.
+For more detailed information on how to use sizers programmatically, please
+refer to the section @ref overview_sizer_box.
+
+
+@section overview_sizer_features Common Features
+
+All sizers are containers, that is, they are used to lay out one dialog item
+(or several dialog items), which they contain. Such items are sometimes
+referred to as the children of the sizer. Independent of how the individual
+sizers lay out their children, all children have certain features in common:
+
+<b>A minimal size</b>: This minimal size is usually identical to the initial
+size of the controls and may either be set explicitly in the wxSize field of
+the control constructor or may be calculated by wxWidgets, typically by setting
+the height and/or the width of the item to -1. Note that only some controls can
+calculate their size (such as a checkbox) whereas others (such as a listbox)
+don't have any natural width or height and thus require an explicit size. Some
+controls can calculate their height, but not their width (e.g. a single line
+text control):
+
+@image html overview_sizer_03.png
+
+@image html overview_sizer_04.png
+
+@image html overview_sizer_05.png
+
+<b>A border</b>: The border is just empty space and is used to separate dialog
+items in a dialog. This border can either be all around, or at any combination
+of sides such as only above and below the control. The thickness of this border
+must be set explicitly, typically 5 points. The following samples show dialogs
+with only one dialog item (a button) and a border of 0, 5, and 10 pixels around
+the button:
+
+@image html overview_sizer_00.png
+
+@image html overview_sizer_01.png
+
+@image html overview_sizer_02.png
+
+<b>An alignment</b>: Often, a dialog item is given more space than its minimal
+size plus its border. Depending on what flags are used for the respective
+dialog item, the dialog item can be made to fill out the available space
+entirely, i.e. it will grow to a size larger than the minimal size, or it will
+be moved to either the centre of the available space or to either side of the
+space. The following sample shows a listbox and three buttons in a horizontal
+box sizer; one button is centred, one is aligned at the top, one is aligned at
+the bottom:
+
+@image html overview_sizer_06.png
+
+<b>A stretch factor</b>: If a sizer contains more than one child and it is
+offered more space than its children and their borders need, the question
+arises how to distribute the surplus space among the children. For this
+purpose, a stretch factor may be assigned to each child, where the default
+value of 0 indicates that the child will not get more space than its requested
+minimum size. A value of more than zero is interpreted in relation to the sum
+of all stretch factors in the children of the respective sizer, i.e. if two
+children get a stretch factor of 1, they will get half the extra space each
+<em>independent of whether one control has a minimal sizer inferior to the
+other or not</em>. The following sample shows a dialog with three buttons, the
+first one has a stretch factor of 1 and thus gets stretched, whereas the other
+two buttons have a stretch factor of zero and keep their initial width:
+
+@image html overview_sizer_07.png
+
+Within wxDesigner, this stretch factor gets set from the @e Option menu.
+
+
+@section overview_sizer_hiding Hiding Controls Using Sizers
+
+You can hide controls contained in sizers the same way you would hide any
+control, using the wxWindow::Show method. However, wxSizer also offers a
+separate method which can tell the sizer not to consider that control in its
+size calculations. To hide a window using the sizer, call wxSizer::Show. You
+must then call Layout on the sizer to force an update.
+
+This is useful when hiding parts of the interface, since you can avoid removing
+the controls from the sizer and having to add them back later.
+
+@note This is supported only by wxBoxSizer and wxFlexGridSizer.
+
+@subsection overview_sizer_hiding_box wxBoxSizer
+
+wxBoxSizer can lay out its children either vertically or horizontally,
+depending on what flag is being used in its constructor. When using a vertical
+sizer, each child can be centered, aligned to the right or aligned to the left.
+Correspondingly, when using a horizontal sizer, each child can be centered,
+aligned at the bottom or aligned at the top. The stretch factor described in
+the last paragraph is used for the main orientation, i.e. when using a
+horizontal box sizer, the stretch factor determines how much the child can be
+stretched horizontally. The following sample shows the same dialog as in the
+last sample, only the box sizer is a vertical box sizer now:
+
+@image html overview_sizer_08.png
+
+@subsection overview_sizer_hiding_static wxStaticBoxSizer
+
+wxStaticBoxSixer is the same as a wxBoxSizer, but surrounded by a static box.
+Here is a sample:
+
+@image html overview_sizer_09.png
+
+@subsection overview_sizer_hiding_grid wxGridSizer
+
+wxGridSizer is a two-dimensional sizer. All children are given the same size,
+which is the minimal size required by the biggest child, in this case the text
+control in the left bottom border. Either the number of columns or the number
+or rows is fixed and the grid sizer will grow in the respectively other
+orientation if new children are added:
+
+@image html overview_sizer_10.png
+
+For programming information, see wxGridSizer.
+
+@subsection overview_sizer_hiding_flexgrid wxFlexGridSizer
+
+Another two-dimensional sizer derived from wxGridSizer. The width of each
+column and the height of each row are calculated individually according to the
+minimal requirements from the respectively biggest child. Additionally, columns
+and rows can be declared to be stretchable if the sizer is assigned a size
+different from the one it requested. The following sample shows the same dialog
+as the one above, but using a flex grid sizer:
+
+@image html overview_sizer_11.png
+
+
+@section overview_sizer_box Programming with wxBoxSizer
+
+The basic idea behind a wxBoxSizer is that windows will most often be laid out
+in rather simple basic geometry, typically in a row or a column or several
+hierarchies of either.
+
+As an example, we will construct a dialog that will contain a text field at the
+top and two buttons at the bottom. This can be seen as a top-hierarchy column
+with the text at the top and buttons at the bottom and a low-hierarchy row with
+an OK button to the left and a Cancel button to the right. In many cases
+(particularly dialogs under Unix and normal frames) the main window will be
+resizable by the user and this change of size will have to get propagated to
+its children. In our case, we want the text area to grow with the dialog,
+whereas the button shall have a fixed size. In addition, there will be a thin
+border around all controls to make the dialog look nice and - to make matter
+worse - the buttons shall be centred as the width of the dialog changes.
+
+It is the unique feature of a box sizer, that it can grow in both directions
+(height and width) but can distribute its growth in the main direction
+(horizontal for a row) @e unevenly among its children. In our example case, the
+vertical sizer is supposed to propagate all its height changes to only the text
+area, not to the button area. This is determined by the @e proportion parameter
+when adding a window (or another sizer) to a sizer. It is interpreted as a
+weight factor, i.e. it can be zero, indicating that the window may not be
+resized at all, or above zero. If several windows have a value above zero, the
+value is interpreted relative to the sum of all weight factors of the sizer, so
+when adding two windows with a value of 1, they will both get resized equally
+much and each half as much as the sizer owning them. Then what do we do when a
+column sizer changes its width? This behaviour is controlled by @e flags (the
+second parameter of the Add() function): Zero or no flag indicates that the
+window will preserve it is original size, wxGROW flag (same as wxEXPAND) forces
+the window to grow with the sizer, and wxSHAPED flag tells the window to change
+it is size proportionally, preserving original aspect ratio. When wxGROW flag
+is not used, the item can be aligned within available space. wxALIGN_LEFT,
+wxALIGN_TOP, wxALIGN_RIGHT, wxALIGN_BOTTOM, wxALIGN_CENTER_HORIZONTAL and
+wxALIGN_CENTER_VERTICAL do what they say. wxALIGN_CENTRE (same as
+wxALIGN_CENTER) is defined as (wxALIGN_CENTER_HORIZONTAL |
+wxALIGN_CENTER_VERTICAL). Default alignment is wxALIGN_LEFT | wxALIGN_TOP.
+
+As mentioned above, any window belonging to a sizer may have a border, and it
+can be specified which of the four sides may have this border, using the wxTOP,
+wxLEFT, wxRIGHT and wxBOTTOM constants or wxALL for all directions (and you may
+also use wxNORTH, wxWEST etc instead). These flags can be used in combination
+with the alignment flags above as the second parameter of the Add() method
+using the binary or operator |. The sizer of the border also must be made
+known, and it is the third parameter in the Add() method. This means, that the
+entire behaviour of a sizer and its children can be controlled by the three
+parameters of the Add() method.
+
+@code
+// We want to get a dialog that is stretchable because it
+// has a text ctrl at the top and two buttons at the bottom.
+
+MyDialog::MyDialog(wxFrame *parent, wxWindowID id, const wxString &title )
+: wxDialog(parent, id, title, wxDefaultPosition, wxDefaultSize,
+ wxDEFAULT_DIALOG_STYLE | wxRESIZE_BORDER)
+{
+ wxBoxSizer *topsizer = new wxBoxSizer( wxVERTICAL );
+
+ // create text ctrl with minimal size 100x60
+ topsizer->Add(
+ new wxTextCtrl( this, -1, "My text.", wxDefaultPosition, wxSize(100,60), wxTE_MULTILINE),
+ 1, // make vertically stretchable
+ wxEXPAND | // make horizontally stretchable
+ wxALL, // and make border all around
+ 10 ); // set border width to 10
+
+ wxBoxSizer *button_sizer = new wxBoxSizer( wxHORIZONTAL );
+ button_sizer->Add(
+ new wxButton( this, wxID_OK, "OK" ),
+ 0, // make horizontally unstretchable
+ wxALL, // make border all around (implicit top alignment)
+ 10 ); // set border width to 10
+ button_sizer->Add(
+ new wxButton( this, wxID_CANCEL, "Cancel" ),
+ 0, // make horizontally unstretchable
+ wxALL, // make border all around (implicit top alignment)
+ 10 ); // set border width to 10
+
+ topsizer->Add(
+ button_sizer,
+ 0, // make vertically unstretchable
+ wxALIGN_CENTER ); // no border and centre horizontally
+
+ SetSizerAndFit(topsizer); // use the sizer for layout and size window
+ // accordingly and prevent it from being resized
+ // to smaller size
+}
+@endcode
+
+Note that the new way of specifying flags to wxSizer is via wxSizerFlags. This
+class greatly eases the burden of passing flags to a wxSizer.
+
+Here's how you'd do the previous example with wxSizerFlags:
+
+@code
+// We want to get a dialog that is stretchable because it
+// has a text ctrl at the top and two buttons at the bottom.
+
+MyDialog::MyDialog(wxFrame *parent, wxWindowID id, const wxString &title )
+: wxDialog(parent, id, title, wxDefaultPosition, wxDefaultSize,
+ wxDEFAULT_DIALOG_STYLE | wxRESIZE_BORDER)
+{
+ wxBoxSizer *topsizer = new wxBoxSizer( wxVERTICAL );
+
+ // create text ctrl with minimal size 100x60 that is horizontally and
+ // vertically stretchable with a border width of 10
+ topsizer->Add(
+ new wxTextCtrl( this, -1, "My text.", wxDefaultPosition, wxSize(100,60), wxTE_MULTILINE),
+ wxSizerFlags(1).Align().Expand().Border(wxALL, 10));
+
+ wxBoxSizer *button_sizer = new wxBoxSizer( wxHORIZONTAL );
+
+ //create two buttons that are horizontally unstretchable,
+ // with an all-around border with a width of 10 and implicit top alignment
+ button_sizer->Add(
+ new wxButton( this, wxID_OK, "OK" ),
+ wxSizerFlags(0).Align().Border(wxALL, 10));
+
+ button_sizer->Add(
+ new wxButton( this, wxID_CANCEL, "Cancel" ),
+ wxSizerFlags(0).Align().Border(wxALL, 10));
+
+ //create a sizer with no border and centered horizontally
+ topsizer->Add(
+ button_sizer,
+ wxSizerFlags(0).Center() );
+
+ SetSizerAndFit(topsizer); // use the sizer for layout and set size and hints
+}
+@endcode
+
+
+
+@section overview_sizer_types Other Types of Sizers
+
+wxGridSizer is a sizer which lays out its children in a two-dimensional table
+with all table fields having the same size, i.e. the width of each field is the
+width of the widest child, the height of each field is the height of the
+tallest child.
+
+wxFlexGridSizer is a sizer which lays out its children in a two-dimensional
+table with all table fields in one row having the same height and all fields in
+one column having the same width, but all rows or all columns are not
+necessarily the same height or width as in the wxGridSizer.
+
+wxStaticBoxSizer is a sizer derived from wxBoxSizer but adds a static box
+around the sizer. Note that this static box has to be created separately.
+
+wxGridBagSizer is a rather special kind of sizer which, unlike the other
+classes, allows to directly put the elements at the given position in the
+sizer. Please see its documentation for more details.
+
+@section overview_sizer_button CreateButtonSizer
+
+As a convenience, wxDialog::CreateButtonSizer(long flags) can be used to create a
+standard button sizer in which standard buttons are displayed. The following
+flags can be passed to this function:
+
+@code
+wxYES_NO // Add Yes/No subpanel
+wxYES // return wxID_YES
+wxNO // return wxID_NO
+wxNO_DEFAULT // make the wxNO button the default,
+ // otherwise wxYES or wxOK button will be default
+
+wxOK // return wxID_OK
+wxCANCEL // return wxID_CANCEL
+wxHELP // return wxID_HELP
+
+wxFORWARD // return wxID_FORWARD
+wxBACKWARD // return wxID_BACKWARD
+wxSETUP // return wxID_SETUP
+wxMORE // return wxID_MORE
+@endcode
+
+*/
+