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wxSizer

wxSizer is the abstract base class used for laying out subwindows in a window. You cannot use wxSizer directly; instead, you will have to use one of the sizer classes derived from it. Currently there are wxBoxSizer, wxStaticBoxSizer, wxGridSizer wxFlexGridSizer and wxGridBagSizer.

The layout algorithm used by sizers in wxWidgets is closely related to layout in other GUI toolkits, such as Java's AWT, the GTK toolkit or the Qt toolkit. It is based upon the idea of the 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 original size of a dialog in the beginning, rather the dialog will be assigned a sizer and this sizer will be queried about the recommended size. The 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 little 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. If e.g. the standard font as well as the overall design of Motif widgets requires more space than on Windows, the initial dialog size will automatically be bigger on Motif than on Windows.

Sizers may also be used to control the layout of custom drawn items on the window. The Add, Insert, and Prepend functions return a pointer to the newly added wxSizerItem. Just add empty space of the desired size and attributes, and then use the wxSizerItem::GetRect method to determine where the drawing operations should take place.

Please notice that sizers, like child windows, are owned by the library and will be deleted by it which implies that they must be allocated on the heap. However if you create a sizer and do not add it to another sizer or window, the library wouldn't be able to delete such an orphan sizer and in this, and only this, case it should be deleted explicitly.

wxPython note: If you wish to create a sizer class in wxPython you should derive the class from wxPySizer in order to get Python-aware capabilities for the various virtual methods.

Derived from

wxObject
wxClientDataContainer

Include files

<wx/sizer.h>

See also

Sizer overview

Members

wxSizer::wxSizer
wxSizer::~wxSizer
wxSizer::Add
wxSizer::AddSpacer
wxSizer::AddStretchSpacer
wxSizer::CalcMin
wxSizer::Clear
wxSizer::ComputeFittingClientSize
wxSizer::ComputeFittingWindowSize
wxSizer::Detach
wxSizer::Fit
wxSizer::FitInside
wxSizer::GetChildren
wxSizer::GetContainingWindow
wxSizer::GetItem
wxSizer::GetSize
wxSizer::GetPosition
wxSizer::GetMinSize
wxSizer::Hide
wxSizer::Insert
wxSizer::InsertSpacer
wxSizer::InsertStretchSpacer
wxSizer::IsShown
wxSizer::Layout
wxSizer::Prepend
wxSizer::PrependSpacer
wxSizer::PrependStretchSpacer
wxSizer::RecalcSizes
wxSizer::Remove
wxSizer::Replace
wxSizer::SetDimension
wxSizer::SetMinSize
wxSizer::SetItemMinSize
wxSizer::SetSizeHints
wxSizer::SetVirtualSizeHints
wxSizer::Show


wxSizer::wxSizer

wxSizer()

The constructor. Note that wxSizer is an abstract base class and may not be instantiated.


wxSizer::~wxSizer

~wxSizer()

The destructor.


wxSizer::Add

wxSizerItem* Add(wxWindow* window, const wxSizerFlags& flags)

wxSizerItem* Add(wxWindow* window, int proportion = 0,int flag = 0, int border = 0, wxObject* userData = NULL)

wxSizerItem* Add(wxSizer* sizer, const wxSizerFlags& flags)

wxSizerItem* Add(wxSizer* sizer, int proportion = 0, int flag = 0, int border = 0, wxObject* userData = NULL)

wxSizerItem* Add(int width, int height, int proportion = 0, int flag = 0, int border = 0, wxObject* userData = NULL)

Appends a child to the sizer. wxSizer itself is an abstract class, but the parameters are equivalent in the derived classes that you will instantiate to use it so they are described here:

window

sizer

width and height

proportion

flag

border

userData

flags


wxSizer::AddSpacer

wxSizerItem* AddSpacer(int size)

Adds non-stretchable space to the sizer. More readable way of calling Add(size, size, 0).


wxSizer::AddStretchSpacer

wxSizerItem* AddStretchSpacer(int prop = 1)

Adds stretchable space to the sizer. More readable way of calling Add(0, 0, prop).


wxSizer::CalcMin

wxSize CalcMin()

This method is abstract and has to be overwritten by any derived class. Here, the sizer will do the actual calculation of its children minimal sizes.


wxSizer::Clear

void Clear(bool delete_windows = false)

Detaches all children from the sizer. If delete_windows is true then child windows will also be deleted.


wxSizer::ComputeFittingClientSize

wxSize ComputeFittingClientSize(wxWindow* window)

Computes client area size for window so that it matches the sizer's minimal size. Unlike GetMinSize, this method accounts for other constraints imposed on window, namely display's size (returned size will never be too large for the display) and maximum window size if previously set by wxWindow::SetMaxSize.

The returned value is suitable for passing to wxWindow::SetClientSize.

This function is new since wxWidgets version 2.8.8

See also

ComputeFittingWindowSize, Fit


wxSizer::ComputeFittingWindowSize

wxSize ComputeFittingWindowSize(wxWindow* window)

Like ComputeFittingClientSize, but converts the result into window size.

The returned value is suitable for passing to wxWindow::SetSize or wxWindow::SetMinSize.

This function is new since wxWidgets version 2.8.8

See also

ComputeFittingClientSize, Fit


wxSizer::Detach

bool Detach(wxWindow* window)

bool Detach(wxSizer* sizer)

bool Detach(size_t index)

Detach a child from the sizer without destroying it. window is the window to be detached, sizer is the equivalent sizer and index is the position of the child in the sizer, typically 0 for the first item. This method does not cause any layout or resizing to take place, call wxSizer::Layout to update the layout "on screen" after detaching a child from the sizer.

Returns true if the child item was found and detached, false otherwise.

See also

wxSizer::Remove


wxSizer::Fit

wxSize Fit(wxWindow* window)

Tell the sizer to resize the window to match the sizer's minimal size. This is commonly done in the constructor of the window itself, see sample in the description of wxBoxSizer. Returns the new size.

For a top level window this is the total window size, not client size.

See also

ComputeFittingClientSize, ComputeFittingWindowSize


wxSizer::FitInside

void FitInside(wxWindow* window)

Tell the sizer to resize the virtual size of the window to match the sizer's minimal size. This will not alter the on screen size of the window, but may cause the addition/removal/alteration of scrollbars required to view the virtual area in windows which manage it.

See also

wxScrolledWindow::SetScrollbars, wxSizer::SetVirtualSizeHints


wxSizer::GetChildren

wxSizerItemList& GetChildren()

Returns the list of the items in this sizer. The elements of type-safe wxList wxSizerItemList are objects of type wxSizerItem *.


wxSizer::GetContainingWindow

wxWindow * GetContainingWindow() const

Returns the window this sizer is used in or NULL if none.


wxSizer::GetItem

wxSizerItem * GetItem(wxWindow* window, bool recursive = false)

wxSizerItem * GetItem(wxSizer* sizer, bool recursive = false)

wxSizerItem * GetItem(size_t index)

Finds item of the sizer which holds given window, sizer or is located in sizer at position index. Use parameter recursive to search in subsizers too.

Returns pointer to item or NULL.


wxSizer::GetSize

wxSize GetSize()

Returns the current size of the sizer.


wxSizer::GetPosition

wxPoint GetPosition()

Returns the current position of the sizer.


wxSizer::GetMinSize

wxSize GetMinSize()

Returns the minimal size of the sizer. This is either the combined minimal size of all the children and their borders or the minimal size set by SetMinSize, depending on which is bigger.

Note that the returned value is client size, not window size. In particular, if you use the value to set toplevel window's minimal or actual size, you should convert it using wxWindow::ClientToWindowSize before passing it to wxWindow::SetMinSize or wxWindow::SetSize.


wxSizer::Hide

bool Hide(wxWindow* window, bool recursive = false)

bool Hide(wxSizer* sizer, bool recursive = false)

bool Hide(size_t index)

Hides the window, sizer, or item at index. To make a sizer item disappear, use Hide() followed by Layout(). Use parameter recursive to hide elements found in subsizers.

Returns true if the child item was found, false otherwise.

See also

wxSizer::IsShown, wxSizer::Show


wxSizer::Insert

wxSizerItem* Insert(size_t index, wxWindow* window, const wxSizerFlags& flags)

wxSizerItem* Insert(size_t index, wxWindow* window, int proportion = 0,int flag = 0, int border = 0, wxObject* userData = NULL)

wxSizerItem* Insert(size_t index, wxSizer* sizer, const wxSizerFlags& flags)

wxSizerItem* Insert(size_t index, wxSizer* sizer, int proportion = 0, int flag = 0, int border = 0, wxObject* userData = NULL)

wxSizerItem* Insert(size_t index, int width, int height, int proportion = 0, int flag = 0, int border = 0, wxObject* userData = NULL)

Insert a child into the sizer before any existing item at index.

index

See wxSizer::Add for the meaning of the other parameters.


wxSizer::InsertSpacer

wxSizerItem* InsertSpacer(size_t index, int size)

Inserts non-stretchable space to the sizer. More readable way of calling Insert(size, size, 0).


wxSizer::InsertStretchSpacer

wxSizerItem* InsertStretchSpacer(size_t index, int prop = 1)

Inserts stretchable space to the sizer. More readable way of calling Insert(0, 0, prop).


wxSizer::IsShown

bool IsShown(wxWindow* window) const

bool IsShown(wxSizer* sizer) const

bool IsShown(size_t index) const

Returns true if the window, sizer, or item at index is shown.

See also

wxSizer::Hide, wxSizer::Show


wxSizer::Layout

void Layout()

Call this to force layout of the children anew, e.g. after having added a child to or removed a child (window, other sizer or space) from the sizer while keeping the current dimension.


wxSizer::Prepend

wxSizerItem* Prepend(wxWindow* window, const wxSizerFlags& flags)

wxSizerItem* Prepend(wxWindow* window, int proportion = 0, int flag = 0, int border = 0, wxObject* userData = NULL)

wxSizerItem* Prepend(wxSizer* sizer, const wxSizerFlags& flags)

wxSizerItem* Prepend(wxSizer* sizer, int proportion = 0, int flag = 0, int border = 0, wxObject* userData = NULL)

wxSizerItem* Prepend(int width, int height, int proportion = 0, int flag = 0, int border= 0, wxObject* userData = NULL)

Same as wxSizer::Add, but prepends the items to the beginning of the list of items (windows, subsizers or spaces) owned by this sizer.


wxSizer::PrependSpacer

wxSizerItem* PrependSpacer(int size)

Prepends non-stretchable space to the sizer. More readable way of calling Prepend(size, size, 0).


wxSizer::PrependStretchSpacer

wxSizerItem* PrependStretchSpacer(int prop = 1)

Prepends stretchable space to the sizer. More readable way of calling Prepend(0, 0, prop).


wxSizer::RecalcSizes

void RecalcSizes()

This method is abstract and has to be overwritten by any derived class. Here, the sizer will do the actual calculation of its children's positions and sizes.


wxSizer::Remove

bool Remove(wxWindow* window)

bool Remove(wxSizer* sizer)

bool Remove(size_t index)

Removes a child from the sizer and destroys it if it is a sizer or a spacer, but not if it is a window (because windows are owned by their parent window, not the sizer). sizer is the wxSizer to be removed, index is the position of the child in the sizer, e.g. 0 for the first item. This method does not cause any layout or resizing to take place, call wxSizer::Layout to update the layout "on screen" after removing a child from the sizer.

NB: The method taking a wxWindow* parameter is deprecated as it does not destroy the window as would usually be expected from Remove. You should use wxSizer::Detach in new code instead. There is currently no wxSizer method that will both detach and destroy a wxWindow item.

Returns true if the child item was found and removed, false otherwise.


wxSizer::Replace

bool Replace(wxWindow* oldwin, wxWindow* newwin, bool recursive = false)

bool Replace(wxSizer* oldsz, wxSizer* newsz, bool recursive = false)

bool Remove(size_t oldindex, wxSizerItem* newitem)

Detaches the given oldwin, oldsz child from the sizer and replaces it with the given window, sizer, or wxSizerItem.

The detached child is removed only if it is a sizer or a spacer (because windows are owned by their parent window, not the sizer).

Use parameter recursive to search the given element recursively in subsizers.

This method does not cause any layout or resizing to take place, call wxSizer::Layout to update the layout "on screen" after replacing a child from the sizer.

Returns true if the child item was found and removed, false otherwise.


wxSizer::SetDimension

void SetDimension(int x, int y, int width, int height)

Call this to force the sizer to take the given dimension and thus force the items owned by the sizer to resize themselves according to the rules defined by the parameter in the Add and Prepend methods.


wxSizer::SetMinSize

void SetMinSize(int width, int height)

void SetMinSize(const wxSize& size)

Call this to give the sizer a minimal size. Normally, the sizer will calculate its minimal size based purely on how much space its children need. After calling this method GetMinSize will return either the minimal size as requested by its children or the minimal size set here, depending on which is bigger.


wxSizer::SetItemMinSize

void SetItemMinSize(wxWindow* window, int width, int height)

void SetItemMinSize(wxSizer* sizer, int width, int height)

void SetItemMinSize(size_t index, int width, int height)

Set an item's minimum size by window, sizer, or position. The item will be found recursively in the sizer's descendants. This function enables an application to set the size of an item after initial creation.


wxSizer::SetSizeHints

void SetSizeHints(wxWindow* window)

This method first calls wxSizer::Fit and then SetSizeHints on the window passed to it. This only makes sense when window is actually a wxTopLevelWindow such as a wxFrame or a wxDialog, since SetSizeHints only has any effect in these classes. It does nothing in normal windows or controls.

This method is commonly invoked in the constructor of a toplevel window itself (see the sample in the description of wxBoxSizer) if the toplevel window is resizable.


wxSizer::SetVirtualSizeHints

void SetVirtualSizeHints(wxWindow* window)

Tell the sizer to set the minimal size of the window virtual area to match the sizer's minimal size. For windows with managed scrollbars this will set them appropriately.

See also

wxScrolledWindow::SetScrollbars


wxSizer::Show

bool Show(wxWindow* window, bool show = true, bool recursive = false)

bool Show(wxSizer* sizer, bool show = true, bool recursive = false)

bool Show(size_t index, bool show = true)

Shows or hides the window, sizer, or item at index. To make a sizer item disappear or reappear, use Show() followed by Layout(). Use parameter recursive to show or hide elements found in subsizers.

Returns true if the child item was found, false otherwise.

See also

wxSizer::Hide, wxSizer::IsShown