wxBufferedDC - Functions for wxBufferedDC class
Please see following description for synopsis
wxBufferedDC(3) Erlang Module Definition wxBufferedDC(3)
NAME
wxBufferedDC - Functions for wxBufferedDC class
DESCRIPTION
This class provides a simple way to avoid flicker: when drawing on it,
everything is in fact first drawn on an in-memory buffer (a wxBitmap)
and then copied to the screen, using the associated wxDC, only once,
when this object is destroyed. wxBufferedDC itself is typically associ-
ated with wxClientDC, if you want to use it in your EVT_PAINT handler,
you should look at wxBufferedPaintDC instead.
When used like this, a valid DC must be specified in the constructor
while the buffer bitmap doesn't have to be explicitly provided, by
default this class will allocate the bitmap of required size itself.
However using a dedicated bitmap can speed up the redrawing process by
eliminating the repeated creation and destruction of a possibly big
bitmap. Otherwise, wxBufferedDC can be used in the same way as any
other device context.
Another possible use for wxBufferedDC is to use it to maintain a back-
ing store for the window contents. In this case, the associated DC may
be NULL but a valid backing store bitmap should be specified.
Finally, please note that GTK+ 2.0 as well as macOS provide double
buffering themselves natively. You can either use wxWindow:isDouble-
Buffered/1 to determine whether you need to use buffering or not, or
use wxAutoBufferedPaintDC (not implemented in wx) to avoid needless
double buffering on the systems which already do it automatically.
See: wxDC, wxMemoryDC, wxBufferedPaintDC, wxAutoBufferedPaintDC (not
implemented in wx)
This class is derived (and can use functions) from: wxMemoryDC wxDC
wxWidgets docs: wxBufferedDC
DATA TYPES
wxBufferedDC() = wx:wx_object()
EXPORTS
new() -> wxBufferedDC()
Default constructor.
You must call one of the init/4 methods later in order to use
the device context.
new(Dc) -> wxBufferedDC()
Types:
Dc = wxDC:wxDC()
new(Dc, Area) -> wxBufferedDC()
new(Dc, Area :: [Option]) -> wxBufferedDC()
Types:
Dc = wxDC:wxDC()
Option = {buffer, wxBitmap:wxBitmap()} | {style, integer()}
Creates a buffer for the provided dc.
init/4 must not be called when using this constructor.
new(Dc, Area, Options :: [Option]) -> wxBufferedDC()
Types:
Dc = wxDC:wxDC()
Area = {W :: integer(), H :: integer()}
Option = {style, integer()}
Creates a buffer for the provided dc.
init/4 must not be called when using this constructor.
destroy(This :: wxBufferedDC()) -> ok
Copies everything drawn on the DC so far to the underlying DC
associated with this object, if any.
init(This, Dc) -> ok
Types:
This = wxBufferedDC()
Dc = wxDC:wxDC()
init(This, Dc, Area) -> ok
init(This, Dc, Area :: [Option]) -> ok
Types:
This = wxBufferedDC()
Dc = wxDC:wxDC()
Option = {buffer, wxBitmap:wxBitmap()} | {style, integer()}
init(This, Dc, Area, Options :: [Option]) -> ok
Types:
This = wxBufferedDC()
Dc = wxDC:wxDC()
Area = {W :: integer(), H :: integer()}
Option = {style, integer()}
Initializes the object created using the default constructor.
Please see the constructors for parameter details.
wxWidgets team. wx 2.1.1 wxBufferedDC(3)