Trait gdk4::prelude::DrawContextExt
source · pub trait DrawContextExt: 'static {
// Required methods
fn begin_frame(&self, region: &Region);
fn end_frame(&self);
fn display(&self) -> Option<Display>;
fn surface(&self) -> Option<Surface>;
fn is_in_frame(&self) -> bool;
}
Expand description
Trait containing all DrawContext
methods.
Implementors
Required Methods§
sourcefn begin_frame(&self, region: &Region)
fn begin_frame(&self, region: &Region)
Indicates that you are beginning the process of redrawing @region on the @self’s surface.
Calling this function begins a drawing operation using @self on the
surface that @self was created from. The actual requirements and
guarantees for the drawing operation vary for different implementations
of drawing, so a CairoContext
and a GLContext
need to be treated differently.
A call to this function is a requirement for drawing and must be
followed by a call to end_frame()
, which will
complete the drawing operation and ensure the contents become visible
on screen.
Note that the @region passed to this function is the minimum region that
needs to be drawn and depending on implementation, windowing system and
hardware in use, it might be necessary to draw a larger region. Drawing
implementation must use DrawContextExtManual::frame_region()
to
query the region that must be drawn.
When using GTK, the widget system automatically places calls to
gdk_draw_context_begin_frame() and gdk_draw_context_end_frame() via the
use of Gsk::Renderer
s, so application code does not need to call
these functions explicitly.
region
minimum region that should be drawn
sourcefn end_frame(&self)
fn end_frame(&self)
Ends a drawing operation started with gdk_draw_context_begin_frame().
This makes the drawing available on screen.
See begin_frame()
for more details about drawing.
When using a GLContext
, this function may call glFlush()
implicitly before returning; it is not recommended to call glFlush()
explicitly before calling this function.
sourcefn is_in_frame(&self) -> bool
fn is_in_frame(&self) -> bool
Returns true
if @self is in the process of drawing to its surface.
This is the case between calls to begin_frame()
and end_frame()
. In this situation, drawing commands
may be effecting the contents of the @self’s surface.
Returns
true
if the context is between begin_frame()
and end_frame()
calls.