Trait gdk4::prelude::DrawContextExt [−][src]
pub trait DrawContextExt: 'static {
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
fn 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
begin_frame() and end_frame() via the
use of Gsk::Renderers, so application code does not need to call
these functions explicitly.
region
minimum region that should be drawn
Ends a drawing operation started with 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.
fn 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.