pub trait DrawingBackend {
type ErrorType: Error;
// Required methods
fn get_size(&self) -> (u32, u32);
fn ensure_prepared(
&mut self,
) -> Result<(), DrawingErrorKind<Self::ErrorType>>;
fn present(&mut self) -> Result<(), DrawingErrorKind<Self::ErrorType>>;
fn draw_pixel<S: Color>(
&mut self,
point: BackendCoord,
color: &S,
) -> Result<(), DrawingErrorKind<Self::ErrorType>>;
// Provided methods
fn draw_line<S: BackendStyle>(
&mut self,
from: BackendCoord,
to: BackendCoord,
style: &S,
) -> Result<(), DrawingErrorKind<Self::ErrorType>> { ... }
fn draw_rect<S: BackendStyle>(
&mut self,
upper_left: BackendCoord,
bottom_right: BackendCoord,
style: &S,
fill: bool,
) -> Result<(), DrawingErrorKind<Self::ErrorType>> { ... }
fn draw_path<S: BackendStyle, I: IntoIterator<Item = BackendCoord>>(
&mut self,
path: I,
style: &S,
) -> Result<(), DrawingErrorKind<Self::ErrorType>> { ... }
fn draw_circle<S: BackendStyle>(
&mut self,
center: BackendCoord,
radius: u32,
style: &S,
fill: bool,
) -> Result<(), DrawingErrorKind<Self::ErrorType>> { ... }
fn draw_text<'a, C: Color>(
&mut self,
text: &str,
font: &FontDesc<'a>,
pos: BackendCoord,
color: &C,
) -> Result<(), DrawingErrorKind<Self::ErrorType>> { ... }
}Expand description
The drawing backend trait, which implemenets the low-level drawing APIs.
This trait has a set of default implementation. And the minimal requirement of
implementing a drawing backend is implementing the draw_pixel function.
If the drawing backend supports vector graphics, the other drawing APIs should be overrided by the backend specific implementation. Otherwise, the default implementation will use the pixel-based approach to draw other types of low-level shapes.
Required Associated Types§
Required Methods§
Sourcefn ensure_prepared(&mut self) -> Result<(), DrawingErrorKind<Self::ErrorType>>
fn ensure_prepared(&mut self) -> Result<(), DrawingErrorKind<Self::ErrorType>>
Ensure the backend is ready to draw
Sourcefn present(&mut self) -> Result<(), DrawingErrorKind<Self::ErrorType>>
fn present(&mut self) -> Result<(), DrawingErrorKind<Self::ErrorType>>
Finialize the drawing step and present all the changes.
This is used as the real-time rendering support.
The backend may implement in the following way, when ensure_prepared is called
it checks if it needs a fresh buffer and present is called rendering all the
pending changes on the screen.
Sourcefn draw_pixel<S: Color>(
&mut self,
point: BackendCoord,
color: &S,
) -> Result<(), DrawingErrorKind<Self::ErrorType>>
fn draw_pixel<S: Color>( &mut self, point: BackendCoord, color: &S, ) -> Result<(), DrawingErrorKind<Self::ErrorType>>
Draw a pixel on the drawing backend
point: The backend pixel-based coordinate to drawcolor: The color of the pixel
Provided Methods§
Sourcefn draw_line<S: BackendStyle>(
&mut self,
from: BackendCoord,
to: BackendCoord,
style: &S,
) -> Result<(), DrawingErrorKind<Self::ErrorType>>
fn draw_line<S: BackendStyle>( &mut self, from: BackendCoord, to: BackendCoord, style: &S, ) -> Result<(), DrawingErrorKind<Self::ErrorType>>
Draw a line on the drawing backend
from: The start point of the lineto: The end point of the linestyle: The style of the line
Sourcefn draw_rect<S: BackendStyle>(
&mut self,
upper_left: BackendCoord,
bottom_right: BackendCoord,
style: &S,
fill: bool,
) -> Result<(), DrawingErrorKind<Self::ErrorType>>
fn draw_rect<S: BackendStyle>( &mut self, upper_left: BackendCoord, bottom_right: BackendCoord, style: &S, fill: bool, ) -> Result<(), DrawingErrorKind<Self::ErrorType>>
Draw a rectangle on the drawing backend
upper_left: The coordinate of the upper-left corner of the rectbottom_right: The coordinate of the bottom-right corner of the rectstyle: The stylefill: If the rectangle should be filled
Sourcefn draw_path<S: BackendStyle, I: IntoIterator<Item = BackendCoord>>(
&mut self,
path: I,
style: &S,
) -> Result<(), DrawingErrorKind<Self::ErrorType>>
fn draw_path<S: BackendStyle, I: IntoIterator<Item = BackendCoord>>( &mut self, path: I, style: &S, ) -> Result<(), DrawingErrorKind<Self::ErrorType>>
Draw a path on the drawing backend
path: The iterator of key points of the pathstyle: The style of the path
Sourcefn draw_circle<S: BackendStyle>(
&mut self,
center: BackendCoord,
radius: u32,
style: &S,
fill: bool,
) -> Result<(), DrawingErrorKind<Self::ErrorType>>
fn draw_circle<S: BackendStyle>( &mut self, center: BackendCoord, radius: u32, style: &S, fill: bool, ) -> Result<(), DrawingErrorKind<Self::ErrorType>>
Draw a circle on the drawing backend
center: The center coordinate of the circleradius: The radius of the circlestyle: The style of the shapefill: If the circle should be filled
Sourcefn draw_text<'a, C: Color>(
&mut self,
text: &str,
font: &FontDesc<'a>,
pos: BackendCoord,
color: &C,
) -> Result<(), DrawingErrorKind<Self::ErrorType>>
fn draw_text<'a, C: Color>( &mut self, text: &str, font: &FontDesc<'a>, pos: BackendCoord, color: &C, ) -> Result<(), DrawingErrorKind<Self::ErrorType>>
Draw a text on the drawing backend
text: The text to drawfont: The description of the fontpos: The position backendcolor: The color of the text
Dyn Compatibility§
This trait is not dyn compatible.
In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.