Struct piet_direct2d::d2d::DeviceContext

pub struct DeviceContext(_);

The main context that takes drawing operations.

This type is a thin wrapper for ID2D1DeviceContext.

This struct is public only to use for system integration in piet_common and druid-shell. It is not intended that end-users directly use this struct.

Implementations

impl DeviceContext

pub unsafe fn new(ptr: ComPtr<ID2D1DeviceContext>) -> DeviceContext

Create a new device context from an existing COM object.

Marked as unsafe because the device must be in a good state. This might be overly conservative.

Safety

TODO

pub fn get_raw(&self) -> *mut ID2D1DeviceContext

Get the raw pointer

pub fn get_comptr(&self) -> &ComPtr<ID2D1DeviceContext>

Get the Com ptr TODO rename to inner, like for D3D11Device?

pub unsafe fn create_bitmap_from_dxgi(
    &self,
    dxgi: &ComPtr<IDXGISurface>,
    dpi_scale: f32
) -> Result<Bitmap, Error>

Create a bitmap from a DXGI surface.

Most often, this bitmap will be used to set the target of a DeviceContext.

Assumes RGBA8 format and premultiplied alpha.

The unsafe might be conservative, but we assume the dxgi argument is in good shape to be a target.

Safety

TODO

pub fn set_target(&mut self, target: &Bitmap)

Set the target for the device context.

Useful for rendering into bitmaps.

pub fn set_dpi_scale(&mut self, dpi_scale: f32)

Set the dpi scale.

Mostly useful when rendering into bitmaps.

pub fn get_dpi_scale(&self) -> (f32, f32)

pub fn begin_draw(&mut self)

Begin drawing.

This must be done before any piet drawing operations.

There may be safety concerns (not clear what happens if the sequence is not followed).

pub fn end_draw(&mut self) -> Result<(), Error>

End drawing.

Trait Implementations

impl Clone for DeviceContext

fn clone(&self) -> DeviceContext

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.