Trait Screen

pub trait Screen<'a> {
    // Required methods
    fn set_client(&self, client: &'a dyn ScreenClient);
    fn get_resolution(&self) -> (usize, usize);
    fn get_pixel_format(&self) -> ScreenPixelFormat;
    fn get_rotation(&self) -> ScreenRotation;
    fn set_write_frame(
        &self,
        x: usize,
        y: usize,
        width: usize,
        height: usize,
    ) -> Result<(), ErrorCode>;
    fn write(
        &self,
        buffer: SubSliceMut<'static, u8>,
        continue_write: bool,
    ) -> Result<(), ErrorCode>;
    fn set_brightness(&self, brightness: u16) -> Result<(), ErrorCode>;
    fn set_power(&self, enabled: bool) -> Result<(), ErrorCode>;
    fn set_invert(&self, enabled: bool) -> Result<(), ErrorCode>;
}

Basic interface for screens.

Required Methods

fn set_client(&self, client: &'a dyn ScreenClient)

Set the object to receive the asynchronous command callbacks.

fn get_resolution(&self) -> (usize, usize)

Get a tuple (width, height) with the current resolution (in pixels).

This function is synchronous as the driver should know this value without requesting it from the screen.

Note that width and height may change due to rotation.

fn get_pixel_format(&self) -> ScreenPixelFormat

Get the current pixel format.

This function is synchronous as the driver should know this value without requesting it from the screen.

fn get_rotation(&self) -> ScreenRotation

Get the current rotation.

This function is synchronous as the driver should know this value without requesting it from the screen.

fn set_write_frame( &self, x: usize, y: usize, width: usize, height: usize, ) -> Result<(), ErrorCode>

Sets the write frame.

This function has to be called before the first call to the write function. This will generate a command_complete() callback when finished.

Return values:

• Ok(()): The write frame is valid.
• INVAL: The parameters of the write frame are not valid.
• BUSY: Unable to set the write frame on the device.

fn write( &self, buffer: SubSliceMut<'static, u8>, continue_write: bool, ) -> Result<(), ErrorCode>

Write data from buffer to the selected write frame.

When finished, the driver will call the write_complete() callback.

This function can be called multiple times if the write frame is larger than the size of the available buffer by setting continue_write to true. If continue_write is false, the buffer write position will be reset before the data are written.

Return values:

• Ok(()): Write is valid and will be sent to the screen.
• SIZE: The buffer is too long for the selected write frame.
• BUSY: Another write is in progress.

fn set_brightness(&self, brightness: u16) -> Result<(), ErrorCode>

Set the display brightness value.

Depending on the display, this may not cause any actual changes until and unless power is enabled (see set_power).

The following values must be supported:

• 0: completely no light emitted
• 1..65536: set brightness to the given level

The display should interpret the brightness value as lightness (each increment should change perceived brightness the same). 1 shall be the minimum supported brightness, 65536 is the maximum brightness. Values in between should approximate the intermediate values; minimum and maximum included (e.g. when there is only 1 level).

fn set_power(&self, enabled: bool) -> Result<(), ErrorCode>

Controls the screen power supply.

Use it to initialize the display device.

For screens where display needs nonzero brightness (e.g. LED), this shall set brightness to a default value if set_brightness was not called first.

The device may implement power independently from brightness, so call set_brightness to turn on/off the module completely.

To allow starting in the correct configuration, the driver is allowed to cache values like brightness or invert mode and apply them together when power is enabled. If the display cannot use selected configuration, this call returns INVAL.

When finished, calls ScreenClient::screen_is_ready, both when power is enabled and disabled.

fn set_invert(&self, enabled: bool) -> Result<(), ErrorCode>

Controls the color inversion mode.

Pixels already in the frame buffer, as well as newly submitted, will be inverted. What that means depends on the current pixel format. May get disabled when switching to another pixel format. Returns NOSUPPORT if the device does not accelerate color inversion. Returns INVAL if the current pixel format does not support color inversion.

Implementors