pw_display#

Graphic display support and framebuffer management

Experimental

Attention

This module’s initial implementation is informed by SEED 0104: Display Support, but is being reevaluated as it is migrated from Pigweed’s experimental repsitory.

Libraries#

See also

Color API: Color API

The color library defines base pixel format types and the ColorRgba class for converting between various types.

Display controllers often support a variety of data formats for representing a single pixel. For example:

256 color grayscale:: 8 bits per pixel for a total of 256 shades of gray
4k color: RGB444: 12 bits total; 4 bits for each color: red, green, blue
65k color: RGB565: 16 bits total; 5 bits for red, 6 bits for green and 5 bits for blue
262k color: RGB666: 18 bits total; 6 bits for each color: red, green, blue
16.7M color: RGB888: 24 bits total; 8 bits for each color: red, green, blue

Note

pw_display drawing libraries will initially only operate on RGB565 pixels for a few reasons:

16 bits per color is easily represented as a single 16 bit unsigned integer. No special framebuffer data packing logic is needed for 100% memory utilization.
RGB565 is 65k color which is a good compromise on color fidelity and memory footprint.
RGB565 has wide support by common display controllers used in the embedded space.