Add back CONFIG_LV_COLOR_16_SWAP about lvgl HOT 10 CLOSED

I've opened #6225

from lvgl.

Makes sense, can you prepare a PR?

from lvgl.

The main purpose of this would be backward compatibility or ease of use?

from lvgl.

Mainly for backward compatibility. Without CONFIG_LV_COLOR_16_SW_SWAP , those listed configurations will be break in lvgl v9 and it's tough for me to upgrade all LCD drivers to support hardware swap.

from lvgl.

If the LCD driver does not support the endian setting, the SPI can be switched to Bit Order set to MSB FIRST+16bit mode when sending the image buffer with DMA, and then switched to 8bit mode after sending, so that the code is simple and efficient.
I believe most MCUs can support this mode.

See:

from lvgl.

Nice work.

Calling lv_draw_sw_rgb565_swap also has limitation. It performs byte order swap in place, thus needs to swap back before drawing next frame.

from lvgl.

It performs byte order swap in place, thus needs to swap back before drawing next frame.

Why? The buffer into which the UI drawn is dropped after sending the image. Or do you use LVGL in direct mode?

from lvgl.

Yes, we have to consider direct mode too.

from lvgl.

In this case we should swap the bytes only on a given area. Adding lv_draw_sw_rgb565_swap_area can be useful.

from lvgl.

We need some feedback on this issue.

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from lvgl.