Qt World Summit: Register Today!

Qt QWS with 18-bit Linux frame buffer

  • Hi!

    I have a silly problem that I would like to fix. I'm using an embedded system with a 32 bit frame buffer. But we are using only a 18-bit LCD. Due to an error in the electric schematic the LCD is connected to the lower 18-bits of the 32-bits. Unfortionatly we have order quit many of these cards and I would like to get them up and running to save us some money.

    My problem is that my kernel driver is 32-bit but I need Qt to back the data as 18-bit. I need every pixel to look like this:
    So what I need is a stride of four bytes per pixel but packing the 6-bit data in the lower 18-bits.

    Is it possible to change Qt so it will pack my data in this way?

    Best regards and happy hacking!

  • there is a config option to handle this:

    -depths <list> ...... Comma-separated list of supported bit-per-pixel
                          depths, from: 1, 4, 8, 12, 15, 16, 18, 24, 32 and 'all'.

  • The whitepaper says that
    "Linear frame-buffers with 1, 4, 8, 15, 16, 24 and 32 bit depths and VGA16
    are supported. "

    But when configuring qt-everywhere-opensource-4.7.4, there is no options to select
    1bpp pixel-depth.

    QtE doesn't support 1bpp frame buffer?
    If it can, how can I configure?

    Thanks in advance.

Log in to reply