Determine color mode of connected display

[projectitis]

Hi there,

I need to push pixels generated on the fly. My colors are always RGB888.
How do I determine the color mode of the display so that I can convert RGB888 to correct format and use the correct tft_Write_ commands?

startWrite();
setAddrWindow( x, y, numPixels, 1);

switch ( tftColorMode ) { // <-- how to determine color mode?
    case ColorMode::RGB565:
        while(numPixels--) pushBlock( convert888to565( generatePixelAs888() ), 1 );
        break;
    case ColorMode::Grey8:
        // etc
}

endWrite();

Also,

1. pushBlock takes a len. Is there an alternative for writing just a single pixel? I can't use the macro tft_Write_16 (etc) directly because it causes problems in my code when expanded.
2. pushBlock always assumes 16 bit color. Are there alternatives for other color modes?