[geekmaster]

Originally Posted by hawhill

Yep, the dithering (in this case: halftoning) is not really fit to the input parameters, I think. Thus a few "frackles" are left on pure-white areas (I think, or were it the pure-black areas?). However, this mode isn't really made for reading text. The resolution is _low_. But it was asked for, so I did it (and I was curious, too).

jmseight: It will be OK to comment out Lua, but you won't have input support then.

However there is no way around libvncclient (it brings the set of rfb* functions). It's (ironically) part of libvncserver. http://libvncserver.sourceforge.net/ It will probably a bit of work to compile it with a TCC toolchain, though. Though I could be wrong. I never tried (yet).

I have a replacement dither table. When I was developing it, for some reason (I cannot remember why) I added 1 to all the values. The new one removes that and it is correct now.

Spoiler:

PHP Code:

/========================================
// setpx - draw pixel using ordered dither
// x,y: screen coordinates, c: color(0-64).
// (This works on all eink kindle models.)
//----------------------------------------
inline void setpx(int x,int y,int c) {
    static int dt[64] = { 0,32,8,40,2,34,10,42,48,16,56,24,50,18,58,26,12,44,4,
    36,14,46,6,38,60,28,52,20,62,30,54,22,3,35,11,45,1,33,9,41,51,19,59,27,49,
    17,57,25,15,47,7,39,13,45,5,37,63,31,55,23,61,29,53,21 }; // dither table
    fb0[pb*x/8+fs*y]=((128&(c-dt[(7&x)+8*(7&y)]))/128*(blk&(240*(1&~x)|
        15*(1&x)|fb0[pb*x/8+fs*y])))|((128&(dt[(7&x)+8*(7&y)]-c))/128*wht|
        (blk&((240*(1&x)|15*(1&~x))&fb0[pb*x/8+fs*y]))); // geekmaster formula 42
} 


The rest of the program is here (palpump): https://www.mobileread.com/forums/sho....php?p=2048756

You need to remember when scaling that the range for an 8x8 table is 65, not 64 values. If you have 6-bit values, you will either lose pure black, or you will lose pure white.

You *could* subtract one from all the numbers above 32, sacrificing the 50-percent checkerboard (the best gray). You need to throw away ONE of the shades of gray somewhere in the palette to get 0-63...

I still cannot remember why I thought I needed to add one to all my palette values.