public static Block Encode(List <RGB> colors)
{
// regular case: just try our best to compress and minimise error
var bestsolns = new SolutionSet();
foreach (var flip in new[] { false, true })
{
var pixels = new[] { 0, 1 }.Select(i => colors.Where((c, j) => (j / (flip ? 2 : 8)) % 2 == i).ToArray()).ToArray();
foreach (var diff in new[] { false, true }) // let's again just assume no diff
{
var solns = new Solution[2];
int limit = diff ? 32 : 16;
int i;
for (i = 0; i < 2; i++)
{
var errorThreshold = bestsolns.TotalError;
if (i == 1)
{
errorThreshold -= solns[0].error;
}
var opt = new Optimizer(pixels[i], limit, errorThreshold);
if (i == 1 && diff)
{
opt.baseColor = solns[0].blockColor;
if (!opt.ComputeDeltas(-4, -3, -2, -1, 0, 1, 2, 3))
{
break;
}
}
else
{
if (!opt.ComputeDeltas(-4, -3, -2, -1, 0, 1, 2, 3, 4))
{
break;
}
// TODO: Fix fairly arbitrary/unrefined thresholds that control how far away to scan for potentially better solutions.
if (opt.best_soln.error > 9000)
{
if (opt.best_soln.error > 18000)
{
opt.ComputeDeltas(-8, -7, -6, -5, 5, 6, 7, 8);
}
else
{
opt.ComputeDeltas(-5, 5);
}
}
}
if (opt.best_soln.error >= errorThreshold)
{
break;
}
solns[i] = opt.best_soln;
}
if (i == 2)
{
var solnset = new SolutionSet(flip, diff, solns[0], solns[1]);
if (solnset.TotalError < bestsolns.TotalError)
{
bestsolns = solnset;
}
}
}
}
return(bestsolns.ToBlock());
}