画像中の色数を数える何か

app.d

// source/app.d

import derelict.freeimage.freeimage;
import std.algorithm;
import std.string;
import std.range;
import std.utf;
import std.stdio;

void main(string[] args)
{
    DerelictFI.load();

    auto fileu = args[1].toUTF16z();

    auto fif = FreeImage_GetFIFFromFilenameU(fileu);
    auto img = FreeImage_LoadU(fif, fileu);

    auto w = FreeImage_GetWidth(img);
    auto h = FreeImage_GetWidth(img);
    writeln(w, h);

    enum mx = 0;
    enum my = 0;

    bool[ubyte[3]] colors;
    foreach (y; my .. (h - my)) {
        foreach (x; mx .. (w - mx)) {
            RGBQUAD color;
            FreeImage_GetPixelColor(img, x, y, &color);
            colors[[color.rgbRed, color.rgbGreen, color.rgbBlue]] = true;
        }
    }

    auto list = colors.keys.filter!(a => colors[a])().map!(a => (format("#%02x%02x%02x", a[0], a[1], a[2])))().array;
    list.sort();
    foreach (color; list) {
        writeln(color);
    }
    writeln(list.length);
}

dub.json

{
	"name": "colors",
	"description": "A minimal D application.",
	"copyright": "Copyright © 2015, ukatama",
	"authors": ["ukatama"],
	"dependencies": {
                "derelict-fi": "~>2.0.1"
	}
}