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void PixelsAntialiased::drawLineAntialiased(int16_t x1, int16_t y1, int16_t x2, int16_t y2) {

    boolean steep = (y2 > y1 ? y2 - y1 : y1 - y2) > (x2 > x1 ? x2 - x1 : x1 - x2);
    if (steep) {
        int16_t tmp = x1;
        x1 = y1;
        y1 = tmp;
        tmp = x2;
        x2 = y2;
        y2 = tmp;
    }
    if (x1 > x2) {
        int16_t tmp = x1;
        x1 = x2;
        x2 = tmp;
        tmp = y1;
        y1 = y2;
        y2 = tmp;
    }
    int16_t deltax = x2 - x1;
    int16_t deltay = y2 - y1;
    double gradient = 1.0 * deltay / deltax;

    int16_t xend = x1; // round(x1);
    double yend = y1 + gradient * (xend - x1);
    double xgap = rfpart(x1 + 0.5);
    int16_t xpxl1 = xend;
    int16_t ypxl1 = ipart(yend);
    putColor(xpxl1, ypxl1, steep, rfpart(yend)*xgap);
    putColor(xpxl1, ypxl1 + 1, steep, fpart(yend)*xgap);
    double intery = yend + gradient;

    xend = x2; // round(x2);
    yend = y2 + gradient * (xend - x2);
    xgap = rfpart(x2 + 0.5);
    int16_t xpxl2 = xend;
    int16_t ypxl2 = ipart(yend);
    putColor(xpxl2, ypxl2, steep, rfpart(yend)*xgap);
    putColor(xpxl2, ypxl2 + 1, steep, fpart(yend)*xgap);

    for ( int16_t x = xpxl1 + 1; x < xpxl2 - 1; x++ ) {
          putColor(x, ipart(intery), steep, rfpart(intery));
          putColor(x, ipart(intery) + 1, steep, fpart(intery));
          intery += gradient;
    }
}