void drawLine()

in libs/screen/image.cpp [954:1030]

• 71 lines of code
• 21 McCabe index (conditional complexity)

void drawLine(Image_ img, int x0, int y0, int x1, int y1, int c) {
    if (x1 < x0) {
        drawLine(img, x1, y1, x0, y0, c);
        return;
    }
    int w = x1 - x0;
    int h = y1 - y0;

    if (h == 0) {
        if (w == 0)
            setPixel(img, x0, y0, c);
        else
            fillRect(img, x0, y0, w + 1, 1, c);
        return;
    }

    if (w == 0) {
        if (h > 0)
            fillRect(img, x0, y0, 1, h + 1, c);
        else
            fillRect(img, x0, y1, 1, -h + 1, c);
        return;
    }

    if (x1 < 0 || x0 >= img->width())
        return;
    if (x0 < 0) {
        y0 -= (h * x0 / w);
        x0 = 0;
    }
    if (x1 >= img->width()) {
        int d = (img->width() - 1) - x1;
        y1 += (h * d / w);
        x1 = img->width() - 1;
    }

    if (y0 < y1) {
        if (y0 >= img->height() || y1 < 0)
            return;
        if (y0 < 0) {
            x0 -= (w * y0 / h);
            y0 = 0;
        }
        if (y1 >= img->height()) {
            int d = (img->height() - 1) - y1;
            x1 += (w * d / h);
            y1 = img->height() - 1;
        }
    } else {
        if (y1 >= img->height() || y0 < 0)
            return;
        if (y1 < 0) {
            x1 -= (w * y1 / h);
            y1 = 0;
        }
        if (y0 >= img->height()) {
            int d = (img->height() - 1) - y0;
            x0 += (w * d / h);
            y0 = img->height() - 1;
        }
    }

    img->makeWritable();

    if (h < 0) {
        h = -h;
        if (h < w)
            drawLineLow(img, x0, y0, x1, y1, c);
        else
            drawLineHigh(img, x1, y1, x0, y0, c);
    } else {
        if (h < w)
            drawLineLow(img, x0, y0, x1, y1, c);
        else
            drawLineHigh(img, x0, y0, x1, y1, c);
    }
}