Lecture 5 --- 6.837 Fall '98

Simple Line
Based on the simple slope-intercept algorithm from algebra

y = m x + b


    public void lineSimple(int x0, int y0, int x1, int y1, Color color) {
        int pix = color.getRGB();
        int dx = x1 - x0;
        int dy = y1 - y0;

        raster.setPixel(pix, x0, y0);
        if (dx != 0) {
            float m = (float) dy / (float) dx;
            float b = y0 - m*x0;
            dx = (x1 > x0) ? 1 : -1;
            while (x0 != x1) {
                x0 += dx;
                y0 = Math.round(m*x0 + b);
                raster.setPixel(pix, x0, y0);
            }
        }
    }

Lecture 5

Slide 4

6.837 Fall '98

The first line-drawing algorithm presented is called the simple slope-intercept algorithm. It is a striaght forward implementation of the slope-intercept formula for a line.

    public void lineSimple(int x0, int y0, int x1, int y1, Color color)
    {
        int pix = color.getRGB();
        int dx = x1 - x0;
        int dy = y1 - y0;

        raster.setPixel(pix, x0, y0);
        if (dx != 0) {
            float m = (float) dy / (float) dx;
            float b = y0 - m*x0;
            dx = (x1 > x0) ? 1 : -1;
            while (x0 != x1) {
                x0 += dx;
                y0 = Math.round(m*x0 + b);
                raster.setPixel(pix, x0, y0);
            }
        }
    }