Bresehham's Line Drawing Algorithm and PID

Question

Does anyone know that if there is a modified version of Bresehham's line algorithm that uses feedback control with PID filters? Basically, the algorithm is just a P-Feedback Control for the error term amplified by half. I looked at the Graphics Gems series, Abrash's book,..etc can't find any yet

Answer 1

Here it is: From Here. This uses the P parameter (see steps in pseudo code shown at top of link)

The provided example code was written in an old environment (references to TurboC in code) and contains functions that will have to be written by you. eg. initgraph(), putpixel(), etc. But the algorithm appears to be complete.

#include <stdio.h>
  #include <conio.h>
  #include <graphics.h>
  #include <math.h>
  #include <dos.h>

  int main() {
        /* request auto detection */
        int gdriver = DETECT, gmode;
        int x1 = 0, y1 = 0, x2, y2;
        int err, x, y, dx, dy, dp, xEnd;
        int twody, twodxdy;

        /* initialize graphic driver */
        initgraph(&gdriver, &gmode, "C:/TURBOC3/BGI");
        err = graphresult();

        if (err != grOk) {
                /* error occurred */
                printf("Graphics Error: %s\n",
                                grapherrormsg(err));
                return 0;
        }

        /* max position in x and y axis */
        x2 = getmaxx();
        y2 = getmaxy();

        /* draws line from (0, 0) to (x2, y2) */
        dx = x2 - x1;
        dy = y2 - y1;

        twody = 2 * dy;
        twodxdy = 2 * (dy - dx);

        dp = twody - dx;

        if (x1 > x2) {
                x = x2;
                y = y2;
                xEnd = x1;
        } else {
                x = x1;
                y = y1;
                xEnd = x2;
        }

        /* put a dot at the position (x, y) */
        putpixel(x, y, WHITE);

        /* calculate x and y successor and plot the points */
        while (x < xEnd) {
                x = x + 1;
                if (dp < 0) {
                        dp = dp + twody;
                } else {
                        y = y + 1;
                        dp = dp + twodxdy;
                }

                /* put a dot at the given position(x, y) */
                putpixel(x, y, WHITE);

                /* sleep for 50 milliseconds */
                delay(50);
        }

        getch();

        /* deallocate memory allocated for graphic screen */
        closegraph();

        return 0;
  }