C Mandelbrot设置着色

Question

我正在使用C中的以下代码.到目前为止它已经全部工作并且它被缩放到正确的级别等,但是我正在努力让颜色按照我的意愿工作.理想情况下,无论颜色如何,我都希望得到类似的东西:

但是我的程序如下所示产生的内容如下:

因此,我很感激任何帮助,我可以得到颜色,因为我希望他们.

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#define ITERMAX 100.0
#define DIVERGING 1.1
#define XMAX 500
#define YMAX 500
#define COLORINTENSITY 255

/* allow up to ITERMAX feedbacks searching for convergence
for the feedback
  z0 = 0 + 0i
  znew = z^2 + c
If we have not diverged to distance DIVERGING before ITERMAX feedbacks
we will assume the feedback is convergent at this value of c.
We will report divergence if |z|^2 > DIVERGING
*/

/* We will print color values for each pixel from (0, 0) to (XMAX, YMAX)
The color of pixel (cx, cy) will be set by convergent()
                                    or by divergent()
depending on the convergence or divergence of the feedback
when c = cx + icy
*/

/* The max value of the red, green, or blue component of a color */

void convergent();   /* one color for convergence */
void divergent();    /* a different color for divergence */

void feedback(double *x, double *y, double cx, double cy);
void pixel(char red, char green, char blue);
FILE *fp;


int main()
{
  fp = fopen("mandelbrot.ppm", "wb");
  double x, y, cx, cy;
  int iteration,squarex, squarey, pixelx, pixely;
  double grow=1.0;

/* header for PPM output */
fprintf(fp, "P6\n# CREATOR: EK, BB, RPJ via the mandel program\n");
fprintf(fp, "%d %d\n%d\n",XMAX, YMAX, COLORINTENSITY);

for (pixely = 0; pixely < YMAX; pixely++)  {
    for (pixelx = 0; pixelx < XMAX; pixelx++)  {
        cx = (((float)pixelx)/((float)XMAX)-0.5)/grow*3.0-0.7;
        cy = (((float)pixely)/((float)YMAX)-0.5)/grow*3.0;
        x = 0.0; y = 0.0;
        for (iteration=1;iteration<ITERMAX;iteration++)  {
                     feedback(&x, &y, cx, cy);
                     if (x*x + y*y > 100.0) iteration = 1000;
        }
        if (iteration==ITERMAX) {
          iteration = x*x + y*y;
          pixel((char) 0, (char) 0, (char) 0);
        }
        else {
          iteration = sqrt(x*x + y*y);
          pixel((char) iteration, (char) 0, (char) iteration);
               }
           }
    }
}

void feedback(double *x, double *y, double cx, double cy) {
/* Update x and y according to the feedback equation
 xnew = x^2 - y^2 + cx
 ynew = 2xy + cy
 (these are the real and imaginary parts of the complex equation:
  znew = z^2 + c)
*/
 double xnew = (*x) * (*x) - (*y) * (*y) + cx;
 double ynew  = 2 * *x * *y + cy;
 *x = xnew;
 *y = ynew;
}

void pixel(char red, char green, char blue)  {
/* put a r-g-b triple to the standard out */
 fputc(red, fp);
 fputc(green, fp);
 fputc(blue, fp);
}

Answer 1

要修复条带，您需要迭代表以找到迭代计数的最大值，然后缩放其他值以相对于该最大值（即标准化值）。您可能还希望以对数方式重新调整值以调整颜色变化的斜率。

您可能不想直接在 RGB 空间中工作。如果您在 HSB 空间中定义颜色，则可以设置恒定的色调和饱和度，并根据标准化迭代计数按比例改变亮度。