function plotter

 1 #include <stdio.h>
 2 #include <math.h>
 3 #include <stdlib.h>
 4 #include <stdbool.h>
 5 #define max(x, y) ((x)>(y)?(x):(y))
 6 
 7 #define XDIM 1024    //此项必须为8的倍数，否则有BUG
 8 #define YDIM 768
 9 
10 //为图形协调，请保持与XDIM、YDIM的比例
11 #define X_RANGE 2*4
12 #define Y_RANGE 2*3
13 
14 #define INACCURACY 1.0 //单位：像素
15 
16 #define XI XDIM/2
17 #define YI YDIM/2
18 bool tof(int i, int j)
19 {
20     //坐标转换
21     double x = (double)(i-XI)*X_RANGE/XDIM;
22     double y = Y_RANGE-(double)(j+YI)*Y_RANGE/YDIM;
23     double d = INACCURACY*max(X_RANGE/(double)XDIM, Y_RANGE/(double)YDIM);
24     
25     if
26     ( 
27         i == XI || j == YI-1 ||
28         j == YI || i == XI-1 ||
29         fabs(x-(int)x)<d    ||
30         fabs(y-(int)y)<d    ||
31         //添加函数
32         fabs(y-x*x)<d       ||
33         fabs(y-sin(x))<d    ||
34         fabs(x+y*y*y-3*2*x*y+3)<2*d    ||
35         fabs(y-exp(x))<d    ||
36         fabs(y*y+x*x-2)<d   ||
37         fabs(y-exp(-x*x))<d
38     )
39         return true;
40     return false;
41 }
42 
43 void writeBit(bool bit, FILE * fp)
44 {   //白色为true
45     static int bitNum = 0;
46     static unsigned char Byte = 0;
47     if(bitNum==8)
48     {
49         fputc(Byte, fp);
50         Byte = 0;
51         bitNum = 0;
52     }
53     Byte ^= bit<<(7-bitNum);
54     bitNum++;
55 }
56 
57 int main() {
58     FILE *fp;
59     fp = fopen("picture.pbm","wb");
60     fprintf(fp, "P4 %d %d\n", XDIM, YDIM);
61     for(int j=0; j<YDIM; j++)
62         for(int i=0; i<XDIM; i++)
63             writeBit(tof(i, j), fp);
64     fclose(fp);
65     return 0;
66 }

Source Code

Demo