呵呵昨天花了一个圆，今天想画个太极图，我知道没啥技术含量，但是挺有意思的，希望各位看官不要鄙视我不务正业，画完此图，不再做这些事情。
先展示下画出来的图像的情况，因为不支持pgm格式的图像，所以我用的 QQ截图：
今天，二话不说上代码。
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
typedefstruct{
size_t width;
size_t height;
unsignedchar*data;
}Image;
staticImage *
image_new(size_t width,
size_t height)
{
Image *image;
image=malloc(sizeof *image);
image->width=width;
image->height=height;
image->data=malloc(width *height);
returnimage;
}
staticvoid
image_free(Image *image)
{
free(image->data);
free(image);
}
staticvoid
image_fill(Image *image,
unsignedcharvalue)
{
memset(image->data,value,image->width *image->height);
}
/**
* image_set_pixel:
*
* Sets a pixel passed in signed (x, y) coordinates, where (0,0) is at
* the center of the image.
**/
staticvoid
image_set_pixel(Image *image,
ssize_tx,
ssize_ty,
unsignedcharvalue)
{
size_t tx,ty;
unsignedchar*p;
tx=(image->width/2)+x;
ty=(image->height/2)+y;
p=image->data+(ty *image->width)+tx;
*p=value;
}
staticvoid
image_save(constImage *image,
constchar*filename)
{
FILE *out;
out=fopen(filename,"wb");
if(!out)
return;
fprintf(out,"P5\n");
fprintf(out,"%zu %zu\n",image->width,image->height);
fprintf(out,"255\n");
fwrite(image->data,1,image->width *image->height,out);
fclose(out);
}
staticvoiddraw_Taijitu(Image *image,intradius,intvalue)
{
intx,y;
intrlimit,llimit;
intradius_2=radius*radius;
for(y=-radius;y<radius;y++)
for(x=-radius;x<radius;x++)
if(x*x+y*y<=radius_2)
image_set_pixel(image,x,y,0xff);
for(y=-radius;y<0;y++)
for(x=0;x<radius;x++)
if((x*x)+(y*y)<=radius_2)
image_set_pixel(image,x,y,value);
for(y=-radius;y<0;y++)
for(x=-(int)sqrt((double)(-radius*y-y*y));x<0;x++)
image_set_pixel(image,x,y,value);
for(y=0;y<radius;y++)
{
llimit=(int)sqrt((double)(radius*y-y*y));
rlimit=(int)sqrt((double)(radius_2-y*y));
for(x=llimit;x<rlimit;x++)
image_set_pixel(image,x,y,value);
}
for(y=2*radius/6;y<4*radius/6;y++)
{
rlimit=(int)sqrt((double)(radius*y-y*y-2*radius_2/9));
llimit=-rlimit;
for(x=llimit;x<rlimit;x++)
image_set_pixel(image,x,y,value);
}
for(y=-4*radius/6;y<-2*radius/6;y++)
{
rlimit=sqrt(-radius*y-y*y-2*radius_2/9);
llimit=-rlimit;
for(x=llimit;x<rlimit;x++)
image_set_pixel(image,x,y,0xff);
}
return;
}
int
main(intargc,char*argv[])
{
Image *image;
image=image_new(800,800);
image_fill(image,0xaa);
draw_Taijitu(image,300,0);
image_save(image,"taiji_6.pgm");
image_free(image);
return0;
}
畅学电子
