int main(int argc, char **argv) {
FrameBuffer *f;
Plot2D *p2;
ColorMap *cm;
double x,y;
double dx,dy;
double z1,z2,z3,z4,za;
int c;
/* Create a framebuffer */
f = new_FrameBuffer(600,600);
/* Load a colormap */
cm = new_ColorMap("cm15");
/* Create a new 2D image */
FrameBuffer_clear(f,BLACK);
p2 = new_Plot2D(f,-6.3,-6.3,6.3,6.3);
/* Set viewing region in 2D plot */
Plot2D_setview(p2,50,50,550,550);
/* Make a frame */
FrameBuffer_noclip(f);
FrameBuffer_box(f,49,49,550,550,WHITE);
Plot2D_start(p2); /* Always call this prior to making an image */
Plot2D_clear(p2,BLACK);
x = -6.3;
dx = 0.25;
while (x < 6.3) {
y = -6.3;
dy = 0.25;
while (y < 6.3) {
z1 = func(x,y);
z2 = func(x+dx,y);
z3 = func(x+dx,y+dy);
z4 = func(x,y+dy);
za = 0.25*(z1+z2+z3+z4);
c = (int) ((za + 1.0)*120) + 16;
if (c < 16) c = 16;
if (c > 254) c = 254;
Plot2D_solidbox(p2,x,y,x+dx,y+dy,c);
y = y + dy;
}
x = x + dx;
}
/* Make a GIF file */
FrameBuffer_writeGIF(f,cm,"plot.gif");
}
/* -------------------------------------------------------------------------------
Plot2D_box(Plot2D *p2, double x1, double y1, double x2, double y2, Pixel Color)
Plot an outline box on the 2D plot
------------------------------------------------------------------------------- */
void
Plot2D_box(Plot2D *p2, double x1, double y1,double x2, double y2, Pixel color) {
int ix1, ix2,iy1, iy2;
Plot2D_transform(p2,x1,y1,&ix1,&iy1);
Plot2D_transform(p2,x2,y2,&ix2,&iy2);
FrameBuffer_box(p2->frame,ix1,iy1,ix2,iy2,color);
}