#include "gd.h"
#include "cgic.h"
#define IMAGE_FILE "/CHANGE/THIS/FILE/name.gif"
void Magnify(int x, int y, gdImagePtr im);
int cgiMain() {
int x = -1, y = -1;
gdImagePtr im = 0;
if (strstr(cgiPathInfo, ".gif")) {
/* This is a request for an image */
FILE *in;
in = fopen(IMAGE_FILE, "rb");
im = gdImageCreateFromGif(in);
fclose(in);
}
sscanf(cgiQueryString, "%d,%d", &x, &y);
if ((x != -1) && (y != -1)) {
/* This is a request for a magnified portion
of the image, or the page it will appear in */
Magnify(x, y, im);
return 0;
}
if (im) {
/* Top view: no magnification */
cgiHeaderContentType("image/gif");
gdImageGif(im, cgiOut);
} else {
/* Top page, with an ![]()
tag pointing to
an unmagnified gif */
cgiHeaderContentType("text/html");
fprintf(cgiOut, "\n");
fprintf(cgiOut, "\n");
fprintf(cgiOut, "CGI Magnifying Glass\n");
fprintf(cgiOut, "\n");
fprintf(cgiOut, "\n");
fprintf(cgiOut, "CGI Magnifying Glass
\n");
fprintf(cgiOut, "Click anywhere in the image for a\n");
fprintf(cgiOut, "magnified view.\n");
fprintf(cgiOut, "\n");
fprintf(cgiOut, "\n");
fprintf(cgiOut, "![](\"image.gif\")
\n");
fprintf(cgiOut, "\n");
fprintf(cgiOut, "\n");
fprintf(cgiOut, "\n");
}
/* Free the memory associated with the image */
if (im) {
gdImageDestroy(im);
}
return 0;
}
void Magnify(int x, int y, gdImagePtr im)
{
if (im) {
/* Generate a 4x magnified image */
gdImagePtr mag;
mag = gdImageCreate(200, 200);
/* Copies and stretches the desired portion of the image */
gdImageCopyResized(mag, im,
0, 0,
x - 25, y - 25,
200, 200,
50, 50);
cgiHeaderContentType("image/gif");
gdImageGif(mag, cgiOut);
gdImageDestroy(mag);
} else {
/* A page with an ![]()
tag pointing to
the magnified GIF and a link to return
to the normal top-down view */
cgiHeaderContentType("text/html");
fprintf(cgiOut, "\n");
fprintf(cgiOut, "
\n");
fprintf(cgiOut, "Magnified View\n");
fprintf(cgiOut, "\n");
fprintf(cgiOut, "\n");
fprintf(cgiOut, "Magnified View
\n");
fprintf(cgiOut, "\n");
fprintf(cgiOut, "Up to the complete image\n");
/* A trick to remember: we generate a src attribute
which will appear to the program just like the original
imagemap click did, but with "/image.gif" in
the PATH_INFO variable. This will invoke the
other branch of this function to generate the image. */
fprintf(cgiOut, "![](\"image.gif?%d,%d\")
\n", x, y);
fprintf(cgiOut, "\n");
fprintf(cgiOut, "\n");
}
if (im) {
gdImageDestroy(im);
}
}