如何用VC生成GIF文件

[xuying]

我现在开发一个程序，是基于WEB的，后台用VC编写一个服务程序，定时获取数据，然后，生成一副GIF格式的曲线图（纵坐标是数据，横坐标是时间），放在制定目录下。类似于股市行情的实时、动态显示。
但我不知道如何根据所获得的数据，用VC生成一副GIF格式的曲线图，请高手指点。

[xenogear]

你要了解gif文件格式, 然后具体怎么转换数据那是你的事了

[cloud]

在一本书叫什么VC++技术内幕的，不是机械出版的那本，比机械出版的
要薄很多，60元左右的，专门讲类库的，有操作GIF图象的类库，你找来
看看，类库的原代码在他的附带光盘中有。

[DOU]

可以使用c的gd库，但由于专利权问题，最新版本的gd去掉了对gif的支持，转而支持PNG格式。
Now that PNG is supported by both Microsoft Internet Explorer and Netscape (in their recent releases),
一个简单例子
/* Bring in gd library functions */
#include "gd.h"

/* Bring in standard I/O so we can output the PNG to a file */
#include <stdio.h>

int main() {
/* Declare the image */
gdImagePtr im;
/* Declare an output file */
FILE *out;
/* Declare color indexes */
int black;
int white;

/* Allocate the image: 64 pixels across by 64 pixels tall */
im = gdImageCreate(64, 64);

/* Allocate the color black (red, green and blue all minimum).
Since this is the first color in a new image, it will
be the background color. */
black = gdImageColorAllocate(im, 0, 0, 0);

/* Allocate the color white (red, green and blue all maximum). */
white = gdImageColorAllocate(im, 255, 255, 255);

/* Draw a line from the upper left to the lower right,
using white color index. */
gdImageLine(im, 0, 0, 63, 63, white);

/* Open a file for writing. "wb" means "write binary", important
under MSDOS, harmless under Unix. */
out = fopen("test.png", "wb");

/* Output the image to the disk file. */
gdImagePng(im, out);

/* Close the file. */
fclose(out);

/* Destroy the image in memory. */
gdImageDestroy(im);
}
When executed, this program creates an image, allocates two colors (the first color allocated becomes the background color), draws a diagonal line (note that 0, 0 is the upper left corner), writes the image to a PNG file, and destroys the image.
gd库功能非常强大，详情请见http://www.boutell.com/gd/