使用GD库生成的图片在windows中不能正常显示

[xlstc7]

使用c++，生成后的文件有数据，可是在windows中打开显示的是乱七八糟的一些颜色，这只是针对jpeg的，如果生成png，在windows中打开都不行。
有在c++中使用过gd的吗？谢谢帮忙看看。

代码是官方的示例：

int main() 
{ 
	/* Declare the image */  
	gdImagePtr im;  
	/* Declare output files */  
	FILE *pngout, *jpegout; 
	/* 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. */
	pngout = fopen("test.png", "wb");
	/* Do the same for a JPEG-format file. */
	jpegout = fopen("test.jpg", "wb");
	/* Output the image to the disk file in PNG format. */
	gdImagePng(im, pngout);
	/* Output the same image in JPEG format, using the default    JPEG quality setting. */
	gdImageJpeg(im, jpegout, -1);   /* Close the files. */
	fclose(pngout);
	fclose(jpegout);  
	/* Destroy the image in memory. */
	gdImageDestroy(im);
}

[ceasar1134]

gd库是么?我们使用的jpeg库...

[xlstc7]

直接用jpeg库？就是那个libjpeg？它可不可以在图片中写字？还有读取另一个图片文件的像素？

[xlstc7]

刚刚看了看jpeg库的文档 ，它只是用来转换图片格式的，压缩成jpeg和解压缩jpeg。

以前cximage也试过，同样的代码在windows中生成图片正常，可是放到solaris下生成的图片在windows中打开后读出来的就不正常，看到是一些乱七八糟的颜色。难道是solaris环境没设置好造成的？

[x86]

我用你的代码生成的jpg和png在windows下打开都没问题。
我用的是官方最新的版本，你可以到这里下载源码：
http://www.libgd.org/
编译很简单，只需./configure然后make install，缺省安装到/usr/local/下，在你的代码加上一行：
#include "/usr/local/include/gd.h"

编译：
g++ -o test test.cpp -lgd

[xlstc7]

我的gd版本也是官方最新的，如果你能正常显示，那是不是因为我的机器环境造成的呢？或者要进行什么配置？或者jpeg库或png库的版本太低？我用的是solaris 10，jpeg和png的库是自带的。

[dhshuai]

我也遇到了这个问题，原来是没有认真读取GD安装要求：
Why does bgd.dll crash with my C program?
You are trying to use gd's stdio library functions with a different C runtime library. Read on for notes on individual compilers.
Microsoft Visual C++: If you want to use gdImageCreateFromPng, gdImagePng, and other functions that take a FILE *, you MUST use Visual C++ 6.0 or earlier and you MUST link with the "multithreaded DLL" runtime library option. If you wish to use the .NET compiler, read the "Borland C++" section for an alternative method.

具体操作如下(在VC6.0）：
Project-->Setting--> C/C++ -->Category下拉框中选择Code Generation,在出现的界面中有一个Use run-time library选择框，下拉选择"multithreaded DLL"，确定再运行即可

[marrylayking]

dhshuai，为什么我按照上面的设置了，我的程序还是不能运行啊？gdImagePng(im, pngout);这一步就出错 了！！！！！！因为我用的bgd.DLL。
/* 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>

#include"StdAfx.h"

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


typedef gdImagePtr(__stdcall *Create)(int sx, int sy);
typedef int(__stdcall *Allocate)(gdImagePtr im, int r, int g, int b);

typedef void(__stdcall *ImageLine)(gdImagePtr im, int x1, int y1, int x2, int y2, int color);

typedef void *(__stdcall *ImagePngPtr)(gdImagePtr im, int *size);

typedef void(__stdcall *ImageDestroy)(gdImagePtr im);




typedef void(__stdcall *ImagePng)(gdImagePtr im, FILE * out);

HINSTANCE hDLL;
hDLL=LoadLibrary("bgd.dll");

Create gdImageCreate;
gdImageCreate=(Create)GetProcAddress(hDLL,"gdImageCreate@8");


Allocate gdImageColorAllocate;
gdImageColorAllocate=(Allocate)GetProcAddress(hDLL,"gdImageColorAllocate@16");



ImageLine gdImageLine;
gdImageLine=(ImageLine)GetProcAddress(hDLL,"gdImageLine@24");


ImagePngPtr gdImagePngPtr;
gdImagePngPtr=(ImagePngPtr)GetProcAddress(hDLL,"gdImagePngPtr@8");

ImageDestroy gdImageDestroy;
gdImageDestroy=(ImageDestroy)GetProcAddress(hDLL,"gdImageDestroy@4");

ImagePng gdImagePng;
gdImagePng=(ImagePng)GetProcAddress(hDLL,"gdImagePng@8");

/* 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 ");


/*int size;
char *data;


Output the image to the disk file.
data = (char *) gdImagePngPtr(im, &size);
fwrite(data, 1, size, out); */

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



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

/* Destroy the image in memory. */
gdImageDestroy(im);
FreeLibrary(hDLL);

}