libpng安装与配置(Win7+VS2010)

一、下载

libpng：http://libmng.com/pub/png/libpng.html

zlib：http://www.zlib.net/

IDE：VS2010

二、编译

将下载的两个zip解压到同一目录下

打开ibpng目录下的projects\vstudio中的工程文件(低版本的VS可以打开projects\visualc71中的工程)。

编译运行，在输出目录(Debug或Realse)中得到输出文件libpng16.dll、libpng16.lib、zlib.lib。

三、创建工程

创建一个工程，右键点击工程名打开Properties(属性)对话框

在C/C++->General(常规)->Additional Include Directories(附加包含目录)中添加libpng目录

在Linker->General(常规)->Additional Library Directories(附加库目录)中添加刚刚生成的lib文件所在的路径

在Linker->Input(输入)->Additional Dependencies(附加依赖项)中添加libpng16.lib、zlib.lib两个文件

四、运行

这里有一个简单的例子，原文：http://zarb.org/~gc/html/libpng.html

/*
 * Copyright 2002-2010 Guillaume Cottenceau.
 *
 * This software may be freely redistributed under the terms
 * of the X11 license.
 *
 */

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdarg.h>

#define PNG_DEBUG 3
#include <png.h>

void abort_(const char * s, ...)
{
        va_list args;
        va_start(args, s);
        vfprintf(stderr, s, args);
        fprintf(stderr, "\n");
        va_end(args);
        abort();
}

int x, y;

int width, height;
png_byte color_type;
png_byte bit_depth;

png_structp png_ptr;
png_infop info_ptr;
int number_of_passes;
png_bytep * row_pointers;

void read_png_file(char* file_name)
{
        char header[8];    // 8 is the maximum size that can be checked

        /* open file and test for it being a png */
        FILE *fp = fopen(file_name, "rb");
        if (!fp)
                abort_("[read_png_file] File %s could not be opened for reading", file_name);
        fread(header, 1, 8, fp);
        if (png_sig_cmp(header, 0, 8))
                abort_("[read_png_file] File %s is not recognized as a PNG file", file_name);

        /* initialize stuff */
        png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);

        if (!png_ptr)
                abort_("[read_png_file] png_create_read_struct failed");

        info_ptr = png_create_info_struct(png_ptr);
        if (!info_ptr)
                abort_("[read_png_file] png_create_info_struct failed");

        if (setjmp(png_jmpbuf(png_ptr)))
                abort_("[read_png_file] Error during init_io");

        png_init_io(png_ptr, fp);
        png_set_sig_bytes(png_ptr, 8);

        png_read_info(png_ptr, info_ptr);

        width = png_get_image_width(png_ptr, info_ptr);
        height = png_get_image_height(png_ptr, info_ptr);
        color_type = png_get_color_type(png_ptr, info_ptr);
        bit_depth = png_get_bit_depth(png_ptr, info_ptr);

        number_of_passes = png_set_interlace_handling(png_ptr);
        png_read_update_info(png_ptr, info_ptr);

        /* read file */
        if (setjmp(png_jmpbuf(png_ptr)))
                abort_("[read_png_file] Error during read_image");

        row_pointers = (png_bytep*) malloc(sizeof(png_bytep) * height);
        for (y=0; y<height; y++)
                row_pointers[y] = (png_byte*) malloc(png_get_rowbytes(png_ptr,info_ptr));

        png_read_image(png_ptr, row_pointers);

        fclose(fp);
}

void write_png_file(char* file_name)
{
        /* create file */
        FILE *fp = fopen(file_name, "wb");
        if (!fp)
                abort_("[write_png_file] File %s could not be opened for writing", file_name);

        /* initialize stuff */
        png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);

        if (!png_ptr)
                abort_("[write_png_file] png_create_write_struct failed");

        info_ptr = png_create_info_struct(png_ptr);
        if (!info_ptr)
                abort_("[write_png_file] png_create_info_struct failed");

        if (setjmp(png_jmpbuf(png_ptr)))
                abort_("[write_png_file] Error during init_io");

        png_init_io(png_ptr, fp);

        /* write header */
        if (setjmp(png_jmpbuf(png_ptr)))
                abort_("[write_png_file] Error during writing header");

        png_set_IHDR(png_ptr, info_ptr, width, height,
                     bit_depth, color_type, PNG_INTERLACE_NONE,
                     PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);

        png_write_info(png_ptr, info_ptr);

        /* write bytes */
        if (setjmp(png_jmpbuf(png_ptr)))
                abort_("[write_png_file] Error during writing bytes");

        png_write_image(png_ptr, row_pointers);

        /* end write */
        if (setjmp(png_jmpbuf(png_ptr)))
                abort_("[write_png_file] Error during end of write");

        png_write_end(png_ptr, NULL);

        /* cleanup heap allocation */
        for (y=0; y<height; y++)
                free(row_pointers[y]);
        free(row_pointers);

        fclose(fp);
}

void process_file(void)
{
        if (png_get_color_type(png_ptr, info_ptr) == PNG_COLOR_TYPE_RGB)
                abort_("[process_file] input file is PNG_COLOR_TYPE_RGB but must be PNG_COLOR_TYPE_RGBA "
                       "(lacks the alpha channel)");

        if (png_get_color_type(png_ptr, info_ptr) != PNG_COLOR_TYPE_RGBA)
                abort_("[process_file] color_type of input file must be PNG_COLOR_TYPE_RGBA (%d) (is %d)",
                       PNG_COLOR_TYPE_RGBA, png_get_color_type(png_ptr, info_ptr));

        for (y=0; y<height; y++) {
                png_byte* row = row_pointers[y];
                for (x=0; x<width; x++) {
                        png_byte* ptr = &(row[x*4]);
                        printf("Pixel at position [ %d - %d ] has RGBA values: %d - %d - %d - %d\n",
                               x, y, ptr[0], ptr[1], ptr[2], ptr[3]);

                        /* set red value to 0 and green value to the blue one */
                        ptr[0] = 0;
                        ptr[1] = ptr[2];
                }
        }
}

int main(int argc, char **argv)
{
        if (argc != 3)
                abort_("Usage: program_name <file_in> <file_out>");

        read_png_file(argv[1]);
        process_file();
        write_png_file(argv[2]);

        return 0;
}

simple example

若编译错误，需要注意：C语言中，变量需要在函数或语句块的开始声明和定义。

若运行时提示缺少libpng16.dll，则将刚刚生成的libpng16.dll文件复制到工程目录(Debug或Realse)中即可。也可以复制到系统目录Windows\System32(64位操作系统需复制到Windows\SysWOW64)中。

若在执行png_read_info(png_ptr, info_ptr)时，出现错误"Unhandled exception at 0x7c928fea in myApp.exe: 0xC0000005: Access violation writing location 0x00000010."，则引用一段话

I solved my problem...
I found someone on LibPNG‘s mailing who had the same problem.
The solution is relatively simple: just be sure that the project in which you are using LibPng is compiled with the same "Runtime Library" settings. I think that by default the lib is compiled in "/MD" (multi-threaded DLL) and a lot of projects are single threaded by default. This setting can be found in the project‘s property under C++/Code Generation (in VC7.1).
So, just insure that the setting are the same for both the library and your project and you should be all set.
This is something that really ought to be mentionned in the documents somewhere (I know that GnuWin32 does not make any documents, but maybe a quick readme with the installer?).
Anyway, thanks!
--Yop83

也就是说，在编译libpng和调用它执行程序时，必须用相同的"Runtime Library"设置。

这里我也碰到了这个问题，是因为编译的时候用的VS2010，创建工程用的VS2008。后来改用为VS2010创建工程，没有问题。

转载请注明出处：
http://www.cnblogs.com/lvrcbl/p/3948641.html