获取PNG图片的RGBA

http://www.cnblogs.com/mr-wid/archive/2013/04/19/3029842.html

先看这篇文章，关于pnglib的入门讲解

下面贴上源代码（在VC 6.0下编译通过）：

#include "stdafx.h"
#include <stdio.h>
#include "png.h"
#include <stdlib.h>


typedef struct {
    unsigned char* pixelData;
    int imageWidth;
    int imageHeight;
}ImageInfo; 


typedef struct {
    unsigned char* data;
    int size;
    int offset;
}ImageSource;


ImageInfo*  decodePNGFromFile(char* fileName)
{
    char png_header[8];
    png_structp png_ptr;
    png_infop info_ptr;
    int width, height, rowBytes;
    png_byte color_type; 
    png_byte bit_depth;
    png_colorp palette;


    /* open file and test for it being a png */
    FILE *file = fopen(fileName, "rb");
    fread(png_header, 1, 8, file);
    if(png_sig_cmp((png_bytep)png_header, 0, 8))
    {