C# 调用C++的dll进行图像加载存储

C++图像处理函数

// TestBitMap.cpp : Defines the entry point for the DLL application.

//

#include "stdafx.h"

#include <stdio.h>

#include <stdlib.h>

#include <Windows.h>

extern "C" int _declspec (dllexport) readBitmap(void ** pBmpBuf,BITMAPINFO &bm);

int _declspec (dllexport) readBitmap(void ** pBmpBuf,BITMAPINFO &bm)

{

FILE *fp=fopen("工区0110.bmp","rb");//二进制读方式打开指定的图像文件

if(fp==0) return 0;

//跳过位图文件头结构BITMAPFILEHEADER

// fseek(fp, sizeof(BITMAPFILEHEADER),0);

BITMAPFILEHEADER bmpFileHeader;

fread(&bmpFileHeader,sizeof(BITMAPFILEHEADER),1,fp);

//定义位图信息头结构变量，读取位图信息头进内存，存放在变量head中

BITMAPINFOHEADER bmpInfoHeader;

fread(&bmpInfoHeader, sizeof(BITMAPINFOHEADER), 1,fp); //获取图像宽、高、每像素所占位数等信息

int bmpWidth = bmpInfoHeader.biWidth;

int bmpHeight = bmpInfoHeader.biHeight;

int biBitCount = bmpInfoHeader.biBitCount;//定义变量，计算图像每行像素所占的字节数（必须是4的倍数）

int lineByte=(bmpWidth * biBitCount/8+3)/4*4;//灰度图像有颜色表，且颜色表表项为256

bm.bmiHeader = bmpInfoHeader;

if(biBitCount==8)

{

//申请颜色表所需要的空间，读颜色表进内存

RGBQUAD *pColorTable=new RGBQUAD[256];

fread(pColorTable,sizeof(RGBQUAD),256,fp);

delete []pColorTable;

}

//申请位图数据所需要的空间，读位图数据进内存

// pBmpBuf=new unsigned char[lineByte * bmpHeight];

// *pBmpBuf = malloc(lineByte*bmpHeight);

// if (*pBmpBuf == NULL)

// {

// return -1;

// }

fread(*pBmpBuf,1,lineByte * bmpHeight,fp);

fclose(fp);//关闭文件

return 1;//读取文件成功

}

C# 调用

[DllImport("TestBitMap", EntryPoint = "readBitmap",CallingConvention = CallingConvention.Cdecl)]

public static extern int readBitmap(ref IntPtr a,ref BITMAPINFO bm);

public int getBitmap()

{

BITMAPINFO bm = new BITMAPINFO();

// int d = 0;

IntPtr e = Marshal.AllocHGlobal(3000*89);//3000*89为实际位图数据的大小

int x = readBitmap(ref e,ref bm);

int bmpWidth = bm.bmiHeader.biWidth;

int bmpHeight = bm.bmiHeader.biHeight;

int bmpBitCount = bm.bmiHeader.biBitCount;

int stride = (bmpWidth * bmpBitCount / 8 + 3) / 4 * 4;

Bitmap bt = new Bitmap(bmpWidth, bmpHeight, stride, PixelFormat.Format24bppRgb, e);//存储为24位图像

bt.Save("testBt.bmp");

//其他操作

int x = readBitmap(ref e,ref bm);

// Bitmap bt1 = new Bitmap("工区0110.bmp");

// Bitmap bt2 = new Bitmap("工区0120.bmp");

// BitmapData bd = new BitmapData();

// Rectangle rect = new Rectangle(0, 0, bt1.Width, bt1.Height);

// System.Drawing.Imaging.BitmapData bmpData1 =

//bt1.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite,

//bt1.PixelFormat);

// System.Drawing.Imaging.BitmapData bmpData2 =

//bt2.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite,

//bt2.PixelFormat);

// bmpData1 = bmpData2;

// int bytes = bmpData1.Stride * bmpData1.Height;

// byte[] rgbValues = new byte[bytes];

// IntPtr testptr = bmpData1.Scan0;

// Marshal.Copy(bmpData1.Scan0, rgbValues, 0, bytes);

// Marshal.Copy(rgbValues, 0, bmpData2.Scan0, bytes);

//// Marshal.Copy(bmpData1.Scan0, 0, bmpData2.Scan0, bmpData1.Stride * bmpData1.Height);

// // bmpData2.Scan0 = bmpData1.Scan0;

// bt1.UnlockBits(bmpData2);

// bt2.UnlockBits(bmpData1);

// bt1.Save("testBt1.bmp");

// bt2.Save("testBt2.bmp");

// // Create a new bitmap.

// Bitmap bmp = new Bitmap("c:\\fakePhoto.jpg");

// // Lock the bitmap's bits.

// Rectangle rect = new Rectangle(0, 0, bmp.Width, bmp.Height);

// System.Drawing.Imaging.BitmapData bmpData =

// bmp.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite,

// bmp.PixelFormat);

// // Get the address of the first line.

//IntPtr ptr = bmpData.Scan0;

// // Declare an array to hold the bytes of the bitmap.

// int bytes = bmpData.Stride * bmp.Height;

// byte[] rgbValues = new byte[bytes];

// // Copy the RGB values into the array.

// System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues, 0, bytes);

// // Set every red value to 255.

// for (int counter = 0; counter < rgbValues.Length; counter+=3)

// rgbValues[counter] = 255;

// // Copy the RGB values back to the bitmap

// System.Runtime.InteropServices.Marshal.Copy(rgbValues, 0, ptr, bytes);

// // Unlock the bits.

// bmp.UnlockBits(bmpData);

// // Draw the modified image.

// e.Graphics.DrawImage(bmp, 0, 150);

}