1 目标
C#调用C++的dll，调节图片对比度亮度
2 生成C++的dll
2.1建立C++ dll工程
用VS2015，建立C++的dll工程。具体步骤见下图。
#include <opencv2/opencv.hpp>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include "opencv2/imgproc/imgproc.hpp"
#include <iostream>
// 下列 ifdef 块是创建使从 DLL 导出更简单的
// 宏的标准方法。此 DLL 中的所有文件都是用命令行上定义的 CPLUSPLUSTEST_EXPORTS
// 符号编译的。在使用此 DLL 的
// 任何其他项目上不应定义此符号。这样，源文件中包含此文件的任何其他项目都会将
// CPLUSPLUSTEST_API 函数视为是从 DLL 导入的，而此 DLL 则将用此宏定义的
// 符号视为是被导出的。
#ifdef CPLUSPLUSTEST_EXPORTS
#define CPLUSPLUSTEST_API __declspec(dllexport)
extern "C"
CPLUSPLUSTEST_API int opencvtest(unsigned char* src, int w, int h, int channel, float contrastValue, int brightValue);
#else
#define CPLUSPLUSTEST_API __declspec(dllimport)
#endif
// 此类是从 CPlusPlusTest.dll 导出的
class CPLUSPLUSTEST_API CCPlusPlusTest {
public:
CCPlusPlusTest(void);
// TODO: 在此添加您的方法。
extern CPLUSPLUSTEST_API int nCPlusPlusTest;
CPLUSPLUSTEST_API int fnCPlusPlusTest(void);
源文件：CPlusPlusTest.cpp
// CPlusPlusTest.cpp : 定义 DLL 应用程序的导出函数。
#include "stdafx.h"
#include "CPlusPlusTest.h"
//-----------------------------------【命名空间声明部分】---------------------------------------
// 描述：包含程序所使用的命名空间
//-----------------------------------------------------------------------------------------------
using namespace std;
using namespace cv;
int CPLUSPLUSTEST_API opencvtest(unsigned char* src, int w, int h, int channel, float contrastValue, int brightValue)
if (!src)
return 0;
int format = CV_8UC3;
switch (channel)
case 1:
format = CV_8UC1;
break;
case 2:
format = CV_8UC2;
break;
case 3:
format = CV_8UC3;
break;
default:
return 0;
break;
Mat img(h, w, format, src);
// 三个for循环，执行运算 g_dstImage(i,j) = a*g_srcImage(i,j) + b
for (int y = 0; y < img.rows; y++)
for (int x = 0; x < img.cols; x++)
for (int c = 0; c < channel; c++)
switch (channel)
case 1:
img.at<uchar>(y, x) = saturate_cast<uchar>((contrastValue)*(img.at<uchar>(y, x)) + brightValue);
break;
case 2:
img.at<Vec2b>(y, x)[c] = saturate_cast<uchar>((contrastValue)*(img.at<Vec2b>(y, x)[c]) + brightValue);
break;
case 3:
img.at<Vec3b>(y, x)[c] = saturate_cast<uchar>((contrastValue)*(img.at<Vec3b>(y, x)[c]) + brightValue);
break;
default:
break;
return 1;
// 这是导出变量的一个示例
CPLUSPLUSTEST_API int nCPlusPlusTest = 0;
// 这是导出函数的一个示例。
CPLUSPLUSTEST_API int fnCPlusPlusTest(void)
return 42;
// 这是已导出类的构造函数。
// 有关类定义的信息，请参阅 CPlusPlusTest.h
CCPlusPlusTest::CCPlusPlusTest()
return;
3C#调用C++的dll
将C++生成的dll复制粘贴到C#的debug文件夹中。
C++生成的dll文件如下图：
partial class Form1
[DllImport("CPlusPlusTest.dll", EntryPoint = "opencvtest", SetLastError = true, CharSet = CharSet.Ansi)]
public extern static int opencvtest(byte[] src, int w, int h, int channel, float contrastValue, int brightValue);
Bitmap bmp;
/// <summary>
/// 必需的设计器变量。
/// </summary>
private System.ComponentModel.IContainer components = null;
/// <summary>
/// 清理所有正在使用的资源。
/// </summary>
/// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>
protected override void Dispose(bool disposing)
if (disposing && (components != null))
components.Dispose();
base.Dispose(disposing);
#region Windows 窗体设计器生成的代码
/// <summary>
/// 设计器支持所需的方法 - 不要修改
/// 使用代码编辑器修改此方法的内容。
/// </summary>
private void InitializeComponent()
bmp = new Bitmap("E:\\VS2015 OpenCV3\\CSharp\\2.jpg");
this.button1 = new System.Windows.Forms.Button();
this.button2 = new System.Windows.Forms.Button();
this.pictureBox1 = new System.Windows.Forms.PictureBox();
this.pictureBox2 = new System.Windows.Forms.PictureBox();
((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).BeginInit();
((System.ComponentModel.ISupportInitialize)(this.pictureBox2)).BeginInit();
this.SuspendLayout();
// button1
this.button1.Location = new System.Drawing.Point(128, 5);
this.button1.Name = "button1";
this.button1.Size = new System.Drawing.Size(75, 23);
this.button1.TabIndex = 0;
this.button1.Text = "button1";
this.button1.UseVisualStyleBackColor = true;
// button2
this.button2.Location = new System.Drawing.Point(666, -4);
this.button2.Name = "button2";
this.button2.Size = new System.Drawing.Size(75, 23);
this.button2.TabIndex = 1;
this.button2.Text = "button2";
this.button2.UseVisualStyleBackColor = true;
// pictureBox1
this.pictureBox1.Location = new System.Drawing.Point(31, 34);
this.pictureBox1.Name = "pictureBox1";
this.pictureBox1.Size = new System.Drawing.Size(368, 243);
this.pictureBox1.TabIndex = 2;
this.pictureBox1.TabStop = false;
this.pictureBox1.Image = bmp;
// pictureBox2
this.pictureBox2.Location = new System.Drawing.Point(488, 34);
this.pictureBox2.Name = "pictureBox2";
this.pictureBox2.Size = new System.Drawing.Size(344, 243);
this.pictureBox2.TabIndex = 3;
this.pictureBox2.TabStop = false;
int stride;
byte[] source = GetBGRValues(bmp, out stride);
int channel = Image.GetPixelFormatSize(bmp.PixelFormat) / 8;
// 在原来的基础上，对比度和亮度加多少
opencvtest(source, bmp.Width, bmp.Height, channel, (float)(0.3), 0); //C++ opencv对内存操作
this.pictureBox2.Image = getBitmapByBytes(source, bmp.Width, bmp.Height, stride, bmp.PixelFormat); //从byte[]数组中获取到的图像已经发生对比度，亮度的变换，说明成功
// Form1
this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.ClientSize = new System.Drawing.Size(881, 321);
this.Controls.Add(this.pictureBox2);
this.Controls.Add(this.pictureBox1);
this.Controls.Add(this.button2);
this.Controls.Add(this.button1);
this.Name = "Form1";
this.Text = "Form1";
((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).EndInit();
((System.ComponentModel.ISupportInitialize)(this.pictureBox2)).EndInit();
this.ResumeLayout(false);
/// <summary>
/// 生成灰度图的调色板
/// </summary>
/// <returns></returns>
public static ColorPalette getGrayPalette()
// 下面的代码是为了修改生成位图的索引表，从伪彩修改为灰度
ColorPalette tempPalette;
using (Bitmap tempBmp = new Bitmap(1, 1, System.Drawing.Imaging.PixelFormat.Format8bppIndexed))
tempPalette = tempBmp.Palette;
for (int i = 0; i < 256; i++)
tempPalette.Entries[i] = System.Drawing.Color.FromArgb(i, i, i);
return tempPalette;
/// <summary>
/// 从图像Byte数组获取Bitmap
/// </summary>
/// <param name="src"></param>
/// <param name="w"></param>
/// <param name="h"></param>
/// <param name="stride"></param>
/// <param name="format"></param>
/// <returns></returns>
public static Bitmap getBitmapByBytes(byte[] src, int w, int h, int stride, PixelFormat format)
IntPtr ptr = getBytesPtr(src);
int rowBytes = w * Image.GetPixelFormatSize(format) / 8;
byte[] rgbValues = new byte[stride * h];
for (var i = 0; i < h; i++)
//int len = stride - (stride-rowBytes);
Marshal.Copy(ptr, rgbValues, i * stride, rowBytes); //对齐
ptr += rowBytes; // next row
//Marshal.FreeHGlobal(ptr);
ptr = getBytesPtr(rgbValues);
Bitmap bitmap = new Bitmap(w, h, stride, format, ptr);
if (format == PixelFormat.Format8bppIndexed)
//bitmap.Palette = getGrayPalette(); //如果是单通道灰度图，默认的bitmap调色板不对，需要手动设置
return bitmap;
/// <summary>
/// 获取bytes数组的头指针，非托管
/// </summary>
/// <param name="bytes"></param>
/// <returns></returns>
public static IntPtr getBytesPtr(byte[] bytes)
GCHandle hObject = GCHandle.Alloc(bytes, GCHandleType.Pinned);
return hObject.AddrOfPinnedObject();
/// <summary>
/// 获取bitmap的byte数据，并输出stride
/// </summary>
/// <param name="bmp"></param>
/// <param name="stride"></param>
/// <returns></returns>
public static byte[] GetBGRValues(Bitmap bmp, out int stride)
var rect = new Rectangle(0, 0, bmp.Width, bmp.Height);
var bmpData = bmp.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadOnly, bmp.PixelFormat);
stride = bmpData.Stride;
//int channel = bmpData.Stride / bmp.Width;
var rowBytes = bmpData.Width * Image.GetPixelFormatSize(bmp.PixelFormat) / 8;
var imgBytes = bmp.Height * rowBytes;
byte[] rgbValues = new byte[imgBytes];
IntPtr ptr = bmpData.Scan0;
for (var i = 0; i < bmp.Height; i++)
Marshal.Copy(ptr, rgbValues, i * rowBytes, rowBytes); //对齐
ptr += bmpData.Stride; // next row
bmp.UnlockBits(bmpData);
return rgbValues;
#endregion
private System.Windows.Forms.Button button1;
private System.Windows.Forms.Button button2;
private System.Windows.Forms.PictureBox pictureBox1;
private System.Windows.Forms.PictureBox pictureBox2;