Opencv图像对比度和亮度的调整-滚动条

#include
#include
#include"stdio.h"

using namespace std;
using namespace cv;

Mat srcImage, resultImage;
int g_nContrast, g_nBright;
const int g_nContrastMax = 300, g_nBright_Max = 300;

//a控制对比度，b控制亮度
void ContrastBright(const Mat &srcImage, Mat &dstImage, double a, double b);

//有滚动条事件时，可以进入回调函数
void on_Trackbar(int, void *);

int main()
{
	srcImage = imread("group.jpg");

	namedWindow("滚动条窗口");

	g_nContrast = 50;
	g_nBright = 50;
	createTrackbar("对比度", "滚动条窗口", &g_nContrast, g_nContrastMax, on_Trackbar);
	createTrackbar("亮度", "滚动条窗口", &g_nBright, g_nBright_Max, on_Trackbar);
	on_Trackbar(g_nContrast, 0);
	on_Trackbar(g_nBright, 0);

	waitKey(0);

	return 0;
}

void ContrastBright(const Mat &srcImage, Mat &dstImage, double a, double b)
{
	srcImage.copyTo(dstImage);

	const int imageRows = srcImage.rows;
	const int imageCols = srcImage.cols * srcImage.channels();
	for (int i = 0; i < imageRows; i++)
	{
		uchar *data = dstImage.ptr(i);
		for (int j = 0; j < imageCols; j++)
		{
			data[j] = saturate_cast(a * data[j] + b);
		}
	}
}

void on_Trackbar(int, void *)
{
	const double contrastValue = g_nContrast / 100.0;
	const double brightValue = g_nBright;

	ContrastBright(srcImage, resultImage, contrastValue, brightValue);

	imshow("【处理后的图像】", resultImage);
}