opencv实现魔幻笔效果

简介

　　在使用美图秀秀之类工具的时候，发现了一个魔幻笔效果，然后这里用opencv实现了类似效果。

实现原理

具体实现

　　表现效果是，当鼠标左键在图片窗口上按下时候，会从鼠标当前坐标位置，不断的出现小方框向四面八方散去。使用的基本原理，就是前面讲过的图像比例混合。两种图片，一张是背景图片，另外一种是各色小方框图片。当鼠标按下时候，小方框图片源源不断的生成，然后和背景图片比例混合后，以随机的速度，发散出去。

实现代码

#include <math.h>#include <string.h>#include <stdio.h>#include <stdlib.h>#include <opencv2/core/core.hpp>#include <opencv2/highgui/highgui.hpp>#include <opencv/cv.h>#include "lib/normal.h"#include <math.h> using namespace cv; #define RECT_NUMBER 16 Mat src, src2, imageROI;int width=0, height=0;int src2_width, src2_height;int mouse_width, mouse_height;double alpha = 0.3, beta;char pic_name[20];bool mouse_left = false; int curRectAddr[RECT_NUMBER][5];Scalar scalar[RECT_NUMBER];int rect_num = 2;RNG rng(0xFFFFFFFF); void on_mouse( int event, int x, int y, int flags, void* ustc){int i; if(event == CV_EVENT_LBUTTONDOWN){mouse_left = true;}else if(event == CV_EVENT_LBUTTONUP){mouse_left = false;}if(mouse_left){rect_num ++;if(rect_num >= 2){for(i=0; i<RECT_NUMBER; i++){if(curRectAddr[i][4] == 0){curRectAddr[i][0] = x;                      /*rect(i)的初始width*/curRectAddr[i][1] = y;                      /*rect(i)的初始height*/curRectAddr[i][2] = rng.uniform(-20, 20);   /*rect(i)的width偏移速度*/curRectAddr[i][3] = rng.uniform(-20, 20);   /*rect(i)的height偏移速度*/if((curRectAddr[i][2] == 0) && (curRectAddr[i][3] == 0)){curRectAddr[i][2] = 10;curRectAddr[i][3] = 10;}curRectAddr[i][4] = 1;                      /*rect(i)的存在状态*/rect_num = 0;scalar[i][0] = rng.uniform(0, 255);scalar[i][1] = rng.uniform(0, 255);scalar[i][2] = rng.uniform(0, 255);break;}}}}}   void add_rect(Mat mat, int num){curRectAddr[num][0] = curRectAddr[num][0] - curRectAddr[num][2];curRectAddr[num][1] = curRectAddr[num][1] - curRectAddr[num][3];if((curRectAddr[num][0] < 0) || (curRectAddr[num][1] < 0)){curRectAddr[num][4] = 0;return;}if(curRectAddr[num][0] > (width - src2_height)){curRectAddr[num][4] = 0;return;}if(curRectAddr[num][1] > (height - src2_width)){curRectAddr[num][4] = 0;return;}imageROI = src(cv::Rect(curRectAddr[num][0], curRectAddr[num][1], src2_height, src2_width));beta = 1 - alpha;addWeighted(imageROI, alpha, src2, beta, 0.0, imageROI);} int main(int agrc, char* argv[]){char c;int i; memcpy(pic_name,argv[1],sizeof(argv[1]));src=imread(pic_name,1);width = src.cols;height = src.rows;src2_width = width / 10;src2_height = height / 10;src2 = Mat(src2_width, src2_height, CV_8UC3, 1);IplImage img = src2;cvZero(&img);mouse_width = width/2;mouse_height = height/2; namedWindow("src", 1);cvSetMouseCallback("src", on_mouse, NULL);while(1){c = waitKey(20);if(c == 'q'){break;}if(mouse_left){src=imread(pic_name,1);for(i=0; i<RECT_NUMBER; i++){if(curRectAddr[i][4] != 0){rectangle(src2,cvPoint(0, 0), cvPoint(src2_height, src2_width), scalar[i], -1);add_rect(src, i);}}}imshow("src",src);}cvDestroyAllWindows();   return 0;  }

代码讲解

　　1、首先是打开传入的背景图片src，获得它的相关信息。接着初始化小方块图片，设置它的大小，和将用cvZero进行初始化。

        memcpy(pic_name,argv[1],sizeof(argv[1])); src=imread(pic_name,1);width = src.cols;height = src.rows;src2_width = width / 10;src2_height = height / 10;src2 = Mat(src2_width, src2_height, CV_8UC3, 1);IplImage img = src2;cvZero(&img);

　　2、接着进入一个死循环中，当鼠标没有按下的时候，除了键值等待之外，不做任何操作。注意如果按下键值'q',则会退出程序。

        while(1){c = waitKey(20);if(c == 'q'){break;         }                ..........               imshow("src",src);        }

　　3、鼠标左键按下，mouse_left为true，则对方框进行初始化，rect_num作为方块产生的延时，同时一共设置了最多可以生成RECT_NUMBER 16个方块。方块参数保存在：curRectAddr和scalar中，假设以第一个方框为例：它的参数就保存在curRectAddr[0]和scalar[0]中。具体参数解释如下:      curRectAddr[i][0] = x;                      /*rect(i)的初始width*/      curRectAddr[i][1] = y;                      /*rect(i)的初始height*/      curRectAddr[i][2] = rng.uniform(-20, 20);   /*rect(i)的width偏移速度*/      curRectAddr[i][3] = rng.uniform(-20, 20);   /*rect(i)的height偏移速度*/      curRectAddr[i][4] = 1;                      /*rect(i)的生存状态*/      scalar[0]                                   /*方块的颜色*/　　注意，如果随机生成出来的方块width和height的便宜速度都为0的话，则强行设置它们的偏移速度都为10。　　当鼠标左键抬起之后，mouse_left为false。停止生成小方块。

void on_mouse( int event, int x, int y, int flags, void* ustc){int i; if(event == CV_EVENT_LBUTTONDOWN){mouse_left = true;}else if(event == CV_EVENT_LBUTTONUP){mouse_left = false;}if(mouse_left){rect_num ++;if(rect_num >= 2){for(i=0; i<RECT_NUMBER; i++){if(curRectAddr[i][4] == 0){curRectAddr[i][0] = x;                      /*rect(i)的初始width*/curRectAddr[i][1] = y;                      /*rect(i)的初始height*/curRectAddr[i][2] = rng.uniform(-20, 20);   /*rect(i)的width偏移速度*/curRectAddr[i][3] = rng.uniform(-20, 20);   /*rect(i)的height偏移速度*/if((curRectAddr[i][2] == 0) && (curRectAddr[i][3] == 0)){curRectAddr[i][2] = 10;curRectAddr[i][3] = 10;}curRectAddr[i][4] = 1;                      /*rect(i)的存在状态*/rect_num = 0;scalar[i][0] = rng.uniform(0, 255);scalar[i][1] = rng.uniform(0, 255);scalar[i][2] = rng.uniform(0, 255);break;}}}}}

　　4、在main的循环中，由于鼠标左键按下，mouse_left为true。就会实时更新存在状态为1的小方块在背景图的位置。当小方块偏移出背景图之后。就会将该方块生存状态置为0.停止对它的刷新。

void add_rect(Mat mat, int num){curRectAddr[num][0] = curRectAddr[num][0] - curRectAddr[num][2];curRectAddr[num][1] = curRectAddr[num][1] - curRectAddr[num][3];if((curRectAddr[num][0] < 0) || (curRectAddr[num][1] < 0)){curRectAddr[num][4] = 0;return;}if(curRectAddr[num][0] > (width - src2_height)){curRectAddr[num][4] = 0;return;}if(curRectAddr[num][1] > (height - src2_width)){curRectAddr[num][4] = 0;return;}imageROI = src(cv::Rect(curRectAddr[num][0], curRectAddr[num][1], src2_height, src2_width));beta = 1 - alpha;addWeighted(imageROI, alpha, src2, beta, 0.0, imageROI);}    if(mouse_left){src=imread(pic_name,1);for(i=0; i<RECT_NUMBER; i++){    if(curRectAddr[i][4] != 0){rectangle(src2,cvPoint(0, 0), cvPoint(src2_height, src2_width), scalar[i], -1);add_rect(src, i);    }}   }

效果演示

　　对应的效果演示如下: