Photoshop中的套索工具通過鼠標多次點擊可以選中一個任意多邊形的區域,然後單獨對這塊區域進行編輯,下面就使用OpenCV實現一個簡單的功能,模擬Photoshop中的套索工具。
這裏的套索工具通過鼠標左鍵在圖片上多次點擊創建任意多個點,右鍵點擊後將這些點連成封閉的多邊形,形成一塊待編輯的區域,鍵盤方向鍵控制該區域的移動,從而將該區域內的圖像複製到原圖像的其他地方。
首先定義下列全局變量
const char* winName = "TaoSuoTool";//窗口名稱
cv::Mat resultImg;//最終在OpenCV窗口上顯示的圖像
cv::Mat foregroundImg;//編輯前的圖像
cv::Mat areaMask;//蒙版,多邊形區域實際繪製在該蒙版上
cv::Point maskLocation;//蒙版位置,通過方向鍵移動後蒙版位置隨之變化
std::vector<cv::Point> drawingPoints;//區域完成前正在點擊的所有點
std::vector<cv::Point> areaPoints;//區域完成後其多邊形頂點
main函數
int main(int argc, char **arv)
{
foregroundImg = cv::imread("test.jpg");
foregroundImg.copyTo(resultImg);
areaMask = cv::Mat::zeros(foregroundImg.size(), CV_8U);
cv::imshow(winName, resultImg);
maskLocation.x = maskLocation.y = 0;
cv::setMouseCallback(winName, OnMouseEvent);
int key = cv::waitKeyEx(0);
while (key != VK_ESCAPE)
{
key = cv::waitKeyEx(0);
}
return 0;
}
在鼠標回調函數OnMouseEvent中處理三個消息:鼠標左鍵按下,鼠標右鍵按下和鼠標移動
void OnMouseEvent(int event, int x, int y, int flags, void* userdata)
{
if (event == cv::EVENT_LBUTTONDOWN)
{
OnLeftMouseButtonDown(x,y);
}
else if (event == cv::EVENT_RBUTTONDOWN)
{
OnRightMouseButtonDown(x,y);
}
if (event == cv::EVENT_MOUSEMOVE)
{
OnMouseMove(x,y);
}
}
在編寫鼠標事件前先定義一個函數
void OnCompleteArea(bool bDrawOutline);
它表示完成當前區域的編輯,包括右鍵點擊完成封閉多邊形、移動區域以及合成最終圖片。參數bDrawOutline表示繪製區域多邊形的外輪廓,右鍵點擊完成封閉多邊形和移動區域過程中都要顯示輪廓(bDrawOutline=true),合成最終圖片後就不需要顯示輪廓了(bDrawOutline=false)。
鼠標左鍵按下事件:先判斷是否有前一個區域存在,存在則先完成前一個區域並且不顯示區域輪廓,然後開始繪製新的區域多邊形的點,點與點之間用藍色線連接,點位置處繪製一個4X4的紅色矩形。
void OnLeftMouseButtonDown(int x,int y)
{
if (drawingPoints.empty() && areaPoints.size() > 0)
{
OnCompleteArea(false);
}
drawingPoints.push_back(cv::Point(x, y));
cv::rectangle(resultImg, cv::Rect(x - 2, y - 2, 4, 4), CV_RGB(255, 0, 0), -1);
if (drawingPoints.size() >= 2)
{
cv::line(resultImg, drawingPoints[drawingPoints.size() - 2], cv::Point(x, y), CV_RGB(0, 0, 255), 1);
}
cv::imshow(winName, resultImg);
}
鼠標移動事件:判斷drawingPoints是否爲空,如果已經存在點則繪製線和點,並且還要繪製一根連接到鼠標當前位置的線。
void OnMouseMove(int x,int y)
{
if (drawingPoints.size() > 0)
{
foregroundImg.copyTo(resultImg);
for (int i = 0; i < drawingPoints.size() - 1; i++)
{
cv::rectangle(resultImg, cv::Rect(drawingPoints[i].x - 2, drawingPoints[i].y - 2, 4, 4), CV_RGB(255, 0, 0), -1);
cv::line(resultImg, drawingPoints[i], drawingPoints[i + 1], CV_RGB(0, 0, 255), 1);
}
cv::rectangle(resultImg, cv::Rect(drawingPoints[drawingPoints.size() - 1].x - 2, drawingPoints[drawingPoints.size() - 1].y - 2, 4, 4), CV_RGB(255, 0, 0), -1);
cv::line(resultImg, drawingPoints[drawingPoints.size() - 1], cv::Point(x, y), CV_RGB(0, 0, 255), 1);
cv::imshow(winName, resultImg);
}
}
鼠標右鍵按下事件:如果點個數少於2,不能形成有效區域則不做處理(不考慮多個點共線),否則就在蒙版Area上繪製一個多邊形區域,然後調用OnCompleteArea完成區域編輯,這裏需要畫多邊形輪廓,參數傳入true。
void OnRightMouseButtonDown(int x,int y)
{
if (drawingPoints.size() >= 3)
{
areaPoints = drawingPoints;
std::vector<std::vector<cv::Point>> polys;
polys.push_back(areaPoints);
cv::fillPoly(areaMask, polys, cv::Scalar::all(255));
OnCompleteArea(true);
}
else
{
foregroundImg.copyTo(resultImg);
}
drawingPoints.clear();
cv::imshow(winName, resultImg);
}
下面是OnCompleteArea函數的實現,其中MergeImages函數通過蒙版以及蒙版的位置合成最終的圖像,蒙版中區域內的像素值大於0,其他像素值都爲0,默認圖像是三通道(destImg.at<cv::Vec3b>)
void MergeImages(cv::Mat& destImg, const cv::Mat& srcImg, const cv::Mat& maskImg, int x, int y)
{
int top = y > 0 ? y : 0;
int left = x > 0 ? x : 0;
int right = destImg.cols > x + srcImg.cols ? x + srcImg.cols : destImg.cols;
int bottom = destImg.rows > y + srcImg.rows ? y + srcImg.rows : destImg.rows;
for (int i = top; i < bottom; i++)
{
for (int j = left; j < right; j++)
{
int destIndex = i * destImg.cols + j;
int srcIndex = (i - top)*srcImg.cols + j - left;
int channel = destImg.channels();
if (maskImg.at<uchar>(i - y, j - x) > 0)
{
destImg.at<cv::Vec3b>(i, j)[0] = srcImg.at<cv::Vec3b>(i - y, j - x)[0];
destImg.at<cv::Vec3b>(i, j)[1] = srcImg.at<cv::Vec3b>(i - y, j - x)[1];
destImg.at<cv::Vec3b>(i, j)[2] = srcImg.at<cv::Vec3b>(i - y, j - x)[2];
}
}
}
}
void OnCompleteArea(bool bDrawOutline)
{
foregroundImg.copyTo(resultImg);
MergeImages(resultImg, foregroundImg, areaMask, maskLocation.x, maskLocation.y);
if (bDrawOutline)
{
if (areaPoints.size() >= 3)
{
std::vector<std::vector<cv::Point>> polys;
polys.push_back(areaPoints);
cv::polylines(resultImg, polys, true, cv::Scalar::all(255));
}
}
else
{
resultImg.copyTo(foregroundImg);
areaPoints.clear();
memset(areaMask.data, 0, areaMask.rows*areaMask.cols*areaMask.elemSize());
maskLocation.x = maskLocation.y = 0;
}
}
繪製區域之後就可以通過方向按鍵控制區域圖像的移動了(也可以實現爲鼠標左鍵按下拖動來移動區域),移動主要是更新maskLocation和areaPoints的座標值,然後調用OnCompleteArea(true),依然顯示區域的輪廓。
void OnDirectionKeyDown(short keyCode)
{
int x = keyCode == VK_LEFT ? -2 : (keyCode == VK_RIGHT ? 2 : 0);
int y = keyCode == VK_UP ? -2 : (keyCode == VK_DOWN ? 2 : 0);
maskLocation.x += x;
maskLocation.y += y;
for (int i = 0; i < areaPoints.size(); i++)
{
areaPoints[i].x += x;
areaPoints[i].y += y;
}
OnCompleteArea(true);
cv::imshow(winName, resultImg);
}
將上面函數在主函數的按鍵循環中調用,方向按鍵通過key的高16位判斷,在Windows下可以使用虛擬鍵碼宏表示。 同時爲了能看到最終合成的圖片加入Enter按鍵消息處理,將圖像合成並去掉輪廓。
int key = cv::waitKeyEx(0);
short lowKey = key;
short highKey = key >> 16;
while (key != VK_ESCAPE)
{
if (key == VK_RETURN)//Enter
{
OnCompleteArea(false);
cv::imshow(winName, resultImg);
}
else if (lowKey == 0 && (highKey == VK_UP || highKey == VK_DOWN || highKey == VK_LEFT || highKey == VK_RIGHT))
{
OnDirectionKeyDown(highKey);
}
key = cv::waitKeyEx(0);
lowKey = key;
highKey = key >> 16;
}
這樣一個簡單的套索工具功能就做好了(上面的代碼都是簡化處理,還有很多可以優化的地方,從而使編輯更加流暢)
完整代碼
#include<iostream>
#include"opencv2/opencv.hpp"
#include<windows.h>
const char* winName = "TaoSuoTool";
cv::Point maskLocation;
cv::Mat resultImg;
cv::Mat foregroundImg;
cv::Mat areaMask;
std::vector<cv::Point> drawingPoints;
std::vector<cv::Point> areaPoints;
void MergeImages(cv::Mat& destImg, const cv::Mat& srcImg, const cv::Mat& maskImg, int x, int y)
{
int top = y > 0 ? y : 0;
int left = x > 0 ? x : 0;
int right = destImg.cols > x + srcImg.cols ? x + srcImg.cols : destImg.cols;
int bottom = destImg.rows > y + srcImg.rows ? y + srcImg.rows : destImg.rows;
for (int i = top; i < bottom; i++)
{
for (int j = left; j < right; j++)
{
int destIndex = i * destImg.cols + j;
int srcIndex = (i - top)*srcImg.cols + j - left;
int channel = destImg.channels();
if (maskImg.at<uchar>(i - y, j - x) > 0)
{
destImg.at<cv::Vec3b>(i, j)[0] = srcImg.at<cv::Vec3b>(i - y, j - x)[0];
destImg.at<cv::Vec3b>(i, j)[1] = srcImg.at<cv::Vec3b>(i - y, j - x)[1];
destImg.at<cv::Vec3b>(i, j)[2] = srcImg.at<cv::Vec3b>(i - y, j - x)[2];
}
}
}
}
void OnCompleteArea(bool bDrawOutline)
{
foregroundImg.copyTo(resultImg);
MergeImages(resultImg, foregroundImg, areaMask, maskLocation.x, maskLocation.y);
if (bDrawOutline)
{
if (areaPoints.size() >= 3)
{
std::vector<std::vector<cv::Point>> polys;
polys.push_back(areaPoints);
cv::polylines(resultImg, polys, true, cv::Scalar::all(255));
}
}
else
{
resultImg.copyTo(foregroundImg);
areaPoints.clear();
memset(areaMask.data, 0, areaMask.rows*areaMask.cols*areaMask.elemSize());
maskLocation.x = maskLocation.y = 0;
}
}
void OnLeftMouseButtonDown(int x,int y)
{
if (drawingPoints.empty() && areaPoints.size() > 0)
{
OnCompleteArea(false);
}
drawingPoints.push_back(cv::Point(x, y));
cv::rectangle(resultImg, cv::Rect(x - 2, y - 2, 4, 4), CV_RGB(255, 0, 0), -1);
if (drawingPoints.size() >= 2)
{
cv::line(resultImg, drawingPoints[drawingPoints.size() - 2], cv::Point(x, y), CV_RGB(0, 0, 255), 1);
}
cv::imshow(winName, resultImg);
}
void OnRightMouseButtonDown(int x,int y)
{
if (drawingPoints.size() >= 3)
{
areaPoints = drawingPoints;
std::vector<std::vector<cv::Point>> polys;
polys.push_back(areaPoints);
cv::fillPoly(areaMask, polys, cv::Scalar::all(255));
OnCompleteArea(true);
}
else
{
foregroundImg.copyTo(resultImg);
}
drawingPoints.clear();
cv::imshow(winName, resultImg);
}
void OnMouseMove(int x,int y)
{
if (drawingPoints.size() > 0)
{
foregroundImg.copyTo(resultImg);
for (int i = 0; i < drawingPoints.size() - 1; i++)
{
cv::rectangle(resultImg, cv::Rect(drawingPoints[i].x - 2, drawingPoints[i].y - 2, 4, 4), CV_RGB(255, 0, 0), -1);
cv::line(resultImg, drawingPoints[i], drawingPoints[i + 1], CV_RGB(0, 0, 255), 1);
}
cv::rectangle(resultImg, cv::Rect(drawingPoints[drawingPoints.size() - 1].x - 2, drawingPoints[drawingPoints.size() - 1].y - 2, 4, 4), CV_RGB(255, 0, 0), -1);
cv::line(resultImg, drawingPoints[drawingPoints.size() - 1], cv::Point(x, y), CV_RGB(0, 0, 255), 1);
cv::imshow(winName, resultImg);
}
}
void OnMouseEvent(int event, int x, int y, int flags, void* userdata)
{
if (event == cv::EVENT_LBUTTONDOWN)
{
OnLeftMouseButtonDown(x,y);
}
else if (event == cv::EVENT_RBUTTONDOWN)
{
OnRightMouseButtonDown(x,y);
}
if (event == cv::EVENT_MOUSEMOVE)
{
OnMouseMove(x,y);
}
}
void OnDirectionKeyDown(short keyCode)
{
int x = keyCode == VK_LEFT ? -2 : (keyCode == VK_RIGHT ? 2 : 0);
int y = keyCode == VK_UP ? -2 : (keyCode == VK_DOWN ? 2 : 0);
maskLocation.x += x;
maskLocation.y += y;
for (int i = 0; i < areaPoints.size(); i++)
{
areaPoints[i].x += x;
areaPoints[i].y += y;
}
OnCompleteArea(true);
cv::imshow(winName, resultImg);
}
int main(int argc, char **arv)
{
foregroundImg = cv::imread("test.jpg");
foregroundImg.copyTo(resultImg);
areaMask = cv::Mat::zeros(foregroundImg.size(), CV_8U);
cv::imshow(winName, resultImg);
maskLocation.x = maskLocation.y = 0;
cv::setMouseCallback(winName, OnMouseEvent);
int key = cv::waitKeyEx(0);
short lowKey = key;
short highKey = key >> 16;
while (key != VK_ESCAPE)
{
if (key == VK_RETURN)//Enter
{
OnCompleteArea(false);
cv::imshow(winName, resultImg);
}
else if (lowKey == 0 && (highKey == VK_UP || highKey == VK_DOWN || highKey == VK_LEFT || highKey == VK_RIGHT))
{
OnDirectionKeyDown(highKey);
}
key = cv::waitKeyEx(0);
lowKey = key;
highKey = key >> 16;
}
return 0;
}