利用opencv实现鼠标指针停留获取像素坐标和像素值，也可以实现仿射变换

#include "show-pixel-value.h" #include <opencv2/imgproc/imgproc.hpp> #include <opencv2/highgui/highgui.hpp> #include <opencv2/core/types_c.h> // for cvScalarAll ShowPixelValue::ShowPixelValue(const std::string& windowName, const cv::Mat& input) : windowName(windowName), input(input) { assert(input.type() == CV_8UC1 || input.type() == CV_8UC3); cv::imshow(windowName, input); cv::setMouseCallback(windowName, ShowPixelValue::OnMouse, this); } ShowPixelValue::~ShowPixelValue() { cv::setMouseCallback(windowName, NULL, this); } cv::Scalar GetOuterColor() { return cvScalarAll(0); } cv::Scalar GetInnerColor(int imageType) { return imageType == CV_8UC3 ? cv::Scalar(128, 255, 128) : cv::Scalar(255, 255, 255); } void PutText(cv::Mat& input, const std::string& text, const cv::Point& origin) { const double fontSize = 1.0; cv::putText(input, text, origin, cv::FONT_HERSHEY_PLAIN, fontSize, GetOuterColor(), 3); cv::putText(input, text, origin, cv::FONT_HERSHEY_PLAIN, fontSize, GetInnerColor(input.type()), 1); } std::string GetPixelValueText(const cv::Mat& input, int mouseX, int mouseY) { std::ostringstream oss; if (input.type() == CV_8UC1) { int value = input.at<unsigned char>(cv::Point(mouseX, mouseY)); oss << value; } else if (input.type() == CV_8UC3) { cv::Vec3b value = input.at<cv::Vec3b>(cv::Point(mouseX, mouseY)); if (value[0] == value[1] && value[1] == value[2]) { oss << static_cast<int>(value[0]) << "*"; } else { oss << static_cast<int>(value[0]) << "," << static_cast<int>(value[1]) << "," << static_cast<int>(value[2]); } } else { // TODO: implement support for other input image types as needed. oss << "Error: unsupported image type (" << input.type() << ")"; } return oss.str(); } std::string GetCoordinatesText(int mouseX, int mouseY) { std::ostringstream oss; oss << "X=" << mouseX << ", Y=" << mouseY; return oss.str(); } void ShowPixelValue::OnMouse(int event, int mouseX, int mouseY, int flags, void* userdata) { ShowPixelValue* showPixelValue = reinterpret_cast<ShowPixelValue*>(userdata); if (showPixelValue == NULL) { return; } showPixelValue->Update(mouseX, mouseY, false); showPixelValue->UpdateOthers(mouseX, mouseY); } void ShowPixelValue::Update(int mouseX, int mouseY, bool showPoint) { if (input.data == NULL) { return; } if (mouseX < 0 || mouseY < 0 || mouseX >= input.cols || mouseY >= input.rows) { return; } input.copyTo(output); cv::Point pixelValueOrigin(mouseX + 4, mouseY - 4); cv::Point coordinatesOrigin(pixelValueOrigin.x, pixelValueOrigin.y + 20); PutText(output, GetPixelValueText(input, mouseX, mouseY), pixelValueOrigin); PutText(output, GetCoordinatesText(mouseX, mouseY), coordinatesOrigin); if (showPoint) { cv::Point point(mouseX, mouseY); cv::circle(output, point, 1, GetOuterColor(), 1); cv::circle(output, point, 0, GetInnerColor(input.type()), 1); } cv::imshow(windowName, output); } void ShowPixelValue::UpdateOthers(int mouseX, int mouseY) { for (ShowPixelValue* updateTarget : updateTargets) { updateTarget->Update(mouseX, mouseY, true); } } void ShowPixelValue::KeepUpdating(ShowPixelValue* other) { assert(updateTargets.find(other) == updateTargets.end()); updateTargets.insert(other); } void ShowPixelValue::StopUpdating(ShowPixelValue* other) { assert(updateTargets.find(other) != updateTargets.end()); updateTargets.erase(other); }