Example: img_basic_example
![img_basic_example screenshot](_images/img_basic_example_screenshot.png)
![img_basic_example screenshot](_images/img_basic_example_screenshot.png)
![img_basic_example screenshot](_images/img_basic_example_screenshot.png)
![img_basic_example screenshot](_images/img_basic_example_screenshot.png)
C++ example source code:
/* +------------------------------------------------------------------------+ | Mobile Robot Programming Toolkit (MRPT) | | https://www.mrpt.org/ | | | | Copyright (c) 2005-2024, Individual contributors, see AUTHORS file | | See: https://www.mrpt.org/Authors - All rights reserved. | | Released under BSD License. See: https://www.mrpt.org/License | +------------------------------------------------------------------------+ */ #include <mrpt/gui/CDisplayWindow.h> #include <mrpt/math/CMatrixF.h> #include <mrpt/system/CTicTac.h> #include <mrpt/system/CTimeLogger.h> #include <iostream> using namespace mrpt; using namespace mrpt::gui; using namespace mrpt::img; using namespace mrpt::math; using namespace mrpt::system; using namespace std; #include <mrpt/examples_config.h> string myDataDir(MRPT_EXAMPLES_BASE_DIRECTORY + string("img_basic_example/")); // ------------------------------------------------------ // TestImageCap // ------------------------------------------------------ void TestImageConversion() { // BMP -> JPEG conversion tester: // -------------------------------- CImage img; CTicTac tictac; CTimeLogger timlog; tictac.Tic(); if (!img.loadFromFile(myDataDir + string("frame_color.jpg"))) { cerr << "Cannot load " << myDataDir + string("frame_color.jpg") << endl; return; } printf("Image loaded in %.03fms\n", 1000 * tictac.Tac()); if (false) // A very simple test: { CDisplayWindow win1("JPEG file, color"); win1.setPos(10, 10); win1.showImage(img); cout << "Push a key in the console or in the window to continue..."; win1.waitForKey(); cout << "Done" << endl; timlog.enter("grayscale1"); img = img.grayscale(); timlog.leave("grayscale1"); CDisplayWindow win2("JPEG file, gray"); win2.showImage(img); win1.setPos(300, 10); cout << "Push a key in the console or in the window to continue..."; win2.waitForKey(); cout << "Done" << endl; mrpt::system::pause(); return; } CDisplayWindow win1("win1"), win2("win2"), win3("win3"), win4("win4"); CImage imgSmall(img); CImage imgGray; for (int i = 0; i < 50; i++) { timlog.enter("grayscale2"); imgSmall.grayscale(imgGray); timlog.leave("grayscale2"); } CImage imgSmall2 = imgGray.scaleHalf(IMG_INTERP_LINEAR); CImage imgSmallRGB = img.scaleHalf(IMG_INTERP_LINEAR); // Test some draw capabilities: // --------------------------------- imgSmall.rectangle(85, 35, 170, 170, TColor(255, 0, 0), 10); imgSmall.line(550, 75, 650, 25, TColor(0, 0, 255)); imgSmall.line(-10, -20, 20, 30, TColor(0, 0, 255)); CMatrixDouble22 COV; COV(0, 0) = 100; COV(1, 1) = 50; COV(0, 1) = COV(1, 0) = -30; imgSmall.ellipseGaussian(COV, 600.0, 50.0, 2, TColor(255, 255, 0), 4); imgGray.ellipseGaussian(COV, 100.0, 100.0, 2, TColor(0, 0, 255), 4); imgGray.drawImage(50, 40, imgSmall2); // Show the windows now: // ------------------------------------------------------ win1.showImage(imgSmall); win1.setPos(0, 0); win2.showImage(imgSmall2); win2.setPos(810, 0); win3.showImage(imgGray); win3.setPos(810, 300); win4.showImage(imgSmallRGB); win4.setPos(300, 400); cout << "Press any key on 'win4' to exit" << endl; win4.waitForKey(); tictac.Tic(); imgGray.saveToFile("frame_out.jpg"); printf("jpeg file saved in %.03fms\n", 1000.0 * tictac.Tac()); imgSmall2.saveToFile("frame_out_small.png"); return; } // ------------------------------------------------------ // MAIN // ------------------------------------------------------ int main() { try { TestImageConversion(); return 0; } catch (const std::exception& e) { std::cerr << "MRPT error: " << mrpt::exception_to_str(e) << std::endl; return -1; } }