add pixelate func and example

CMakeLists.txt

@@ -7,7 +7,7 @@ project(ftxui
 )
 
 option(FTXUI_QUIET "Set to ON for FTXUI to be quiet" OFF)
-option(FTXUI_BUILD_EXAMPLES "Set to ON to build examples" OFF)
+option(FTXUI_BUILD_EXAMPLES "Set to ON to build examples" ON)
 option(FTXUI_BUILD_DOCS "Set to ON to build docs" OFF)
 option(FTXUI_BUILD_TESTS "Set to ON to build tests" OFF)
 option(FTXUI_BUILD_TESTS_FUZZER "Set to ON to enable fuzzing" OFF)
@@ -173,5 +173,21 @@ include(cmake/ftxui_export.cmake)
 include(cmake/ftxui_install.cmake)
 include(cmake/ftxui_package.cmake)
 
+# --- Find OpenCV and add as a dependency ---
+find_package(OpenCV REQUIRED)
+include_directories(${OpenCV_INCLUDE_DIRS})
+
+target_link_libraries(screen
+  PUBLIC ${OpenCV_LIBS}
+)
+target_link_libraries(dom
+  PUBLIC ${OpenCV_LIBS}
+)
+target_link_libraries(component
+  PUBLIC ${OpenCV_LIBS}
+)
+
 add_subdirectory(examples)
 add_subdirectory(doc)
+
+

examples/CMakeLists.txt

@@ -14,6 +14,10 @@ endfunction(example)
 add_subdirectory(component)
 add_subdirectory(dom)
 
+# Add the pixelate example
+add_executable(pixelate ${CMAKE_CURRENT_SOURCE_DIR}/dom/pixelate.cpp)
+target_link_libraries(pixelate PRIVATE dom)
+
 if (EMSCRIPTEN)
   string(APPEND CMAKE_EXE_LINKER_FLAGS " -s ALLOW_MEMORY_GROWTH=1")
   target_link_options(component PUBLIC "SHELL: -s ALLOW_MEMORY_GROWTH=1")

examples/dom/pixelate.cpp

@@ -0,0 +1,37 @@
+#include "ftxui/dom/canvas.hpp"
+#include <stdio.h>                 // for getchar
+#include <cmath>                   // for cos
+#include <ftxui/dom/elements.hpp>  // for Fit, canvas, operator|, border, Element
+#include <ftxui/screen/screen.hpp> // for Pixel, Screen
+#include <vector>                  // for vector, allocator
+
+#include "ftxui/dom/canvas.hpp"    // for Canvas
+#include "ftxui/dom/node.hpp"      // for Render
+#include "ftxui/screen/color.hpp"  // for Color, Color::Red, Color::Blue, Color::Green, ftxui
+
+using namespace ftxui;
+using namespace cv;
+
+int main(int argc, char* argv[]) {
+  if (argc != 2 && argc != 4) {
+    std::cerr << "Usage: " << argv[0] << " <image_path> [width] [height]" << std::endl;
+    return 1;
+  }
+
+  std::string image_path = argv[1];
+  int width, height;
+
+  if (argc == 4) {
+    width = std::stoi(argv[2]);
+    height = std::stoi(argv[3]);
+  } else {
+    // default-values
+    width = 100;
+    height = 50;
+  }
+
+  // call static method
+  Canvas::DrawImageOnTerminal(image_path, width, height);
+
+  return 0;
+}

include/ftxui/dom/canvas.hpp

@@ -12,6 +12,8 @@
 #include "ftxui/screen/color.hpp"  // for Color
 #include "ftxui/screen/image.hpp"  // for Pixel, Image
 
+#include <opencv2/opencv.hpp> //for OpenCV
+
 #ifdef DrawText
 // Workaround for WinUsr.h (via Windows.h) defining macros that break things.
 // https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-drawtext
@@ -106,6 +108,10 @@ struct Canvas {
   // y is considered to be a multiple of 4.
   void Style(int x, int y, const Stylizer& style);
 
+  static void DrawImageOnTerminal(const std::string& image_path, int width = 80, int height = 24);
+
+
+
  private:
   bool IsIn(int x, int y) const {
     return x >= 0 && x < width_ && y >= 0 && y < height_;

src/ftxui/dom/canvas.cpp

@@ -20,6 +20,7 @@
 #include "ftxui/screen/screen.hpp"    // for Pixel, Screen
 #include "ftxui/screen/string.hpp"    // for Utf8ToGlyphs
 #include "ftxui/util/ref.hpp"         // for ConstRef
+#include <opencv2/opencv.hpp>         // for OpenCV
 
 namespace ftxui {
 
@@ -861,6 +862,45 @@ void Canvas::Style(int x, int y, const Stylizer& style) {
   }
 }
 
+/**
+ * @brief Places Dots on Canvas and prints it on Terminal
+ * @param image_path absolute path to image
+ * @param width number of Pixels on x-axis
+ * @param height number of Pixels on y-axis
+ */
+
+void Canvas::DrawImageOnTerminal(const std::string& image_path, int width, int height) {
+  using namespace cv;
+
+  // read image via OpenCV
+  Mat image = imread(image_path, IMREAD_COLOR);
+  if (image.empty()) {
+    std::cerr << "Could not read the image: " << image_path << std::endl;
+    return;
+  }
+
+  // modify images dimensions
+  resize(image, image, Size(width, height));
+
+  Canvas c(width, height);
+
+  // transfer images pixels onto canvas
+  for (int y = 0; y < height; ++y) {
+    for (int x = 0; x < width; ++x) {
+        Vec3b color = image.at<Vec3b>(y, x);
+      c.DrawPoint(x, y, true, Color::RGB(color[2], color[1], color[0]));
+    }
+  }
+
+  // render canvas as element
+  auto document = canvas(&c);
+  auto screen = Screen::Create(Dimension::Full(), Dimension::Fit(document));
+  Render(screen, document);
+  screen.Print();
+}
+
+
+
 namespace {
 
 class CanvasNodeBase : public Node {