variant_shapes.cpp

#include "BitmapPlusPlus.hpp"
#include <filesystem>
#include <iostream>
#include <variant>

struct Rectangle {
  int x, y;
  int width, height;
  bmp::Pixel color;

  Rectangle(int x, int y, int w, int h, bmp::Pixel color)
    : width(w), height(h), x(x), y(y), color(color) {
  }

  void draw(bmp::Bitmap& image) const {
    image.fill_rect(x, y, width, height, color);
  }
};

struct Triangle {
  int x1, y1, x2, y2, x3, y3;
  bmp::Pixel color;


  Triangle(int x1, int y1, int x2, int y2, int x3, int y3, bmp::Pixel color)
    : x1(x1), y1(y1), x2(x2), y2(y2), x3(x3), y3(y3), color(color) {
  }

  void draw(bmp::Bitmap& image) const {
    image.fill_triangle(x1, y1, x2, y2, x3, y3, color);
  }
};

struct Circle {
  int x, y;
  int radius;
  bmp::Pixel color;

  Circle(int x, int y, int radius, bmp::Pixel color)
    : radius(radius), x(x), y(y), color(color) {
  }

  void draw(bmp::Bitmap& image) const {
    image.fill_circle(x, y, radius, color);
  }
};

struct ShapeDrawer {
  bmp::Bitmap& bitmap;

  explicit ShapeDrawer(bmp::Bitmap& bitmap)
    : bitmap(bitmap) {
  }

  void operator()(const Rectangle& rectangle) const {
    const auto& [x, y, width, height, color] = rectangle;
    bitmap.fill_rect(x, y, width, height, color);
  }

  void operator()(const Triangle& triangle) const {
    const auto& [x1, y1, x2, y2, x3, y3, color] = triangle;
    bitmap.fill_triangle(x1, y1, x2, y2, x3, y3, color);
  }

  void operator()(const Circle& circle) const {
    const auto& [x, y, radius, color] = circle;
    bitmap.fill_circle(x, y, radius, color);
  }
};


int main() {
  try {
    bmp::Bitmap image(640, 256);
    image.clear(bmp::Teal);

    ShapeDrawer drawer{image};

    // No OOP polymorphism + faster
    // for more details, watch this great talk by Klaus Iglberger: https://www.youtube.com/watch?v=m3UmABVf55g
    using Shape = std::variant<Rectangle, Triangle, Circle>;
    Shape shapes[] = {
      Rectangle(20, 20, 180, 180, bmp::Gold),
      Triangle(310, 20, 230, 200, 400, 200, bmp::Violet),
      Circle(500, 110, 90, bmp::Coral)};

    for (Shape& shape: shapes) {
      std::visit(drawer, shape); // visit will call the appropriate ShapeDrawer::operator() for each shape
    }

    auto p1 = std::filesystem::path(BIN_DIR) / "variant_shapes.bmp";
    const auto s1 = p1.string();
    image.save(s1.c_str());

    return EXIT_SUCCESS;
  } catch (const bmp::Exception& e) {
    std::cerr << "[BMP ERROR]: " << e.what() << '\n';
    return EXIT_FAILURE;
  }
}