painting.cpp

demonstrates the use of xtd::forms::form controls with mouse_down, mouse_move and paint events.

Windows

macOS

Gnome

#include <xtd/xtd>
 
namespace painting_example {
  class form1 : public form {
  public:
    form1() {
      text("Painting example");
      client_size({640, 480});
      
      panel_colors_container.parent(*this);
      panel_colors_container.border_style(forms::border_style::fixed_single);
      panel_colors_container.location({10, 10});
      panel_colors_container.client_size({512, 32});
      
      for (auto color : {color::dark_magenta, color::dark_cyan, color::brown, color::dark_blue, color::dark_green, color::dark_red, color::gray, color::dark_gray, color::magenta, color::cyan, color::yellow, color::blue, color::green, color::red, color::white, color::black}) {
        auto panel_color = new_ptr<panel>();
        panel_color->parent(panel_colors_container);
        panel_color->size({32, 32});
        panel_color->back_color(color);
        panel_color->dock(dock_style::left);
        panel_color->click += event_handler {*this, &form1::choose_current_color};
        panel_colors.push_back(panel_color);
      }
      current_color = panel_colors[panel_colors.size() - 1]->back_color();
      panel_colors[panel_colors.size() - 1]->border_style(forms::border_style::fixed_single);
      
      button_clear.parent(*this);
      button_clear.text("Clear");
      button_clear.location({542, 13});
      button_clear.click += delegate_ {
        picture = bitmap {picture.width(), picture.height()};
        panel_painting.invalidate();
      };
      
      button_open.parent(*this);
      button_open.text("Open...");
      button_open.location({542, 47});
      button_open.click += delegate_ {
        open_file_dialog ofd;
        if (ofd.show_dialog() == forms::dialog_result::ok) {
          bitmap new_picture(ofd.file_name());
          if (new_picture.width() > 128 || new_picture.height() > 128)
            message_box::show(*this, "The size of the image must be less than or equal to 128 x 128 pixels.", "Painting example", message_box_buttons::ok, message_box_icon::error);
          else {
            picture = new_picture;
            panel_painting.size({picture.width() * zoom, picture.height() * zoom});
            panel_painting.invalidate();
          }
        }
      };
      
      label_zoom.parent(*this);
      label_zoom.auto_size(false);
      label_zoom.location({10, 60});
      label_zoom.anchor(anchor_styles::top | anchor_styles::left);
      label_zoom.text("Zoom");
      
      track_bar_zoom.parent(*this);
      track_bar_zoom.auto_size(false);
      track_bar_zoom.location({60, 55});
      track_bar_zoom.anchor(anchor_styles::top | anchor_styles::left);
      track_bar_zoom.set_range(1, 50);
      track_bar_zoom.tick_style(forms::tick_style::none);
      track_bar_zoom.value(zoom);
      track_bar_zoom.value_changed += delegate_ {
        zoom = track_bar_zoom.value();
        numeric_up_down_zoom.value(zoom);
        panel_painting.size({picture.width() * zoom, picture.height() * zoom});
        panel_painting.invalidate();
      };
      track_bar_zoom.size({390, 25});
      
      numeric_up_down_zoom.parent(*this);
      numeric_up_down_zoom.location({470, 55});
      numeric_up_down_zoom.set_range(1, 50);
      numeric_up_down_zoom.value(zoom);
      numeric_up_down_zoom.value_changed += delegate_ {
        zoom = as<int>(numeric_up_down_zoom.value());
        track_bar_zoom.value(zoom);
        panel_painting.size({picture.width() * zoom, picture.height() * zoom});
        panel_painting.invalidate();
      };
      numeric_up_down_zoom.width(52);
      
      panel_main.parent(*this);
      panel_main.auto_scroll(true);
      panel_main.border_style(forms::border_style::fixed_single);
      panel_main.location({10, 90});
      panel_main.size({620, 380});
      panel_main.anchor(anchor_styles::top | anchor_styles::left | anchor_styles::bottom | anchor_styles::right);
      
      panel_painting.parent(panel_main);
      panel_painting.back_color(color::white_smoke);
      panel_painting.size({picture.width() * zoom, picture.height() * zoom});
      
      panel_painting.mouse_down += delegate_(object & sender, const mouse_event_args & e) {
        if (e.x() / zoom >= 0 && e.x() / zoom < picture.width() && e.y() / zoom >= 0 && e.y() / zoom < picture.height()) {
          picture.set_pixel(e.x() / zoom, e.y() / zoom, e.button() == mouse_buttons::left ? current_color : color::from_argb(0, 0, 0, 0));
          panel_painting.invalidate(rectangle(e.x() / zoom * zoom, e.y() / zoom * zoom, zoom, zoom));
        }
      };
      
      panel_painting.mouse_move += delegate_(object & sender, const mouse_event_args & e) {
        if (e.button() == mouse_buttons::left && e.x() / zoom >= 0 && e.x() / zoom < picture.width() && e.y() / zoom >= 0 && e.y() / zoom < picture.height()) {
          picture.set_pixel(e.x() / zoom, e.y() / zoom, current_color);
          panel_painting.invalidate(rectangle(e.x() / zoom * zoom, e.y() / zoom * zoom, zoom, zoom));
        }
      };
      
      panel_painting.paint += delegate_(object & sender, paint_event_args & e) {
        for (auto y = 0; y < panel_painting.client_size().height; y += zoom)
          for (auto x = 0; x < panel_painting.client_size().width; x += zoom)
            if (picture.get_pixel(x / zoom, y / zoom) != color::from_argb(0, 0, 0, 0))
              e.graphics().fill_rectangle(solid_brush(picture.get_pixel(x / zoom, y / zoom)), x, y, zoom, zoom);
        if (zoom > 3) {
          for (auto index = 0; index < panel_painting.client_size().width; index += zoom)
            e.graphics().draw_line(pens::light_blue(), index, 0, index, panel_painting.client_size().height);
          for (auto index = 0; index < panel_painting.client_size().height; index += zoom)
            e.graphics().draw_line(pens::light_blue(), 0, index, panel_painting.client_size().width, index);
        }
      };
    }
    
  private:
    void choose_current_color(object& sender, const event_args& e) {
      for (auto panel : panel_colors)
        panel->border_style(panel->handle() != as<control>(sender).handle() ? forms::border_style::none : forms::border_style::fixed_single);
      current_color = as<control>(sender).back_color();
    }
    
    int zoom = 20;
    drawing::color current_color;
    bitmap picture {32, 32};
    
    panel panel_colors_container;
    list<ptr<panel>> panel_colors;
    button button_clear;
    button button_open;
    panel panel_main;
    panel panel_painting;
    label label_zoom;
    track_bar track_bar_zoom;
    numeric_up_down numeric_up_down_zoom;
  };
}
 
auto main() -> int {
  application::run(painting_example::form1 {});
}