LibUI 0.5.11용 Glimmer DSL - 기본 모양 드래그 앤 드롭

# From: https://github.com/AndyObtiva/glimmer-dsl-libui#shape-coloring

require 'glimmer-dsl-libui'

class ShapeColoring
  include Glimmer::LibUI::Application

  COLOR_SELECTION = Glimmer::LibUI.interpret_color(:red)

  before_body {
    @shapes = []
  }

  body {
    window('Shape Coloring', 200, 220) {
      margined false

      grid {
        label("Drag & drop shapes to move or\nclick a shape to select and\nchange color via color button") {
          left 0
          top 0
          hexpand true
          halign :center
          vexpand false
        }

        color_button { |cb|
          left 0
          top 1
          hexpand true
          vexpand false

          on_changed do
            @selected_shape&.fill = cb.color
          end
        }

        area {
          left 0
          top 2
          hexpand true
          vexpand true

          rectangle(0, 0, 600, 400) { # background shape
            fill :white
          }

          @shapes << colorable(:rectangle, 20, 20, 40, 20) {
            fill :lime
          }

          @shapes << colorable(:square, 80, 20, 20) {
            fill :blue
          }

          @shapes << colorable(:circle, 75, 70, 20) {
            fill :green
          }

          @shapes << colorable(:arc, 120, 70, 40, 0, 145) {
            fill :orange
          }

          @shapes << colorable(:polygon, 120, 10, 120, 50, 150, 10, 150, 50) {
            fill :cyan
          }

          @shapes << colorable(:polybezier, 20, 40,
                     30, 100, 50, 80, 80, 110,
                     40, 120, 20, 120, 30, 91) {
            fill :pink
          }

          on_mouse_dragged do |area_mouse_event|
            mouse_dragged(area_mouse_event)
          end

          on_mouse_dropped do |area_mouse_event|
            mouse_dropped(area_mouse_event)
          end
        }
      }
    }
  }

  def colorable(shape_symbol, *args, &content)
    send(shape_symbol, *args) do |shape|
      on_mouse_up do |area_mouse_event|
        unless @dragged_shape
          old_stroke = Glimmer::LibUI.interpret_color(shape.stroke).slice(:r, :g, :b)
          @shapes.each {|sh| sh.stroke = nil}
          @selected_shape = nil
          unless old_stroke == COLOR_SELECTION
            shape.stroke = COLOR_SELECTION.merge(thickness: 2)
            @selected_shape = shape
          end
        end
      end

      on_mouse_drag_started do |area_mouse_event|
        mouse_drag_started(shape, area_mouse_event)
      end

      on_mouse_dragged do |area_mouse_event|
        mouse_dragged(area_mouse_event)
      end

      on_mouse_dropped do |area_mouse_event|
        mouse_dropped(area_mouse_event)
      end

      content.call(shape)
    end
  end

  def mouse_drag_started(dragged_shape, area_mouse_event)
    @dragged_shape = dragged_shape
    @dragged_shape_x = area_mouse_event[:x]
    @dragged_shape_y = area_mouse_event[:y]
  end

  def mouse_dragged(area_mouse_event)
    if @dragged_shape && @dragged_shape_x && @dragged_shape_y
      x_delta = area_mouse_event[:x] - @dragged_shape_x
      y_delta = area_mouse_event[:y] - @dragged_shape_y
      @dragged_shape.move_by(x_delta, y_delta)
      @dragged_shape_x = area_mouse_event[:x]
      @dragged_shape_y = area_mouse_event[:y]
    end
  end

  def mouse_dropped(area_mouse_event)
    @dragged_shape = nil
    @dragged_shape_x = nil
    @dragged_shape_y = nil
  end
end

ShapeColoring.launch