Glimmer DSL for SWT Custom Shapes

Glimmer DSL for SWT just had a new feature release (4.18.7.0) introducing the concept of custom shapes, which is similar to custom widgets, except it is applied to shapes from the Canvas Shape DSL.

In fact, it supports both a method-based approach and a class-based more modular approach for defining new custom shape keywords.

This enables higher order visual concepts, such as defining a car from polygons, defining a beach_scene from tree, sand, and sunset, etc... The possibilities are endless!

This realizes Lisp's ultimate vision of code as data and data as code by being able to abstract and hide an entire concept like `boat` that is consisting of hundreds of `polygon` shapes behind a single keyword representing `boat` data, which in turn embodies the entire `boat` shape visual code. Just imagine the possibilities of having something like this with Ruby's ultra-fluid pliable syntax! It is time Ruby upended all other languages in desktop development, no!?! You can now productively enlarge your GUI DSL vocabulary endlessly and compose ever higher visual concepts as well as decorations for existing widgets. 

I will let the newly added code samples explain more about custom shapes.

Hello, Shape!

This sample enables leveraging the generic `shape` keyword as a sort of a shape composite (similar to widget `composite`) that contains other nested shapes and defines common shared attributes for all of them. It uses that keyword in fact to build a method-based custom shape.

	# From: https://github.com/AndyObtiva/glimmer-dsl-swt/blob/master/docs/reference/GLIMMER_SAMPLES.md#hello-shape
	require 'glimmer-dsl-swt'
	class HelloShape
	include Glimmer::UI::CustomShell
	body {
	shell {
	text 'Hello, Shape!'
	minimum_size 200, 225
	@canvas = canvas {
	background :white
	15.times { |n|
	x_location = (rand*125).to_i%200 + (rand*25).to_i
	y_location = (rand*125).to_i%200 + (rand*25).to_i
	foreground_color = rgb(rand*255, rand*255, rand*255)
	stick_figure(x_location, y_location, 50, 50) {
	foreground foreground_color
	}
	}
	}
	}
	}
	# method-based custom shape using `shape` keyword as a composite shape containing nested shapes
	def stick_figure(x, y, width, height, &block)
	head_width = width*0.2
	head_height = height*0.2
	trunk_height = height*0.4
	extremity_length = height*0.4
	shape(x + head_width/2.0 + extremity_length, y) {
	# common attributes go here before nested shapes
	block.call # invoking content block (e.g. used from the outside to set foreground)
	# nested shapes go here
	oval(0, 0, head_width, head_height)
	line(head_width/2.0, head_height, head_width/2.0, head_height + trunk_height)
	line(head_width/2.0, head_height + trunk_height, head_width/2.0 + extremity_length, head_height + trunk_height + extremity_length)
	line(head_width/2.0, head_height + trunk_height, head_width/2.0 - extremity_length, head_height + trunk_height + extremity_length)
	line(head_width/2.0, head_height*2, head_width/2.0 + extremity_length, head_height + trunk_height - extremity_length)
	line(head_width/2.0, head_height*2, head_width/2.0 - extremity_length, head_height + trunk_height - extremity_length)
	}
	end
	end
	HelloShape.launch

view raw glimmer-hello-shape.rb hosted with ❤ by GitHub

Hello, Custom Shape!

This reimplements the previous sample with a class-based custom shape definition instead of method-based. This enables higher separation of concerns and extraction of code into a separate class, which is useful when defining highly complex and parametric shapes, resulting in cleaner code for better maintainability. It additionally provides support for defining default options and before_body/after_body hooks. 

	# From: https://github.com/AndyObtiva/glimmer-dsl-swt/blob/master/docs/reference/GLIMMER_SAMPLES.md#hello-custom-shape
	require 'glimmer-dsl-swt'
	# Creates a class-based custom shape representing the `stick_figure` keyword by convention
	class StickFigure
	include Glimmer::UI::CustomShape
	options :x, :y, :width, :height
	before_body {
	@head_width = width*0.2
	@head_height = height*0.2
	@trunk_height = height*0.4
	@extremity_length = height*0.4
	}
	body {
	shape(x + @head_width/2.0 + @extremity_length, y) {
	oval(0, 0, @head_width, @head_height)
	line(@head_width/2.0, @head_height, @head_width/2.0, @head_height + @trunk_height)
	line(@head_width/2.0, @head_height + @trunk_height, @head_width/2.0 + @extremity_length, @head_height + @trunk_height + @extremity_length)
	line(@head_width/2.0, @head_height + @trunk_height, @head_width/2.0 - @extremity_length, @head_height + @trunk_height + @extremity_length)
	line(@head_width/2.0, @head_height*2, @head_width/2.0 + @extremity_length, @head_height + @trunk_height - @extremity_length)
	line(@head_width/2.0, @head_height*2, @head_width/2.0 - @extremity_length, @head_height + @trunk_height - @extremity_length)
	}
	}
	end
	class HelloCustomShape
	include Glimmer::UI::CustomShell
	WIDTH = 220
	HEIGHT = 235
	body {
	shell {
	text 'Hello, Custom Shape!'
	minimum_size WIDTH, HEIGHT
	@canvas = canvas {
	background :white
	15.times { |n|
	x_location = (rand*WIDTH/2).to_i%WIDTH + (rand*15).to_i
	y_location = (rand*HEIGHT/2).to_i%HEIGHT + (rand*15).to_i
	foreground_color = rgb(rand*255, rand*255, rand*255)
	a_stick_figure = stick_figure(x: x_location, y: y_location, width: 35+n*2, height: 35+n*2) {
	foreground foreground_color
	drag_and_move true
	# on mouse click, change color
	on_mouse_up do
	a_stick_figure.foreground = rgb(rand*255, rand*255, rand*255)
	end
	}
	}
	}
	}
	}
	end
	HelloCustomShape.launch

view raw gistfile1.txt hosted with ❤ by GitHub

Happy Glimmering!