From: Jay McGavren <jay@...>
Date: 2007-10-04T12:40:02+09:00
Subject: wxRuby: MemoryDC problems...

I'm trying to put together a quick test of buffered animation with
WxRuby, but I'm encountering a fair amount of trouble...  I'm drawing
to a Wx::Bitmap first, then using Wx::DC#draw_bitmap to copy it to a
Wx::Window.  But I get the following error:

C:/ruby/lib/ruby/gems/1.8/gems/wxruby-1.9.1-i386-mswin32/lib/wx/
classes/bitmap.rb:18:in `draw': uninitialized constant
Wxruby2::Bitmap::MemoryDC (NameError)
        from dc_draw_line.rb:30:in `on_init'
        ...

Is MemoryDC not implemented yet in WxRuby 1.9.1?  It's in the
documentation, but I know large chunks of that are auto-generated, so
I don't totally trust it.  Maybe I'm doing something wrong, though?

My code is below.  Any advice would be most appreciated!

-Jay



gems_loaded = false
begin
	require 'wx'
rescue LoadError
	if gems_loaded == false
		require 'rubygems'
		gems_loaded = true
		retry
	else
		raise
	end
end

class MyApp < Wx::App
	def on_init
		#Create the top window.
		frame = Wx::Frame.new(nil, :size => [300, 300])
		#Create a panel within it.
		view = Wx::Window.new(frame)

        buffer = Wx::Bitmap.new(300, 300)

        @x = 0

		#Set up a handler for paint events.
		view.evt_paint do |event|
			#Wx::Window#paint takes a block.
			#This will later be called with a device context to paint on.
			view.paint do |dc|
				buffer.draw do |buffer_dc|
					buffer_dc.clear
					buffer_dc.pen = Wx::Pen.new(Wx::Colour.new(128, 128, 128), 5)
					buffer_dc.draw_line(@x, 0, @x + 100, 100)
				end
				dc.draw_bitmap(buffer, 0, 0, false)
			end
			@x += 1
		end
		#Show the window.
		frame.show
		return true
	end
end

app = MyApp.new

app.main_loop