wxruby development - Oct 2007 - [ wxruby-Patches-14375 ] bigdemo/wxScrolledWindow - paint bug with scrolled window

Patches item #14375, was opened at 2007-10-02 13:12
You can respond by visiting: 
http://rubyforge.org/tracker/?func=detail&atid=220&aid=14375&group_id=35

Category: None
Group: None
Status: Open
Resolution: None
Priority: 3
Submitted By: Christopher Bludau (count_cb)
Assigned to: Nobody (None)
Summary: bigdemo/wxScrolledWindow - paint bug with scrolled window

Initial Comment:
I found a bug in bigdemo/wxScrolledWindow.rbw

When you scroll the window and then draw with the mouse the lines
aren''t drawn at the correct position. After a repaint the lines are
drawn correctly.
So they are saved correctly to the lines array but there is an error when they
are first drawn.

I changed two methods to get the correct behaviour:
(file with changes attached)

From:
def on_left_button_event_down(event)
  if event.left_is_down() and !@drawing
    set_focus()
    set_XY(event)
    @curLine = []
    capture_mouse()
    @drawing = true
  end
end

To:
def on_left_button_event_down(event)
  if event.left_is_down() and !@drawing
    set_focus()
    set_XY(event)
    @event_x_old =  event.get_x # added this to save the current absolute... 
    @event_y_old = event.get_y  # ... mouse position
    @curLine = []
    capture_mouse()
    @drawing = true
  end
end

----

And in on_left_button_event_motion

From:
paint do | dc |
  dc.set_pen(Wx::Pen.new("MEDIUM FOREST GREEN", 4, Wx::SOLID))
  coords = [@x, @y] + convert_event_coords(event)
  @curLine.push(coords)
  coords.flatten!()
  dc.draw_line(coords[0], coords[1], coords[2], coords[3])
  set_XY(event)
end

To:
paint do | dc |
  dc.set_pen(Wx::Pen.new("MEDIUM FOREST GREEN", 4, Wx::SOLID))
  save_coords = [@x, @y] + convert_event_coords(event)             # translate
the absolute coords to save them in the array
  coords = [@event_x_old, @event_y_old, event.get_x, event.get_y]  # the
absolute coords to use for the first draw
  @curLine.push(save_coords)                                       # use the
translated coords here
  coords.flatten!()
  dc.draw_line(coords[0], coords[1], coords[2], coords[3])         # and the
absolute coords here
  set_XY(event)
  @event_x_old = event.get_x                                       # saving the
new ...
  @event_y_old = event.get_y                                       # ...
absolute coords
end

----------------------------------------------------------------------

You can respond by visiting: 
http://rubyforge.org/tracker/?func=detail&atid=220&aid=14375&group_id=35