From: Hidetoshi NAGAI <nagai@...>
Date: 2008-12-01T16:46:10+09:00
Subject: Re: Ruby Tk and X/Y coordinates

From: Johnny Johnnybgood <jarek123@comcast.net>
Subject: Re: Ruby Tk and X/Y coordinates
Date: Mon, 1 Dec 2008 13:45:46 +0900
Message-ID: <34bb72b14d3241af75850c11c3951c66@ruby-forum.com>
> What I'm trying to do is this:  I have an array of x,y coordinates 
> (example=[[0,0], [1,1], [2,2], [3,3], [50,50], etc]...I want my script 
> to create an *application* window the size of my screen (1024, 768) and 
> draw dots (pixels) at the X/Y coordinates provided by my array.

To draw dots, please use an Oval item or a very short Line item.

There are some ways to fill your screen; safe or danger, 
depend on OS/window-manager or not, and dened on Tcl/Tk version or not.

One, which is safe and not depend on an environment, is 
-------------------------------------------------------------------
root = Tk.root
width, height = root.maxsize
root.geometry "#{width}x#{height}+0+0"
-------------------------------------------------------------------

But, it sometimes fails to fill the screen because of a border given 
by a window-manager.

If you use Windows or MacOS X, you can use "Tk.root.state(:zoomed)".
Or, if you use Ruby/Tk with Tcl/Tk8.5 on X Window System
and your window-manager support 'zoomed', you can use 
"Tk.root.attributes(:zoomed=>true)".

A danger one is, 
-------------------------------------------------------------------
root = Tk.root
root.bind('1'){exit}  # for SAFE; Click the left button, and exit.
width = root.winfo_screenwidth
height = root.winfo_screenheight
root.withdraw
root.overrideredirect true  # NOT controlled by a window-manager.
root.deiconify
root.geometry "#{width}x#{height}+0+0"
-------------------------------------------------------------------

This will fill your screen completely. 
The application is NOT under control of a window-manager. 
So, if you forget to make the way to exit the application, 
you may have to shutdown your window system. 

If you use Tcl/Tk8.5, another version of the danger one is, 
-------------------------------------------------------------------
root = Tk.root
root.bind('1'){exit}  # for SAFE; Click the left button, and exit.
root.attributes(:fullscreen=>true)
-------------------------------------------------------------------

> I know that with lines, "to create a line, the one piece of information 
> you'll need to specify is where the line should be. This is done by 
> using the coordinates of the starting and ending point, expressed as a 
> list of the form x0 y0 x1 y1."  I guess if I set the x1 y1 to x0 y0 then 
> I should just get dots and not lines (I don't know if that will even 
> work but I'll test it).  Is there an easier way (something that's 
> specifically created for drawing x/y coordinates)?  Thanks

If you want dashed lines instead of solid lines, 
"dash" option may be usefull.

For example, 
------------------------------------------------------------------
require 'tk'

c = TkCanvas.new(:width=>200, :height=>400).pack

# put dots
samples = [
  [10,10], [15,15], [20,20], [25,25], [30,30], [35,35], [40,40], [45,45], 
  [50,50], [55,55], [60,60], [65,65], [70,70], [75,75], [80,80], [85,85], 
  [90,90], [95,95], [100,100], [105,105], [110,110], [115,115], [120,120], 
  [125,125], [130,130], [135,135], [140,140], [145,145], [150,150]
]
delta = 0.5
samples.each{|x,y| 
  TkcOval.new(c, x, y, x, y, :fill=>'red', :outline=>'red')
  TkcOval.new(c, x - delta, y + 15 - delta, x + delta, y + 15 + delta, 
              :fill=>'red', :outline=>'red')
  TkcOval.new(c, x - delta*3, y + 30 - delta*3, x + delta*3, y + 30 + delta*3, 
              :fill=>'red', :outline=>'red')
}

# very short lines
samples.each{|x,y| 
  TkcLine.new(c, x+30, y, x+30+0.5, y+0.5, :fill=>'black', :width=>1)
}

# dash line
coords = [[10, 80], [150, 220]]
TkcLine.new(c, coords, :fill=>'red', :width=>1, :dash=>'.')

coords.map!{|x,y| [x, y+15]}
TkcLine.new(c, coords, :fill=>'red', :width=>3, :dash=>'.')

coords.map!{|x,y| [x, y+15]}
TkcLine.new(c, coords, :fill=>'red', :width=>1, :dash=>'-')

coords.map!{|x,y| [x, y+15]}
TkcLine.new(c, coords, :fill=>'red', :width=>3, :dash=>'-')

coords.map!{|x,y| [x, y+15]}
TkcLine.new(c, coords, :fill=>'red', :width=>1, :dash=>'-.')

coords.map!{|x,y| [x, y+15]}
TkcLine.new(c, coords, :fill=>'red', :width=>3, :dash=>'-.')

coords.map!{|x,y| [x, y+15]}
TkcLine.new(c, coords, :fill=>'red', :width=>1, :dash=>[2,2])

coords.map!{|x,y| [x, y+15]}
TkcLine.new(c, coords, :fill=>'red', :width=>3, :dash=>[2,2])

coords.map!{|x,y| [x, y+15]}
TkcLine.new(c, coords, :fill=>'red', :width=>1, :dash=>[6,2,2,2])

coords.map!{|x,y| [x, y+15]}
TkcLine.new(c, coords, :fill=>'red', :width=>3, :dash=>[6,2,2,2])

coords.map!{|x,y| [x, y+15]}
TkcLine.new(c, coords, :fill=>'red', :width=>3, :dash=>[12,4,4,4])

Tk.mainloop
------------------------------------------------------------------
-- 
Hidetoshi NAGAI (nagai@ai.kyutech.ac.jp)