From: David Vallner <david@...>
Date: 2006-01-16T02:21:18+09:00
Subject: Re: "Programming Ruby", ed. 2, P747. Script generated different image to book's example

On Sun, 15 Jan 2006 18:02:20 +0100, Hidetoshi NAGAI  
<nagai@ai.kyutech.ac.jp> wrote:

>
> [snip]
>
>> >>             TkcLine.new(canvas,
>> >>                         points[0],[0], points[0],[1],
>> >>                         points[1],[0], points[1],[1],
>> >>                         points[2],[0], points[2],[1],
>> >>                         'smooth' => 'on',
>> >>                         'width' => 7,
>> >>                         'fill'      => col,
>> >>                         'capstyle'  => 'round')
>
> On current Ruby/Tk, a canvas Item can accept an array or arrays
> as its coords.
> That is, all of the followings are valid.
> ----------------------------------------------------------------
> (0) TkcLine.new(canvas,
>                 points[0][0], points[0][1],
>                 points[1][0], points[1][1],
>                 points[2][0], points[2][1],
>                 :smooth=>'on', :width =>7, :fill=>col,  
> :capstyle=>'round')
>
> (1) TkcLine.new(canvas,
>                 points[0], points[1], points[2],
>                 :smooth=>'on', :width =>7, :fill=>col,  
> :capstyle=>'round')
>
> (2) TkcLine.new(canvas,
>                 points.flatten,
>                 :smooth=>'on', :width =>7, :fill=>col,  
> :capstyle=>'round')
>
> (3) TkcLine.new(canvas,
>                 points,
>                 :smooth=>'on', :width =>7, :fill=>col,  
> :capstyle=>'round')
> ----------------------------------------------------------------


The bug was passing in literal arrays with one element, 0, or 1, to  
TkcLine::new. Using the whole 2D array at once looks nifty, it would  
indeed prevent that typo / slip of mind.

David Vallner