gistfile1.txt

Coding challenge

Graphical editors allow users to edit images in the same way text editors let us modify documents. Images are represented as an M x N array of pixels with each pixel given colour.
Produce a program that simulates a simple interactive graphical editor.

Input

The input consists of a line containing a sequence of commands. Each command is represented by a single capital letter at the start of the line. Arguments to the command are separated by spaces and follow the command character.

Pixel co-ordinates are represented by a pair of integers: 1) a column number between 1 and M, and 2) a row number between 1 and N. Where 1 <= M, N <= 250. The origin sits in the upper-left of the table. Colours are specified by capital letters.

Commands

The editor supports 7 commands:

1.	I M N. Create a new M x N image with all pixels coloured white (O).

2.	C. Clears the table, setting all pixels to white (O).

3.	L X Y C. Colours the pixel (X,Y) with colour C.

4.	V X Y1 Y2 C. Draw a vertical segment of colour C in column X between rows Y1 and Y2 (inclusive).

5.	H X1 X2 Y C. Draw a horizontal segment of colour C in row Y between columns X1 and X2 (inclusive).

6.	F X Y C. Fill the region R with the colour C. R is defined as: Pixel (X,Y) belongs to R. Any other pixel which is the same colour as (X,Y) and shares a common side with any pixel in R also belongs to this region.

7.	S. Show the contents of the current image 

8.	8. X. Terminate the session

 
Example

In the example below, > denotes input, => denotes program output.

>I 5 6 
>L 2 3 A 
>S
=> 
OOOOO 
OOOOO 
OAOOO 
OOOOO 
OOOOO 
OOOOO

>F 3 3 J
>V 2 3 4 W 
>H 3 4 2 Z 
>S
=> 
JJJJJ 
JJZZJ 
JWJJJ 
JWJJJ 
JJJJJ 
JJJJJ

Submission

We prefer submissions in Ruby although we will accept them in other languages. 
Please provide an executable solution with any source files in a common archive format (ZIP,  TAR etc.).