Technical Test Ruby developer

Produce a Ruby 2.0 program that simulates a basic interactive bitmap editor. Bitmaps are represented as an M x N matrix of pixels with each element representing a colour.

Program input

The input consists of a string containing a sequence of commands, where a command is represented by a single capital letter at the beginning of the line. Parameters of the command are separated by white spaces and they follow the command character.

Pixel co-ordinates are a pair of integers: a column number between 1 and 250, and a row number between 1 and 250. Bitmaps starts at coordinates 1,1. Colours are specified by capital letters.

Commands

There are 7 supported commands:

• I M N - Create a new M x N image with all pixels coloured white (O).
• C - Clears the table, setting all pixels to white (O).
• L X Y C - Colours the pixel (X,Y) with colour C.
• V X Y1 Y2 C - Draw a vertical segment of colour C in column X between rows Y1 and Y2 (inclusive).
• H X1 X2 Y C - Draw a horizontal segment of colour C in row Y between columns X1 and X2 (inclusive).
• 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.
• S - Show the contents of the current image
• X - Terminate the session

Example

In the example below, > represents input

> 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

When implementing this program focus on quality and best practices. DO NOT RUSH! It's not a speed test. Make sure the program works with odd input and doesn't crash. After implementing the required features, please implement a feature you think would make this program better/more useful and describe it in a README file.

Pattern feature

to use this feature follow the example below

> I 5 6
> P 2 B
> S
B O B O B
B O B O B
B O B O B
B O B O B
B O B O B
B O B O B