Bitmap editor

This is a 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 file 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 coordinates 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 6 supported commands:
I N M - 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).
S - Show the contents of the current image

Example

To run the application you must supply a command file like so bin/bitmap_editor examples/show.txt
Input File:
I 5 6
L 1 3 A
V 2 3 6 W
H 3 5 2 Z
S

Expected Output:
OOOOO
OOZZZ
AWOOO
OWOOO
OWOOO
OWOOO

Format

The grid is formatted from the top left cell:


1, 1	2, 1	3, 1
1, 2	2, 2	3, 2
1, 3	2, 3	3, 3

Running

>bin/bitmap_editor examples/show.txt

Further Work

lib/bitmap/grid.rb:
- Refactor to remove duplication.
- Many more validation checks. Some are listed as TODO's in the valid_params method.
- Refactor method order, so that the code reads from top to bottom.
- Specs for #vertical.
- Specs for #horizontal.
- Specs for all validations checks.
- Comment: I am not so happy with the current state of this class. I feel it is becoming too bloated and needs extracting to other classes.
lib/bitmap/presenter.rb:
- Specs written for all methods.
- Comment: I feel this is a tidy Class. It carries out its functionality without pulling in lots of other logic.
lib/bitmap_editor.rb:
- Comment: This file I also feel encapsulates some logic that it shouldn't. I feel that the command validations would be better suited elsewhere.