Graphical_editor_exercise is a project mainly written in Ruby, based on the View license.
An exercise to simulate a simple graphic editor
== GraphicalEditorExercise
== Test this solution
ruby graphical_editor_exercise.rb
This is the exercise
== Technical Test 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:
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, > 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