Setting up Vim to work with Python - part 1

You need to use mercurial.

Mercurial is a free, distributed source control management tool.

It is mainly implemented using the Python programming language and C.

To use it , just see the next command.

# hg clone https://vim.googlecode.com/hg/ vim 
requesting all changes
adding changesets
adding manifests
adding file changes
added 3831 changesets with 24526 changes to 2566 files (+2 heads)
updating working directory
2385 files updated, 0 files merged, 0 files removed, 0 files unresolved

Go to vim folder.

# cd vim/src/

Use configure to builds a Makefile file.

src # ./configure --enable-pythoninterp --with-features=huge --prefix=$HOME/opt/vim
configure: creating cache auto/config.cache
checking whether make sets $(MAKE)... yes
checking for gcc... gcc
checking whether the C compiler works... yes
...

The next commands make builds the program and make install to install the program.

src # make && make install
mkdir objects
...

Now let's try to make working well.

src # mkdir -p $HOME/bin
src # cd $HOME/bin
bin # ls
vim
bin # ln -s $HOME/opt/vim/bin/vim
bin # ls
vim
bin # which vim
/usr/bin/vim
bin # vim --version 
VIM - Vi IMproved 7.2 (2008 Aug 9, compiled Sep 21 2009 11:22:49)
Included patches: 1-245

If you read all the output , will see something like this:

+profile +python +quickfix 

The main goal is to use vimrc.

For example you cand do this.

" Wrapping and tabs spaces.
set tw=78 ts=4 sw=4 sta et sts=4 ai

" Update syntax highlighting.
let python_highlight_all = 1

" Create smart indenting
set smartindent cinwords=if,elif,else,for,while,try,except,finally,def,class

" Auto completion using ctrl-space
set omnifunc=pythoncomplete#Complete
inoremap <nul> <C-x><C-o>

With just few lines can change and improve your work.

How to compile your python script .

There're situations when we want to compile the python script.

In this case , we have a python script named your_script.py.

The next script code will make one new your_script.pyc file.

import py_compile
py_compile.compile('your_script.py')

Note: this will hide the python code, but some strings can be view.

For example , if you use this in your_script.py.

print 'This is a string'

The string This is a string can be show in pyc file.

Simple python script - Voronoi diagram

Today I show you how to make Voronoi diagram using python.

I use this to make textures for underwater.

This is just one example. But you can improve to control all cells of voronoi diagram.

The theory say:

In mathematics, a Voronoi diagram is a special kind of decomposition of a metric space, determined by distances to a specified family of objects (subsets) in the space. These objects are usually called the sites or the generators...Source : wikipedia.

I used the euclidean distance to make the Voronoi diagram because it's the most familiar case.

About wikipedia - Euclidean_distance: In mathematics, the Euclidean distance or Euclidean metric is the "ordinary" distance between two points that one would measure with a ruler, and is given by the Pythagorean formula...

My python script use the next python modules:

PIL - this allow me to use image functions.

random - this module give me... random numbers.

math - some math functions.

Let's see the source code :

from PIL import Image
import random
import math

Now I make the function named gen_voronoi.

This take the height and width of the output image and the number of cells.

The function has some random variables for red , green , blue - nr,ng,nb.

The function hypot is not accessible directly so we need to import math module and using math static object.

The return value is the Euclidean norm : sqrt(x*x + y*y).

def gen_voronoi(w, h, cells):
 image = Image.new("RGB", (w, h))
 putpixel = image.putpixel
 img_x, img_y = image.size
 nx = []
 ny = []
 nr = []
 ng = []
 nb = []
 for i in range(cells):
  nx.append(random.randrange(img_x))
  ny.append(random.randrange(img_y))
  nr.append(random.randrange(256))
  ng.append(random.randrange(256))
  nb.append(random.randrange(256))
 for y in range(img_y):
  for x in range(img_x):
   dmin = math.hypot(img_x-1, img_y-1)
   j = -1
   for i in range(cells):
    d = math.hypot(nx[i]-x, ny[i]-y)
    if d < dmin:
     dmin = d
     j = i
   putpixel((x, y), (nr[j], ng[j], nb[j]))
 image.save("output.png", "PNG")
 image.show()

Use the function to make the output.png image.

gen_voronoi(200, 200, 55)

The result is :