Title: Emboss / Cutout Text Effects

Author: Sherwyn Ramkissoon (bei at sympatico.ca)
Submission date: December 18, 2001

Description: A script that demonstrates several common image manipulation effects on a text string.

Download: cutout.py

pygame version required: Any (with numeric)
SDL version required: Any
Python version required: Any

Comments: This is a pretty terrifyingly complex script that uses Numeric to generate some very attractive filter effects on some text. It's not actually a module, so you can't really import and reuse it, but the necessary fixes to allow that are pretty simple. The overloading of the word 'filter' as a function name and argument doesn't necessarily conflict with the built-in python keyword 'filter', but reduces readability somewhat. Still, very pretty.

Messages: 0

# cutout.py
# Having recently discovered Python, this looked like a
# fun way to learn the language...
# Uses 5x5 convolution matrices to do Emboss, Cutout, Blur & Edge effects.
# Generates a somewhat random circular gradient texture.
# Even using Numpy this is pretty slow. 
# Bits of code blatantly stolen from the Pygame site.
# Author: Sherwyn Ramkissoon (bei@sympatico.ca)

# Import some useful (or not) stuff
import os
import sys
import pygame
import pygame.image
import pygame.transform
import pygame.font
import Numeric as N
import math as math
import time as time
import random as random
import pygame.surfarray as surfarray
from pygame.locals import *

# Convolution Kernels
blurFilter = [[0,1,2,1,0],[1,2,4,2,1],[2,4,8,4,2],[1,2,4,2,1],[0,1,2,1,0]]
blurDiv = 48
cutoutFilter = [[-4,-3,-2,0,0],[-3,-2,-1,0,0],[-2,-1,18,1,2],[0,0,1,2,3],[0,0,2,3,4]]
embossFilter = [[4,3,2,0,0],[3,2,1,0,0],[2,1,18,-1,-2],[0,0,-1,-2,-3],[0,0,-2,-3,-4]]
cutDiv = 18
edgeFilter = [[0,0,0,0,0],[0,0,-1,0,0],[0,-1,5,-1,0],[0,0,-1,0,0],[0,0,0,0,0]]
edgeDiv = 1

# 5x5 Convolution filter
def Filter(inarray,filter,divisor):	
	size = len(filter)	
	out = N.zeros(inarray.shape)
	(R,C,D) = out.shape
	for i in range((1-size)/2,(size+1)/2):
		for j in range((1-size)/2,(size+1)/2):
			if filter[i+2][j+2] != 0:
				out[2:R-2,2:C-2] += inarray[2+i:R-2+i,2+j:C-2+j]*filter[i+2][j+2]
	out = N.clip(out/divisor,0,255)
	return out

# Blur Filter
def Blur(inarray):
	return Filter(inarray,blurFilter,blurDiv)

# If font color is lighter than background, Cutout produces an embossed effect.
# If font color is darker than background, Cutout produces a cutout effect.
def Cutout(inarray):
	return Filter(inarray,cutoutFilter,cutDiv)

# The opposite of Cutout 			
def Emboss(inarray):
	return Filter(inarray,embossFilter,cutDiv)

def Edge(inarray):
	return Filter(inarray,edgeFilter,edgeDiv)

# Apply Filter to surface
def Effect(surf,filterFunc):
	pix = pygame.surfarray.array3d(surf)
	surf = pygame.Surface((pix.shape[0], pix.shape[1]), 32)
	return surf


def R(m):
	return random.uniform(0,m)
# Silly gradient function using polar coordinates
def circGradient(rad,theta,freq,phase,noise):
	g = int(math.fabs((255-noise)*math.cos(rad/50.0+phase)) + R(noise))
	r = int(math.fabs((255-noise)*math.cos(freq*theta+phase)) + R(noise))
	b = int(math.fabs((255-noise)*math.sin(freq*theta/2+phase)) + R(noise))
	return (r,g,b)
# Gradient Generator - Generates some pixels & interpolates the rest
def calcGradient(W,H,Cx,Cy,freq,phase,noise,step):
	# Screen seems to be in column-major order
	bg = N.zeros((W,H,3))
	for i in range(0,W,step):
		xpos = i-W/2-Cx
		for j in range(0,H,step):
			ypos = j-H/2-Cy
			theta = math.atan2(ypos,xpos)
			rad = math.sqrt(xpos*xpos+ypos*ypos)
			bg[i][j] = circGradient(rad,theta,freq,phase,noise)
	# Interpolate along y
	ns = step
	while (ns > 1):
		ns2 = ns/2
		bg[0::step,ns2:-ns2:ns,:] = (bg[0::step,0:-ns:ns,:] + bg[0::step,ns::ns,:])/2		
		ns = ns2
	# Interpolate along x
	ns = step
	while (ns > 1):
		ns2 = ns/2
		bg[ns2:-ns2:ns,:,:] = (bg[0:-ns:ns,:,:] + bg[ns::ns,:,:])/2		
		ns = ns2		
	return bg

# Couldn't get alpha to work, so simulate it (slowly) :-|
def CalcAlpha(inarray):
	inarray = calcGradient(inarray.shape[0],inarray.shape[1],50,0,5,0,80,8)
	return inarray

# Apply pseudo-alpha gradient
def PAlpha(surf):
	pix = pygame.surfarray.array3d(surf)
	pix = N.array(pix,N.Int16)
	pAlpha = N.ones(pix.shape)*255
	pAlpha = CalcAlpha(pAlpha)
	pix = (pAlpha*pix)/255
 		pix = (pix*255)/N.argmax(N.argmax(N.argmax(pix)))
	surf = pygame.Surface((pix.shape[0], pix.shape[1]), 32)
	return surf

# Setup	Pygame
font = pygame.font.Font(None, 90)
#font = pygame.font.Font("c:/windows/fonts/stencil.ttf",80)

# Generate Text
text = []
print "Thinking..",
print "\b.",
print "\b.",
print "\b.",
print "\b.",
print "\b.",
print "\b.",
print "\b.",
print "Done!",

# Setup screen
H = text[0].get_height()*len(text)/2
W = text[0].get_width() + text[1].get_width()
screen = pygame.display.set_mode((W,H), 0, 32)
pygame.display.set_caption("Filter Effects")

# Display everything
for i in range(len(text)):
	screen.blit(text[i], ((i%2)*text[0].get_width(),(int(i/2))*text[0].get_height()) )	

#wait for the finish
while 1:
    event = pygame.event.wait()
    if event.type is KEYDOWN and event.key == K_s: #save it
        name = os.path.splitext(sys.argv[0])[0] + '.bmp'
        print 'Saving image to:', name
        pygame.image.save(screen, name)
    elif event.type in (QUIT,KEYDOWN,MOUSEBUTTONDOWN):

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