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/*
* The Python Imaging Library
* $Id$
*
* various special effects and image generators
*
* history:
* 1997-05-21 fl Just for fun
* 1997-06-05 fl Added mandelbrot generator
* 2003-05-24 fl Added perlin_turbulence generator (in progress)
*
* Copyright (c) 1997-2003 by Fredrik Lundh.
* Copyright (c) 1997 by Secret Labs AB.
*
* See the README file for information on usage and redistribution.
*/
#include "Imaging.h"
#include <math.h>
Imaging
ImagingEffectMandelbrot(int xsize, int ysize, double extent[4], int quality)
{
/* Generate a Mandelbrot set covering the given extent */
Imaging im;
int x, y, k;
double width, height;
double x1, y1, xi2, yi2, cr, ci, radius;
double dr, di;
/* Check arguments */
width = extent[2] - extent[0];
height = extent[3] - extent[1];
if (width < 0.0 || height < 0.0 || quality < 2)
return (Imaging) ImagingError_ValueError(NULL);
im = ImagingNewDirty("L", xsize, ysize);
if (!im)
return NULL;
dr = width/(xsize-1);
di = height/(ysize-1);
radius = 100.0;
for (y = 0; y < ysize; y++) {
UINT8* buf = im->image8[y];
for (x = 0; x < xsize; x++) {
x1 = y1 = xi2 = yi2 = 0.0;
cr = x*dr + extent[0];
ci = y*di + extent[1];
for (k = 1;; k++) {
y1 = 2*x1*y1 + ci;
x1 = xi2 - yi2 + cr;
xi2 = x1*x1;
yi2 = y1*y1;
if ((xi2 + yi2) > radius) {
buf[x] = k*255/quality;
break;
}
if (k > quality) {
buf[x] = 0;
break;
}
}
}
}
return im;
}
Imaging
ImagingEffectNoise(int xsize, int ysize, float sigma)
{
/* Generate Gaussian noise centered around 128 */
Imaging imOut;
int x, y;
int nextok;
double this, next;
imOut = ImagingNewDirty("L", xsize, ysize);
if (!imOut)
return NULL;
next = 0.0;
nextok = 0;
for (y = 0; y < imOut->ysize; y++) {
UINT8* out = imOut->image8[y];
for (x = 0; x < imOut->xsize; x++) {
if (nextok) {
this = next;
nextok = 0;
} else {
/* after numerical recipes */
double v1, v2, radius, factor;
do {
v1 = rand()*(2.0/RAND_MAX) - 1.0;
v2 = rand()*(2.0/RAND_MAX) - 1.0;
radius= v1*v1 + v2*v2;
} while (radius >= 1.0);
factor = sqrt(-2.0*log(radius)/radius);
this = factor * v1;
next = factor * v2;
}
out[x] = CLIP8(128 + sigma * this);
}
}
return imOut;
}
Imaging
ImagingEffectSpread(Imaging imIn, int distance)
{
/* Randomly spread pixels in an image */
Imaging imOut;
int x, y;
imOut = ImagingNewDirty(imIn->mode, imIn->xsize, imIn->ysize);
if (!imOut)
return NULL;
#define SPREAD(type, image)\
for (y = 0; y < imOut->ysize; y++)\
for (x = 0; x < imOut->xsize; x++) {\
int xx = x + (rand() % distance) - distance/2;\
int yy = y + (rand() % distance) - distance/2;\
if (xx >= 0 && xx < imIn->xsize && yy >= 0 && yy < imIn->ysize) {\
imOut->image[yy][xx] = imIn->image[y][x];\
imOut->image[y][x] = imIn->image[yy][xx];\
} else\
imOut->image[y][x] = imIn->image[y][x];\
}
if (imIn->image8) {
SPREAD(UINT8, image8);
} else {
SPREAD(INT32, image32);
}
ImagingCopyPalette(imOut, imIn);
return imOut;
}
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