cpython/Modules/imageop.c

/***********************************************************
Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam,
The Netherlands.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in
supporting documentation, and that the names of Stichting Mathematisch
Centrum or CWI or Corporation for National Research Initiatives or
CNRI not be used in advertising or publicity pertaining to
distribution of the software without specific, written prior
permission.

While CWI is the initial source for this software, a modified version
is made available by the Corporation for National Research Initiatives
(CNRI) at the Internet address ftp://ftp.python.org.

STICHTING MATHEMATISCH CENTRUM AND CNRI DISCLAIM ALL WARRANTIES WITH
REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH
CENTRUM OR CNRI BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
PERFORMANCE OF THIS SOFTWARE.

******************************************************************/

/* imageopmodule - Various operations on pictures */

#ifdef sun
#define signed
#endif

#include "Python.h"

#define CHARP(cp, xmax, x, y) ((char *)(cp+y*xmax+x))
#define SHORTP(cp, xmax, x, y) ((short *)(cp+2*(y*xmax+x)))
#define LONGP(cp, xmax, x, y) ((long *)(cp+4*(y*xmax+x)))

static PyObject *ImageopError;
 
static PyObject *
imageop_crop(self, args)
	PyObject *self;
PyObject *args;
{
	char *cp, *ncp;
	short *nsp;
	long *nlp;
	int len, size, x, y, newx1, newx2, newy1, newy2;
	int ix, iy, xstep, ystep;
	PyObject *rv;

	if ( !PyArg_Parse(args, "(s#iiiiiii)", &cp, &len, &size, &x, &y,
			  &newx1, &newy1, &newx2, &newy2) )
		return 0;
    
	if ( size != 1 && size != 2 && size != 4 ) {
		PyErr_SetString(ImageopError, "Size should be 1, 2 or 4");
		return 0;
	}
	if ( len != size*x*y ) {
		PyErr_SetString(ImageopError, "String has incorrect length");
		return 0;
	}
	xstep = (newx1 < newx2)? 1 : -1;
	ystep = (newy1 < newy2)? 1 : -1;
    
	rv = PyString_FromStringAndSize(NULL,
			     (abs(newx2-newx1)+1)*(abs(newy2-newy1)+1)*size);
	if ( rv == 0 )
		return 0;
	ncp = (char *)PyString_AsString(rv);
	nsp = (short *)ncp;
	nlp = (long *)ncp;
	newy2 += ystep;
	newx2 += xstep;
	for( iy = newy1; iy != newy2; iy+=ystep ) {
		for ( ix = newx1; ix != newx2; ix+=xstep ) {
			if ( iy < 0 || iy >= y || ix < 0 || ix >= x ) {
				if ( size == 1 )
					*ncp++ = 0;
				else
					*nlp++ = 0;
			} else {
				if ( size == 1 )
					*ncp++ = *CHARP(cp, x, ix, iy);
				else if ( size == 2 )
					*nsp++ = *SHORTP(cp, x, ix, iy);
				else
					*nlp++ = *LONGP(cp, x, ix, iy);
			}
		}
	}
	return rv;
}
 
static PyObject *
imageop_scale(self, args)
	PyObject *self;
PyObject *args;
{
	char *cp, *ncp;
	short *nsp;
	long *nlp;
	int len, size, x, y, newx, newy;
	int ix, iy;
	int oix, oiy;
	PyObject *rv;

	if ( !PyArg_Parse(args, "(s#iiiii)",
			  &cp, &len, &size, &x, &y, &newx, &newy) )
		return 0;
    
	if ( size != 1 && size != 2 && size != 4 ) {
		PyErr_SetString(ImageopError, "Size should be 1, 2 or 4");
		return 0;
	}
	if ( len != size*x*y ) {
		PyErr_SetString(ImageopError, "String has incorrect length");
		return 0;
	}
    
	rv = PyString_FromStringAndSize(NULL, newx*newy*size);
	if ( rv == 0 )
		return 0;
	ncp = (char *)PyString_AsString(rv);
	nsp = (short *)ncp;
	nlp = (long *)ncp;
	for( iy = 0; iy < newy; iy++ ) {
		for ( ix = 0; ix < newx; ix++ ) {
			oix = ix * x / newx;
			oiy = iy * y / newy;
			if ( size == 1 )
				*ncp++ = *CHARP(cp, x, oix, oiy);
			else if ( size == 2 )
				*nsp++ = *SHORTP(cp, x, oix, oiy);
			else
				*nlp++ = *LONGP(cp, x, oix, oiy);
		}
	}
	return rv;
}

/* Note: this routine can use a bit of optimizing */

static PyObject *
imageop_tovideo(self, args)
	PyObject *self;
PyObject *args;
{
	int maxx, maxy, x, y, len;
	int i;
	unsigned char *cp, *ncp;
	int width;
	PyObject *rv;
   
    
	if ( !PyArg_Parse(args, "(s#iii)", &cp, &len, &width, &maxx, &maxy) )
		return 0;

	if ( width != 1 && width != 4 ) {
		PyErr_SetString(ImageopError, "Size should be 1 or 4");
		return 0;
	}
	if ( maxx*maxy*width != len ) {
		PyErr_SetString(ImageopError, "String has incorrect length");
		return 0;
	}
    
	rv = PyString_FromStringAndSize(NULL, len);
	if ( rv == 0 )
		return 0;
	ncp = (unsigned char *)PyString_AsString(rv);

	if ( width == 1 ) {
		memcpy(ncp, cp, maxx);		/* Copy first line */
		ncp += maxx;
		for (y=1; y<maxy; y++) {	/* Interpolate other lines */
			for(x=0; x<maxx; x++) {
				i = y*maxx + x;
				*ncp++ = ((int)cp[i] + (int)cp[i-maxx]) >> 1;
			}
		}
	} else {
		memcpy(ncp, cp, maxx*4);		/* Copy first line */
		ncp += maxx*4;
		for (y=1; y<maxy; y++) {	/* Interpolate other lines */
			for(x=0; x<maxx; x++) {
				i = (y*maxx + x)*4 + 1;
				*ncp++ = 0;	/* Skip alfa comp */
				*ncp++ = ((int)cp[i] + (int)cp[i-4*maxx]) >> 1;
				i++;
				*ncp++ = ((int)cp[i] + (int)cp[i-4*maxx]) >> 1;
				i++;
				*ncp++ = ((int)cp[i] + (int)cp[i-4*maxx]) >> 1;
			}
		}
	}
	return rv;
}

static PyObject *
imageop_grey2mono(self, args)
	PyObject *self;
PyObject *args;
{
	int tres, x, y, len;
	unsigned char *cp, *ncp;
	unsigned char ovalue;
	PyObject *rv;
	int i, bit;
   
    
	if ( !PyArg_Parse(args, "(s#iii)", &cp, &len, &x, &y, &tres) )
		return 0;

	if ( x*y != len ) {
		PyErr_SetString(ImageopError, "String has incorrect length");
		return 0;
	}
    
	rv = PyString_FromStringAndSize(NULL, (len+7)/8);
	if ( rv == 0 )
		return 0;
	ncp = (unsigned char *)PyString_AsString(rv);

	bit = 0x80;
	ovalue = 0;
	for ( i=0; i < len; i++ ) {
		if ( (int)cp[i] > tres )
			ovalue |= bit;
		bit >>= 1;
		if ( bit == 0 ) {
			*ncp++ = ovalue;
			bit = 0x80;
			ovalue = 0;
		}
	}
	if ( bit != 0x80 )
		*ncp++ = ovalue;
	return rv;
}

static PyObject *
imageop_grey2grey4(self, args)
	PyObject *self;
PyObject *args;
{
	int x, y, len;
	unsigned char *cp, *ncp;
	unsigned char ovalue;
	PyObject *rv;
	int i;
	int pos;
   
    
	if ( !PyArg_Parse(args, "(s#ii)", &cp, &len, &x, &y) )
		return 0;

	if ( x*y != len ) {
		PyErr_SetString(ImageopError, "String has incorrect length");
		return 0;
	}
    
	rv = PyString_FromStringAndSize(NULL, (len+1)/2);
	if ( rv == 0 )
		return 0;
	ncp = (unsigned char *)PyString_AsString(rv);
	pos = 0;
	ovalue = 0;
	for ( i=0; i < len; i++ ) {
		ovalue |= ((int)cp[i] & 0xf0) >> pos;
		pos += 4;
		if ( pos == 8 ) {
			*ncp++ = ovalue;
			ovalue = 0;
			pos = 0;
		}
	}
	if ( pos != 0 )
		*ncp++ = ovalue;
	return rv;
}

static PyObject *
imageop_grey2grey2(self, args)
	PyObject *self;
PyObject *args;
{
	int x, y, len;
	unsigned char *cp, *ncp;
	unsigned char ovalue;
	PyObject *rv;
	int i;
	int pos;
   
    
	if ( !PyArg_Parse(args, "(s#ii)", &cp, &len, &x, &y) )
		return 0;

	if ( x*y != len ) {
		PyErr_SetString(ImageopError, "String has incorrect length");
		return 0;
	}
    
	rv = PyString_FromStringAndSize(NULL, (len+3)/4);
	if ( rv == 0 )
		return 0;
	ncp = (unsigned char *)PyString_AsString(rv);
	pos = 0;
	ovalue = 0;
	for ( i=0; i < len; i++ ) {
		ovalue |= ((int)cp[i] & 0xc0) >> pos;
		pos += 2;
		if ( pos == 8 ) {
			*ncp++ = ovalue;
			ovalue = 0;
			pos = 0;
		}
	}
	if ( pos != 0 )
		*ncp++ = ovalue;
	return rv;
}

static PyObject *
imageop_dither2mono(self, args)
	PyObject *self;
PyObject *args;
{
	int sum, x, y, len;
	unsigned char *cp, *ncp;
	unsigned char ovalue;
	PyObject *rv;
	int i, bit;
   
    
	if ( !PyArg_Parse(args, "(s#ii)", &cp, &len, &x, &y) )
		return 0;

	if ( x*y != len ) {
		PyErr_SetString(ImageopError, "String has incorrect length");
		return 0;
	}
    
	rv = PyString_FromStringAndSize(NULL, (len+7)/8);
	if ( rv == 0 )
		return 0;
	ncp = (unsigned char *)PyString_AsString(rv);

	bit = 0x80;
	ovalue = 0;
	sum = 0;
	for ( i=0; i < len; i++ ) {
		sum += cp[i];
		if ( sum >= 256 ) {
			sum -= 256;
			ovalue |= bit;
		}
		bit >>= 1;
		if ( bit == 0 ) {
			*ncp++ = ovalue;
			bit = 0x80;
			ovalue = 0;
		}
	}
	if ( bit != 0x80 )
		*ncp++ = ovalue;
	return rv;
}

static PyObject *
imageop_dither2grey2(self, args)
	PyObject *self;
PyObject *args;
{
	int x, y, len;
	unsigned char *cp, *ncp;
	unsigned char ovalue;
	PyObject *rv;
	int i;
	int pos;
	int sum = 0, nvalue;
   
    
	if ( !PyArg_Parse(args, "(s#ii)", &cp, &len, &x, &y) )
		return 0;

	if ( x*y != len ) {
		PyErr_SetString(ImageopError, "String has incorrect length");
		return 0;
	}
    
	rv = PyString_FromStringAndSize(NULL, (len+3)/4);
	if ( rv == 0 )
		return 0;
	ncp = (unsigned char *)PyString_AsString(rv);
	pos = 1;
	ovalue = 0;
	for ( i=0; i < len; i++ ) {
		sum += cp[i];
		nvalue = sum & 0x180;
		sum -= nvalue;
		ovalue |= nvalue >> pos;
		pos += 2;
		if ( pos == 9 ) {
			*ncp++ = ovalue;
			ovalue = 0;
			pos = 1;
		}
	}
	if ( pos != 0 )
		*ncp++ = ovalue;
	return rv;
}

static PyObject *
imageop_mono2grey(self, args)
	PyObject *self;
PyObject *args;
{
	int v0, v1, x, y, len, nlen;
	unsigned char *cp, *ncp;
	PyObject *rv;
	int i, bit;
    
	if ( !PyArg_Parse(args, "(s#iiii)", &cp, &len, &x, &y, &v0, &v1) )
		return 0;

	nlen = x*y;
	if ( (nlen+7)/8 != len ) {
		PyErr_SetString(ImageopError, "String has incorrect length");
		return 0;
	}
    
	rv = PyString_FromStringAndSize(NULL, nlen);
	if ( rv == 0 )
		return 0;
	ncp = (unsigned char *)PyString_AsString(rv);

	bit = 0x80;
	for ( i=0; i < nlen; i++ ) {
		if ( *cp & bit )
			*ncp++ = v1;
		else
			*ncp++ = v0;
		bit >>= 1;
		if ( bit == 0 ) {
			bit = 0x80;
			cp++;
		}
	}
	return rv;
}

static PyObject *
imageop_grey22grey(self, args)
	PyObject *self;
PyObject *args;
{
	int x, y, len, nlen;
	unsigned char *cp, *ncp;
	PyObject *rv;
	int i, pos, value = 0, nvalue;
    
	if ( !PyArg_Parse(args, "(s#ii)", &cp, &len, &x, &y) )
		return 0;

	nlen = x*y;
	if ( (nlen+3)/4 != len ) {
		PyErr_SetString(ImageopError, "String has incorrect length");
		return 0;
	}
    
	rv = PyString_FromStringAndSize(NULL, nlen);
	if ( rv == 0 )
		return 0;
	ncp = (unsigned char *)PyString_AsString(rv);

	pos = 0;
	for ( i=0; i < nlen; i++ ) {
		if ( pos == 0 ) {
			value = *cp++;
			pos = 8;
		}
		pos -= 2;
		nvalue = (value >> pos) & 0x03;
		*ncp++ = nvalue | (nvalue << 2) |
			 (nvalue << 4) | (nvalue << 6);
	}
	return rv;
}

static PyObject *
imageop_grey42grey(self, args)
	PyObject *self;
PyObject *args;
{
	int x, y, len, nlen;
	unsigned char *cp, *ncp;
	PyObject *rv;
	int i, pos, value = 0, nvalue;
    
	if ( !PyArg_Parse(args, "(s#ii)", &cp, &len, &x, &y) )
		return 0;

	nlen = x*y;
	if ( (nlen+1)/2 != len ) {
		PyErr_SetString(ImageopError, "String has incorrect length");
		return 0;
	}
    
	rv = PyString_FromStringAndSize(NULL, nlen);
	if ( rv == 0 )
		return 0;
	ncp = (unsigned char *)PyString_AsString(rv);

	pos = 0;
	for ( i=0; i < nlen; i++ ) {
		if ( pos == 0 ) {
			value = *cp++;
			pos = 8;
		}
		pos -= 4;
		nvalue = (value >> pos) & 0x0f;
		*ncp++ = nvalue | (nvalue << 4);
	}
	return rv;
}

static PyObject *
imageop_rgb2rgb8(self, args)
	PyObject *self;
PyObject *args;
{
	int x, y, len, nlen;
	unsigned long *cp;
	unsigned char *ncp;
	PyObject *rv;
	int i, r, g, b;
	unsigned long value, nvalue;
    
	if ( !PyArg_Parse(args, "(s#ii)", &cp, &len, &x, &y) )
		return 0;

	nlen = x*y;
	if ( nlen*4 != len ) {
		PyErr_SetString(ImageopError, "String has incorrect length");
		return 0;
	}
    
	rv = PyString_FromStringAndSize(NULL, nlen);
	if ( rv == 0 )
		return 0;
	ncp = (unsigned char *)PyString_AsString(rv);

	for ( i=0; i < nlen; i++ ) {
		/* Bits in source: aaaaaaaa BBbbbbbb GGGggggg RRRrrrrr */
		value = *cp++;
#if 0
		r = (value >>  5) & 7;
		g = (value >> 13) & 7;
		b = (value >> 22) & 3;
#else
		r = (int) ((value & 0xff) / 255. * 7. + .5);
		g = (int) (((value >> 8) & 0xff) / 255. * 7. + .5);
		b = (int) (((value >> 16) & 0xff) / 255. * 3. + .5);
#endif
		nvalue = (r<<5) | (b<<3) | g;
		*ncp++ = (unsigned char)nvalue;
	}
	return rv;
}

static PyObject *
imageop_rgb82rgb(self, args)
	PyObject *self;
PyObject *args;
{
	int x, y, len, nlen;
	unsigned char *cp;
	unsigned long *ncp;
	PyObject *rv;
	int i, r, g, b;
	unsigned long value, nvalue;
    
	if ( !PyArg_Parse(args, "(s#ii)", &cp, &len, &x, &y) )
		return 0;

	nlen = x*y;
	if ( nlen != len ) {
		PyErr_SetString(ImageopError, "String has incorrect length");
		return 0;
	}
    
	rv = PyString_FromStringAndSize(NULL, nlen*4);
	if ( rv == 0 )
		return 0;
	ncp = (unsigned long *)PyString_AsString(rv);

	for ( i=0; i < nlen; i++ ) {
		/* Bits in source: RRRBBGGG
		** Red and Green are multiplied by 36.5, Blue by 85
		*/
		value = *cp++;
		r = (value >> 5) & 7;
		g = (value     ) & 7;
		b = (value >> 3) & 3;
		r = (r<<5) | (r<<3) | (r>>1);
		g = (g<<5) | (g<<3) | (g>>1);
		b = (b<<6) | (b<<4) | (b<<2) | b;
		nvalue = r | (g<<8) | (b<<16);
		*ncp++ = nvalue;
	}
	return rv;
}

static PyObject *
imageop_rgb2grey(self, args)
	PyObject *self;
PyObject *args;
{
	int x, y, len, nlen;
	unsigned long *cp;
	unsigned char *ncp;
	PyObject *rv;
	int i, r, g, b;
	unsigned long value, nvalue;
    
	if ( !PyArg_Parse(args, "(s#ii)", &cp, &len, &x, &y) )
		return 0;

	nlen = x*y;
	if ( nlen*4 != len ) {
		PyErr_SetString(ImageopError, "String has incorrect length");
		return 0;
	}
    
	rv = PyString_FromStringAndSize(NULL, nlen);
	if ( rv == 0 )
		return 0;
	ncp = (unsigned char *)PyString_AsString(rv);

	for ( i=0; i < nlen; i++ ) {
		value = *cp++;
		r = (value      ) & 0xff;
		g = (value >>  8) & 0xff;
		b = (value >> 16) & 0xff;
		nvalue = (int)(0.30*r + 0.59*g + 0.11*b);
		if ( nvalue > 255 ) nvalue = 255;
		*ncp++ = (unsigned char)nvalue;
	}
	return rv;
}

static PyObject *
imageop_grey2rgb(self, args)
	PyObject *self;
PyObject *args;
{
	int x, y, len, nlen;
	unsigned char *cp;
	unsigned long *ncp;
	PyObject *rv;
	int i;
	unsigned long value;
    
	if ( !PyArg_Parse(args, "(s#ii)", &cp, &len, &x, &y) )
		return 0;

	nlen = x*y;
	if ( nlen != len ) {
		PyErr_SetString(ImageopError, "String has incorrect length");
		return 0;
	}
    
	rv = PyString_FromStringAndSize(NULL, nlen*4);
	if ( rv == 0 )
		return 0;
	ncp = (unsigned long *)PyString_AsString(rv);

	for ( i=0; i < nlen; i++ ) {
		value = *cp++;
		*ncp++ = value | (value << 8 ) | (value << 16);
	}
	return rv;
}

/*
static object *
imageop_mul(self, args)
	object *self;
object *args;
{
	char *cp, *ncp;
	int len, size, x, y;
	object *rv;
	int i;

	if ( !getargs(args, "(s#iii)", &cp, &len, &size, &x, &y) )
		return 0;
    
	if ( size != 1 && size != 4 ) {
		err_setstr(ImageopError, "Size should be 1 or 4");
		return 0;
	}
	if ( len != size*x*y ) {
		err_setstr(ImageopError, "String has incorrect length");
		return 0;
	}
    
	rv = newsizedstringobject(NULL, XXXX);
	if ( rv == 0 )
		return 0;
	ncp = (char *)getstringvalue(rv);
    
    
	for ( i=0; i < len; i += size ) {
	}
	return rv;
}
*/

static PyMethodDef imageop_methods[] = {
	{ "crop",		imageop_crop },
	{ "scale",		imageop_scale },
	{ "grey2mono",	        imageop_grey2mono },
	{ "grey2grey2",	        imageop_grey2grey2 },
	{ "grey2grey4",	        imageop_grey2grey4 },
	{ "dither2mono",	imageop_dither2mono },
	{ "dither2grey2",	imageop_dither2grey2 },
	{ "mono2grey",	        imageop_mono2grey },
	{ "grey22grey",	        imageop_grey22grey },
	{ "grey42grey",	        imageop_grey42grey },
	{ "tovideo",	        imageop_tovideo },
	{ "rgb2rgb8",	        imageop_rgb2rgb8 },
	{ "rgb82rgb",	        imageop_rgb82rgb },
	{ "rgb2grey",	        imageop_rgb2grey },
	{ "grey2rgb",	        imageop_grey2rgb },
	{ 0,                    0 }
};


void
initimageop()
{
	PyObject *m, *d;
	m = Py_InitModule("imageop", imageop_methods);
	d = PyModule_GetDict(m);
	ImageopError = PyErr_NewException("imageop.error", NULL, NULL);
	if (ImageopError != NULL)
		PyDict_SetItemString(d, "error", ImageopError);
}