pixacc.c File Reference

#include "allheaders.h"
#include "pix_internal.h"

Go to the source code of this file.

Functions
PIXACC *	pixaccCreate (l_int32 w, l_int32 h, l_int32 negflag)
PIXACC *	pixaccCreateFromPix (PIX *pix, l_int32 negflag)
void	pixaccDestroy (PIXACC **ppixacc)
PIX *	pixaccFinal (PIXACC *pixacc, l_int32 outdepth)
PIX *	pixaccGetPix (PIXACC *pixacc)
l_int32	pixaccGetOffset (PIXACC *pixacc)
l_ok	pixaccAdd (PIXACC *pixacc, PIX *pix)
l_ok	pixaccSubtract (PIXACC *pixacc, PIX *pix)
l_ok	pixaccMultConst (PIXACC *pixacc, l_float32 factor)
l_ok	pixaccMultConstAccumulate (PIXACC *pixacc, PIX *pix, l_float32 factor)

Detailed Description

     Pixacc creation, destruction
          PIXACC   *pixaccCreate()
          PIXACC   *pixaccCreateFromPix()
          void      pixaccDestroy()

     Pixacc finalization
          PIX      *pixaccFinal()

     Pixacc accessors
          PIX      *pixaccGetPix()
          l_int32   pixaccGetOffset()

     Pixacc accumulators
          l_int32   pixaccAdd()
          l_int32   pixaccSubtract()
          l_int32   pixaccMultConst()
          l_int32   pixaccMultConstAccumulate()

 This is a simple interface for some of the pixel arithmetic operations
 in pixarith.c.  These are easy to code up, but not as fast as
 hand-coded functions that do arithmetic on corresponding pixels.

 Suppose you want to make a linear combination of pix1 and pix2:
    pixd = 0.4 * pix1 + 0.6 * pix2
 where pix1 and pix2 are the same size and have depth 'd'.  Then:
    Pixacc *pacc = pixaccCreateFromPix(pix1, 0);  // first; addition only
    pixaccMultConst(pacc, 0.4);
    pixaccMultConstAccumulate(pacc, pix2, 0.6);  // Add in 0.6 of the second
    pixd = pixaccFinal(pacc, d);  // Get the result
    pixaccDestroy(&pacc);

Definition in file pixacc.c.

Function Documentation

pixaccAdd()

l_ok pixaccAdd	(	PIXACC *	pixacc,
		PIX *	pix )

pixaccAdd()

Parameters

[in]	pixacc
[in]	pix	to be added

Returns

0 if OK, 1 on error

Definition at line 243 of file pixacc.c.

References pixaccGetPix().

Referenced by pixaccCreateFromPix(), and pixaccMultConstAccumulate().

pixaccCreate()

PIXACC * pixaccCreate	(	l_int32	w,
		l_int32	h,
		l_int32	negflag )

pixaccCreate()

Parameters

[in]	w,h	of 32 bpp internal Pix
[in]	negflag	0 if only positive numbers are involved; 1 if there will be negative numbers

Returns

pixacc, or NULL on error

Notes:
     (1) Use negflag = 1 for safety if any negative numbers are going
         to be used in the chain of operations.  Negative numbers
         arise, e.g., by subtracting a pix, or by adding a pix
         that has been pre-multiplied by a negative number.
     (2) Initializes the internal 32 bpp pix, similarly to the
         initialization in pixInitAccumulate().

Definition at line 93 of file pixacc.c.

References Pixacc::h, Pixacc::offset, Pixacc::pix, pixaccDestroy(), and Pixacc::w.

Referenced by pixaccCreateFromPix(), and pixaccMultConstAccumulate().

pixaccCreateFromPix()

PIXACC * pixaccCreateFromPix	(	PIX *	pix,
		l_int32	negflag )

pixaccCreateFromPix()

Parameters

[in]	pix
[in]	negflag	0 if only positive numbers are involved; 1 if there will be negative numbers

Returns

pixacc, or NULL on error

Notes:
     (1) See pixaccCreate()

Definition at line 131 of file pixacc.c.

References pixaccAdd(), and pixaccCreate().

pixaccDestroy()

void pixaccDestroy

(

PIXACC **

ppixacc

)

pixaccDestroy()

Parameters

[in,out]

ppixacc

will be set to null before returning

Returns

void

Notes:
     (1) Always nulls the input ptr.

Definition at line 159 of file pixacc.c.

References Pixacc::pix.

Referenced by pixaccCreate(), and pixaccMultConstAccumulate().

pixaccFinal()

PIX * pixaccFinal	(	PIXACC *	pixacc,
		l_int32	outdepth )

pixaccFinal()

Parameters

[in]	pixacc
[in]	outdepth	8, 16 or 32 bpp

Returns

pixd 8, 16 or 32 bpp, or NULL on error

Definition at line 188 of file pixacc.c.

References pixaccGetOffset(), and pixaccGetPix().

Referenced by pixaccMultConstAccumulate().

pixaccGetOffset()

l_int32 pixaccGetOffset

(

PIXACC *

pixacc

)

pixaccGetOffset()

Parameters

[in]

pixacc

Returns

offset, or -1 on error

Definition at line 224 of file pixacc.c.

References Pixacc::offset.

Referenced by pixaccFinal(), and pixaccMultConst().

pixaccGetPix()

PIX * pixaccGetPix

(

PIXACC *

pixacc

)

pixaccGetPix()

Parameters

[in]

pixacc

Returns

pix, or NULL on error

Definition at line 209 of file pixacc.c.

References Pixacc::pix.

Referenced by pixaccAdd(), pixaccFinal(), pixaccMultConst(), and pixaccSubtract().

pixaccMultConst()

l_ok pixaccMultConst	(	PIXACC *	pixacc,
		l_float32	factor )

pixaccMultConst()

Parameters

[in]	pixacc
[in]	factor

Returns

0 if OK, 1 on error

Definition at line 283 of file pixacc.c.

References pixaccGetOffset(), and pixaccGetPix().

Referenced by pixaccMultConstAccumulate().

pixaccMultConstAccumulate()

l_ok pixaccMultConstAccumulate	(	PIXACC *	pixacc,
		PIX *	pix,
		l_float32	factor )

pixaccMultConstAccumulate()

Parameters

[in]	pixacc
[in]	pix
[in]	factor

Returns

0 if OK, 1 on error

Notes:
     (1) This creates a temp pix that is pix multiplied by the
         constant factor.  It then adds that into pixacc.

Definition at line 309 of file pixacc.c.

References pixaccAdd(), pixaccCreate(), pixaccDestroy(), pixaccFinal(), and pixaccMultConst().

pixaccSubtract()

l_ok pixaccSubtract	(	PIXACC *	pixacc,
		PIX *	pix )

pixaccSubtract()

Parameters

[in]	pixacc
[in]	pix	to be subtracted

Returns

0 if OK, 1 on error

Definition at line 263 of file pixacc.c.

References pixaccGetPix().