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rop.c

/*====================================================================*
 -  Copyright (C) 2001 Leptonica.  All rights reserved.
 -  This software is distributed in the hope that it will be
 -  useful, but with NO WARRANTY OF ANY KIND.
 -  No author or distributor accepts responsibility to anyone for the
 -  consequences of using this software, or for whether it serves any
 -  particular purpose or works at all, unless he or she says so in
 -  writing.  Everyone is granted permission to copy, modify and
 -  redistribute this source code, for commercial or non-commercial
 -  purposes, with the following restrictions: (1) the origin of this
 -  source code must not be misrepresented; (2) modified versions must
 -  be plainly marked as such; and (3) this notice may not be removed
 -  or altered from any source or modified source distribution.
 *====================================================================*/

/*
 *  rop.c
 *
 *      General rasterop
 *           l_int32    pixRasterop()
 *
 *      In-place full band rasterop
 *           l_int32    pixRasteropVip()
 *           l_int32    pixRasteropHip()
 *
 *      In-place shift
 *           l_int32    pixRasteropIP()
 *
 *      Full image rasterop with no shifts
 *           l_int32    pixRasteropFullImage()
 */


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "allheaders.h"


/*--------------------------------------------------------------------*
 *               Intermediate-level rasterop interface                *
 *--------------------------------------------------------------------*/
/*!
 *  pixRasterop()
 *
 *      Input:  pixd   (dest pix)
 *              dx     (x val of UL corner of dest rectangle)
 *              dy     (y val of UL corner of dest rectangle)
 *              dw     (width of dest rectangle)
 *              dh     (height of dest rectangle)
 *              op     (op code)
 *              pixs   (src pix)
 *              sx     (x val of UL corner of src rectangle)
 *              sy     (y val of UL corner of src rectangle)
 *      Return: 0 if OK; 1 on error.
 *
 *  Action: If the operation involves only dest, this calls
 *          rasteropUniLow().  Otherwise, checks depth of the
 *          src and dest, and if they match, calls rasteropLow().
 *          This has the standard set of 9 args for rasterop.
 *
 *  Background:
 *  -----------
 *
 *  There are 18 operations, described by the op codes in pix.h.
 *
 *  One, PIX_DST, is a no-op.
 *
 *  Three, PIX_CLR, PIX_SET, and PIX_NOT(PIX_DST) operate only on the dest.
 *  These are handled by the low-level rasteropUniLow().
 *
 *  The other 14 involve the both the src and the dest, and depend on
 *  the bit values of either just the src or the bit values of both
 *  src and dest.  They are handled by rasteropLow():
 *
 *          PIX_SRC                             s
 *          PIX_NOT(PIX_SRC)                   ~s
 *          PIX_SRC | PIX_DST                   s | d
 *          PIX_SRC & PIX_DST                   s & d
 *          PIX_SRC ^ PIX_DST                   s ^ d
 *          PIX_NOT(PIX_SRC) | PIX_DST         ~s | d
 *          PIX_NOT(PIX_SRC) & PIX_DST         ~s & d
 *          PIX_NOT(PIX_SRC) ^ PIX_DST         ~s ^ d
 *          PIX_SRC | PIX_NOT(PIX_DST)          s | ~d
 *          PIX_SRC & PIX_NOT(PIX_DST)          s & ~d
 *          PIX_SRC ^ PIX_NOT(PIX_DST)          s ^ ~d
 *          PIX_NOT(PIX_SRC | PIX_DST)         ~(s | d)
 *          PIX_NOT(PIX_SRC & PIX_DST)         ~(s & d)
 *          PIX_NOT(PIX_SRC ^ PIX_DST)         ~(s ^ d)
 *
 *  Each of these is implemented with one of three low-level
 *  functions, depending on the alignment of the left edge
 *  of the src and dest rectangles:
 *      * a fastest implementation if both left edges are
 *        (32-bit) word aligned
 *      * a very slightly slower implementation if both left
 *        edges have the same relative (32-bit) word alignment
 *      * the general routine that is invoked when
 *        both left edges have different word alignment
 *
 *  Of the 14 binary rasterops above, only 12 are unique
 *  logical combinations (out of a possible 16) of src
 *  and dst bits:
 *
 *        (sd)         (11)   (10)   (01)   (00)
 *   -----------------------------------------------
 *         s            1      1      0      0
 *        ~s            0      1      0      1
 *       s | d          1      1      1      0
 *       s & d          1      0      0      0
 *       s ^ d          0      1      1      0
 *      ~s | d          1      0      1      1
 *      ~s & d          0      0      1      0
 *      ~s ^ d          1      0      0      1
 *       s | ~d         1      1      0      1
 *       s & ~d         0      1      0      0
 *       s ^ ~d         1      0      0      1
 *      ~(s | d)        0      0      0      1
 *      ~(s & d)        0      1      1      1
 *      ~(s ^ d)        1      0      0      1
 *
 *  Note that the following three operations are equivalent:
 *      ~(s ^ d)
 *      ~s ^ d
 *      s ^ ~d
 *  and in the implementation, we call them out with the first form;
 *  namely, ~(s ^ d).
 *
 *  Of the 16 possible binary combinations of src and dest bits,
 *  the remaining 4 unique ones are independent of the src bit.
 *  They depend on either just the dest bit or on neither
 *  the src nor dest bits:
 *
 *         d            1      0      1      0    (indep. of s)
 *        ~d            0      1      0      1    (indep. of s)
 *        CLR           0      0      0      0    (indep. of both s & d)
 *        SET           1      1      1      1    (indep. of both s & d)
 *
 *  As mentioned above, three of these are implemented by
 *  rasteropUniLow(), and one is a no-op.
 *
 *  How can these operation codes be represented by bits
 *  in such a way that when the basic operations are performed
 *  on the bits the results are unique for unique
 *  operations, and mimic the logic table given above?
 *
 *  The answer is to choose a particular order of the pairings:
 *         (sd)         (11)   (10)   (01)   (00)
 *  (which happens to be the same as in the above table)
 *  and to translate the result into 4-bit representations
 *  of s and d.  For example, the Sun rasterop choice
 *  (omitting the extra bit for clipping) is
 *
 *      PIX_SRC      0xc
 *      PIX_DST      0xa
 *
 *  This corresponds to our pairing order given above:
 *         (sd)         (11)   (10)   (01)   (00)
 *  where for s = 1 we get the bit pattern
 *       PIX_SRC:        1      1      0      0     (0xc)
 *  and for d = 1 we get the pattern
 *       PIX_DST:         1      0      1      0    (0xa)
 *
 *  OK, that's the pairing order that Sun chose.  How many different
 *  ways can we assign bit patterns to PIX_SRC and PIX_DST to get
 *  the boolean ops to work out?  Any of the 4 pairs can be put
 *  in the first position, any of the remaining 3 pairs can go
 *  in the second; and one of the remaining 2 pairs can go the the third.
 *  There is a total of 4*3*2 = 24 ways these pairs can be permuted.
 */
l_int32
pixRasterop(PIX     *pixd,
            l_int32  dx,
            l_int32  dy,
            l_int32  dw,
            l_int32  dh,
            l_int32  op,
            PIX     *pixs,
            l_int32  sx,
            l_int32  sy)
{
l_int32  dd;

    PROCNAME("pixRasterop");

    if (!pixd)
      return ERROR_INT("pixd not defined", procName, 1);

    if (op == PIX_DST)   /* no-op */
      return 0;

      /* check if operation is only on dest */
    dd = pixGetDepth(pixd);
    if (op == PIX_CLR || op == PIX_SET || op == PIX_NOT(PIX_DST)) {
        rasteropUniLow(pixGetData(pixd),
                     pixGetWidth(pixd), pixGetHeight(pixd), dd,
                   pixGetWpl(pixd),
                   dx, dy, dw, dh,
                   op);
      return 0;
    }

    if (!pixs)
      return ERROR_INT("pixs not defined", procName, 1);

      /* check depth of src and depth; these must agree */
    if (dd != pixGetDepth(pixs))
      return ERROR_INT("depths of pixs and pixd differ", procName, 1);

    rasteropLow(pixGetData(pixd),
            pixGetWidth(pixd), pixGetHeight(pixd), dd,
            pixGetWpl(pixd),
            dx, dy, dw, dh,
            op,
            pixGetData(pixs),
            pixGetWidth(pixs), pixGetHeight(pixs),
            pixGetWpl(pixs),
            sx, sy);

    return 0;
}


/*--------------------------------------------------------------------*
 *                     In-place full band rasterop                    *
 *--------------------------------------------------------------------*/
/*!
 *  pixRasteropVip()
 *
 *      Input:  pixd (in-place)
 *              x    (left edge of vertical band)
 *              w    (width of vertical band)
 *              vshift (vertical shift of band; vshift > 0 is down)
 *              incolor (L_BRING_IN_WHITE, L_BRING_IN_BLACK)
 *      Return: 0 if OK; 1 on error
 *
 *  Notes:
 *      (1) This rasterop brings in either white or black pixels
 *          from outside the image.
 */
l_int32
pixRasteropVip(PIX     *pixd,
               l_int32  x,
               l_int32  w,
               l_int32  vshift,
             l_int32  incolor)
{
l_int32  h, d, op;

    PROCNAME("pixRasteropVip");

    if (!pixd)
      return ERROR_INT("pixd not defined", procName, 1);
    if (incolor != L_BRING_IN_WHITE && incolor != L_BRING_IN_BLACK)
      return ERROR_INT("invalid value for incolor", procName, 1);

    if (vshift == 0)
      return 0;

    rasteropVipLow(pixGetData(pixd),
                   pixGetWidth(pixd), pixGetHeight(pixd),
               pixGetDepth(pixd), pixGetWpl(pixd),
               x, w, vshift);

    d = pixGetDepth(pixd);
    if ((d == 1 && incolor == L_BRING_IN_BLACK) ||
        (d > 1 && incolor == L_BRING_IN_WHITE))
      op = PIX_SET;
    else
      op = PIX_CLR;

        /* Set the pixels brought in at top or bottom */
    if (vshift > 0)
      pixRasterop(pixd, x, 0, w, vshift, op, NULL, 0, 0);
    else {   /* vshift < 0 */
      h = pixGetHeight(pixd);
      pixRasterop(pixd, x, h + vshift, w, -vshift, op, NULL, 0, 0);
    }

    return 0;
}


/*!
 *  pixRasteropHip()
 *
 *      Input:  pixd (in-place)
 *              y    (top of horizontal band)
 *              h    (height of horizontal band)
 *              hshift (horizontal shift of band; hshift > 0 is to right)
 *              incolor (L_BRING_IN_WHITE, L_BRING_IN_BLACK)
 *      Return: 0 if OK; 1 on error
 *
 *  Notes:
 *      (1) This rasterop brings in either white or black pixels
 *          from outside the image.
 */
l_int32
pixRasteropHip(PIX     *pixd,
               l_int32  y,
               l_int32  h,
               l_int32  hshift,
             l_int32  incolor)
{
l_int32  w, d, op;

    PROCNAME("pixRasteropHip");

    if (!pixd)
      return ERROR_INT("pixd not defined", procName, 1);

    if (hshift == 0)
      return 0;

    rasteropHipLow(pixGetData(pixd), pixGetHeight(pixd),
               pixGetDepth(pixd), pixGetWpl(pixd),
               y, h, hshift);

    d = pixGetDepth(pixd);
    if ((d == 1 && incolor == L_BRING_IN_BLACK) ||
        (d > 1 && incolor == L_BRING_IN_WHITE))
      op = PIX_SET;
    else
      op = PIX_CLR;

        /* Set the pixels brought in at left or right */
    if (hshift > 0)
      pixRasterop(pixd, 0, y, hshift, h, op, NULL, 0, 0);
    else {   /* hshift < 0 */
      w = pixGetWidth(pixd);
      pixRasterop(pixd, w + hshift, y, -hshift, h, op, NULL, 0, 0);
    }

    return 0;
}


/*--------------------------------------------------------------------*
 *                            In-place shift                          *
 *--------------------------------------------------------------------*/
/*!
 *  pixRasteropIP()
 *
 *      Input:  pixd (in-place)
 *              hshift (horizontal shift; hshift > 0 is to right)
 *              vshift (vertical shift; vshift > 0 is down)
 *              incolor (L_BRING_IN_WHITE, L_BRING_IN_BLACK)
 *      Return: 0 if OK; 1 on error
 */
l_int32
pixRasteropIP(PIX     *pixd,
              l_int32  hshift,
              l_int32  vshift,
            l_int32  incolor)
{
l_int32  w, h;

    PROCNAME("pixRasteropIP");

    if (!pixd)
      return ERROR_INT("pixd not defined", procName, 1);

    w = pixGetWidth(pixd);
    h = pixGetHeight(pixd);
    pixRasteropHip(pixd, 0, h, hshift, incolor);
    pixRasteropVip(pixd, 0, w, vshift, incolor);

    return 0;
}


/*--------------------------------------------------------------------*
 *                 Full image rasterop with no shifts                 *
 *--------------------------------------------------------------------*/
/*!
 *  pixRasteropFullImage()
 *
 *      Input:  pixd
 *              pixs
 *              op (any of the op-codes)
 *      Return: 0 if OK; 1 on error
 *
 *  Notes:
 *      - this is a wrapper for a common 2-image raster operation
 *      - both pixs and pixd must be defined
 *      - the operation is performed with aligned UL corners of pixs and pixd
 *      - the operation clips to the smallest pix; if the width or height
 *        of pixd is larger than pixs, some pixels in pixd will be unchanged
 */
l_int32
pixRasteropFullImage(PIX     *pixd,
                     PIX     *pixs,
                 l_int32  op)
{
    PROCNAME("pixRasteropFullImage");

    if (!pixd)
      return ERROR_INT("pixd not defined", procName, 1);
    if (!pixs)
      return ERROR_INT("pixs not defined", procName, 1);

    pixRasterop(pixd, 0, 0, pixGetWidth(pixd), pixGetHeight(pixd), op,
              pixs, 0, 0);
    return 0;
}



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