rotate.c

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/*====================================================================*
 -  Copyright (C) 2001 Leptonica.  All rights reserved.
 -
 -  Redistribution and use in source and binary forms, with or without
 -  modification, are permitted provided that the following conditions
 -  are met:
 -  1. Redistributions of source code must retain the above copyright
 -     notice, this list of conditions and the following disclaimer.
 -  2. Redistributions in binary form must reproduce the above
 -     copyright notice, this list of conditions and the following
 -     disclaimer in the documentation and/or other materials
 -     provided with the distribution.
 -
 -  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 -  ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 -  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 -  A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL ANY
 -  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 -  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 -  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 -  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 -  OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 -  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 -  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *====================================================================*/


#include <math.h>
#include "allheaders.h"

extern l_float32  AlphaMaskBorderVals[2];
static const l_float32  MIN_ANGLE_TO_ROTATE = 0.001;  /* radians; ~0.06 deg */
static const l_float32  MAX_1BPP_SHEAR_ANGLE = 0.06;  /* radians; ~3 deg    */
static const l_float32  LIMIT_SHEAR_ANGLE = 0.35;     /* radians; ~20 deg   */


/*------------------------------------------------------------------*
 *                  General rotation about the center               *
 *------------------------------------------------------------------*/
PIX *
pixRotate(PIX       *pixs,
          l_float32  angle,
          l_int32    type,
          l_int32    incolor,
          l_int32    width,
          l_int32    height)
{
l_int32    w, h, d;
l_uint32   fillval;
PIX       *pix1, *pix2, *pix3, *pixd;
PIXCMAP   *cmap;

    PROCNAME("pixRotate");

    if (!pixs)
        return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
    if (type != L_ROTATE_SHEAR && type != L_ROTATE_AREA_MAP &&
        type != L_ROTATE_SAMPLING)
        return (PIX *)ERROR_PTR("invalid type", procName, NULL);
    if (incolor != L_BRING_IN_WHITE && incolor != L_BRING_IN_BLACK)
        return (PIX *)ERROR_PTR("invalid incolor", procName, NULL);

    if (L_ABS(angle) < MIN_ANGLE_TO_ROTATE)
        return pixClone(pixs);

        /* Adjust rotation type if necessary:
         *  - If d == 1 bpp and the angle is more than about 6 degrees,
         *    rotate by sampling; otherwise rotate by shear.
         *  - If d > 1, only allow shear rotation up to about 20 degrees;
         *    beyond that, default a shear request to sampling. */
    if (pixGetDepth(pixs) == 1) {
        if (L_ABS(angle) > MAX_1BPP_SHEAR_ANGLE) {
            if (type != L_ROTATE_SAMPLING)
                L_INFO("1 bpp, large angle; rotate by sampling\n", procName);
            type = L_ROTATE_SAMPLING;
        } else if (type != L_ROTATE_SHEAR) {
            L_INFO("1 bpp; rotate by shear\n", procName);
            type = L_ROTATE_SHEAR;
        }
    } else if (L_ABS(angle) > LIMIT_SHEAR_ANGLE && type == L_ROTATE_SHEAR) {
        L_INFO("large angle; rotate by sampling\n", procName);
        type = L_ROTATE_SAMPLING;
    }

        /* Remove colormap if we rotate by area mapping. */
    cmap = pixGetColormap(pixs);
    if (cmap && type == L_ROTATE_AREA_MAP)
        pix1 = pixRemoveColormap(pixs, REMOVE_CMAP_BASED_ON_SRC);
    else
        pix1 = pixClone(pixs);
    cmap = pixGetColormap(pix1);

        /* Otherwise, if there is a colormap and we're not embedding,
         * add white color if it doesn't exist. */
    if (cmap && width == 0) {  /* no embedding; generate %incolor */
        if (incolor == L_BRING_IN_BLACK)
            pixcmapAddBlackOrWhite(cmap, 0, NULL);
        else  /* L_BRING_IN_WHITE */
            pixcmapAddBlackOrWhite(cmap, 1, NULL);
    }

        /* Request to embed in a larger image; do if necessary */
    pix2 = pixEmbedForRotation(pix1, angle, incolor, width, height);

        /* Area mapping requires 8 or 32 bpp.  If less than 8 bpp and
         * area map rotation is requested, convert to 8 bpp. */
    d = pixGetDepth(pix2);
    if (type == L_ROTATE_AREA_MAP && d < 8)
        pix3 = pixConvertTo8(pix2, FALSE);
    else
        pix3 = pixClone(pix2);

        /* Do the rotation: shear, sampling or area mapping */
    pixGetDimensions(pix3, &w, &h, &d);
    if (type == L_ROTATE_SHEAR) {
        pixd = pixRotateShearCenter(pix3, angle, incolor);
    } else if (type == L_ROTATE_SAMPLING) {
        pixd = pixRotateBySampling(pix3, w / 2, h / 2, angle, incolor);
    } else {  /* rotate by area mapping */
        fillval = 0;
        if (incolor == L_BRING_IN_WHITE) {
            if (d == 8)
                fillval = 255;
            else  /* d == 32 */
                fillval = 0xffffff00;
        }
        if (d == 8)
            pixd = pixRotateAMGray(pix3, angle, fillval);
        else  /* d == 32 */
            pixd = pixRotateAMColor(pix3, angle, fillval);
    }

    pixDestroy(&pix1);
    pixDestroy(&pix2);
    pixDestroy(&pix3);
    return pixd;
}


PIX *
pixEmbedForRotation(PIX       *pixs,
                    l_float32  angle,
                    l_int32    incolor,
                    l_int32    width,
                    l_int32    height)
{
l_int32    w, h, d, w1, h1, w2, h2, maxside, wnew, hnew, xoff, yoff, setcolor;
l_float64  sina, cosa, fw, fh;
PIX       *pixd;

    PROCNAME("pixEmbedForRotation");

    if (!pixs)
        return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
    if (incolor != L_BRING_IN_WHITE && incolor != L_BRING_IN_BLACK)
        return (PIX *)ERROR_PTR("invalid incolor", procName, NULL);
    if (L_ABS(angle) < MIN_ANGLE_TO_ROTATE)
        return pixClone(pixs);

        /* Test if big enough to hold any rotation of the original image */
    pixGetDimensions(pixs, &w, &h, &d);
    maxside = (l_int32)(sqrt((l_float64)(width * width) +
                             (l_float64)(height * height)) + 0.5);
    if (w >= maxside && h >= maxside)  /* big enough */
        return pixClone(pixs);

        /* Find the new sizes required to hold the image after rotation.
         * Note that the new dimensions must be at least as large as those
         * of pixs, because we're rasterop-ing into it before rotation. */
    cosa = cos(angle);
    sina = sin(angle);
    fw = (l_float64)w;
    fh = (l_float64)h;
    w1 = (l_int32)(L_ABS(fw * cosa - fh * sina) + 0.5);
    w2 = (l_int32)(L_ABS(-fw * cosa - fh * sina) + 0.5);
    h1 = (l_int32)(L_ABS(fw * sina + fh * cosa) + 0.5);
    h2 = (l_int32)(L_ABS(-fw * sina + fh * cosa) + 0.5);
    wnew = L_MAX(w, L_MAX(w1, w2));
    hnew = L_MAX(h, L_MAX(h1, h2));

    if ((pixd = pixCreate(wnew, hnew, d)) == NULL)
        return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
    pixCopyResolution(pixd, pixs);
    pixCopyColormap(pixd, pixs);
    pixCopySpp(pixd, pixs);
    pixCopyText(pixd, pixs);
    xoff = (wnew - w) / 2;
    yoff = (hnew - h) / 2;

        /* Set background to color to be rotated in */
    setcolor = (incolor == L_BRING_IN_BLACK) ? L_SET_BLACK : L_SET_WHITE;
    pixSetBlackOrWhite(pixd, setcolor);

        /* Rasterop automatically handles all 4 channels for rgba */
    pixRasterop(pixd, xoff, yoff, w, h, PIX_SRC, pixs, 0, 0);
    return pixd;
}


/*------------------------------------------------------------------*
 *                    General rotation by sampling                  *
 *------------------------------------------------------------------*/
PIX *
pixRotateBySampling(PIX       *pixs,
                    l_int32    xcen,
                    l_int32    ycen,
                    l_float32  angle,
                    l_int32    incolor)
{
l_int32    w, h, d, i, j, x, y, xdif, ydif, wm1, hm1, wpld;
l_uint32   val;
l_float32  sina, cosa;
l_uint32  *datad, *lined;
void     **lines;
PIX       *pixd;

    PROCNAME("pixRotateBySampling");

    if (!pixs)
        return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
    if (incolor != L_BRING_IN_WHITE && incolor != L_BRING_IN_BLACK)
        return (PIX *)ERROR_PTR("invalid incolor", procName, NULL);
    pixGetDimensions(pixs, &w, &h, &d);
    if (d != 1 && d != 2 && d != 4 && d != 8 && d != 16 && d != 32)
        return (PIX *)ERROR_PTR("invalid depth", procName, NULL);

    if (L_ABS(angle) < MIN_ANGLE_TO_ROTATE)
        return pixClone(pixs);

    if ((pixd = pixCreateTemplateNoInit(pixs)) == NULL)
        return (PIX *)ERROR_PTR("pixd not made", procName, NULL);
    pixSetBlackOrWhite(pixd, incolor);

    sina = sin(angle);
    cosa = cos(angle);
    datad = pixGetData(pixd);
    wpld = pixGetWpl(pixd);
    wm1 = w - 1;
    hm1 = h - 1;
    lines = pixGetLinePtrs(pixs, NULL);

        /* Treat 1 bpp case specially */
    if (d == 1) {
        for (i = 0; i < h; i++) {  /* scan over pixd */
            lined = datad + i * wpld;
            ydif = ycen - i;
            for (j = 0; j < w; j++) {
                xdif = xcen - j;
                x = xcen + (l_int32)(-xdif * cosa - ydif * sina);
                if (x < 0 || x > wm1) continue;
                y = ycen + (l_int32)(-ydif * cosa + xdif * sina);
                if (y < 0 || y > hm1) continue;
                if (incolor == L_BRING_IN_WHITE) {
                    if (GET_DATA_BIT(lines[y], x))
                        SET_DATA_BIT(lined, j);
                } else {
                    if (!GET_DATA_BIT(lines[y], x))
                        CLEAR_DATA_BIT(lined, j);
                }
            }
        }
        LEPT_FREE(lines);
        return pixd;
    }

    for (i = 0; i < h; i++) {  /* scan over pixd */
        lined = datad + i * wpld;
        ydif = ycen - i;
        for (j = 0; j < w; j++) {
            xdif = xcen - j;
            x = xcen + (l_int32)(-xdif * cosa - ydif * sina);
            if (x < 0 || x > wm1) continue;
            y = ycen + (l_int32)(-ydif * cosa + xdif * sina);
            if (y < 0 || y > hm1) continue;
            switch (d)
            {
            case 8:
                val = GET_DATA_BYTE(lines[y], x);
                SET_DATA_BYTE(lined, j, val);
                break;
            case 32:
                val = GET_DATA_FOUR_BYTES(lines[y], x);
                SET_DATA_FOUR_BYTES(lined, j, val);
                break;
            case 2:
                val = GET_DATA_DIBIT(lines[y], x);
                SET_DATA_DIBIT(lined, j, val);
                break;
            case 4:
                val = GET_DATA_QBIT(lines[y], x);
                SET_DATA_QBIT(lined, j, val);
                break;
            case 16:
                val = GET_DATA_TWO_BYTES(lines[y], x);
                SET_DATA_TWO_BYTES(lined, j, val);
                break;
            default:
                return (PIX *)ERROR_PTR("invalid depth", procName, NULL);
            }
        }
    }

    LEPT_FREE(lines);
    return pixd;
}


/*------------------------------------------------------------------*
 *                 Nice (slow) rotation of 1 bpp image              *
 *------------------------------------------------------------------*/
PIX *
pixRotateBinaryNice(PIX       *pixs,
                    l_float32  angle,
                    l_int32    incolor)
{
PIX  *pix1, *pix2, *pix3, *pix4, *pixd;

    PROCNAME("pixRotateBinaryNice");

    if (!pixs || pixGetDepth(pixs) != 1)
        return (PIX *)ERROR_PTR("pixs undefined or not 1 bpp", procName, NULL);
    if (incolor != L_BRING_IN_WHITE && incolor != L_BRING_IN_BLACK)
        return (PIX *)ERROR_PTR("invalid incolor", procName, NULL);

    pix1 = pixConvertTo8(pixs, 0);
    pix2 = pixBlockconv(pix1, 1, 1);  /* smallest blur allowed */
    pix3 = pixRotateAM(pix2, angle, incolor);
    pix4 = pixUnsharpMasking(pix3, 1, 1.0);  /* sharpen a bit */
    pixd = pixThresholdToBinary(pix4, 128);
    pixDestroy(&pix1);
    pixDestroy(&pix2);
    pixDestroy(&pix3);
    pixDestroy(&pix4);
    return pixd;
}


/*------------------------------------------------------------------*
 *             Rotation including alpha (blend) component           *
 *------------------------------------------------------------------*/
PIX *
pixRotateWithAlpha(PIX       *pixs,
                   l_float32  angle,
                   PIX       *pixg,
                   l_float32  fract)
{
l_int32  ws, hs, d, spp;
PIX     *pixd, *pix32, *pixg2, *pixgr;

    PROCNAME("pixRotateWithAlpha");

    if (!pixs)
        return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
    pixGetDimensions(pixs, &ws, &hs, &d);
    if (d != 32 && pixGetColormap(pixs) == NULL)
        return (PIX *)ERROR_PTR("pixs not cmapped or 32 bpp", procName, NULL);
    if (pixg && pixGetDepth(pixg) != 8) {
        L_WARNING("pixg not 8 bpp; using 'fract' transparent alpha\n",
                  procName);
        pixg = NULL;
    }
    if (!pixg && (fract < 0.0 || fract > 1.0)) {
        L_WARNING("invalid fract; using fully opaque\n", procName);
        fract = 1.0;
    }
    if (!pixg && fract == 0.0)
        L_WARNING("transparent alpha; image will not be blended\n", procName);

        /* Make sure input to rotation is 32 bpp rgb, and rotate it */
    if (d != 32)
        pix32 = pixConvertTo32(pixs);
    else
        pix32 = pixClone(pixs);
    spp = pixGetSpp(pix32);
    pixSetSpp(pix32, 3);  /* ignore the alpha channel for the rotation */
    pixd = pixRotate(pix32, angle, L_ROTATE_AREA_MAP, L_BRING_IN_WHITE, ws, hs);
    pixSetSpp(pix32, spp);  /* restore initial value in case it's a clone */
    pixDestroy(&pix32);

        /* Set up alpha layer with a fading border and rotate it */
    if (!pixg) {
        pixg2 = pixCreate(ws, hs, 8);
        if (fract == 1.0)
            pixSetAll(pixg2);
        else if (fract > 0.0)
            pixSetAllArbitrary(pixg2, (l_int32)(255.0 * fract));
    } else {
        pixg2 = pixResizeToMatch(pixg, NULL, ws, hs);
    }
    if (ws > 10 && hs > 10) {  /* see note 8 */
        pixSetBorderRingVal(pixg2, 1,
                            (l_int32)(255.0 * fract * AlphaMaskBorderVals[0]));
        pixSetBorderRingVal(pixg2, 2,
                            (l_int32)(255.0 * fract * AlphaMaskBorderVals[1]));
    }
    pixgr = pixRotate(pixg2, angle, L_ROTATE_AREA_MAP,
                      L_BRING_IN_BLACK, ws, hs);

        /* Combine into a 4 spp result */
    pixSetRGBComponent(pixd, pixgr, L_ALPHA_CHANNEL);

    pixDestroy(&pixg2);
    pixDestroy(&pixgr);
    return pixd;
}