Mercurial > hgrepos > Python2 > PyMuPDF
diff mupdf-source/thirdparty/leptonica/src/enhance.c @ 2:b50eed0cc0ef upstream
ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4.
The directory name has changed: no version number in the expanded directory now.
| author | Franz Glasner <fzglas.hg@dom66.de> |
|---|---|
| date | Mon, 15 Sep 2025 11:43:07 +0200 |
| parents | |
| children |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mupdf-source/thirdparty/leptonica/src/enhance.c Mon Sep 15 11:43:07 2025 +0200 @@ -0,0 +1,2318 @@ +/*====================================================================* + - 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. + *====================================================================*/ + +/*! + * \file enhance.c + * <pre> + * + * Gamma TRC (tone reproduction curve) mapping + * PIX *pixGammaTRC() + * PIX *pixGammaTRCMasked() + * PIX *pixGammaTRCWithAlpha() + * NUMA *numaGammaTRC() + * + * Contrast enhancement + * PIX *pixContrastTRC() + * PIX *pixContrastTRCMasked() + * NUMA *numaContrastTRC() + * + * Histogram equalization + * PIX *pixEqualizeTRC() + * NUMA *numaEqualizeTRC() + * + * Generic TRC mapper + * l_int32 pixTRCMap() + * l_int32 pixTRCMapGeneral() + * + * Unsharp-masking + * PIX *pixUnsharpMasking() + * PIX *pixUnsharpMaskingGray() + * PIX *pixUnsharpMaskingFast() + * PIX *pixUnsharpMaskingGrayFast() + * PIX *pixUnsharpMaskingGray1D() + * PIX *pixUnsharpMaskingGray2D() + * + * Hue and saturation modification + * PIX *pixModifyHue() + * PIX *pixModifySaturation() + * l_int32 pixMeasureSaturation() + * PIX *pixModifyBrightness() + * + * Color shifting + * PIX *pixMosaicColorShiftRGB() + * PIX *pixColorShiftRGB() + * + * Darken gray (unsaturated) pixels + * PIX *pixDarkenGray() + * + * General multiplicative constant color transform + * PIX *pixMultConstantColor() + * PIX *pixMultMatrixColor() + * + * Edge by bandpass + * PIX *pixHalfEdgeByBandpass() + * + * Gamma correction, contrast enhancement and histogram equalization + * apply a simple mapping function to each pixel (or, for color + * images, to each sample (i.e., r,g,b) of the pixel). + * + * ~ Gamma correction either lightens the image or darkens + * it, depending on whether the gamma factor is greater + * or less than 1.0, respectively. + * + * ~ Contrast enhancement darkens the pixels that are already + * darker than the middle of the dynamic range (128) + * and lightens pixels that are lighter than 128. + * + * ~ Histogram equalization remaps to have the same number + * of image pixels at each of 256 intensity values. This is + * a quick and dirty method of adjusting contrast and brightness + * to bring out details in both light and dark regions. + * + * Unsharp masking is a more complicated enhancement. + * A "high frequency" image, generated by subtracting + * the smoothed ("low frequency") part of the image from + * itself, has all the energy at the edges. This "edge image" + * has 0 average value. A fraction of the edge image is + * then added to the original, enhancing the differences + * between pixel values at edges. Because we represent + * images as l_uint8 arrays, we preserve dynamic range and + * handle negative values by doing all the arithmetic on + * shifted l_uint16 arrays; the l_uint8 values are recovered + * at the end. + * + * Hue and saturation modification work in HSV space. Because + * this is too large for efficient table lookup, each pixel value + * is transformed to HSV, modified, and transformed back. + * It's not the fastest way to do this, but the method is + * easily understood. + * + * Unsharp masking is never in-place, and returns a clone if no + * operation is to be performed. + * </pre> + */ + +#ifdef HAVE_CONFIG_H +#include <config_auto.h> +#endif /* HAVE_CONFIG_H */ + +#include <math.h> +#include "allheaders.h" + + /* Scales contrast enhancement factor to have a useful range + * between 0.0 and 1.0 */ +static const l_float32 EnhanceScaleFactor = 5.0; + +/*-------------------------------------------------------------* + * Gamma TRC (tone reproduction curve) mapping * + *-------------------------------------------------------------*/ +/*! + * \brief pixGammaTRC() + * + * \param[in] pixd [optional] null or equal to pixs + * \param[in] pixs 8 or 32 bpp; or 2, 4 or 8 bpp with colormap + * \param[in] gamma gamma correction; must be > 0.0 + * \param[in] minval input value that gives 0 for output; can be < 0 + * \param[in] maxval input value that gives 255 for output; can be > 255 + * \return pixd always + * + * <pre> + * Notes: + * (1) pixd must either be null or equal to pixs. + * For in-place operation, set pixd == pixs: + * pixGammaTRC(pixs, pixs, ...); + * To get a new image, set pixd == null: + * pixd = pixGammaTRC(NULL, pixs, ...); + * (2) If pixs is colormapped, the colormap is transformed, + * either in-place or in a copy of pixs. + * (3) We use a gamma mapping between minval and maxval. + * (4) If gamma < 1.0, the image will appear darker; + * if gamma > 1.0, the image will appear lighter; + * (5) If gamma = 1.0 and minval = 0 and maxval = 255, no + * enhancement is performed; return a copy unless in-place, + * in which case this is a no-op. + * (6) For color images that are not colormapped, the mapping + * is applied to each component. + * (7) minval and maxval are not restricted to the interval [0, 255]. + * If minval < 0, an input value of 0 is mapped to a + * nonzero output. This will turn black to gray. + * If maxval > 255, an input value of 255 is mapped to + * an output value less than 255. This will turn + * white (e.g., in the background) to gray. + * (8) Increasing minval darkens the image. + * (9) Decreasing maxval bleaches the image. + * (10) Simultaneously increasing minval and decreasing maxval + * will darken the image and make the colors more intense; + * e.g., minval = 50, maxval = 200. + * (11) See numaGammaTRC() for further examples of use. + * (12) Use pixTRCMapGeneral() if applying different mappings + * to each channel in an RGB image. + * </pre> + */ +PIX * +pixGammaTRC(PIX *pixd, + PIX *pixs, + l_float32 gamma, + l_int32 minval, + l_int32 maxval) +{ +l_int32 d; +NUMA *nag; +PIXCMAP *cmap; + + if (!pixs) + return (PIX *)ERROR_PTR("pixs not defined", __func__, pixd); + if (pixd && (pixd != pixs)) + return (PIX *)ERROR_PTR("pixd not null or pixs", __func__, pixd); + if (gamma <= 0.0) { + L_WARNING("gamma must be > 0.0; setting to 1.0\n", __func__); + gamma = 1.0; + } + if (minval >= maxval) + return (PIX *)ERROR_PTR("minval not < maxval", __func__, pixd); + cmap = pixGetColormap(pixs); + d = pixGetDepth(pixs); + if (!cmap && d != 8 && d != 32) + return (PIX *)ERROR_PTR("depth not 8 or 32 bpp", __func__, pixd); + + if (gamma == 1.0 && minval == 0 && maxval == 255) /* no-op */ + return pixCopy(pixd, pixs); + + if (!pixd) /* start with a copy if not in-place */ + pixd = pixCopy(NULL, pixs); + + if (cmap) { + pixcmapGammaTRC(pixGetColormap(pixd), gamma, minval, maxval); + return pixd; + } + + /* pixd is 8 or 32 bpp */ + if ((nag = numaGammaTRC(gamma, minval, maxval)) == NULL) + return (PIX *)ERROR_PTR("nag not made", __func__, pixd); + pixTRCMap(pixd, NULL, nag); + numaDestroy(&nag); + + return pixd; +} + + +/*! + * \brief pixGammaTRCMasked() + * + * \param[in] pixd [optional] null or equal to pixs + * \param[in] pixs 8 or 32 bpp; not colormapped + * \param[in] pixm [optional] null or 1 bpp + * \param[in] gamma gamma correction; must be > 0.0 + * \param[in] minval input value that gives 0 for output; can be < 0 + * \param[in] maxval input value that gives 255 for output; can be > 255 + * \return pixd always + * + * <pre> + * Notes: + * (1) Same as pixGammaTRC() except mapping is optionally over + * a subset of pixels described by pixm. + * (2) Masking does not work for colormapped images. + * (3) See pixGammaTRC() for details on how to use the parameters. + * </pre> + */ +PIX * +pixGammaTRCMasked(PIX *pixd, + PIX *pixs, + PIX *pixm, + l_float32 gamma, + l_int32 minval, + l_int32 maxval) +{ +l_int32 d; +NUMA *nag; + + if (!pixm) + return pixGammaTRC(pixd, pixs, gamma, minval, maxval); + + if (!pixs) + return (PIX *)ERROR_PTR("pixs not defined", __func__, pixd); + if (pixGetColormap(pixs)) + return (PIX *)ERROR_PTR("invalid: pixs has a colormap", __func__, pixd); + if (pixd && (pixd != pixs)) + return (PIX *)ERROR_PTR("pixd not null or pixs", __func__, pixd); + d = pixGetDepth(pixs); + if (d != 8 && d != 32) + return (PIX *)ERROR_PTR("depth not 8 or 32 bpp", __func__, pixd); + if (minval >= maxval) + return (PIX *)ERROR_PTR("minval not < maxval", __func__, pixd); + if (gamma <= 0.0) { + L_WARNING("gamma must be > 0.0; setting to 1.0\n", __func__); + gamma = 1.0; + } + + if (gamma == 1.0 && minval == 0 && maxval == 255) + return pixCopy(pixd, pixs); + + if (!pixd) /* start with a copy if not in-place */ + pixd = pixCopy(NULL, pixs); + + if ((nag = numaGammaTRC(gamma, minval, maxval)) == NULL) + return (PIX *)ERROR_PTR("nag not made", __func__, pixd); + pixTRCMap(pixd, pixm, nag); + numaDestroy(&nag); + + return pixd; +} + + +/*! + * \brief pixGammaTRCWithAlpha() + * + * \param[in] pixd [optional] null or equal to pixs + * \param[in] pixs 32 bpp + * \param[in] gamma gamma correction; must be > 0.0 + * \param[in] minval input value that gives 0 for output; can be < 0 + * \param[in] maxval input value that gives 255 for output; can be > 255 + * \return pixd always + * + * <pre> + * Notes: + * (1) See usage notes in pixGammaTRC(). + * (2) This version saves the alpha channel. It is only valid + * for 32 bpp (no colormap), and is a bit slower. + * </pre> + */ +PIX * +pixGammaTRCWithAlpha(PIX *pixd, + PIX *pixs, + l_float32 gamma, + l_int32 minval, + l_int32 maxval) +{ +NUMA *nag; +PIX *pixalpha; + + if (!pixs || pixGetDepth(pixs) != 32) + return (PIX *)ERROR_PTR("pixs undefined or not 32 bpp", __func__, pixd); + if (pixd && (pixd != pixs)) + return (PIX *)ERROR_PTR("pixd not null or pixs", __func__, pixd); + if (gamma <= 0.0) { + L_WARNING("gamma must be > 0.0; setting to 1.0\n", __func__); + gamma = 1.0; + } + if (minval >= maxval) + return (PIX *)ERROR_PTR("minval not < maxval", __func__, pixd); + + if (gamma == 1.0 && minval == 0 && maxval == 255) + return pixCopy(pixd, pixs); + if (!pixd) /* start with a copy if not in-place */ + pixd = pixCopy(NULL, pixs); + + pixalpha = pixGetRGBComponent(pixs, L_ALPHA_CHANNEL); /* save */ + if ((nag = numaGammaTRC(gamma, minval, maxval)) == NULL) + return (PIX *)ERROR_PTR("nag not made", __func__, pixd); + pixTRCMap(pixd, NULL, nag); + pixSetRGBComponent(pixd, pixalpha, L_ALPHA_CHANNEL); /* restore */ + pixSetSpp(pixd, 4); + + numaDestroy(&nag); + pixDestroy(&pixalpha); + return pixd; +} + + +/*! + * \brief numaGammaTRC() + * + * \param[in] gamma gamma factor; must be > 0.0 + * \param[in] minval input value that gives 0 for output + * \param[in] maxval input value that gives 255 for output + * \return na, or NULL on error + * + * <pre> + * Notes: + * (1) The map is returned as a numa; values are clipped to [0, 255]. + * (2) For a linear mapping, set gamma = 1.0. + * (3) To force all intensities into a range within fraction delta + * of white, use: minval = -256 * (1 - delta) / delta + * maxval = 255 + * (4) To force all intensities into a range within fraction delta + * of black, use: minval = 0 + * maxval = 256 * (1 - delta) / delta + * </pre> + */ +NUMA * +numaGammaTRC(l_float32 gamma, + l_int32 minval, + l_int32 maxval) +{ +l_int32 i, val; +l_float32 x, invgamma; +NUMA *na; + + if (minval >= maxval) + return (NUMA *)ERROR_PTR("minval not < maxval", __func__, NULL); + if (gamma <= 0.0) { + L_WARNING("gamma must be > 0.0; setting to 1.0\n", __func__); + gamma = 1.0; + } + + invgamma = 1. / gamma; + na = numaCreate(256); + for (i = 0; i < minval; i++) + numaAddNumber(na, 0); + for (i = minval; i <= maxval; i++) { + if (i < 0) continue; + if (i > 255) continue; + x = (l_float32)(i - minval) / (l_float32)(maxval - minval); + val = (l_int32)(255. * powf(x, invgamma) + 0.5); + val = L_MAX(val, 0); + val = L_MIN(val, 255); + numaAddNumber(na, val); + } + for (i = maxval + 1; i < 256; i++) + numaAddNumber(na, 255); + + return na; +} + + +/*-------------------------------------------------------------* + * Contrast enhancement * + *-------------------------------------------------------------*/ +/*! + * \brief pixContrastTRC() + * + * \param[in] pixd [optional] null or equal to pixs + * \param[in] pixs 8 or 32 bpp; or 2, 4 or 8 bpp with colormap + * \param[in] factor 0.0 is no enhancement + * \return pixd always + * + * <pre> + * Notes: + * (1) pixd must either be null or equal to pixs. + * For in-place operation, set pixd == pixs: + * pixContrastTRC(pixs, pixs, ...); + * To get a new image, set pixd == null: + * pixd = pixContrastTRC(NULL, pixs, ...); + * (2) If pixs is colormapped, the colormap is transformed, + * either in-place or in a copy of pixs. + * (3) Contrast is enhanced by mapping each color component + * using an atan function with maximum slope at 127. + * Pixels below 127 are lowered in intensity and pixels + * above 127 are increased. + * (4) The useful range for the contrast factor is scaled to + * be in (0.0 to 1.0), but larger values can also be used. + * (5) If factor == 0.0, no enhancement is performed; return a copy + * unless in-place, in which case this is a no-op. + * (6) For color images that are not colormapped, the mapping + * is applied to each component. + * </pre> + */ +PIX * +pixContrastTRC(PIX *pixd, + PIX *pixs, + l_float32 factor) +{ +l_int32 d; +NUMA *nac; +PIXCMAP *cmap; + + if (!pixs) + return (PIX *)ERROR_PTR("pixs not defined", __func__, pixd); + if (pixd && (pixd != pixs)) + return (PIX *)ERROR_PTR("pixd not null or pixs", __func__, pixd); + if (factor < 0.0) { + L_WARNING("factor must be >= 0.0; using 0.0\n", __func__); + factor = 0.0; + } + if (factor == 0.0) + return pixCopy(pixd, pixs); + + cmap = pixGetColormap(pixs); + d = pixGetDepth(pixs); + if (!cmap && d != 8 && d != 32) + return (PIX *)ERROR_PTR("depth not 8 or 32 bpp", __func__, pixd); + + if (!pixd) /* start with a copy if not in-place */ + pixd = pixCopy(NULL, pixs); + + if (cmap) { + pixcmapContrastTRC(pixGetColormap(pixd), factor); + return pixd; + } + + /* pixd is 8 or 32 bpp */ + if ((nac = numaContrastTRC(factor)) == NULL) + return (PIX *)ERROR_PTR("nac not made", __func__, pixd); + pixTRCMap(pixd, NULL, nac); + numaDestroy(&nac); + + return pixd; +} + + +/*! + * \brief pixContrastTRCMasked() + * + * \param[in] pixd [optional] null or equal to pixs + * \param[in] pixs 8 or 32 bpp; or 2, 4 or 8 bpp with colormap + * \param[in] pixm [optional] null or 1 bpp + * \param[in] factor 0.0 is no enhancement + * \return pixd always + * + * <pre> + * Notes: + * (1) Same as pixContrastTRC() except mapping is optionally over + * a subset of pixels described by pixm. + * (2) Masking does not work for colormapped images. + * (3) See pixContrastTRC() for details on how to use the parameters. + * </pre> + */ +PIX * +pixContrastTRCMasked(PIX *pixd, + PIX *pixs, + PIX *pixm, + l_float32 factor) +{ +l_int32 d; +NUMA *nac; + + if (!pixm) + return pixContrastTRC(pixd, pixs, factor); + + if (!pixs) + return (PIX *)ERROR_PTR("pixs not defined", __func__, pixd); + if (pixGetColormap(pixs)) + return (PIX *)ERROR_PTR("invalid: pixs has a colormap", __func__, pixd); + if (pixd && (pixd != pixs)) + return (PIX *)ERROR_PTR("pixd not null or pixs", __func__, pixd); + d = pixGetDepth(pixs); + if (d != 8 && d != 32) + return (PIX *)ERROR_PTR("depth not 8 or 32 bpp", __func__, pixd); + + if (factor < 0.0) { + L_WARNING("factor must be >= 0.0; using 0.0\n", __func__); + factor = 0.0; + } + if (factor == 0.0) + return pixCopy(pixd, pixs); + + if (!pixd) /* start with a copy if not in-place */ + pixd = pixCopy(NULL, pixs); + + if ((nac = numaContrastTRC(factor)) == NULL) + return (PIX *)ERROR_PTR("nac not made", __func__, pixd); + pixTRCMap(pixd, pixm, nac); + numaDestroy(&nac); + + return pixd; +} + + +/*! + * \brief numaContrastTRC() + * + * \param[in] factor generally between 0.0 [no enhancement] + * and 1.0, but can be larger than 1.0 + * \return na, or NULL on error + * + * <pre> + * Notes: + * (1) The mapping is monotonic increasing, where 0 is mapped + * to 0 and 255 is mapped to 255. + * (2) As 'factor' is increased from 0.0 (where the mapping is linear), + * the map gets closer to its limit as a step function that + * jumps from 0 to 255 at the center (input value = 127). + * </pre> + */ +NUMA * +numaContrastTRC(l_float32 factor) +{ +l_int32 i, val; +l_float64 x, ymax, ymin, dely, scale; +NUMA *na; + + if (factor < 0.0) { + L_WARNING("factor must be >= 0.0; using 0.0; no enhancement\n", + __func__); + factor = 0.0; + } + if (factor == 0.0) + return numaMakeSequence(0, 1, 256); /* linear map */ + + scale = EnhanceScaleFactor; + ymax = atan((l_float64)(1.0 * factor * scale)); + ymin = atan((l_float64)(-127. * factor * scale / 128.)); + dely = ymax - ymin; + na = numaCreate(256); + for (i = 0; i < 256; i++) { + x = (l_float64)i; + val = (l_int32)((255. / dely) * + (-ymin + atan((l_float64)(factor * scale * (x - 127.) / 128.))) + + 0.5); + numaAddNumber(na, val); + } + + return na; +} + + +/*-------------------------------------------------------------* + * Histogram equalization * + *-------------------------------------------------------------*/ +/*! + * \brief pixEqualizeTRC() + * + * \param[in] pixd [optional] null or equal to pixs + * \param[in] pixs 8 bpp gray, 32 bpp rgb, or colormapped + * \param[in] fract fraction of equalization movement of pixel values + * \param[in] factor subsampling factor; integer >= 1 + * \return pixd, or NULL on error + * + * <pre> + * Notes: + * (1) pixd must either be null or equal to pixs. + * For in-place operation, set pixd == pixs: + * pixEqualizeTRC(pixs, pixs, ...); + * To get a new image, set pixd == null: + * pixd = pixEqualizeTRC(NULL, pixs, ...); + * (2) In histogram equalization, a tone reproduction curve + * mapping is used to make the number of pixels at each + * intensity equal. + * (3) If fract == 0.0, no equalization is performed; return a copy + * unless in-place, in which case this is a no-op. + * If fract == 1.0, equalization is complete. + * (4) Set the subsampling factor > 1 to reduce the amount of computation. + * (5) If pixs is colormapped, the colormap is removed and + * converted to rgb or grayscale. + * (6) If pixs has color, equalization is done in each channel + * separately. + * (7) Note that even if there is a colormap, we can get an + * in-place operation because the intermediate image pixt + * is copied back to pixs (which for in-place is the same + * as pixd). + * </pre> + */ +PIX * +pixEqualizeTRC(PIX *pixd, + PIX *pixs, + l_float32 fract, + l_int32 factor) +{ +l_int32 d; +NUMA *na; +PIX *pixt, *pix8; +PIXCMAP *cmap; + + if (!pixs) + return (PIX *)ERROR_PTR("pixs not defined", __func__, NULL); + if (pixd && (pixd != pixs)) + return (PIX *)ERROR_PTR("pixd not null or pixs", __func__, pixd); + cmap = pixGetColormap(pixs); + d = pixGetDepth(pixs); + if (d != 8 && d != 32 && !cmap) + return (PIX *)ERROR_PTR("pixs not 8/32 bpp or cmapped", __func__, NULL); + if (fract < 0.0 || fract > 1.0) + return (PIX *)ERROR_PTR("fract not in [0.0 ... 1.0]", __func__, NULL); + if (factor < 1) + return (PIX *)ERROR_PTR("sampling factor < 1", __func__, NULL); + + if (fract == 0.0) + return pixCopy(pixd, pixs); + + /* If there is a colormap, remove it. */ + if (cmap) + pixt = pixRemoveColormap(pixs, REMOVE_CMAP_BASED_ON_SRC); + else + pixt = pixClone(pixs); + + /* Make a copy if necessary */ + pixd = pixCopy(pixd, pixt); + pixDestroy(&pixt); + + d = pixGetDepth(pixd); + if (d == 8) { + na = numaEqualizeTRC(pixd, fract, factor); + pixTRCMap(pixd, NULL, na); + numaDestroy(&na); + } else { /* 32 bpp */ + pix8 = pixGetRGBComponent(pixd, COLOR_RED); + na = numaEqualizeTRC(pix8, fract, factor); + pixTRCMap(pix8, NULL, na); + pixSetRGBComponent(pixd, pix8, COLOR_RED); + numaDestroy(&na); + pixDestroy(&pix8); + pix8 = pixGetRGBComponent(pixd, COLOR_GREEN); + na = numaEqualizeTRC(pix8, fract, factor); + pixTRCMap(pix8, NULL, na); + pixSetRGBComponent(pixd, pix8, COLOR_GREEN); + numaDestroy(&na); + pixDestroy(&pix8); + pix8 = pixGetRGBComponent(pixd, COLOR_BLUE); + na = numaEqualizeTRC(pix8, fract, factor); + pixTRCMap(pix8, NULL, na); + pixSetRGBComponent(pixd, pix8, COLOR_BLUE); + numaDestroy(&na); + pixDestroy(&pix8); + } + + return pixd; +} + + +/*! + * \brief numaEqualizeTRC() + * + * \param[in] pix 8 bpp, no colormap + * \param[in] fract fraction of equalization movement of pixel values + * \param[in] factor subsampling factor; integer >= 1 + * \return nad, or NULL on error + * + * <pre> + * Notes: + * (1) If fract == 0.0, no equalization will be performed. + * If fract == 1.0, equalization is complete. + * (2) Set the subsampling factor > 1 to reduce the amount of computation. + * (3) The map is returned as a numa with 256 values, specifying + * the equalized value (array value) for every input value + * (the array index). + * </pre> + */ +NUMA * +numaEqualizeTRC(PIX *pix, + l_float32 fract, + l_int32 factor) +{ +l_int32 iin, iout, itarg; +l_float32 val, sum; +NUMA *nah, *nasum, *nad; + + if (!pix) + return (NUMA *)ERROR_PTR("pix not defined", __func__, NULL); + if (pixGetDepth(pix) != 8) + return (NUMA *)ERROR_PTR("pix not 8 bpp", __func__, NULL); + if (fract < 0.0 || fract > 1.0) + return (NUMA *)ERROR_PTR("fract not in [0.0 ... 1.0]", __func__, NULL); + if (factor < 1) + return (NUMA *)ERROR_PTR("sampling factor < 1", __func__, NULL); + + if (fract == 0.0) + L_WARNING("fract = 0.0; no equalization requested\n", __func__); + + if ((nah = pixGetGrayHistogram(pix, factor)) == NULL) + return (NUMA *)ERROR_PTR("histogram not made", __func__, NULL); + numaGetSum(nah, &sum); + nasum = numaGetPartialSums(nah); + + nad = numaCreate(256); + for (iin = 0; iin < 256; iin++) { + numaGetFValue(nasum, iin, &val); + itarg = (l_int32)(255. * val / sum + 0.5); + iout = iin + (l_int32)(fract * (itarg - iin)); + iout = L_MIN(iout, 255); /* to be safe */ + numaAddNumber(nad, iout); + } + + numaDestroy(&nah); + numaDestroy(&nasum); + return nad; +} + + +/*-------------------------------------------------------------* + * Generic TRC mapping * + *-------------------------------------------------------------*/ +/*! + * \brief pixTRCMap() + * + * \param[in] pixs 8 grayscale or 32 bpp rgb; not colormapped + * \param[in] pixm [optional] 1 bpp mask + * \param[in] na mapping array + * \return 0 if OK, 1 on error + * + * <pre> + * Notes: + * (1) This operation is in-place on pixs. + * (2) For 32 bpp, this applies the same map to each of the r,g,b + * components. + * (3) The mapping array is of size 256, and it maps the input + * index into values in the range [0, 255]. + * (4) If defined, the optional 1 bpp mask pixm has its origin + * aligned with pixs, and the map function is applied only + * to pixels in pixs under the fg of pixm. + * (5) For 32 bpp, this does not save the alpha channel. + * </pre> + */ +l_int32 +pixTRCMap(PIX *pixs, + PIX *pixm, + NUMA *na) +{ +l_int32 w, h, d, wm, hm, wpl, wplm, i, j, sval8, dval8; +l_uint32 sval32, dval32; +l_uint32 *data, *datam, *line, *linem, *tab; + + if (!pixs) + return ERROR_INT("pixs not defined", __func__, 1); + if (pixGetColormap(pixs)) + return ERROR_INT("pixs is colormapped", __func__, 1); + if (!na) + return ERROR_INT("na not defined", __func__, 1); + if (numaGetCount(na) != 256) + return ERROR_INT("na not of size 256", __func__, 1); + pixGetDimensions(pixs, &w, &h, &d); + if (d != 8 && d != 32) + return ERROR_INT("pixs not 8 or 32 bpp", __func__, 1); + if (pixm) { + if (pixGetDepth(pixm) != 1) + return ERROR_INT("pixm not 1 bpp", __func__, 1); + } + + tab = (l_uint32 *)numaGetIArray(na); /* get the array for efficiency */ + wpl = pixGetWpl(pixs); + data = pixGetData(pixs); + if (!pixm) { + if (d == 8) { + for (i = 0; i < h; i++) { + line = data + i * wpl; + for (j = 0; j < w; j++) { + sval8 = GET_DATA_BYTE(line, j); + dval8 = tab[sval8]; + SET_DATA_BYTE(line, j, dval8); + } + } + } else { /* d == 32 */ + for (i = 0; i < h; i++) { + line = data + i * wpl; + for (j = 0; j < w; j++) { + sval32 = *(line + j); + dval32 = + tab[(sval32 >> L_RED_SHIFT) & 0xff] << L_RED_SHIFT | + tab[(sval32 >> L_GREEN_SHIFT) & 0xff] << L_GREEN_SHIFT | + tab[(sval32 >> L_BLUE_SHIFT) & 0xff] << L_BLUE_SHIFT; + *(line + j) = dval32; + } + } + } + } else { + datam = pixGetData(pixm); + wplm = pixGetWpl(pixm); + pixGetDimensions(pixm, &wm, &hm, NULL); + if (d == 8) { + for (i = 0; i < h; i++) { + if (i >= hm) + break; + line = data + i * wpl; + linem = datam + i * wplm; + for (j = 0; j < w; j++) { + if (j >= wm) + break; + if (GET_DATA_BIT(linem, j) == 0) + continue; + sval8 = GET_DATA_BYTE(line, j); + dval8 = tab[sval8]; + SET_DATA_BYTE(line, j, dval8); + } + } + } else { /* d == 32 */ + for (i = 0; i < h; i++) { + if (i >= hm) + break; + line = data + i * wpl; + linem = datam + i * wplm; + for (j = 0; j < w; j++) { + if (j >= wm) + break; + if (GET_DATA_BIT(linem, j) == 0) + continue; + sval32 = *(line + j); + dval32 = + tab[(sval32 >> L_RED_SHIFT) & 0xff] << L_RED_SHIFT | + tab[(sval32 >> L_GREEN_SHIFT) & 0xff] << L_GREEN_SHIFT | + tab[(sval32 >> L_BLUE_SHIFT) & 0xff] << L_BLUE_SHIFT; + *(line + j) = dval32; + } + } + } + } + + LEPT_FREE(tab); + return 0; +} + + +/*! + * \brief pixTRCMapGeneral() + * + * \param[in] pixs 32 bpp rgb; not colormapped + * \param[in] pixm [optional] 1 bpp mask + * \param[in] nar, nag, nab mapping arrays + * \return 0 if OK, 1 on error + * + * <pre> + * Notes: + * (1) This operation is in-place on %pixs. + * (2) Each of the r,g,b mapping arrays is of size 256. They map the + * input value for that color component into values in the + * range [0, 255]. + * (3) In the special case where the r, g and b mapping arrays are + * all the same, call pixTRCMap() instead. + * (4) If defined, the optional 1 bpp mask %pixm has its origin + * aligned with %pixs, and the map function is applied only + * to pixels in %pixs under the fg of pixm. + * (5) The alpha channel is not saved. + * </pre> + */ +l_int32 +pixTRCMapGeneral(PIX *pixs, + PIX *pixm, + NUMA *nar, + NUMA *nag, + NUMA *nab) +{ +l_int32 w, h, wm, hm, wpl, wplm, i, j; +l_uint32 sval32, dval32; +l_uint32 *data, *datam, *line, *linem, *tabr, *tabg, *tabb; + + if (!pixs || pixGetDepth(pixs) != 32) + return ERROR_INT("pixs not defined or not 32 bpp", __func__, 1); + if (pixm && pixGetDepth(pixm) != 1) + return ERROR_INT("pixm defined and not 1 bpp", __func__, 1); + if (!nar || !nag || !nab) + return ERROR_INT("na{r,g,b} not all defined", __func__, 1); + if (numaGetCount(nar) != 256 || numaGetCount(nag) != 256 || + numaGetCount(nab) != 256) + return ERROR_INT("na{r,g,b} not all of size 256", __func__, 1); + + /* Get the arrays for efficiency */ + tabr = (l_uint32 *)numaGetIArray(nar); + tabg = (l_uint32 *)numaGetIArray(nag); + tabb = (l_uint32 *)numaGetIArray(nab); + pixGetDimensions(pixs, &w, &h, NULL); + wpl = pixGetWpl(pixs); + data = pixGetData(pixs); + if (!pixm) { + for (i = 0; i < h; i++) { + line = data + i * wpl; + for (j = 0; j < w; j++) { + sval32 = *(line + j); + dval32 = + tabr[(sval32 >> L_RED_SHIFT) & 0xff] << L_RED_SHIFT | + tabg[(sval32 >> L_GREEN_SHIFT) & 0xff] << L_GREEN_SHIFT | + tabb[(sval32 >> L_BLUE_SHIFT) & 0xff] << L_BLUE_SHIFT; + *(line + j) = dval32; + } + } + } else { + datam = pixGetData(pixm); + wplm = pixGetWpl(pixm); + pixGetDimensions(pixm, &wm, &hm, NULL); + for (i = 0; i < h; i++) { + if (i >= hm) + break; + line = data + i * wpl; + linem = datam + i * wplm; + for (j = 0; j < w; j++) { + if (j >= wm) + break; + if (GET_DATA_BIT(linem, j) == 0) + continue; + sval32 = *(line + j); + dval32 = + tabr[(sval32 >> L_RED_SHIFT) & 0xff] << L_RED_SHIFT | + tabg[(sval32 >> L_GREEN_SHIFT) & 0xff] << L_GREEN_SHIFT | + tabb[(sval32 >> L_BLUE_SHIFT) & 0xff] << L_BLUE_SHIFT; + *(line + j) = dval32; + } + } + } + + LEPT_FREE(tabr); + LEPT_FREE(tabg); + LEPT_FREE(tabb); + return 0; +} + + + +/*-----------------------------------------------------------------------* + * Unsharp masking * + *-----------------------------------------------------------------------*/ +/*! + * \brief pixUnsharpMasking() + * + * \param[in] pixs all depths except 1 bpp; with or without colormaps + * \param[in] halfwidth "half-width" of smoothing filter + * \param[in] fract fraction of edge added back into image + * \return pixd, or NULL on error + * + * <pre> + * Notes: + * (1) We use symmetric smoothing filters of odd dimension, + * typically use sizes of 3, 5, 7, etc. The %halfwidth parameter + * for these is (size - 1)/2; i.e., 1, 2, 3, etc. + * (2) The fract parameter is typically taken in the + * range: 0.2 < fract < 0.7 + * (3) Returns a clone if no sharpening is requested. + * </pre> + */ +PIX * +pixUnsharpMasking(PIX *pixs, + l_int32 halfwidth, + l_float32 fract) +{ +l_int32 d; +PIX *pix1, *pixd, *pixr, *pixrs, *pixg, *pixgs, *pixb, *pixbs; + + if (!pixs || (pixGetDepth(pixs) == 1)) + return (PIX *)ERROR_PTR("pixs not defined or 1 bpp", __func__, NULL); + if (fract <= 0.0 || halfwidth <= 0) { + L_WARNING("no sharpening requested; clone returned\n", __func__); + return pixClone(pixs); + } + + if (halfwidth == 1 || halfwidth == 2) + return pixUnsharpMaskingFast(pixs, halfwidth, fract, L_BOTH_DIRECTIONS); + + /* Remove colormap; clone if possible; result is either 8 or 32 bpp */ + if ((pix1 = pixConvertTo8Or32(pixs, L_CLONE, 0)) == NULL) + return (PIX *)ERROR_PTR("pix1 not made", __func__, NULL); + + /* Sharpen */ + d = pixGetDepth(pix1); + if (d == 8) { + pixd = pixUnsharpMaskingGray(pix1, halfwidth, fract); + } else { /* d == 32 */ + pixr = pixGetRGBComponent(pix1, COLOR_RED); + pixrs = pixUnsharpMaskingGray(pixr, halfwidth, fract); + pixDestroy(&pixr); + pixg = pixGetRGBComponent(pix1, COLOR_GREEN); + pixgs = pixUnsharpMaskingGray(pixg, halfwidth, fract); + pixDestroy(&pixg); + pixb = pixGetRGBComponent(pix1, COLOR_BLUE); + pixbs = pixUnsharpMaskingGray(pixb, halfwidth, fract); + pixDestroy(&pixb); + pixd = pixCreateRGBImage(pixrs, pixgs, pixbs); + pixDestroy(&pixrs); + pixDestroy(&pixgs); + pixDestroy(&pixbs); + if (pixGetSpp(pixs) == 4) + pixCopyRGBComponent(pixd, pixs, L_ALPHA_CHANNEL); + } + + pixDestroy(&pix1); + return pixd; +} + + +/*! + * \brief pixUnsharpMaskingGray() + * + * \param[in] pixs 8 bpp; no colormap + * \param[in] halfwidth "half-width" of smoothing filter + * \param[in] fract fraction of edge added back into image + * \return pixd, or NULL on error + * + * <pre> + * Notes: + * (1) We use symmetric smoothing filters of odd dimension, + * typically use sizes of 3, 5, 7, etc. The %halfwidth parameter + * for these is (size - 1)/2; i.e., 1, 2, 3, etc. + * (2) The fract parameter is typically taken in the range: + * 0.2 < fract < 0.7 + * (3) Returns a clone if no sharpening is requested. + * </pre> + */ +PIX * +pixUnsharpMaskingGray(PIX *pixs, + l_int32 halfwidth, + l_float32 fract) +{ +l_int32 w, h, d; +PIX *pixc, *pixd; +PIXACC *pixacc; + + if (!pixs) + return (PIX *)ERROR_PTR("pixs not defined", __func__, NULL); + pixGetDimensions(pixs, &w, &h, &d); + if (d != 8 || pixGetColormap(pixs) != NULL) + return (PIX *)ERROR_PTR("pixs not 8 bpp or has cmap", __func__, NULL); + if (fract <= 0.0 || halfwidth <= 0) { + L_WARNING("no sharpening requested; clone returned\n", __func__); + return pixClone(pixs); + } + if (halfwidth == 1 || halfwidth == 2) + return pixUnsharpMaskingGrayFast(pixs, halfwidth, fract, + L_BOTH_DIRECTIONS); + + if ((pixc = pixBlockconvGray(pixs, NULL, halfwidth, halfwidth)) == NULL) + return (PIX *)ERROR_PTR("pixc not made", __func__, NULL); + + /* Steps: + * (1) edge image is pixs - pixc (this is highpass part) + * (2) multiply edge image by fract + * (3) add fraction of edge to pixs + * + * To show how this is done with both interfaces to arithmetic + * on integer Pix, here is the implementation in the lower-level + * function calls: + * pixt = pixInitAccumulate(w, h, 0x10000000)) == NULL) + * pixAccumulate(pixt, pixs, L_ARITH_ADD); + * pixAccumulate(pixt, pixc, L_ARITH_SUBTRACT); + * pixMultConstAccumulate(pixt, fract, 0x10000000); + * pixAccumulate(pixt, pixs, L_ARITH_ADD); + * pixd = pixFinalAccumulate(pixt, 0x10000000, 8)) == NULL) + * pixDestroy(&pixt); + * + * The code below does the same thing using the Pixacc accumulator, + * hiding the details of the offset that is needed for subtraction. + */ + pixacc = pixaccCreate(w, h, 1); + pixaccAdd(pixacc, pixs); + pixaccSubtract(pixacc, pixc); + pixaccMultConst(pixacc, fract); + pixaccAdd(pixacc, pixs); + pixd = pixaccFinal(pixacc, 8); + pixaccDestroy(&pixacc); + + pixDestroy(&pixc); + return pixd; +} + + +/*! + * \brief pixUnsharpMaskingFast() + * + * \param[in] pixs all depths except 1 bpp; with or without colormaps + * \param[in] halfwidth "half-width" of smoothing filter; 1 and 2 only + * \param[in] fract fraction of high frequency added to image + * \param[in] direction L_HORIZ, L_VERT, L_BOTH_DIRECTIONS + * \return pixd, or NULL on error + * + * <pre> + * Notes: + * (1) The fast version uses separable 1-D filters directly on + * the input image. The halfwidth is either 1 (full width = 3) + * or 2 (full width = 5). + * (2) The fract parameter is typically taken in the + * range: 0.2 < fract < 0.7 + * (3) To skip horizontal sharpening, use %fracth = 0.0; ditto for %fractv + * (4) For one dimensional filtering (as an example): + * For %halfwidth = 1, the low-pass filter is + * L: 1/3 1/3 1/3 + * and the high-pass filter is + * H = I - L: -1/3 2/3 -1/3 + * For %halfwidth = 2, the low-pass filter is + * L: 1/5 1/5 1/5 1/5 1/5 + * and the high-pass filter is + * H = I - L: -1/5 -1/5 4/5 -1/5 -1/5 + * The new sharpened pixel value is found by adding some fraction + * of the high-pass filter value (which sums to 0) to the + * initial pixel value: + * N = I + fract * H + * (5) For 2D, the sharpening filter is not separable, because the + * vertical filter depends on the horizontal location relative + * to the filter origin, and v.v. So we either do the full + * 2D filter (for %halfwidth == 1) or do the low-pass + * convolution separably and then compose with the original pix. + * (6) Returns a clone if no sharpening is requested. + * </pre> + */ +PIX * +pixUnsharpMaskingFast(PIX *pixs, + l_int32 halfwidth, + l_float32 fract, + l_int32 direction) +{ +l_int32 d; +PIX *pixt, *pixd, *pixr, *pixrs, *pixg, *pixgs, *pixb, *pixbs; + + if (!pixs || (pixGetDepth(pixs) == 1)) + return (PIX *)ERROR_PTR("pixs not defined or 1 bpp", __func__, NULL); + if (fract <= 0.0 || halfwidth <= 0) { + L_WARNING("no sharpening requested; clone returned\n", __func__); + return pixClone(pixs); + } + if (halfwidth != 1 && halfwidth != 2) + return (PIX *)ERROR_PTR("halfwidth must be 1 or 2", __func__, NULL); + if (direction != L_HORIZ && direction != L_VERT && + direction != L_BOTH_DIRECTIONS) + return (PIX *)ERROR_PTR("invalid direction", __func__, NULL); + + /* Remove colormap; clone if possible; result is either 8 or 32 bpp */ + if ((pixt = pixConvertTo8Or32(pixs, L_CLONE, 0)) == NULL) + return (PIX *)ERROR_PTR("pixt not made", __func__, NULL); + + /* Sharpen */ + d = pixGetDepth(pixt); + if (d == 8) { + pixd = pixUnsharpMaskingGrayFast(pixt, halfwidth, fract, direction); + } else { /* d == 32 */ + pixr = pixGetRGBComponent(pixs, COLOR_RED); + pixrs = pixUnsharpMaskingGrayFast(pixr, halfwidth, fract, direction); + pixDestroy(&pixr); + pixg = pixGetRGBComponent(pixs, COLOR_GREEN); + pixgs = pixUnsharpMaskingGrayFast(pixg, halfwidth, fract, direction); + pixDestroy(&pixg); + pixb = pixGetRGBComponent(pixs, COLOR_BLUE); + pixbs = pixUnsharpMaskingGrayFast(pixb, halfwidth, fract, direction); + pixDestroy(&pixb); + pixd = pixCreateRGBImage(pixrs, pixgs, pixbs); + if (pixGetSpp(pixs) == 4) + pixCopyRGBComponent(pixd, pixs, L_ALPHA_CHANNEL); + pixDestroy(&pixrs); + pixDestroy(&pixgs); + pixDestroy(&pixbs); + } + + pixDestroy(&pixt); + return pixd; +} + + + +/*! + * \brief pixUnsharpMaskingGrayFast() + * + * \param[in] pixs 8 bpp; no colormap + * \param[in] halfwidth "half-width" of smoothing filter: 1 or 2 + * \param[in] fract fraction of high frequency added to image + * \param[in] direction L_HORIZ, L_VERT, L_BOTH_DIRECTIONS + * \return pixd, or NULL on error + * + * <pre> + * Notes: + * (1) For usage and explanation of the algorithm, see notes + * in pixUnsharpMaskingFast(). + * (2) Returns a clone if no sharpening is requested. + * </pre> + */ +PIX * +pixUnsharpMaskingGrayFast(PIX *pixs, + l_int32 halfwidth, + l_float32 fract, + l_int32 direction) +{ +PIX *pixd; + + if (!pixs) + return (PIX *)ERROR_PTR("pixs not defined", __func__, NULL); + if (pixGetDepth(pixs) != 8 || pixGetColormap(pixs) != NULL) + return (PIX *)ERROR_PTR("pixs not 8 bpp or has cmap", __func__, NULL); + if (fract <= 0.0 || halfwidth <= 0) { + L_WARNING("no sharpening requested; clone returned\n", __func__); + return pixClone(pixs); + } + if (halfwidth != 1 && halfwidth != 2) + return (PIX *)ERROR_PTR("halfwidth must be 1 or 2", __func__, NULL); + if (direction != L_HORIZ && direction != L_VERT && + direction != L_BOTH_DIRECTIONS) + return (PIX *)ERROR_PTR("invalid direction", __func__, NULL); + + if (direction != L_BOTH_DIRECTIONS) + pixd = pixUnsharpMaskingGray1D(pixs, halfwidth, fract, direction); + else /* 2D sharpening */ + pixd = pixUnsharpMaskingGray2D(pixs, halfwidth, fract); + + return pixd; +} + + +/*! + * \brief pixUnsharpMaskingGray1D() + * + * \param[in] pixs 8 bpp; no colormap + * \param[in] halfwidth "half-width" of smoothing filter: 1 or 2 + * \param[in] fract fraction of high frequency added to image + * \param[in] direction filtering direction; use L_HORIZ or L_VERT + * \return pixd, or NULL on error + * + * <pre> + * Notes: + * (1) For usage and explanation of the algorithm, see notes + * in pixUnsharpMaskingFast(). + * (2) Returns a clone if no sharpening is requested. + * </pre> + */ +PIX * +pixUnsharpMaskingGray1D(PIX *pixs, + l_int32 halfwidth, + l_float32 fract, + l_int32 direction) +{ +l_int32 w, h, d, wpls, wpld, i, j, ival; +l_uint32 *datas, *datad; +l_uint32 *lines, *lines0, *lines1, *lines2, *lines3, *lines4, *lined; +l_float32 val, a[5]; +PIX *pixd; + + if (!pixs) + return (PIX *)ERROR_PTR("pixs not defined", __func__, NULL); + pixGetDimensions(pixs, &w, &h, &d); + if (d != 8 || pixGetColormap(pixs) != NULL) + return (PIX *)ERROR_PTR("pixs not 8 bpp or has cmap", __func__, NULL); + if (fract <= 0.0 || halfwidth <= 0) { + L_WARNING("no sharpening requested; clone returned\n", __func__); + return pixClone(pixs); + } + if (halfwidth != 1 && halfwidth != 2) + return (PIX *)ERROR_PTR("halfwidth must be 1 or 2", __func__, NULL); + + /* Initialize pixd with pixels from pixs that will not be + * set when computing the sharpened values. */ + pixd = pixCopyBorder(NULL, pixs, halfwidth, halfwidth, + halfwidth, halfwidth); + datas = pixGetData(pixs); + datad = pixGetData(pixd); + wpls = pixGetWpl(pixs); + wpld = pixGetWpl(pixd); + + if (halfwidth == 1) { + a[0] = -fract / 3.0; + a[1] = 1.0 + fract * 2.0 / 3.0; + a[2] = a[0]; + } else { /* halfwidth == 2 */ + a[0] = -fract / 5.0; + a[1] = a[0]; + a[2] = 1.0 + fract * 4.0 / 5.0; + a[3] = a[0]; + a[4] = a[0]; + } + + if (direction == L_HORIZ) { + for (i = 0; i < h; i++) { + lines = datas + i * wpls; + lined = datad + i * wpld; + if (halfwidth == 1) { + for (j = 1; j < w - 1; j++) { + val = a[0] * GET_DATA_BYTE(lines, j - 1) + + a[1] * GET_DATA_BYTE(lines, j) + + a[2] * GET_DATA_BYTE(lines, j + 1); + ival = (l_int32)val; + ival = L_MAX(0, ival); + ival = L_MIN(255, ival); + SET_DATA_BYTE(lined, j, ival); + } + } else { /* halfwidth == 2 */ + for (j = 2; j < w - 2; j++) { + val = a[0] * GET_DATA_BYTE(lines, j - 2) + + a[1] * GET_DATA_BYTE(lines, j - 1) + + a[2] * GET_DATA_BYTE(lines, j) + + a[3] * GET_DATA_BYTE(lines, j + 1) + + a[4] * GET_DATA_BYTE(lines, j + 2); + ival = (l_int32)val; + ival = L_MAX(0, ival); + ival = L_MIN(255, ival); + SET_DATA_BYTE(lined, j, ival); + } + } + } + } else { /* direction == L_VERT */ + if (halfwidth == 1) { + for (i = 1; i < h - 1; i++) { + lines0 = datas + (i - 1) * wpls; + lines1 = datas + i * wpls; + lines2 = datas + (i + 1) * wpls; + lined = datad + i * wpld; + for (j = 0; j < w; j++) { + val = a[0] * GET_DATA_BYTE(lines0, j) + + a[1] * GET_DATA_BYTE(lines1, j) + + a[2] * GET_DATA_BYTE(lines2, j); + ival = (l_int32)val; + ival = L_MAX(0, ival); + ival = L_MIN(255, ival); + SET_DATA_BYTE(lined, j, ival); + } + } + } else { /* halfwidth == 2 */ + for (i = 2; i < h - 2; i++) { + lines0 = datas + (i - 2) * wpls; + lines1 = datas + (i - 1) * wpls; + lines2 = datas + i * wpls; + lines3 = datas + (i + 1) * wpls; + lines4 = datas + (i + 2) * wpls; + lined = datad + i * wpld; + for (j = 0; j < w; j++) { + val = a[0] * GET_DATA_BYTE(lines0, j) + + a[1] * GET_DATA_BYTE(lines1, j) + + a[2] * GET_DATA_BYTE(lines2, j) + + a[3] * GET_DATA_BYTE(lines3, j) + + a[4] * GET_DATA_BYTE(lines4, j); + ival = (l_int32)val; + ival = L_MAX(0, ival); + ival = L_MIN(255, ival); + SET_DATA_BYTE(lined, j, ival); + } + } + } + } + + return pixd; +} + + +/*! + * \brief pixUnsharpMaskingGray2D() + * + * \param[in] pixs 8 bpp; no colormap + * \param[in] halfwidth "half-width" of smoothing filter: 1 or 2 + * \param[in] fract fraction of high frequency added to image + * \return pixd, or NULL on error + * + * <pre> + * Notes: + * (1) This is for %halfwidth == 1, 2. + * (2) The lowpass filter is implemented separably. + * (3) Returns a clone if no sharpening is requested. + * </pre> + */ +PIX * +pixUnsharpMaskingGray2D(PIX *pixs, + l_int32 halfwidth, + l_float32 fract) +{ +l_int32 w, h, d, wpls, wpld, wplf, i, j, ival, sval; +l_uint32 *datas, *datad, *lines, *lined; +l_float32 val, norm; +l_float32 *dataf, *linef, *linef0, *linef1, *linef2, *linef3, *linef4; +PIX *pixd; +FPIX *fpix; + + if (!pixs) + return (PIX *)ERROR_PTR("pixs not defined", __func__, NULL); + pixGetDimensions(pixs, &w, &h, &d); + if (d != 8 || pixGetColormap(pixs) != NULL) + return (PIX *)ERROR_PTR("pixs not 8 bpp or has cmap", __func__, NULL); + if (fract <= 0.0 || halfwidth <= 0) { + L_WARNING("no sharpening requested; clone returned\n", __func__); + return pixClone(pixs); + } + if (halfwidth != 1 && halfwidth != 2) + return (PIX *)ERROR_PTR("halfwidth must be 1 or 2", __func__, NULL); + + if ((pixd = pixCopyBorder(NULL, pixs, halfwidth, halfwidth, + halfwidth, halfwidth)) == NULL) + return (PIX *)ERROR_PTR("pixd not made", __func__, NULL); + datad = pixGetData(pixd); + wpld = pixGetWpl(pixd); + datas = pixGetData(pixs); + wpls = pixGetWpl(pixs); + + /* Do the low pass separably. Store the result of horizontal + * smoothing in an intermediate fpix. */ + if ((fpix = fpixCreate(w, h)) == NULL) { + pixDestroy(&pixd); + return (PIX *)ERROR_PTR("fpix not made", __func__, NULL); + } + dataf = fpixGetData(fpix); + wplf = fpixGetWpl(fpix); + if (halfwidth == 1) { + for (i = 0; i < h; i++) { + lines = datas + i * wpls; + linef = dataf + i * wplf; + for (j = 1; j < w - 1; j++) { + val = GET_DATA_BYTE(lines, j - 1) + + GET_DATA_BYTE(lines, j) + + GET_DATA_BYTE(lines, j + 1); + linef[j] = val; + } + } + } else { + for (i = 0; i < h; i++) { + lines = datas + i * wpls; + linef = dataf + i * wplf; + for (j = 2; j < w - 2; j++) { + val = GET_DATA_BYTE(lines, j - 2) + + GET_DATA_BYTE(lines, j - 1) + + GET_DATA_BYTE(lines, j) + + GET_DATA_BYTE(lines, j + 1) + + GET_DATA_BYTE(lines, j + 2); + linef[j] = val; + } + } + } + + /* Do vertical smoothing to finish the low-pass filter. + * At each pixel, if L is the lowpass value, I is the + * src pixel value and f is the fraction of highpass to + * be added to I, then the highpass filter value is + * H = I - L + * and the new sharpened value is + * N = I + f * H. */ + if (halfwidth == 1) { + for (i = 1; i < h - 1; i++) { + linef0 = dataf + (i - 1) * wplf; + linef1 = dataf + i * wplf; + linef2 = dataf + (i + 1) * wplf; + lined = datad + i * wpld; + lines = datas + i * wpls; + norm = 1.0f / 9.0f; + for (j = 1; j < w - 1; j++) { + val = norm * (linef0[j] + linef1[j] + + linef2[j]); /* L: lowpass filter value */ + sval = GET_DATA_BYTE(lines, j); /* I: source pixel */ + ival = (l_int32)(sval + fract * (sval - val) + 0.5); + ival = L_MAX(0, ival); + ival = L_MIN(255, ival); + SET_DATA_BYTE(lined, j, ival); + } + } + } else { + for (i = 2; i < h - 2; i++) { + linef0 = dataf + (i - 2) * wplf; + linef1 = dataf + (i - 1) * wplf; + linef2 = dataf + i * wplf; + linef3 = dataf + (i + 1) * wplf; + linef4 = dataf + (i + 2) * wplf; + lined = datad + i * wpld; + lines = datas + i * wpls; + norm = 1.0f / 25.0f; + for (j = 2; j < w - 2; j++) { + val = norm * (linef0[j] + linef1[j] + linef2[j] + linef3[j] + + linef4[j]); /* L: lowpass filter value */ + sval = GET_DATA_BYTE(lines, j); /* I: source pixel */ + ival = (l_int32)(sval + fract * (sval - val) + 0.5); + ival = L_MAX(0, ival); + ival = L_MIN(255, ival); + SET_DATA_BYTE(lined, j, ival); + } + } + } + + fpixDestroy(&fpix); + return pixd; +} + + +/*-----------------------------------------------------------------------* + * Hue and saturation modification * + *-----------------------------------------------------------------------*/ +/*! + * \brief pixModifyHue() + * + * \param[in] pixd [optional] can be null or equal to pixs + * \param[in] pixs 32 bpp rgb + * \param[in] fract between -1.0 and 1.0 + * \return pixd, or NULL on error + * + * <pre> + * Notes: + * (1) pixd must either be null or equal to pixs. + * For in-place operation, set pixd == pixs: + * pixEqualizeTRC(pixs, pixs, ...); + * To get a new image, set pixd == null: + * pixd = pixEqualizeTRC(NULL, pixs, ...); + * (2) Use fract > 0.0 to increase hue value; < 0.0 to decrease it. + * 1.0 (or -1.0) represents a 360 degree rotation; i.e., no change. + * (3) If no modification is requested (fract = -1.0 or 0 or 1.0), + * return a copy unless in-place, in which case this is a no-op. + * (4) This leaves saturation and intensity invariant. + * (5) See discussion of color-modification methods, in coloring.c. + * </pre> + */ +PIX * +pixModifyHue(PIX *pixd, + PIX *pixs, + l_float32 fract) +{ +l_int32 w, h, d, i, j, wpl, delhue; +l_int32 rval, gval, bval, hval, sval, vval; +l_uint32 *data, *line; + + if (!pixs) + return (PIX *)ERROR_PTR("pixs not defined", __func__, NULL); + if (pixGetColormap(pixs) != NULL) + return (PIX *)ERROR_PTR("pixs colormapped", __func__, NULL); + if (pixd && (pixd != pixs)) + return (PIX *)ERROR_PTR("pixd not null or pixs", __func__, pixd); + pixGetDimensions(pixs, &w, &h, &d); + if (d != 32) + return (PIX *)ERROR_PTR("pixs not 32 bpp", __func__, NULL); + if (L_ABS(fract) > 1.0) + return (PIX *)ERROR_PTR("fract not in [-1.0 ... 1.0]", __func__, NULL); + + pixd = pixCopy(pixd, pixs); + + delhue = (l_int32)(240 * fract); + if (delhue == 0 || delhue == 240 || delhue == -240) { + L_WARNING("no change requested in hue\n", __func__); + return pixd; + } + if (delhue < 0) + delhue += 240; + + data = pixGetData(pixd); + wpl = pixGetWpl(pixd); + for (i = 0; i < h; i++) { + line = data + i * wpl; + for (j = 0; j < w; j++) { + extractRGBValues(line[j], &rval, &gval, &bval); + convertRGBToHSV(rval, gval, bval, &hval, &sval, &vval); + hval = (hval + delhue) % 240; + convertHSVToRGB(hval, sval, vval, &rval, &gval, &bval); + composeRGBPixel(rval, gval, bval, line + j); + } + } + if (pixGetSpp(pixs) == 4) + pixCopyRGBComponent(pixd, pixs, L_ALPHA_CHANNEL); + + return pixd; +} + + +/*! + * \brief pixModifySaturation() + * + * \param[in] pixd [optional] can be null, existing or equal to pixs + * \param[in] pixs 32 bpp rgb + * \param[in] fract between -1.0 and 1.0 + * \return pixd, or NULL on error + * + * <pre> + * Notes: + * (1) If fract > 0.0, it gives the fraction that the pixel + * saturation is moved from its initial value toward 255. + * If fract < 0.0, it gives the fraction that the pixel + * saturation is moved from its initial value toward 0. + * The limiting values for fract = -1.0 (1.0) thus set the + * saturation to 0 (255). + * (2) If fract = 0, no modification is requested; return a copy + * unless in-place, in which case this is a no-op. + * (3) This leaves hue and intensity invariant. + * (4) See discussion of color-modification methods, in coloring.c. + * </pre> + */ +PIX * +pixModifySaturation(PIX *pixd, + PIX *pixs, + l_float32 fract) +{ +l_int32 w, h, d, i, j, wpl; +l_int32 rval, gval, bval, hval, sval, vval; +l_uint32 *data, *line; + + if (!pixs) + return (PIX *)ERROR_PTR("pixs not defined", __func__, NULL); + pixGetDimensions(pixs, &w, &h, &d); + if (d != 32) + return (PIX *)ERROR_PTR("pixs not 32 bpp", __func__, NULL); + if (L_ABS(fract) > 1.0) + return (PIX *)ERROR_PTR("fract not in [-1.0 ... 1.0]", __func__, NULL); + + pixd = pixCopy(pixd, pixs); + if (fract == 0.0) { + L_WARNING("no change requested in saturation\n", __func__); + return pixd; + } + + data = pixGetData(pixd); + wpl = pixGetWpl(pixd); + for (i = 0; i < h; i++) { + line = data + i * wpl; + for (j = 0; j < w; j++) { + extractRGBValues(line[j], &rval, &gval, &bval); + convertRGBToHSV(rval, gval, bval, &hval, &sval, &vval); + if (fract < 0.0) + sval = (l_int32)(sval * (1.0 + fract)); + else + sval = (l_int32)(sval + fract * (255 - sval)); + convertHSVToRGB(hval, sval, vval, &rval, &gval, &bval); + composeRGBPixel(rval, gval, bval, line + j); + } + } + if (pixGetSpp(pixs) == 4) + pixCopyRGBComponent(pixd, pixs, L_ALPHA_CHANNEL); + + return pixd; +} + + +/*! + * \brief pixMeasureSaturation() + * + * \param[in] pixs 32 bpp rgb + * \param[in] factor subsampling factor; integer >= 1 + * \param[out] psat average saturation + * \return 0 if OK, 1 on error + */ +l_int32 +pixMeasureSaturation(PIX *pixs, + l_int32 factor, + l_float32 *psat) +{ +l_int32 w, h, d, i, j, wpl, sum, count; +l_int32 rval, gval, bval, hval, sval, vval; +l_uint32 *data, *line; + + if (!psat) + return ERROR_INT("pixs not defined", __func__, 1); + *psat = 0.0; + if (!pixs) + return ERROR_INT("pixs not defined", __func__, 1); + pixGetDimensions(pixs, &w, &h, &d); + if (d != 32) + return ERROR_INT("pixs not 32 bpp", __func__, 1); + if (factor < 1) + return ERROR_INT("subsampling factor < 1", __func__, 1); + + data = pixGetData(pixs); + wpl = pixGetWpl(pixs); + for (i = 0, sum = 0, count = 0; i < h; i += factor) { + line = data + i * wpl; + for (j = 0; j < w; j += factor) { + extractRGBValues(line[j], &rval, &gval, &bval); + convertRGBToHSV(rval, gval, bval, &hval, &sval, &vval); + sum += sval; + count++; + } + } + + if (count > 0) + *psat = (l_float32)sum / (l_float32)count; + return 0; +} + + +/*! + * \brief pixModifyBrightness() + * + * \param[in] pixd [optional] can be null, existing or equal to pixs + * \param[in] pixs 32 bpp rgb + * \param[in] fract between -1.0 and 1.0 + * \return pixd, or NULL on error + * + * <pre> + * Notes: + * (1) If fract > 0.0, it gives the fraction that the v-parameter, + * which is max(r,g,b), is moved from its initial value toward 255. + * If fract < 0.0, it gives the fraction that the v-parameter + * is moved from its initial value toward 0. + * The limiting values for fract = -1.0 (1.0) thus set the + * v-parameter to 0 (255). + * (2) If fract = 0, no modification is requested; return a copy + * unless in-place, in which case this is a no-op. + * (3) This leaves hue and saturation invariant. + * (4) See discussion of color-modification methods, in coloring.c. + * </pre> + */ +PIX * +pixModifyBrightness(PIX *pixd, + PIX *pixs, + l_float32 fract) +{ +l_int32 w, h, d, i, j, wpl; +l_int32 rval, gval, bval, hval, sval, vval; +l_uint32 *data, *line; + + if (!pixs) + return (PIX *)ERROR_PTR("pixs not defined", __func__, NULL); + pixGetDimensions(pixs, &w, &h, &d); + if (d != 32) + return (PIX *)ERROR_PTR("pixs not 32 bpp", __func__, NULL); + if (L_ABS(fract) > 1.0) + return (PIX *)ERROR_PTR("fract not in [-1.0 ... 1.0]", __func__, NULL); + + pixd = pixCopy(pixd, pixs); + if (fract == 0.0) { + L_WARNING("no change requested in brightness\n", __func__); + return pixd; + } + + data = pixGetData(pixd); + wpl = pixGetWpl(pixd); + for (i = 0; i < h; i++) { + line = data + i * wpl; + for (j = 0; j < w; j++) { + extractRGBValues(line[j], &rval, &gval, &bval); + convertRGBToHSV(rval, gval, bval, &hval, &sval, &vval); + if (fract > 0.0) + vval = (l_int32)(vval + fract * (255.0 - vval)); + else + vval = (l_int32)(vval * (1.0 + fract)); + convertHSVToRGB(hval, sval, vval, &rval, &gval, &bval); + composeRGBPixel(rval, gval, bval, line + j); + } + } + if (pixGetSpp(pixs) == 4) + pixCopyRGBComponent(pixd, pixs, L_ALPHA_CHANNEL); + + return pixd; +} + + +/*-----------------------------------------------------------------------* + * Color shifting * + *-----------------------------------------------------------------------*/ +/*! + * \brief pixMosaicColorShiftRGB() + * + * \param[in] pixs 32 bpp rgb + * \param[in] roff center offset of red component + * \param[in] goff center offset of green component + * \param[in] boff center offset of blue component + * \param[in] delta increments from center offsets [0.0 - 0.1]; + * use 0.0 to get the default (0.04) + * \param[in] nincr number of increments in each (positive and negative) + * direction; use 0 to get the default (2). + * \return pix, or NULL on error + * + * <pre> + * Notes: + * (1) This generates a mosaic view of the effect of shifting the RGB + * components. See pixColorShiftRGB() for details on the shifting. + * (2) The offsets (%roff, %goff, %boff) set the color center point, + * and the deviations from this are shown separately for deltas + * in r, g and b. For each component, we show 2 * %nincr + 1 + * images. + * (3) The pix must have minimum dimensions of 100 and an aspect + * ratio not exceeding 5.0. + * (4) Usage: color prints differ from the original due to three factors: + * illumination, calibration of the camera in acquisition, + * and calibration of the printer. This function can be used + * to iteratively match a color print to the original. On each + * iteration, the center offsets are set to the best match so + * far, and the %delta increments are typically reduced. + * </pre> + */ +PIX * +pixMosaicColorShiftRGB(PIX *pixs, + l_float32 roff, + l_float32 goff, + l_float32 boff, + l_float32 delta, + l_int32 nincr) +{ +char buf[64]; +l_int32 i, w, h; +l_float32 del, ratio; +L_BMF *bmf; +PIX *pix1, *pix2, *pix3; +PIXA *pixa; + + if (!pixs || pixGetDepth(pixs) != 32) + return (PIX *)ERROR_PTR("pixs undefined or not rgb", __func__, NULL); + if (roff < -1.0 || roff > 1.0) + return (PIX *)ERROR_PTR("roff not in [-1.0, 1.0]", __func__, NULL); + if (goff < -1.0 || goff > 1.0) + return (PIX *)ERROR_PTR("goff not in [-1.0, 1.0]", __func__, NULL); + if (boff < -1.0 || boff > 1.0) + return (PIX *)ERROR_PTR("boff not in [-1.0, 1.0]", __func__, NULL); + if (delta < 0.0 || delta > 0.1) + return (PIX *)ERROR_PTR("delta not in [0.0, 0.1]", __func__, NULL); + if (delta == 0.0) delta = 0.04f; + if (nincr < 0 || nincr > 6) + return (PIX *)ERROR_PTR("nincr not in [0, 6]", __func__, NULL); + if (nincr == 0) nincr = 2; + + /* Require width and height to be >= 100, and the aspect ratio <= 5.0 */ + pixGetDimensions(pixs, &w, &h, NULL); + if (w < 100 || h < 100) + return (PIX *)ERROR_PTR("w and h not both >= 100", __func__, NULL); + pixMaxAspectRatio(pixs, &ratio); + if (ratio < 1.0 || ratio > 5.0) { + L_ERROR("invalid aspect ratio %5.1f\n", __func__, ratio); + return NULL; + } + + pixa = pixaCreate(3 * (2 * nincr + 1)); + bmf = bmfCreate(NULL, 8); + pix1 = pixScaleToSize(pixs, 400, 0); + for (i = 0, del = - nincr * delta; i < 2 * nincr + 1; i++, del += delta) { + pix2 = pixColorShiftRGB(pix1, roff + del, goff, boff); + snprintf(buf, sizeof(buf), "%4.2f, %4.2f, %4.2f", + roff + del, goff, boff); + pix3 = pixAddSingleTextblock(pix2, bmf, buf, 0xff000000, + L_ADD_BELOW, 0); + pixaAddPix(pixa, pix3, L_INSERT); + pixDestroy(&pix2); + } + for (i = 0, del = - nincr * delta; i < 2 * nincr + 1; i++, del += delta) { + pix2 = pixColorShiftRGB(pix1, roff, goff + del, boff); + snprintf(buf, sizeof(buf), "%4.2f, %4.2f, %4.2f", + roff, goff + del, boff); + pix3 = pixAddSingleTextblock(pix2, bmf, buf, 0xff000000, + L_ADD_BELOW, 0); + pixaAddPix(pixa, pix3, L_INSERT); + pixDestroy(&pix2); + } + for (i = 0, del = - nincr * delta; i < 2 * nincr + 1; i++, del += delta) { + pix2 = pixColorShiftRGB(pix1, roff, goff, boff + del); + snprintf(buf, sizeof(buf), "%4.2f, %4.2f, %4.2f", + roff, goff, boff + del); + pix3 = pixAddSingleTextblock(pix2, bmf, buf, 0xff000000, + L_ADD_BELOW, 0); + pixaAddPix(pixa, pix3, L_INSERT); + pixDestroy(&pix2); + } + pixDestroy(&pix1); + + pix1 = pixaDisplayTiledAndScaled(pixa, 32, 300, 2 * nincr + 1, 0, 30, 2); + pixaDestroy(&pixa); + bmfDestroy(&bmf); + return pix1; +} + + +/*! + * \brief pixColorShiftRGB() + * + * \param[in] pixs 32 bpp rgb + * \param[in] rfract fractional shift in red component + * \param[in] gfract fractional shift in green component + * \param[in] bfract fractional shift in blue component + * \return pixd, or NULL on error + * + * <pre> + * Notes: + * (1) This allows independent fractional shifts of the r,g and b + * components. A positive shift pushes to saturation (255); + * a negative shift pushes toward 0 (black). + * (2) The effect can be imagined using a color wheel that consists + * (for our purposes) of these 6 colors, separated by 60 degrees: + * red, magenta, blue, cyan, green, yellow + * (3) So, for example, a negative shift of the blue component + * (bfract < 0) could be accompanied by positive shifts + * of red and green to make an image more yellow. + * (4) Examples of limiting cases: + * rfract = 1 ==> r = 255 + * rfract = -1 ==> r = 0 + * </pre> + */ +PIX * +pixColorShiftRGB(PIX *pixs, + l_float32 rfract, + l_float32 gfract, + l_float32 bfract) +{ +l_int32 w, h, i, j, wpls, wpld, rval, gval, bval; +l_int32 *rlut, *glut, *blut; +l_uint32 *datas, *datad, *lines, *lined; +l_float32 fi; +PIX *pixd; + + if (!pixs) + return (PIX *)ERROR_PTR("pixs not defined", __func__, NULL); + if (pixGetDepth(pixs) != 32) + return (PIX *)ERROR_PTR("pixs not 32 bpp", __func__, NULL); + if (rfract < -1.0 || rfract > 1.0) + return (PIX *)ERROR_PTR("rfract not in [-1.0, 1.0]", __func__, NULL); + if (gfract < -1.0 || gfract > 1.0) + return (PIX *)ERROR_PTR("gfract not in [-1.0, 1.0]", __func__, NULL); + if (bfract < -1.0 || bfract > 1.0) + return (PIX *)ERROR_PTR("bfract not in [-1.0, 1.0]", __func__, NULL); + if (rfract == 0.0 && gfract == 0.0 && bfract == 0.0) + return pixCopy(NULL, pixs); + + rlut = (l_int32 *)LEPT_CALLOC(256, sizeof(l_int32)); + glut = (l_int32 *)LEPT_CALLOC(256, sizeof(l_int32)); + blut = (l_int32 *)LEPT_CALLOC(256, sizeof(l_int32)); + for (i = 0; i < 256; i++) { + fi = i; + if (rfract >= 0) { + rlut[i] = (l_int32)(fi + (255.0 - fi) * rfract); + } else { + rlut[i] = (l_int32)(fi * (1.0 + rfract)); + } + if (gfract >= 0) { + glut[i] = (l_int32)(fi + (255.0 - fi) * gfract); + } else { + glut[i] = (l_int32)(fi * (1.0 + gfract)); + } + if (bfract >= 0) { + blut[i] = (l_int32)(fi + (255.0 - fi) * bfract); + } else { + blut[i] = (l_int32)(fi * (1.0 + bfract)); + } + } + + pixGetDimensions(pixs, &w, &h, NULL); + datas = pixGetData(pixs); + wpls = pixGetWpl(pixs); + pixd = pixCreate(w, h, 32); + datad = pixGetData(pixd); + wpld = pixGetWpl(pixd); + for (i = 0; i < h; i++) { + lines = datas + i * wpls; + lined = datad + i * wpld; + for (j = 0; j < w; j++) { + extractRGBValues(lines[j], &rval, &gval, &bval); + composeRGBPixel(rlut[rval], glut[gval], blut[bval], lined + j); + } + } + + LEPT_FREE(rlut); + LEPT_FREE(glut); + LEPT_FREE(blut); + return pixd; +} + +/*-----------------------------------------------------------------------* + * Darken gray (unsaturated) pixels + *-----------------------------------------------------------------------*/ +/*! + * \brief pixDarkenGray() + * + * \param[in] pixd [optional] can be null or equal to pixs + * \param[in] pixs 32 bpp rgb + * \param[in] thresh pixels with max component >= %thresh are unchanged + * \param[in] satlimit pixels with saturation >= %satlimit are unchanged + * \return pixd, or NULL on error + * + * <pre> + * Notes: + * (1) This darkens gray pixels, by a fraction (sat/%satlimit), where + * the saturation, sat, is the component difference (max - min). + * The pixel value is unchanged if sat >= %satlimit. A typical + * value of %satlimit might be 40; the larger the value, the + * more that pixels with a smaller saturation will be darkened. + * (2) Pixels with max component >= %thresh are unchanged. This can be + * used to prevent bright pixels with low saturation from being + * darkened. Setting thresh == 0 is a no-op; setting %thresh == 255 + * causes the darkening to be applied to all pixels. + * (3) This function is useful to enhance pixels relative to a + * gray background. + * (4) A related function that builds a 1 bpp mask over the gray + * pixels is pixMaskOverGrayPixels(). + * </pre> + */ +PIX * +pixDarkenGray(PIX *pixd, + PIX *pixs, + l_int32 thresh, + l_int32 satlimit) +{ +l_int32 w, h, i, j, wpls, wpld; +l_int32 rval, gval, bval, minrg, min, maxrg, max, sat; +l_uint32 *datas, *datad, *lines, *lined; +l_float32 ratio; + + if (!pixs || pixGetDepth(pixs) != 32) + return (PIX *)ERROR_PTR("pixs undefined or not 32 bpp", __func__, NULL); + if (thresh < 0 || thresh > 255) + return (PIX *)ERROR_PTR("invalid thresh", __func__, NULL); + if (satlimit < 1) + return (PIX *)ERROR_PTR("invalid satlimit", __func__, NULL); + if (pixd && (pixs != pixd)) + return (PIX *)ERROR_PTR("not new or in-place", __func__, NULL); + + pixGetDimensions(pixs, &w, &h, NULL); + datas = pixGetData(pixs); + wpls = pixGetWpl(pixs); + if ((pixd = pixCopy(pixd, pixs)) == NULL) + return (PIX *)ERROR_PTR("pixd not made", __func__, NULL); + datad = pixGetData(pixd); + wpld = pixGetWpl(pixd); + + for (i = 0; i < h; i++) { + lines = datas + i * wpls; + lined = datad + i * wpld; + for (j = 0; j < w; j++) { + extractRGBValues(lines[j], &rval, &gval, &bval); + minrg = L_MIN(rval, gval); + min = L_MIN(minrg, bval); + maxrg = L_MAX(rval, gval); + max = L_MAX(maxrg, bval); + sat = max - min; + if (max >= thresh || sat >= satlimit) + continue; + ratio = (l_float32)sat / (l_float32)satlimit; + composeRGBPixel((l_int32)(ratio * rval), (l_int32)(ratio * gval), + (l_int32)(ratio * bval), &lined[j]); + } + } + return pixd; +} + + +/*-----------------------------------------------------------------------* + * General multiplicative constant color transform * + *-----------------------------------------------------------------------*/ +/*! + * \brief pixMultConstantColor() + * + * \param[in] pixs colormapped or rgb + * \param[in] rfact red multiplicative factor + * \param[in] gfact green multiplicative factor + * \param[in] bfact blue multiplicative factor + * \return pixd colormapped or rgb, with colors scaled, or NULL on error + * + * <pre> + * Notes: + * (1) rfact, gfact and bfact can only have non-negative values. + * They can be greater than 1.0. All transformed component + * values are clipped to the interval [0, 255]. + * (2) For multiplication with a general 3x3 matrix of constants, + * use pixMultMatrixColor(). + * </pre> + */ +PIX * +pixMultConstantColor(PIX *pixs, + l_float32 rfact, + l_float32 gfact, + l_float32 bfact) +{ +l_int32 i, j, w, h, d, wpls, wpld; +l_int32 ncolors, rval, gval, bval, nrval, ngval, nbval; +l_uint32 nval; +l_uint32 *datas, *datad, *lines, *lined; +PIX *pixd; +PIXCMAP *cmap; + + if (!pixs) + return (PIX *)ERROR_PTR("pixs not defined", __func__, NULL); + pixGetDimensions(pixs, &w, &h, &d); + cmap = pixGetColormap(pixs); + if (!cmap && d != 32) + return (PIX *)ERROR_PTR("pixs not cmapped or 32 bpp", __func__, NULL); + rfact = L_MAX(0.0, rfact); + gfact = L_MAX(0.0, gfact); + bfact = L_MAX(0.0, bfact); + + if (cmap) { + if ((pixd = pixCopy(NULL, pixs)) == NULL) + return (PIX *)ERROR_PTR("pixd not made", __func__, NULL); + cmap = pixGetColormap(pixd); + ncolors = pixcmapGetCount(cmap); + for (i = 0; i < ncolors; i++) { + pixcmapGetColor(cmap, i, &rval, &gval, &bval); + nrval = (l_int32)(rfact * rval); + ngval = (l_int32)(gfact * gval); + nbval = (l_int32)(bfact * bval); + nrval = L_MIN(255, nrval); + ngval = L_MIN(255, ngval); + nbval = L_MIN(255, nbval); + pixcmapResetColor(cmap, i, nrval, ngval, nbval); + } + return pixd; + } + + if ((pixd = pixCreateTemplate(pixs)) == NULL) + return (PIX *)ERROR_PTR("pixd not made", __func__, NULL); + datas = pixGetData(pixs); + datad = pixGetData(pixd); + wpls = pixGetWpl(pixs); + wpld = pixGetWpl(pixd); + for (i = 0; i < h; i++) { + lines = datas + i * wpls; + lined = datad + i * wpld; + for (j = 0; j < w; j++) { + extractRGBValues(lines[j], &rval, &gval, &bval); + nrval = (l_int32)(rfact * rval); + ngval = (l_int32)(gfact * gval); + nbval = (l_int32)(bfact * bval); + nrval = L_MIN(255, nrval); + ngval = L_MIN(255, ngval); + nbval = L_MIN(255, nbval); + composeRGBPixel(nrval, ngval, nbval, &nval); + *(lined + j) = nval; + } + } + + return pixd; +} + + +/*! + * \brief pixMultMatrixColor() + * + * \param[in] pixs colormapped or rgb + * \param[in] kel kernel 3x3 matrix of floats + * \return pixd colormapped or rgb, or NULL on error + * + * <pre> + * Notes: + * (1) The kernel is a data structure used mostly for floating point + * convolution. Here it is a 3x3 matrix of floats that are used + * to transform the pixel values by matrix multiplication: + * nrval = a[0,0] * rval + a[0,1] * gval + a[0,2] * bval + * ngval = a[1,0] * rval + a[1,1] * gval + a[1,2] * bval + * nbval = a[2,0] * rval + a[2,1] * gval + a[2,2] * bval + * (2) The matrix can be generated in several ways. + * See kernel.c for details. Here are two of them: + * (a) kel = kernelCreate(3, 3); + * kernelSetElement(kel, 0, 0, val00); + * kernelSetElement(kel, 0, 1, val01); + * ... + * (b) from a static string; e.g.,: + * const char *kdata = " 0.6 0.3 -0.2 " + * " 0.1 1.2 0.4 " + * " -0.4 0.2 0.9 "; + * kel = kernelCreateFromString(3, 3, 0, 0, kdata); + * (3) For the special case where the matrix is diagonal, it is easier + * to use pixMultConstantColor(). + * (4) Matrix entries can have positive and negative values, and can + * be larger than 1.0. All transformed component values + * are clipped to [0, 255]. + * </pre> + */ +PIX * +pixMultMatrixColor(PIX *pixs, + L_KERNEL *kel) +{ +l_int32 i, j, index, kw, kh, w, h, d, wpls, wpld; +l_int32 ncolors, rval, gval, bval, nrval, ngval, nbval; +l_uint32 nval; +l_uint32 *datas, *datad, *lines, *lined; +l_float32 v[9]; /* use linear array for convenience */ +PIX *pixd; +PIXCMAP *cmap; + + if (!pixs) + return (PIX *)ERROR_PTR("pixs not defined", __func__, NULL); + if (!kel) + return (PIX *)ERROR_PTR("kel not defined", __func__, NULL); + kernelGetParameters(kel, &kw, &kh, NULL, NULL); + if (kw != 3 || kh != 3) + return (PIX *)ERROR_PTR("matrix not 3x3", __func__, NULL); + pixGetDimensions(pixs, &w, &h, &d); + cmap = pixGetColormap(pixs); + if (!cmap && d != 32) + return (PIX *)ERROR_PTR("pixs not cmapped or 32 bpp", __func__, NULL); + + for (i = 0, index = 0; i < 3; i++) + for (j = 0; j < 3; j++, index++) + kernelGetElement(kel, i, j, v + index); + + if (cmap) { + if ((pixd = pixCopy(NULL, pixs)) == NULL) + return (PIX *)ERROR_PTR("pixd not made", __func__, NULL); + cmap = pixGetColormap(pixd); + ncolors = pixcmapGetCount(cmap); + for (i = 0; i < ncolors; i++) { + pixcmapGetColor(cmap, i, &rval, &gval, &bval); + nrval = (l_int32)(v[0] * rval + v[1] * gval + v[2] * bval); + ngval = (l_int32)(v[3] * rval + v[4] * gval + v[5] * bval); + nbval = (l_int32)(v[6] * rval + v[7] * gval + v[8] * bval); + nrval = L_MAX(0, L_MIN(255, nrval)); + ngval = L_MAX(0, L_MIN(255, ngval)); + nbval = L_MAX(0, L_MIN(255, nbval)); + pixcmapResetColor(cmap, i, nrval, ngval, nbval); + } + return pixd; + } + + if ((pixd = pixCreateTemplate(pixs)) == NULL) + return (PIX *)ERROR_PTR("pixd not made", __func__, NULL); + datas = pixGetData(pixs); + datad = pixGetData(pixd); + wpls = pixGetWpl(pixs); + wpld = pixGetWpl(pixd); + for (i = 0; i < h; i++) { + lines = datas + i * wpls; + lined = datad + i * wpld; + for (j = 0; j < w; j++) { + extractRGBValues(lines[j], &rval, &gval, &bval); + nrval = (l_int32)(v[0] * rval + v[1] * gval + v[2] * bval); + ngval = (l_int32)(v[3] * rval + v[4] * gval + v[5] * bval); + nbval = (l_int32)(v[6] * rval + v[7] * gval + v[8] * bval); + nrval = L_MAX(0, L_MIN(255, nrval)); + ngval = L_MAX(0, L_MIN(255, ngval)); + nbval = L_MAX(0, L_MIN(255, nbval)); + composeRGBPixel(nrval, ngval, nbval, &nval); + *(lined + j) = nval; + } + } + + return pixd; +} + + +/*-------------------------------------------------------------* + * Half-edge by bandpass * + *-------------------------------------------------------------*/ +/*! + * \brief pixHalfEdgeByBandpass() + * + * \param[in] pixs 8 bpp gray or 32 bpp rgb + * \param[in] sm1h, sm1v "half-widths" of smoothing filter sm1 + * \param[in] sm2h, sm2v "half-widths" of smoothing filter sm2; + * require sm2 != sm1 + * \return pixd, or NULL on error + * + * <pre> + * Notes: + * (1) We use symmetric smoothing filters of odd dimension, + * typically use 3, 5, 7, etc. The smoothing parameters + * for these are 1, 2, 3, etc. The filter size is related + * to the smoothing parameter by + * size = 2 * smoothing + 1 + * (2) Because we take the difference of two lowpass filters, + * this is actually a bandpass filter. + * (3) We allow both filters to be anisotropic. + * (4) Consider either the h or v component of the 2 filters. + * Depending on whether sm1 > sm2 or sm2 > sm1, we get + * different halves of the smoothed gradients (or "edges"). + * This difference of smoothed signals looks more like + * a second derivative of a transition, which we rectify + * by not allowing the signal to go below zero. If sm1 < sm2, + * the sm2 transition is broader, so the difference between + * sm1 and sm2 signals is positive on the upper half of + * the transition. Likewise, if sm1 > sm2, the sm1 - sm2 + * signal difference is positive on the lower half of + * the transition. + * </pre> + */ +PIX * +pixHalfEdgeByBandpass(PIX *pixs, + l_int32 sm1h, + l_int32 sm1v, + l_int32 sm2h, + l_int32 sm2v) +{ +l_int32 d; +PIX *pixg, *pixacc, *pixc1, *pixc2; + + if (!pixs) + return (PIX *)ERROR_PTR("pixs not defined", __func__, NULL); + if (sm1h == sm2h && sm1v == sm2v) + return (PIX *)ERROR_PTR("sm2 = sm1", __func__, NULL); + d = pixGetDepth(pixs); + if (d != 8 && d != 32) + return (PIX *)ERROR_PTR("pixs not 8 or 32 bpp", __func__, NULL); + if (d == 32) + pixg = pixConvertRGBToLuminance(pixs); + else /* d == 8 */ + pixg = pixClone(pixs); + + /* Make a convolution accumulator and use it twice */ + if ((pixacc = pixBlockconvAccum(pixg)) == NULL) { + pixDestroy(&pixg); + return (PIX *)ERROR_PTR("pixacc not made", __func__, NULL); + } + if ((pixc1 = pixBlockconvGray(pixg, pixacc, sm1h, sm1v)) == NULL) { + pixDestroy(&pixg); + pixDestroy(&pixacc); + return (PIX *)ERROR_PTR("pixc1 not made", __func__, NULL); + } + pixc2 = pixBlockconvGray(pixg, pixacc, sm2h, sm2v); + pixDestroy(&pixg); + pixDestroy(&pixacc); + if (!pixc2) { + pixDestroy(&pixc1); + return (PIX *)ERROR_PTR("pixc2 not made", __func__, NULL); + } + + /* Compute the half-edge using pixc1 - pixc2. */ + pixSubtractGray(pixc1, pixc1, pixc2); + pixDestroy(&pixc2); + return pixc1; +}