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/* Seven Segment Optical Character Recognition Image Processing Functions */
/* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/* Copyright (C) 2004-2025 Erik Auerswald <auerswal@unix-ag.uni-kl.de> */
#ifndef SSOCR2_IMGPROC_H
#define SSOCR2_IMGPROC_H
/* parse luminance keyword */
luminance_t parse_lum(char *keyword);
/* set foreground color */
void set_fg_color(int color);
/* set background color */
void set_bg_color(int color);
/* set imlib color */
void ssocr_set_color(fg_bg_t color);
/* draw a fore- or background pixel */
void draw_fg_bg_pixel(Imlib_Image *image, int x, int y, fg_bg_t color);
/* draw a foreground pixel */
void draw_fg_pixel(Imlib_Image *image, int x, int y);
/* draw a background pixel */
void draw_bg_pixel(Imlib_Image *image, int x, int y);
/* draw a pixel of a given color */
void draw_color_pixel(Imlib_Image *image, int x, int y, Imlib_Color color);
/* check if a pixel is set regarding current foreground/background colors */
int is_pixel_set(int value, double threshold);
/* set pixel if at least mask neighboring pixels (including the pixel to be set)
* are set
* a pixel is set if its luminance value is less than thresh
* mask=1 is the standard dilation filter
* mask=9 is the standard erosion filter */
Imlib_Image set_pixels_filter(Imlib_Image *source_image, double thresh,
luminance_t lt, int mask);
/* perform set pixel filter operation iter times */
Imlib_Image set_pixels_filter_iter(Imlib_Image *source_image, double thresh,
luminance_t lt, int mask, int iter);
/* shortcut for dilation */
Imlib_Image dilation(Imlib_Image *source_image, double thresh, luminance_t lt,
int n);
/* shortcut for erosion */
Imlib_Image erosion(Imlib_Image *source_image, double thresh, luminance_t lt,
int n);
/* shortcut for closing */
Imlib_Image closing(Imlib_Image *source_image, double thresh, luminance_t lt,
int n);
/* shortcut for opening */
Imlib_Image opening(Imlib_Image *source_image, double thresh, luminance_t lt,
int n);
/* keep only pixels that have at least mask-1 neighbors set */
Imlib_Image keep_pixels_filter(Imlib_Image *source_image, double thresh,
luminance_t lt, int mask);
/* remove isolated pixels (shortcut for keep_pixels_filter with mask = 2) */
Imlib_Image remove_isolated(Imlib_Image *source_image, double thresh,
luminance_t lt);
/* gray stretching, i.e. lum<t1 => lum=0, lum>t2 => lum=100,
* else lum=((lum-t1)*MAXRGB)/(t2-t1) */
Imlib_Image gray_stretch(Imlib_Image *source_image, double t1, double t2,
luminance_t lt);
/* use dynamic (aka adaptive) local thresholding to create monochrome image */
Imlib_Image dynamic_threshold(Imlib_Image *source_image, double t,
luminance_t lt ,int ww, int wh);
/* make black and white */
Imlib_Image make_mono(Imlib_Image *source_image, double thresh, luminance_t lt);
/* set pixel to black (0,0,0) if R<T, T=thresh/100*255 */
Imlib_Image r_threshold(Imlib_Image *source_image, double thresh);
/* set pixel to black (0,0,0) if G<T, T=thresh/100*255 */
Imlib_Image g_threshold(Imlib_Image *source_image, double thresh);
/* set pixel to black (0,0,0) if B<T, T=thresh/100*255 */
Imlib_Image b_threshold(Imlib_Image *source_image, double thresh);
/* make the border white */
Imlib_Image white_border(Imlib_Image *source_image, int width);
/* invert image */
Imlib_Image invert(Imlib_Image *source_image, double thresh, luminance_t lt);
/* shear the image
* the top line is unchanged
* the bottom line is moved offset pixels to the right
* the other lines are moved yPos*offset/(height-1) pixels to the right
* white pixels are inserted at the left side */
Imlib_Image shear(Imlib_Image *source_image, int offset);
/* rotate the image */
Imlib_Image rotate(Imlib_Image *source_image, double theta);
/* mirror image horizontally or vertically */
Imlib_Image mirror(Imlib_Image *source_image, direction_t direction);
/* turn image to grayscale */
Imlib_Image grayscale(Imlib_Image *source_image, luminance_t lt);
/* crop image */
Imlib_Image crop(Imlib_Image *source_image, int x, int y, int w, int h);
/* adapt threshold to image values values */
double adapt_threshold(Imlib_Image *image, double thresh, luminance_t lt,
unsigned int flags, int force_update);
/* compute dynamic threshold value from the rectangle (x,y),(x+w,y+h) of
* source_image */
double get_threshold(Imlib_Image *source_image, double fraction, luminance_t lt,
int x, int y, int w, int h);
/* determine threshold by an iterative method */
double iterative_threshold(Imlib_Image *source_image, double thresh,
luminance_t lt);
/* get minimum and maximum gray (luminace) values */
void get_minmaxval(Imlib_Image *source_image, luminance_t lt,
double *min, double *max);
/* compute luminance from RGB values */
int get_lum(Imlib_Color *color, luminance_t lt);
/* compute luminance Y_709 from linear RGB values */
int get_lum_709(Imlib_Color *color);
/* compute luminance Y_601 from gamma corrected (non-linear) RGB values */
int get_lum_601(Imlib_Color *color);
/* compute luminance Y = (R+G+B)/3 */
int get_lum_lin(Imlib_Color *color);
/* compute luminance Y = min(R,G,B) as used in GNU Ocrad 0.14 */
int get_lum_min(Imlib_Color *color);
/* compute luminance Y = max(R,G,B) */
int get_lum_max(Imlib_Color *color);
/* compute luminance Y = R */
int get_lum_red(Imlib_Color *color);
/* compute luminance Y = G */
int get_lum_green(Imlib_Color *color);
/* compute luminance Y = B */
int get_lum_blue(Imlib_Color *color);
/* clip value thus that it is in the given interval [min,max] */
int clip(int value, int min, int max);
/* save image to file */
void save_image(const char *image_type, Imlib_Image *image, const char *fmt,
const char *filename, unsigned int flags);
/* report Imlib2 load/save error to stderr */
void report_imlib_error(Imlib_Load_Error error);
#endif /* SSOCR2_IMGPROC_H */
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