leptonica-projective-transform.c

   1 /*
   2  * leptonica-projective-transform - Example for pixProjectiveSampled()
   3  *
   4  * Copyright (C) 2013  Antonio Ospite <ospite@studenti.unina.it>
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <stdio.h>
  21 #include <errno.h>
  22 #include <leptonica/allheaders.h>
  23
  24 #define WIDTH 800
  25 #define HEIGHT 480
  26
  27 #define X_CORRECTION 200
  28
  29 int main(int argc, char *argv[])
  30 {
  31         int ret;
  32         PIX *image;
  33         BOX *viewport;
  34         PIX *cropped_image;
  35         PTA *src;
  36         PTA *dst;
  37         l_float32 *transform_coeffs;
  38         PIX *transformed_image;
  39
  40         if (argc != 2) {
  41                 fprintf(stderr, "usage: %s <image>\n", argv[0]);
  42                 ret = -EINVAL;
  43                 goto out;
  44         }
  45
  46         image = pixRead(argv[1]);
  47         if (image == NULL) {
  48                 fprintf(stderr, "Cannot load image\n");
  49                 ret = -EINVAL;
  50                 goto out;
  51         }
  52
  53         src = ptaCreate(4);
  54         if (src == NULL) {
  55                 ret = -ENOMEM;
  56                 goto out_destroy_image;
  57         }
  58         ptaAddPt(src, 0, 0);
  59         ptaAddPt(src, WIDTH, 0);
  60         ptaAddPt(src, WIDTH, HEIGHT);
  61         ptaAddPt(src, 0, HEIGHT);
  62
  63         dst = ptaCreate(4);
  64         if (dst == NULL) {
  65                 ret = -ENOMEM;
  66                 goto out_destroy_pta_src;
  67         }
  68         ptaAddPt(dst, X_CORRECTION, 0);
  69         ptaAddPt(dst, WIDTH - X_CORRECTION, 0);
  70         ptaAddPt(dst, WIDTH, HEIGHT);
  71         ptaAddPt(dst, 0, HEIGHT);
  72
  73         transform_coeffs = NULL;
  74         ret = getProjectiveXformCoeffs(dst, src, &transform_coeffs);
  75         if (ret != 0) {
  76                 ret = -ENOMEM;
  77                 goto out_destroy_pta_dst;
  78         }
  79
  80         /* Transform only a part of the whole image */
  81         viewport = boxCreateValid(0, 0, WIDTH, HEIGHT);
  82         if (viewport == NULL) {
  83                 ret = -EINVAL;
  84                 goto out_free_transform_coeffs;
  85         }
  86         cropped_image = pixClipRectangle(image, viewport, NULL);
  87         if (cropped_image == NULL) {
  88                 ret = -EINVAL;
  89                 goto out_destroy_viewport;
  90         }
  91
  92         /* Apply the perspective transformation */
  93         transformed_image = pixProjectiveSampled(cropped_image, transform_coeffs, L_BRING_IN_BLACK);
  94         if (transformed_image == NULL) {
  95                 fprintf(stderr, "Cannot create transformed image\n");
  96                 ret = -EINVAL;
  97                 goto out_free_cropped_image;
  98         }
  99
 100         pixWrite("transformed_image.jpg", transformed_image, IFF_JFIF_JPEG);
 101
 102         ret = 0;
 103
 104         pixDestroy(&transformed_image);
 105 out_free_cropped_image:
 106         pixDestroy(&cropped_image);
 107 out_destroy_viewport:
 108         boxDestroy(&viewport);
 109 out_free_transform_coeffs:
 110         FREE(transform_coeffs);
 111 out_destroy_pta_dst:
 112         ptaDestroy(&dst);
 113 out_destroy_pta_src:
 114         ptaDestroy(&src);
 115 out_destroy_image:
 116         pixDestroy(&image);
 117 out:
 118         return ret;
 119 }