src/histogram.c

   1 /*
   2  * Geeqie
   3  * Copyright (C) 2008 - 2009 The Geeqie Team
   4  *
   5  * Author: Vladimir Nadvornik
   6  * based on a patch by Uwe Ohse
   7  *
   8  * This software is released under the GNU General Public License (GNU GPL).
   9  * Please read the included file COPYING for more information.
  10  * This software comes with no warranty of any kind, use at your own risk!
  11  */
  12
  13 #include "main.h"
  14 #include "histogram.h"
  15
  16 #include "pixbuf_util.h"
  17
  18 #include <math.h>
  19
  20 /*
  21  *----------------------------------------------------------------------------
  22  * image histogram
  23  *----------------------------------------------------------------------------
  24  */
  25
  26 #define HISTOGRAM_SIZE 256
  27
  28 struct _Histogram {
  29         gulong histmap[HISTOGRAM_SIZE*4];
  30         gint histogram_chan;
  31         gint histogram_logmode;
  32 };
  33
  34
  35 Histogram *histogram_new(void)
  36 {
  37         Histogram *histogram;
  38
  39         histogram = g_new0(Histogram, 1);
  40         histogram->histogram_chan = options->histogram.last_channel_mode;
  41         histogram->histogram_logmode = options->histogram.last_log_mode;
  42
  43         return histogram;
  44 }
  45
  46 void histogram_free(Histogram *histogram)
  47 {
  48         g_free(histogram);
  49 }
  50
  51
  52 gint histogram_set_channel(Histogram *histogram, gint chan)
  53 {
  54         if (!histogram) return 0;
  55         options->histogram.last_channel_mode = histogram->histogram_chan = chan;
  56         return chan;
  57 }
  58
  59 gint histogram_get_channel(Histogram *histogram)
  60 {
  61         if (!histogram) return 0;
  62         return histogram->histogram_chan;
  63 }
  64
  65 gint histogram_set_mode(Histogram *histogram, gint mode)
  66 {
  67         if (!histogram) return 0;
  68         options->histogram.last_log_mode = histogram->histogram_logmode = mode;
  69         return mode;
  70 }
  71
  72 gint histogram_get_mode(Histogram *histogram)
  73 {
  74         if (!histogram) return 0;
  75         return histogram->histogram_logmode;
  76 }
  77
  78 const gchar *histogram_label(Histogram *histogram)
  79 {
  80         const gchar *t1 = "";
  81
  82         if (!histogram) return NULL;
  83
  84         if (histogram->histogram_logmode)
  85                 switch (histogram->histogram_chan)
  86                         {
  87                         case HCHAN_R:   t1 = _("logarithmical histogram on red"); break;
  88                         case HCHAN_G:   t1 = _("logarithmical histogram on green"); break;
  89                         case HCHAN_B:   t1 = _("logarithmical histogram on blue"); break;
  90                         case HCHAN_VAL: t1 = _("logarithmical histogram on value"); break;
  91                         case HCHAN_RGB: t1 = _("logarithmical histogram on RGB"); break;
  92                         case HCHAN_MAX: t1 = _("logarithmical histogram on max value"); break;
  93                         }
  94         else
  95                 switch (histogram->histogram_chan)
  96                         {
  97                         case HCHAN_R:   t1 = _("linear histogram on red"); break;
  98                         case HCHAN_G:   t1 = _("linear histogram on green"); break;
  99                         case HCHAN_B:   t1 = _("linear histogram on blue"); break;
 100                         case HCHAN_VAL: t1 = _("linear histogram on value"); break;
 101                         case HCHAN_RGB: t1 = _("linear histogram on RGB"); break;
 102                         case HCHAN_MAX: t1 = _("linear histogram on max value"); break;
 103                         }
 104         return t1;
 105 }
 106
 107 gulong histogram_read(Histogram *histogram, GdkPixbuf *imgpixbuf)
 108 {
 109         gint w, h, i, j, srs, has_alpha, step;
 110         guchar *s_pix;
 111
 112         if (!histogram) return 0;
 113
 114         w = gdk_pixbuf_get_width(imgpixbuf);
 115         h = gdk_pixbuf_get_height(imgpixbuf);
 116         srs = gdk_pixbuf_get_rowstride(imgpixbuf);
 117         s_pix = gdk_pixbuf_get_pixels(imgpixbuf);
 118         has_alpha = gdk_pixbuf_get_has_alpha(imgpixbuf);
 119
 120         memset(histogram->histmap, 0, sizeof(histogram->histmap));
 121
 122         /* code duplication is here to speed up the calculation */
 123         step = 3 + !!(has_alpha);
 124         if (histogram->histogram_chan == HCHAN_MAX)
 125                 {
 126                 for (i = 0; i < h; i++)
 127                         {
 128                         guchar *sp = s_pix + (i * srs); /* 8bit */
 129                         for (j = 0; j < w; j++)
 130                                 {
 131                                 guchar t = sp[0];
 132                                 if (sp[1]>t) t = sp[1];
 133                                 if (sp[2]>t) t = sp[2];
 134
 135                                 histogram->histmap[sp[0] + 0 * HISTOGRAM_SIZE]++;
 136                                 histogram->histmap[sp[1] + 1 * HISTOGRAM_SIZE]++;
 137                                 histogram->histmap[sp[2] + 2 * HISTOGRAM_SIZE]++;
 138                                 histogram->histmap[t + 3 * HISTOGRAM_SIZE]++;
 139                                 sp += step;
 140                                 }
 141                         }
 142                 }
 143         else
 144                 {
 145                 for (i = 0; i < h; i++)
 146                         {
 147                         guchar *sp = s_pix + (i * srs); /* 8bit */
 148                         for (j = 0; j < w; j++)
 149                                 {
 150                                 histogram->histmap[sp[0] + 0 * HISTOGRAM_SIZE]++;
 151                                 histogram->histmap[sp[1] + 1 * HISTOGRAM_SIZE]++;
 152                                 histogram->histmap[sp[2] + 2 * HISTOGRAM_SIZE]++;
 153                                 histogram->histmap[3 * HISTOGRAM_SIZE + (sp[0]+sp[1]+sp[2])/3]++;
 154                                 sp += step;
 155                                 }
 156                         }
 157                 }
 158
 159         return w*h;
 160 }
 161
 162 gint histogram_draw(Histogram *histogram, GdkPixbuf *pixbuf, gint x, gint y, gint width, gint height)
 163 {
 164         /* FIXME: use the coordinates correctly */
 165         gint i;
 166         gulong max = 0;
 167         gdouble logmax;
 168
 169         if (!histogram) return 0;
 170
 171         for (i = 0; i < 1024; i++) {
 172                 gint flag = 0;
 173
 174                 switch (histogram->histogram_chan)
 175                         {
 176                         case HCHAN_RGB: if ((i%4) != 3) flag = 1; break;
 177                         case HCHAN_R:   if ((i%4) == 0) flag = 1; break;
 178                         case HCHAN_G:   if ((i%4) == 1) flag = 1; break;
 179                         case HCHAN_B:   if ((i%4) == 2) flag = 1; break;
 180                         case HCHAN_VAL: if ((i%4) == 3) flag = 1; break;
 181                         case HCHAN_MAX: if ((i%4) == 3) flag = 1; break;
 182                         }
 183                 if (flag && histogram->histmap[i] > max) max = histogram->histmap[i];
 184         }
 185
 186         logmax = log(max);
 187         for (i = 0; i < width; i++)
 188                 {
 189                 gint j;
 190                 glong v[4] = {0, 0, 0, 0};
 191                 gint rplus = 0;
 192                 gint gplus = 0;
 193                 gint bplus = 0;
 194                 gint ii = i * HISTOGRAM_SIZE / width;
 195                 gint combine  = (HISTOGRAM_SIZE - 1) / width + 1;
 196
 197                 for (j = 0; j < combine; j++)
 198                         {
 199                         v[0] += histogram->histmap[ii + j + 0 * HISTOGRAM_SIZE]; // r
 200                         v[1] += histogram->histmap[ii + j + 1 * HISTOGRAM_SIZE]; // g
 201                         v[2] += histogram->histmap[ii + j + 2 * HISTOGRAM_SIZE]; // b
 202                         v[3] += histogram->histmap[ii + j + 3 * HISTOGRAM_SIZE]; // value, max
 203                         }
 204
 205                 for (j = 0; j < 4; j++)
 206                         {
 207                         gint max2 = 0;
 208                         gint k;
 209
 210                         for (k = 1; k < 4; k++)
 211                                 if (v[k] > v[max2]) max2 = k;
 212
 213                         if (histogram->histogram_chan >= HCHAN_RGB
 214                             || max2 == histogram->histogram_chan)
 215                                 {
 216                                 gulong pt;
 217                                 gint r = rplus;
 218                                 gint g = gplus;
 219                                 gint b = bplus;
 220
 221                                 switch (max2)
 222                                         {
 223                                         case HCHAN_R: rplus = r = 255; break;
 224                                         case HCHAN_G: gplus = g = 255; break;
 225                                         case HCHAN_B: bplus = b = 255; break;
 226                                         }
 227
 228                                 switch (histogram->histogram_chan)
 229                                         {
 230                                         case HCHAN_RGB:
 231                                                 if (r == 255 && g == 255 && b == 255)
 232                                                         {
 233                                                         r = 0; b = 0; g = 0;
 234                                                         }
 235                                                 break;
 236                                         case HCHAN_R:          b = 0; g = 0; break;
 237                                         case HCHAN_G:   r = 0; b = 0;        break;
 238                                         case HCHAN_B:   r = 0;        g = 0; break;
 239                                         case HCHAN_MAX:
 240                                         case HCHAN_VAL: r = 0; b = 0; g = 0; break;
 241                                         }
 242
 243                                 if (v[max2] == 0)
 244                                         pt = 0;
 245                                 else if (histogram->histogram_logmode)
 246                                         pt = ((float)log(v[max2])) / logmax * (height - 1);
 247                                 else
 248                                         pt = ((float)v[max2])/ max * (height - 1);
 249
 250                                 pixbuf_draw_line(pixbuf,
 251                                         x, y, width, height,
 252                                         x + i, y + height, x + i, y + height - pt,
 253                                         r, g, b, 255);
 254                                 }
 255                         v[max2] = -1;
 256                         }
 257                 }
 258
 259         return TRUE;
 260 }
 261 /* vim: set shiftwidth=8 softtabstop=0 cindent cinoptions={1s: */