src/histogram.c

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