src/histogram.c

   1 /*
   2  * Geeqie
   3  * Copyright (C) 2008 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()
  36 {
  37         Histogram *histogram;
  38
  39         histogram = g_new0(Histogram, 1);
  40         histogram->histogram_chan = HCHAN_RGB;
  41         histogram->histogram_logmode = 1;
  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         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         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         if (!histogram) return NULL;
  82
  83         if (histogram->histogram_logmode)
  84                         switch (histogram->histogram_chan)
  85                         {
  86                         case HCHAN_R:   t1 = _("logarithmical histogram on red"); break;
  87                         case HCHAN_G:   t1 = _("logarithmical histogram on green"); break;
  88                         case HCHAN_B:   t1 = _("logarithmical histogram on blue"); break;
  89                         case HCHAN_VAL: t1 = _("logarithmical histogram on value"); break;
  90                         case HCHAN_RGB: t1 = _("logarithmical histogram on RGB"); break;
  91                         case HCHAN_MAX: t1 = _("logarithmical histogram on max value"); break;
  92                         }
  93                 else
  94                         switch (histogram->histogram_chan)
  95                         {
  96                         case HCHAN_R:   t1 = _("linear histogram on red"); break;
  97                         case HCHAN_G:   t1 = _("linear histogram on green"); break;
  98                         case HCHAN_B:   t1 = _("linear histogram on blue"); break;
  99                         case HCHAN_VAL: t1 = _("linear histogram on value"); break;
 100                         case HCHAN_RGB: t1 = _("linear histogram on RGB"); break;
 101                         case HCHAN_MAX: t1 = _("linear histogram on max value"); break;
 102                         }
 103         return t1;
 104 }
 105
 106 gulong histogram_read(Histogram *histogram, GdkPixbuf *imgpixbuf)
 107 {
 108         gint w, h, i, j, srs, has_alpha, step;
 109         guchar *s_pix;
 110
 111         if (!histogram) return 0;
 112
 113         w = gdk_pixbuf_get_width(imgpixbuf);
 114         h = gdk_pixbuf_get_height(imgpixbuf);
 115         srs = gdk_pixbuf_get_rowstride(imgpixbuf);
 116         s_pix = gdk_pixbuf_get_pixels(imgpixbuf);
 117         has_alpha = gdk_pixbuf_get_has_alpha(imgpixbuf);
 118
 119         memset(histogram->histmap, 0, sizeof(histogram->histmap));
 120
 121         /* code duplication is here to speed up the calculation */
 122         step = 3 + !!(has_alpha);
 123         if (histogram->histogram_chan == HCHAN_MAX)
 124                 {
 125                 for (i = 0; i < h; i++)
 126                         {
 127                         guchar *sp = s_pix + (i * srs); /* 8bit */
 128                         for (j = 0; j < w; j++)
 129                                 {
 130                                 guchar t = sp[0];
 131                                 if (sp[1]>t) t = sp[1];
 132                                 if (sp[2]>t) t = sp[2];
 133
 134                                 histogram->histmap[sp[0] + 0 * HISTOGRAM_SIZE]++;
 135                                 histogram->histmap[sp[1] + 1 * HISTOGRAM_SIZE]++;
 136                                 histogram->histmap[sp[2] + 2 * HISTOGRAM_SIZE]++;
 137                                 histogram->histmap[t + 3 * HISTOGRAM_SIZE]++;
 138                                 sp += step;
 139                                 }
 140                         }
 141                 }
 142         else
 143                 {
 144                 for (i = 0; i < h; i++)
 145                         {
 146                         guchar *sp = s_pix + (i * srs); /* 8bit */
 147                         for (j = 0; j < w; j++)
 148                                 {
 149                                 histogram->histmap[sp[0] + 0 * HISTOGRAM_SIZE]++;
 150                                 histogram->histmap[sp[1] + 1 * HISTOGRAM_SIZE]++;
 151                                 histogram->histmap[sp[2] + 2 * HISTOGRAM_SIZE]++;
 152                                 histogram->histmap[3 * HISTOGRAM_SIZE + (sp[0]+sp[1]+sp[2])/3]++;
 153                                 sp += step;
 154                                 }
 155                         }
 156                 }
 157
 158         return w*h;
 159 }
 160
 161 gint histogram_draw(Histogram *histogram, GdkPixbuf *pixbuf, gint x, gint y, gint width, gint height)
 162 {
 163         /* FIXME: use the coordinates correctly */
 164         gint i;
 165         gulong max = 0;
 166         double logmax;
 167
 168         if (!histogram) return 0;
 169
 170         for (i = 0; i < 1024; i++) {
 171                 gint flag = 0;
 172
 173                 switch (histogram->histogram_chan)
 174                 {
 175                 case HCHAN_RGB: if ((i%4) != 3) flag = 1; break;
 176                 case HCHAN_R:   if ((i%4) == 0) flag = 1; break;
 177                 case HCHAN_G:   if ((i%4) == 1) flag = 1; break;
 178                 case HCHAN_B:   if ((i%4) == 2) flag = 1; break;
 179                 case HCHAN_VAL: if ((i%4) == 3) flag = 1; break;
 180                 case HCHAN_MAX: if ((i%4) == 3) flag = 1; break;
 181                 }
 182                 if (flag && histogram->histmap[i] > max) max = histogram->histmap[i];
 183         }
 184
 185         logmax = log(max);
 186         for (i = 0; i < width; i++)
 187                 {
 188                 gint j;
 189                 glong v[4] = {0, 0, 0, 0};
 190                 gint rplus = 0;
 191                 gint gplus = 0;
 192                 gint bplus = 0;
 193                 gint ii = i * HISTOGRAM_SIZE / width;
 194                 gint combine  = (HISTOGRAM_SIZE - 1) / width + 1;
 195
 196                 for (j = 0; j < combine; j++)
 197                         {
 198                         v[0] += histogram->histmap[ii + j + 0 * HISTOGRAM_SIZE]; // r
 199                         v[1] += histogram->histmap[ii + j + 1 * HISTOGRAM_SIZE]; // g
 200                         v[2] += histogram->histmap[ii + j + 2 * HISTOGRAM_SIZE]; // b
 201                         v[3] += histogram->histmap[ii + j + 3 * HISTOGRAM_SIZE]; // value, max
 202                         }
 203
 204                 for (j = 0; j < 4; j++)
 205                         {
 206                         gint max2 = 0;
 207                         gint k;
 208
 209                         for (k = 1; k < 4; k++)
 210                                 if (v[k] > v[max2]) max2 = k;
 211
 212                         if (histogram->histogram_chan >= HCHAN_RGB
 213                             || max2 == histogram->histogram_chan)
 214                                 {
 215                                 gulong pt;
 216                                 gint r = rplus;
 217                                 gint g = gplus;
 218                                 gint b = bplus;
 219
 220                                 switch (max2)
 221                                         {
 222                                         case HCHAN_R: rplus = r = 255; break;
 223                                         case HCHAN_G: gplus = g = 255; break;
 224                                         case HCHAN_B: bplus = b = 255; break;
 225                                         }
 226
 227                                 switch (histogram->histogram_chan)
 228                                         {
 229                                         case HCHAN_RGB:
 230                                                 if (r == 255 && g == 255 && b == 255)
 231                                                         {
 232                                                         r = 0; b = 0; g = 0;
 233                                                         }
 234                                                 break;
 235                                         case HCHAN_R:          b = 0; g = 0; break;
 236                                         case HCHAN_G:   r = 0; b = 0;        break;
 237                                         case HCHAN_B:   r = 0;        g = 0; break;
 238                                         case HCHAN_MAX:
 239                                         case HCHAN_VAL: r = 0; b = 0; g = 0; break;
 240                                         }
 241
 242                                 if (v[max2] == 0)
 243                                         pt = 0;
 244                                 else if (histogram->histogram_logmode)
 245                                         pt = ((float)log(v[max2])) / logmax * (height - 1);
 246                                 else
 247                                         pt = ((float)v[max2])/ max * (height - 1);
 248
 249                                 pixbuf_draw_line(pixbuf,
 250                                         x, y, width, height,
 251                                         x + i, y + height, x + i, y + height - pt,
 252                                         r, g, b, 255);
 253                                 }
 254                         v[max2] = -1;
 255                         }
 256                 }
 257
 258         return TRUE;
 259 }