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 "gqview.h"
  13 #include "histogram.h"
  14 #include <math.h>
  15
  16 /*
  17  *----------------------------------------------------------------------------
  18  * image histogram
  19  *----------------------------------------------------------------------------
  20  */
  21
  22
  23 Histogram *histogram_new()
  24 {
  25         Histogram *histogram;
  26
  27         histogram = g_new0(Histogram, 1);
  28         histogram->histogram_chan = HCHAN_RGB;
  29         histogram->histogram_logmode = 1;
  30
  31         return histogram;
  32 }
  33
  34 void histogram_free(Histogram *histogram)
  35 {
  36         g_free(histogram);
  37 }
  38
  39
  40 gint histogram_set_channel(Histogram *histogram, gint chan)
  41 {
  42         if (!histogram) return 0;
  43         histogram->histogram_chan = chan;
  44         return chan;
  45 }
  46
  47 gint histogram_get_channel(Histogram *histogram)
  48 {
  49         if (!histogram) return 0;
  50         return histogram->histogram_chan;
  51 }
  52
  53 gint histogram_set_mode(Histogram *histogram, gint mode)
  54 {
  55         if (!histogram) return 0;
  56         histogram->histogram_logmode = mode;
  57         return mode;
  58 }
  59
  60 gint histogram_get_mode(Histogram *histogram)
  61 {
  62         if (!histogram) return 0;
  63         return histogram->histogram_logmode;
  64 }
  65
  66 const gchar *histogram_label(Histogram *histogram)
  67 {
  68         const gchar *t1 = "";
  69         if (!histogram) return NULL;
  70
  71         if (histogram->histogram_logmode)
  72                         switch (histogram->histogram_chan) {
  73                         case HCHAN_R:   t1 = _("logarithmical histogram on red"); break;
  74                         case HCHAN_G:   t1 = _("logarithmical histogram on green"); break;
  75                         case HCHAN_B:   t1 = _("logarithmical histogram on blue"); break;
  76                         case HCHAN_VAL: t1 = _("logarithmical histogram on value"); break;
  77                         case HCHAN_RGB: t1 = _("logarithmical histogram on RGB"); break;
  78                         case HCHAN_MAX: t1 = _("logarithmical histogram on max value"); break;
  79                         }
  80                 else
  81                         switch (histogram->histogram_chan) {
  82                         case HCHAN_R:   t1 = _("linear histogram on red"); break;
  83                         case HCHAN_G:   t1 = _("linear histogram on green"); break;
  84                         case HCHAN_B:   t1 = _("linear histogram on blue"); break;
  85                         case HCHAN_VAL: t1 = _("linear histogram on value"); break;
  86                         case HCHAN_RGB: t1 = _("linear histogram on RGB"); break;
  87                         case HCHAN_MAX: t1 = _("linear histogram on max value"); break;
  88                         }
  89         return t1;
  90 }
  91
  92 gulong histogram_read(Histogram *histogram, GdkPixbuf *imgpixbuf)
  93 {
  94         gint w, h, i, j, srs, has_alpha;
  95         guchar *s_pix;
  96
  97         if (!histogram) return 0;
  98
  99         w = gdk_pixbuf_get_width(imgpixbuf);
 100         h = gdk_pixbuf_get_height(imgpixbuf);
 101         srs = gdk_pixbuf_get_rowstride(imgpixbuf);
 102         s_pix = gdk_pixbuf_get_pixels(imgpixbuf);
 103         has_alpha = gdk_pixbuf_get_has_alpha(imgpixbuf);
 104
 105         for (i = 0; i < 256*4; i++) histogram->histmap[i] = 0;
 106
 107         for (i = 0; i < h; i++)
 108                 {
 109                 guchar *sp = s_pix + (i * srs); /* 8bit */
 110                 for (j = 0; j < w; j++)
 111                         {
 112                         histogram->histmap[sp[0]+0]++;
 113                         histogram->histmap[sp[1]+256]++;
 114                         histogram->histmap[sp[2]+512]++;
 115                         if (histogram->histogram_chan == HCHAN_MAX)
 116                                 {
 117                                 guchar t = sp[0];
 118                                 if (sp[1]>t) t = sp[1];
 119                                 if (sp[2]>t) t = sp[2];
 120                                 histogram->histmap[t+768]++;
 121                                 }
 122                         else
 123                                 histogram->histmap[768+(sp[0]+sp[1]+sp[2])/3]++;
 124                         sp += 3;
 125                         if (has_alpha) sp++;
 126                         }
 127                 }
 128
 129         return w*h;
 130 }
 131
 132
 133 int histogram_draw(Histogram *histogram, GdkPixbuf *pixbuf, gint x, gint y, gint width, gint height)
 134 {
 135         /* FIXME: use the coordinates correctly */
 136         gint i;
 137         gulong max = 0;
 138         double logmax;
 139
 140         if (!histogram) return 0;
 141
 142         for (i=0; i<1024; i++) {
 143                 int flag = 0;
 144
 145                 switch (histogram->histogram_chan)
 146                 {
 147                 case HCHAN_RGB: if ((i%4) != 3 ) flag = 1; break;
 148                 case HCHAN_R: if ((i%4) == 0) flag = 1; break;
 149                 case HCHAN_G: if ((i%4) == 1) flag = 1; break;
 150                 case HCHAN_B: if ((i%4) == 2) flag = 1; break;
 151                 case HCHAN_VAL: if ((i%4) == 3) flag = 1; break;
 152                 case HCHAN_MAX: if ((i%4) == 3) flag = 1; break;
 153                 }
 154                 if (flag && histogram->histmap[i] > max) max = histogram->histmap[i];
 155         }
 156
 157         logmax = log(max);
 158         for (i=0; i<256; i++)
 159                 {
 160                 gint j;
 161                 glong v[4];
 162                 gint rplus = 0;
 163                 gint gplus = 0;
 164                 gint bplus = 0;
 165
 166                 v[0] = histogram->histmap[i+0*256]; // r
 167                 v[1] = histogram->histmap[i+1*256]; // g
 168                 v[2] = histogram->histmap[i+2*256]; // b
 169                 v[3] = histogram->histmap[i+3*256]; // value, max
 170
 171                 for (j=0; j<4; j++)
 172                         {
 173                         gint r = rplus;
 174                         gint g = gplus;
 175                         gint b = bplus;
 176                         gint max2 = 0;
 177                         gint k;
 178                         gulong pt;
 179
 180                         for (k=1; k<4; k++)
 181                                 if (v[k] > v[max2]) max2 = k;
 182
 183                         switch (max2)
 184                         {
 185                         case HCHAN_R: rplus = r = 255; break;
 186                         case HCHAN_G: gplus = g = 255; break;
 187                         case HCHAN_B: bplus = b = 255; break;
 188                         }
 189
 190                         switch(histogram->histogram_chan)
 191                         {
 192                         case HCHAN_MAX: r = 0; b = 0; g = 0; break;
 193                         case HCHAN_VAL: r = 0; b = 0; g = 0; break;
 194                         case HCHAN_R: g = 0; b = 0; break;
 195                         case HCHAN_G: r = 0; b = 0; break;
 196                         case HCHAN_B: r = 0; g = 0; break;
 197                         case HCHAN_RGB:
 198                                 if (r == 255 && g == 255 && b == 255) {
 199                                         r = 0;
 200                                         g = 0;
 201                                         b = 0;
 202                                 }
 203                                 break;
 204                         }
 205
 206                         if (v[max2] == 0)
 207                                 pt = 0;
 208                         else if (histogram->histogram_logmode)
 209                                 pt = ((float)log(v[max2]))/logmax*255;
 210                         else
 211                                 pt = ((float)v[max2])/max*255;
 212                         if (histogram->histogram_chan >= HCHAN_RGB
 213                             || max2 == histogram->histogram_chan)
 214                                 pixbuf_draw_line(pixbuf,
 215                                         0+5, height-255, 256, 256,
 216                                         i+5, height, i+5, height-pt,
 217                                         r, g, b, 255);
 218                         v[max2] = -1;
 219                         }
 220                 }
 221         return TRUE;
 222 }