static void
gimp_histogram_editor_info_update (GimpHistogramEditor *editor)
{
GimpHistogramView *view = GIMP_HISTOGRAM_BOX (editor->box)->view;
GimpHistogram *hist = editor->histogram;
if (hist)
{
gint n_bins;
gdouble pixels;
gdouble count;
gchar text[12];
n_bins = gimp_histogram_n_bins (hist);
pixels = gimp_histogram_get_count (hist, view->channel, 0, n_bins - 1);
count = gimp_histogram_get_count (hist, view->channel,
view->start, view->end);
g_snprintf (text, sizeof (text), "%.3f",
gimp_histogram_get_mean (hist, view->channel,
view->start, view->end));
gtk_label_set_text (GTK_LABEL (editor->labels[0]), text);
g_snprintf (text, sizeof (text), "%.3f",
gimp_histogram_get_std_dev (hist, view->channel,
view->start, view->end));
gtk_label_set_text (GTK_LABEL (editor->labels[1]), text);
g_snprintf (text, sizeof (text), "%.3f",
gimp_histogram_get_median (hist, view->channel,
view->start,
view->end));
gtk_label_set_text (GTK_LABEL (editor->labels[2]), text);
g_snprintf (text, sizeof (text), "%d", (gint) pixels);
gtk_label_set_text (GTK_LABEL (editor->labels[3]), text);
g_snprintf (text, sizeof (text), "%d", (gint) count);
gtk_label_set_text (GTK_LABEL (editor->labels[4]), text);
g_snprintf (text, sizeof (text), "%.1f", (pixels > 0 ?
(100.0 * count / pixels) :
0.0));
gtk_label_set_text (GTK_LABEL (editor->labels[5]), text);
}
else
{
gint i;
for (i = 0; i < 6; i++)
gtk_label_set_text (GTK_LABEL (editor->labels[i]), NULL);
}
}
static void
equalize_lut_setup (GimpLut *lut,
GimpHistogram *hist,
gint n_channels)
{
gint i, k, j;
hist_lut_struct hlut;
gdouble pixels_per_value;
gdouble desired;
gdouble sum, dif;
g_return_if_fail (lut != NULL);
g_return_if_fail (hist != NULL);
/* Find partition points */
pixels_per_value = gimp_histogram_get_count (hist,
GIMP_HISTOGRAM_VALUE,
0, 255) / 256.0;
for (k = 0; k < n_channels; k++)
{
/* First and last points in partition */
hlut.part[k][0] = 0;
hlut.part[k][256] = 256;
/* Find intermediate points */
j = 0;
sum = (gimp_histogram_get_channel (hist, k, 0) +
gimp_histogram_get_channel (hist, k, 1));
for (i = 1; i < 256; i++)
{
desired = i * pixels_per_value;
while (sum < desired && j < 256)
{
j++;
sum += gimp_histogram_get_channel (hist, k, j + 1);
}
/* Nearest sum */
dif = sum - gimp_histogram_get_channel (hist, k, j);
if ((sum - desired) > (dif / 2.0))
hlut.part[k][i] = j;
else
hlut.part[k][i] = j + 1;
}
}
gimp_lut_setup (lut, (GimpLutFunc) equalize_lut_func, &hlut, n_channels);
}
gdouble
gimp_histogram_get_std_dev (GimpHistogram *histogram,
GimpHistogramChannel channel,
gint start,
gint end)
{
gint i;
gdouble dev = 0.0;
gdouble count;
gdouble mean;
g_return_val_if_fail (histogram != NULL, 0.0);
/* the gray alpha channel is in slot 1 */
if (histogram->n_channels == 3 && channel == GIMP_HISTOGRAM_ALPHA)
channel = 1;
if (! histogram->values ||
start > end ||
(channel == GIMP_HISTOGRAM_RGB && histogram->n_channels < 4) ||
(channel != GIMP_HISTOGRAM_RGB && channel >= histogram->n_channels))
return 0.0;
mean = gimp_histogram_get_mean (histogram, channel, start, end);
count = gimp_histogram_get_count (histogram, channel, start, end);
if (count == 0.0)
count = 1.0;
for (i = start; i <= end; i++)
{
gdouble value;
if (channel == GIMP_HISTOGRAM_RGB)
{
value = (HISTOGRAM_VALUE (GIMP_HISTOGRAM_RED, i) +
HISTOGRAM_VALUE (GIMP_HISTOGRAM_GREEN, i) +
HISTOGRAM_VALUE (GIMP_HISTOGRAM_BLUE, i));
}
else
{
value = gimp_histogram_get_value (histogram, channel, i);
}
dev += value * SQR (i - mean);
}
return sqrt (dev / count);
}
gdouble
gimp_histogram_get_count (GimpHistogram *histogram,
GimpHistogramChannel channel,
gint start,
gint end)
{
gint i;
gdouble count = 0.0;
g_return_val_if_fail (histogram != NULL, 0.0);
/* the gray alpha channel is in slot 1 */
if (histogram->n_channels == 3 && channel == GIMP_HISTOGRAM_ALPHA)
channel = 1;
if (channel == GIMP_HISTOGRAM_RGB)
return (gimp_histogram_get_count (histogram,
GIMP_HISTOGRAM_RED, start, end) +
gimp_histogram_get_count (histogram,
GIMP_HISTOGRAM_GREEN, start, end) +
gimp_histogram_get_count (histogram,
GIMP_HISTOGRAM_BLUE, start, end));
if (! histogram->values ||
start > end ||
channel >= histogram->n_channels)
return 0.0;
start = CLAMP (start, 0, 255);
end = CLAMP (end, 0, 255);
for (i = start; i <= end; i++)
count += HISTOGRAM_VALUE (channel, i);
return count;
}
gint
gimp_histogram_get_median (GimpHistogram *histogram,
GimpHistogramChannel channel,
gint start,
gint end)
{
gint i;
gdouble sum = 0.0;
gdouble count;
g_return_val_if_fail (histogram != NULL, -1);
/* the gray alpha channel is in slot 1 */
if (histogram->n_channels == 3 && channel == GIMP_HISTOGRAM_ALPHA)
channel = 1;
if (! histogram->values ||
start > end ||
(channel == GIMP_HISTOGRAM_RGB && histogram->n_channels < 4) ||
(channel != GIMP_HISTOGRAM_RGB && channel >= histogram->n_channels))
return 0;
start = CLAMP (start, 0, 255);
end = CLAMP (end, 0, 255);
count = gimp_histogram_get_count (histogram, channel, start, end);
if (channel == GIMP_HISTOGRAM_RGB)
for (i = start; i <= end; i++)
{
sum += (HISTOGRAM_VALUE (GIMP_HISTOGRAM_RED, i) +
HISTOGRAM_VALUE (GIMP_HISTOGRAM_GREEN, i) +
HISTOGRAM_VALUE (GIMP_HISTOGRAM_BLUE, i));
if (sum * 2 > count)
return i;
}
else
for (i = start; i <= end; i++)
{
sum += HISTOGRAM_VALUE (channel, i);
if (sum * 2 > count)
return i;
}
return -1;
}
gdouble
gimp_histogram_get_mean (GimpHistogram *histogram,
GimpHistogramChannel channel,
gint start,
gint end)
{
gint i;
gdouble mean = 0.0;
gdouble count;
g_return_val_if_fail (histogram != NULL, 0.0);
/* the gray alpha channel is in slot 1 */
if (histogram->n_channels == 3 && channel == GIMP_HISTOGRAM_ALPHA)
channel = 1;
if (! histogram->values ||
start > end ||
(channel == GIMP_HISTOGRAM_RGB && histogram->n_channels < 4) ||
(channel != GIMP_HISTOGRAM_RGB && channel >= histogram->n_channels))
return 0.0;
start = CLAMP (start, 0, 255);
end = CLAMP (end, 0, 255);
if (channel == GIMP_HISTOGRAM_RGB)
{
for (i = start; i <= end; i++)
mean += (i * HISTOGRAM_VALUE (GIMP_HISTOGRAM_RED, i) +
i * HISTOGRAM_VALUE (GIMP_HISTOGRAM_GREEN, i) +
i * HISTOGRAM_VALUE (GIMP_HISTOGRAM_BLUE, i));
}
else
{
for (i = start; i <= end; i++)
mean += i * HISTOGRAM_VALUE (channel, i);
}
count = gimp_histogram_get_count (histogram, channel, start, end);
if (count > 0.0)
return mean / count;
return mean;
}
void
gimp_levels_config_stretch_channel (GimpLevelsConfig *config,
GimpHistogram *histogram,
GimpHistogramChannel channel)
{
gdouble count;
gdouble bias = 0.006;
gint n_bins;
gint i;
g_return_if_fail (GIMP_IS_LEVELS_CONFIG (config));
g_return_if_fail (histogram != NULL);
g_object_freeze_notify (G_OBJECT (config));
config->gamma[channel] = 1.0;
config->low_output[channel] = 0.0;
config->high_output[channel] = 1.0;
n_bins = gimp_histogram_n_bins (histogram);
count = gimp_histogram_get_count (histogram, channel, 0, n_bins - 1);
if (count == 0.0)
{
config->low_input[channel] = 0.0;
config->high_input[channel] = 0.0;
}
else
{
gdouble new_count;
gdouble percentage;
gdouble next_percentage;
/* Set the low input */
new_count = 0.0;
for (i = 0; i < (n_bins - 1); i++)
{
new_count += gimp_histogram_get_value (histogram, channel, i);
percentage = new_count / count;
next_percentage = (new_count +
gimp_histogram_get_value (histogram,
channel,
i + 1)) / count;
if (fabs (percentage - bias) < fabs (next_percentage - bias))
{
config->low_input[channel] = (gdouble) (i + 1) / (n_bins - 1);
break;
}
}
/* Set the high input */
new_count = 0.0;
for (i = (n_bins - 1); i > 0; i--)
{
new_count += gimp_histogram_get_value (histogram, channel, i);
percentage = new_count / count;
next_percentage = (new_count +
gimp_histogram_get_value (histogram,
channel,
i - 1)) / count;
if (fabs (percentage - bias) < fabs (next_percentage - bias))
{
config->high_input[channel] = (gdouble) (i - 1) / (n_bins - 1);
break;
}
}
}
g_object_notify (G_OBJECT (config), "gamma");
g_object_notify (G_OBJECT (config), "low-input");
g_object_notify (G_OBJECT (config), "high-input");
g_object_notify (G_OBJECT (config), "low-output");
g_object_notify (G_OBJECT (config), "high-output");
g_object_thaw_notify (G_OBJECT (config));
}
