Logarithmic scale depending on variable

histogram.cc

@@ -25,6 +25,7 @@ int histogram_pressed_x;                // window x-coordinate when pressing a b
 int histogram_released_x;               // window x-coordinate when releasing a button
 int histogram_pressed = 0;              // indicates button pressed or not
 int histogram_zoomed = 0;               // indicates zoom
+int histogram_log = 1;                  // logarithmic or linear scale
 
 extern GtkBuilder *_builder_;			// work around for threads
 
@@ -72,7 +73,10 @@ void cb_histogramda_draw(GtkWidget *area, cairo_t *cr, int w, int h, gpointer da
 		int histogram_scale = histogram_width - 1 > 0 ? histogram_width - 1 : 1;
     	for (int i = 0; i < histogram_width; i++) {
 	  px = HISTOGRAM_MARGIN + ((clientw-HISTOGRAM_MARGIN*2) * i) / histogram_scale;
+	  if (histogram_log)
 	    py2 = (clienth-HISTOGRAM_MARGIN) - ((clienth-HISTOGRAM_MARGIN*2) * log10(histogram[chan][histogram_zoom_start+i]+1) / log10(histogram_max));
+	  else
+	    py2 = (clienth-HISTOGRAM_MARGIN) - ((clienth-HISTOGRAM_MARGIN*2) * histogram[chan][histogram_zoom_start+i] / histogram_max);
 
     		if (i == 0) cairo_move_to(cr, px, py2);
     		else 		cairo_line_to(cr, px, py2);