text: // 11 june 2015
  #include "uipriv_unix.h"
  
  /* Number of digits to represent an n-bit number in decimal: log10(2^n)
   * Simplify, truncate & add 1 for full digits, add 1 for negative numbers:
   *   -> n log10(2) + 2   <=   n * 0.302 + 2
   */
  #define MAX_STRLEN_FOR_NBITS_IN_DECIMAL(n) ((int)((n) * 302 / 1000) + 2)
  
  struct uiSlider {
  	uiUnixControl c;
  	GtkWidget *widget;
  	GtkRange *range;
  	GtkScale *scale;
  	void (*onChanged)(uiSlider *, void *);
  	void *onChangedData;
  	void (*onReleased)(uiSlider *, void *);
  	void *onReleasedData;
  	gulong onChangedSignal;
  	gchar tooltip[MAX_STRLEN_FOR_NBITS_IN_DECIMAL(sizeof(int) * CHAR_BIT) + 1];
  };
  
  uiUnixControlAllDefaults(uiSlider)
  
  static void _uiSliderUpdateToolTip(uiSlider *s)
  {
  	g_snprintf(s->tooltip, sizeof(s->tooltip)/sizeof(s->tooltip[0]), "%d", uiSliderValue(s));
  	gtk_widget_set_tooltip_text(s->widget, s->tooltip);
  }
  
  static void onChanged(GtkRange *range, gpointer data)
  {
  	uiSlider *s = uiSlider(data);
  
  	(*(s->onChanged))(s, s->onChangedData);
  
  	if (uiSliderHasToolTip(s))
  		_uiSliderUpdateToolTip(s);
  }
  
  static void defaultOnChanged(uiSlider *s, void *data)
  {
  	// do nothing
  }
  
  static gboolean onReleased(GtkWidget *w, GdkEventButton *event, gpointer data)
  {
  	uiSlider *s = uiSlider(data);
  
  	(*(s->onReleased))(s, s->onReleasedData);
  	return FALSE;
  }
  
  static void defaultOnReleased(uiSlider *s, void *data)
  {
  	// do nothing
  }
  
  int uiSliderValue(uiSlider *s)
  {
  	return gtk_range_get_value(s->range);
  }
  
  void uiSliderSetValue(uiSlider *s, int value)
  {
  	// we need to inhibit sending of ::value-changed because this WILL send a ::value-changed otherwise
  	g_signal_handler_block(s->range, s->onChangedSignal);
  	gtk_range_set_value(s->range, value);
  	g_signal_handler_unblock(s->range, s->onChangedSignal);
  }
  
  int uiSliderHasToolTip(uiSlider *s)
  {
  	return gtk_widget_get_has_tooltip(s->widget);
  }
  
  void uiSliderSetHasToolTip(uiSlider *s, int hasToolTip)
  {
  	gtk_widget_set_has_tooltip(s->widget, hasToolTip);
  
  	if (hasToolTip)
  		_uiSliderUpdateToolTip(s);
  }
  
  void uiSliderOnChanged(uiSlider *s, void (*f)(uiSlider *, void *), void *data)
  {
  	s->onChanged = f;
  	s->onChangedData = data;
  }
  
  void uiSliderOnReleased(uiSlider *s, void (*f)(uiSlider *, void *), void *data)
  {
  	s->onReleased = f;
  	s->onReleasedData = data;
  }
  
  void uiSliderSetRange(uiSlider *s, int min, int max)
  {
  	int temp;
  
  	if (min >= max) {
  		temp = min;
  		min = max;
  		max = temp;
  	}
  
  	// we need to inhibit sending of ::value-changed because this WILL send a ::value-changed otherwise
  	g_signal_handler_block(s->range, s->onChangedSignal);
  	gtk_range_set_range(s->range, min, max);
  	g_signal_handler_unblock(s->range, s->onChangedSignal);
  }
  
  uiSlider *uiNewSlider(int min, int max)
  {
  	uiSlider *s;
  	int temp;
  
  	if (min >= max) {
  		temp = min;
  		min = max;
  		max = temp;
  	}
  
  	uiUnixNewControl(uiSlider, s);
  
  	s->widget = gtk_scale_new_with_range(GTK_ORIENTATION_HORIZONTAL, min, max, 1);
  	s->range = GTK_RANGE(s->widget);
  	s->scale = GTK_SCALE(s->widget);
  
  	// do not draw value, show tooltip instead
  	gtk_scale_set_draw_value(s->scale, 0);
  	uiSliderSetHasToolTip(s, 1);
  
  	// ensure integers, just to be safe
  	gtk_scale_set_digits(s->scale, 0);
  
  	s->onChangedSignal = g_signal_connect(s->scale, "value-changed", G_CALLBACK(onChanged), s);
  	g_signal_connect(s->scale, "button-release-event", G_CALLBACK(onReleased), s);
  	uiSliderOnChanged(s, defaultOnChanged, NULL);
  	uiSliderOnReleased(s, defaultOnReleased, NULL);
  
  	return s;
  }
  