SpinButton Signal Oddness...

[Ron Tarrant]

I posted this over on the gtkD forum, but thought I'd post here, 
too, to get a wider pool of expertise:

> I hooked up some signals to a few SpinButtons and I'm getting 
> double-firings, but not all the time.
> 
> The buttons are as follows:
> - double,
> - float with no extra precision, and
> - float with precision down to 1000ths.
> 
> The results when they're hooked up to the onValueChanged signal:
> 
> - the double never double-fires (how's that for irony?),
> - the float with no extra precision always double-fires, and
> - the 1000ths float only double-fires as it's crossing a 
> boundary of 3/1000ths in either direction.
> 
> With the onOutput signal:
> 
> - double always double-fires,
> - float with no extra precision always double-fires except for 
> the first time it's clicked, and
> - 1000ths float always double-fires.
> 
> When I say "double-fires" I mean that writeln() in a callback 
> reports the value before and after the value changes, so 
> something like:
> 
> click:
> - 0.1
> - 0.2
> click:
> - 0.2
> - 0.3
> click:
> - 0.3
> - 0.4
> 
> Here's the code:
> 
> ```
> // SpinButton madness
> 
> import std.stdio;
> 
> import gtk.MainWindow;
> import gtk.Main;
> import gtk.Box;
> import gtk.Widget;
> import gtk.SpinButton;
> import gtk.Adjustment;
> import gtk.c.types;
> 
> void main(string[] args)
> {
> 	Main.init(args);
> 
> 	TestRigWindow myTestRig = new TestRigWindow("Test Rig with 
> SpinButton");
> 	
> 	Main.run();
> 	
> } // main()
> 
> 
> class TestRigWindow : MainWindow
> {
> 	AppBox appBox;
> 	
> 	this(string title)
> 	{
> 		super(title);
> 		addOnDestroy(&quitApp);
> 		
> 		appBox = new AppBox();
> 		add(appBox);
> 		
> 		showAll();
> 
> 	} // this() CONSTRUCTOR
> 	
> 		
> 	void quitApp(Widget widget)
> 	{
> 		writeln("Bye.");
> 		Main.quit();
> 		
> 	} // quitApp()
> 
> } // class myAppWindow
> 
> 
> class AppBox : Box
> {
> 	DoubleSpinButton doubleSpinButton;
> 	FloatSpinButton floatSpinButton;
> 	PrecisionSpinButton precisionSpinButton;
> 		
> 	this()
> 	{
> 		super(Orientation.VERTICAL, 10);
> 		
> 		doubleSpinButton = new DoubleSpinButton();
> 		packStart(doubleSpinButton, false, false, 0);
> 
> 		floatSpinButton = new FloatSpinButton();
> 		packStart(floatSpinButton, false, false, 0);
> 
> 		precisionSpinButton = new PrecisionSpinButton();
> 		packStart(precisionSpinButton, false, false, 0);
> 
> 	} // this()
> 
> } // class AppBox
> 
> 
> class DoubleSpinButton : SpinButton
> {
> 	double minimum = -48;
> 	double maximum = 48;
> 	double step = 2;
> 
> 	Adjustment adjustment;
> 	double initialValue = 0;
> 	double pageIncrement = 8;
> 	double pageSize = 0;
> 	
> 	this()
> 	{
> 		super(minimum, maximum, step);
> 
> 		adjustment = new Adjustment(initialValue, minimum, maximum, 
> step, pageIncrement, pageSize);
> 		setAdjustment(adjustment);
> //		addOnValueChanged(&valueChanged);
> 		addOnOutput(&outputValue);
> 		
> 	} // this()
> 
> 	void valueChanged(SpinButton sb)
> 	{
> 		writeln("Double", getValue());
> 		
> 	} // valueChanged()
> 
> 	
> 	bool outputValue(SpinButton sb)
> 	{
> 		writeln("Double: ", getValue());
> 		
> 		return(false);
> 		
> 	} // outputValue()
> 	
> } // class DoubleSpinButton
> 
> 
> class FloatSpinButton : SpinButton
> {
> 	float minimum = -1.0;
> 	float maximum = 1.0;
> 	float step = .1;
> 
> 	Adjustment adjustment;
> 	float initialValue = 0.0;
> 	float pageIncrement = 0.5;
> 	float pageSize = 0.0;
> 	
> 	this()
> 	{
> 		super(minimum, maximum, step);
> 		adjustment = new Adjustment(initialValue, minimum, maximum, 
> step, pageIncrement, pageSize);
> 		setAdjustment(adjustment);
> 		setWrap(true);
> 		
> 		// WHY do these trigger twice?
> 		addOnValueChanged(&valueChanged);
> //		addOnOutput(&outputValue);
> 		
> 	} // this()
> 
> 	void valueChanged(SpinButton sb)
> 	{
> 		writeln("Float Standard", getValue());
> 		
> 	} // valueChanged()
> 
> 	
> 	bool outputValue(SpinButton sb)
> 	{
> 		writeln("Float Standard: ", getValue());
> 		
> 		return(false);
> 		
> 	} // outputValue()
> 	
> } // class FloatSpinButton
> 
> 
> class PrecisionSpinButton : SpinButton
> {
> 	float minimum = -1.0;
> 	float maximum = 1.0;
> 	float step = .001;
> 	uint precision = 3;
> 
> 	Adjustment adjustment;
> 	float initialValue = 0.0;
> 	float pageIncrement = 0.01;
> 	float pageSize = 0.0;
> 	
> 	this()
> 	{
> 		super(minimum, maximum, step);
> 		adjustment = new Adjustment(initialValue, minimum, maximum, 
> step, pageIncrement, pageSize);
> 		setAdjustment(adjustment);
> 		setDigits(precision);
> 
> //		addOnValueChanged(&valueChanged);
> 		addOnOutput(&outputValue);
> 		
> 	} // this()
> 
> 	void valueChanged(SpinButton sb)
> 	{
> 		writeln("Float Precision", getValue());
> 		
> 	} // valueChanged()
> 
> 	
> 	bool outputValue(SpinButton sb)
> 	{
> 		writeln("Float Precision: ", getValue());
> 		
> 		return(false);
> 		
> 	} // outputValue()
> 	
> } // class PrecisionSpinButton
> 
> ```