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	1	/////////////////////////////////////////////////////////////////////////////
	2	// Name: wx/cocoa/private/scrollview.h
	3	// Purpose: wxWindowCocoaScrollView
	4	// Author: David Elliott
	5	// Modified by:
	6	// Created: 2008/02/14
	7	// RCS-ID: $Id$
	8	// Copyright: (c) 2003- David Elliott
	9	// Licence: wxWindows licence
	10	/////////////////////////////////////////////////////////////////////////////
	11
	12	#ifndef _WX_COCOA_SCROLLVIEW_H__
	13	#define _WX_COCOA_SCROLLVIEW_H__
	14
	15	@class NSScroller;
	16
	17	// ========================================================================
	18	// wxWindowCocoaScrollView
	19	// ========================================================================
	20	class wxWindowCocoaScrollView: protected wxCocoaNSView
	21	{
	22	wxDECLARE_NO_COPY_CLASS(wxWindowCocoaScrollView);
	23	public:
	24	wxWindowCocoaScrollView(wxWindow *owner);
	25	virtual ~wxWindowCocoaScrollView();
	26	inline WX_NSScrollView GetNSScrollView() { return m_cocoaNSScrollView; }
	27	void ClientSizeToSize(int &width, int &height);
	28	void DoGetClientSize(int x, int y) const;
	29	void Encapsulate();
	30	void Unencapsulate();
	31
	32	// wxWindow calls this to do the work. Note that we don't have the refresh parameter
	33	// because wxWindow handles that itself.
	34	void SetScrollbar(int orientation, int position, int thumbSize, int range);
	35	int GetScrollPos(wxOrientation orient);
	36	void SetScrollPos(wxOrientation orient, int position);
	37	int GetScrollRange(wxOrientation orient);
	38	int GetScrollThumb(wxOrientation orient);
	39	void ScrollWindow(int dx, int dy, const wxRect*);
	40	void UpdateSizes();
	41
	42	void _wx_doScroller(NSScroller *sender);
	43
	44	protected:
	45	wxWindowCocoa *m_owner;
	46	WX_NSScrollView m_cocoaNSScrollView;
	47	virtual void Cocoa_FrameChanged(void);
	48	virtual void Cocoa_synthesizeMouseMoved(void) {}
	49	/*!
	50	Flag as to whether we're scrolling for a native view or a custom
	51	wxWindow. This controls the scrolling behaviour. When providing
	52	scrolling for a native view we don't catch scroller action messages
	53	and thus don't send scroll events and we don't actually scroll the
	54	window when the application calls ScrollWindow.
	55
	56	When providing scrolling for a custom wxWindow, we make the NSScroller
	57	send their action messages to us which we in turn package as wx window
	58	scrolling events. At this point, the window will not physically be
	59	scrolled. The application will most likely handle the event by calling
	60	ScrollWindow which will do the real scrolling. On the other hand,
	61	the application may instead not call ScrollWindow until some threshold
	62	is reached. This causes the window to only scroll in steps which is
	63	what, for instance, wxScrolledWindow does.
	64	*/
	65	bool m_isNativeView;
	66	/*!
	67	The range as the application code wishes to see it. That is, the
	68	range from the last SetScrollbar call for the appropriate dimension.
	69	The horizontal dimension is the first [0] element and the vertical
	70	dimension the second [1] element.
	71
	72	In wxMSW, a SCROLLINFO with nMin=0 and nMax=range-1 is used which
	73	gives exactly range possible positions so long as nPage (which is
	74	the thumb size) is less than or equal to 1.
	75	*/
	76	int m_scrollRange[2];
	77	/*!
	78	The thumb size is intended to reflect the size of the visible portion
	79	of the scrolled document. As the document size increases, the thumb
	80	visible thumb size decreases. As document size decreases, the visible
	81	thumb size increases. However, the thumb size on wx is defined in
	82	terms of scroll units (which are effectively defined by the scroll
	83	range) and so increasing the number of scroll units to reflect increased
	84	document size will have the effect of decreasing the visible thumb
	85	size even though the number doesn't change.
	86
	87	It's also important to note that subtracting the thumb size from the
	88	full range gives you the real range that can be used. Microsoft
	89	defines nPos (the current scrolling position) to be within the range
	90	from nMin to nMax - max(nPage - 1, 0). We know that wxMSW code always
	91	sets nMin = 0 and nMax = range -1. So let's algebraically reduce the
	92	definition of the maximum allowed position:
	93
	94	Begin:
	95	= nMax - max(nPage - 1, 0)
	96	Substitute (range - 1) for nMax and thumbSize for nPage:
	97	= range - 1 - max(thumbSize - 1, 0)
	98	Add one inside the max conditional and subtract one outside of it:
	99	= range - 1 - (max(thumbSize - 1 + 1, 1) - 1)
	100	Reduce some constants:
	101	= range - 1 - (max(thumbSize, 1) - 1)
	102	Distribute the negative across the parenthesis:
	103	= range - 1 - max(thumbSize, 1) + 1
	104	Reduce the constants:
	105	= range - max(thumbSize, 1)
	106
	107	Also keep in mind that thumbSize may never be greater than range but
	108	can be equal to it. Thus for the smallest possible thumbSize there
	109	are exactly range possible scroll positions (numbered from 0 to
	110	range - 1) and for the largest possible thumbSize there is exactly
	111	one possible scroll position (numbered 0).
	112	*/
	113	int m_scrollThumb[2];
	114
	115	/*!
	116	The origin of the virtual coordinate space expressed in terms of client
	117	coordinates. Starts at (0,0) and each call to ScrollWindow accumulates
	118	into it. Thus if the user scrolls the window right (thus causing the
	119	contents to move left with respect to the client origin, the
	120	application code (typically wxScrolledWindow) will be called with
	121	dx of -something, for example -20. This is added to m_virtualOrigin
	122	and thus m_virtualOrigin will be (-20,0) in this example.
	123	*/
	124	wxPoint m_virtualOrigin;
	125	private:
	126	wxWindowCocoaScrollView();
	127	};
	128
	129	#endif //ndef _WX_COCOA_SCROLLVIEW_H__