wm_checkscrollpos.c

MCB2300_ucgui_LCD320240.rar LPC2368的uc/gui的移植

/*
*********************************************************************************************************
*   											 uC/GUI
*   					 Universal graphic software for embedded applications
*
*   					(c) Copyright 2002, Micrium Inc., Weston, FL
*   					(c) Copyright 2002, SEGGER Microcontroller Systeme GmbH
*
*   		   礐/GUI is protected by international copyright laws. Knowledge of the
*   		   source code may not be used to write a similar product. This file may
*   		   only be used in accordance with a license and should not be redistributed
*   		   in any way. We appreciate your understanding and fairness.
*
----------------------------------------------------------------------
File		: WM_SetScrollPos.c
Purpose 	: Windows manager, optional routines
----------------------------------------------------------------------
*/

#include "WM_Intern.h"

#if GUI_WINSUPPORT

/*********************************************************************
*
*   	Public code
*
**********************************************************************
*/



/*********************************************************************
*
*   	WM_CheckScrollBounds
*
*/
void WM_CheckScrollBounds(WM_SCROLL_STATE *pScrollState)
{
	int Max;
	Max = pScrollState->NumItems - pScrollState->PageSize;
	if (Max < 0)
	{
		Max = 0;
	}
	/* Make sure scroll pos is in bounds */
	if (pScrollState->v < 0)
	{
		pScrollState->v = 0;
	}
	if (pScrollState->v > Max)
	{
		pScrollState->v = Max;
	}
}


/*********************************************************************
*
*   	WM_CheckScrollPos
*
* Return value: Difference between old an new Scroll value.
*   			Therefor 0 if settings have not changed.
*/
int WM_CheckScrollPos(WM_SCROLL_STATE *pScrollState, int Pos, int LowerDist, int UpperDist)
{
	int vOld;
	vOld = pScrollState->v;
	/* Check upper limit */
	if (Pos > pScrollState->v + pScrollState->PageSize - 1)
	{
		pScrollState->v = Pos - (pScrollState->PageSize - 1) + UpperDist;
	}
	/* Check lower limit */
	if (Pos < pScrollState->v)
	{
		pScrollState->v = Pos - LowerDist;
	}
	WM_CheckScrollBounds(pScrollState);
	return pScrollState->v - vOld;
}

/*********************************************************************
*
*   	WM_SetScrollValue
*
* Return value: Difference between old an new Scroll value.
*   			Therefor 0 if settings have not changed.
*/
int WM_SetScrollValue(WM_SCROLL_STATE *pScrollState, int v)
{
	int vOld;
	vOld = pScrollState->v;
	pScrollState->v = v;
	WM_CheckScrollBounds(pScrollState);
	return pScrollState->v - vOld;
}

#else
void WM_CheckScrollPos_c(void)
{
} /* avoid empty object files */
#endif

/*************************** End of file ****************************/