/*

    File:       ScrollBars.c

    Contains:   List Manager stuff and associated routines

    Written by: Chris White 

    Copyright:  Copyright © 1996-1999 by Apple Computer, Inc., All Rights Reserved.

                You may incorporate this Apple sample source code into your program(s) without

                restriction. This Apple sample source code has been provided "AS IS" and the

                responsibility for its operation is yours. You are not permitted to redistribute

                this Apple sample source code as "Apple sample source code" after having made

                changes. If you're going to re-distribute the source, we require that you make

                it clear in the source that the code was descended from Apple sample source

                code, but that you've made changes.

    Change History (most recent first):

                8/6/1999    Karl Groethe    Updated for Metrowerks Codewarror Pro 2.1

*/

#pragma segment Core

// System Includes

// Application Includes

#ifndef __BAREBONES__

    #include "BareBones.h"

#endif

#ifndef __PROTOTYPES__

    #include "Prototypes.h"

#endif

static ControlRef   gControl;

static SInt32       gValueSlop;

static SInt32       gSaveValue;

static SInt32       gStartValue;

static RgnHandle    gSaveClip = nil;

static SInt32   CalcValueFromPoint ( ControlRef theControl, Point thePoint );

static void     DisableDrawing ( void );

static void     EnableDrawing ( void );

OSErr BeginThumbTracking ( ControlRef theControl )

{

    const SInt32 kMinLowMem = 512;

    OSErr   theErr = noErr;

    Size    theGrow;

    Point   thePoint;

    gControl = theControl;

    gStartValue = GetControlValue ( theControl );

    gValueSlop = 0;

    GetMouse ( &thePoint );

    gValueSlop = GetControlValue ( theControl ) - CalcValueFromPoint ( theControl, thePoint );  

    // Preflight memory for call to NewRgn

    if ( MaxMem ( &theGrow ) < kMinLowMem )

    {

        theErr = memFullErr;

        goto CleanupAndBail;

    }

    gSaveClip = NewRgn ( );

    DisableDrawing ( );

CleanupAndBail:

    // Don't have to do any cleanup here

    return theErr;

}

void EndThumbTracking ( void )

{

    EnableDrawing ( );

    DisposeRgn ( gSaveClip );

    SetControlValue ( gControl, gSaveValue );

    return;

}

pascal void ScrollThumbActionProc ( void )

{

    SInt32          theValue;

    WindowRef       theWindow;

    ControlRef      theControl = gControl;

    Point           thePoint;

    Rect            theRect;

    tWindowInfoPtr  theInfo;

    theWindow = (*theControl)->contrlOwner;

    theInfo = (tWindowInfoPtr) GetWRefCon ( theWindow );

    #if DEBUGGING

    if ( theInfo == nil ) DebugStr ( "\p theInfo == nil" );

    #endif

    theRect = (*theControl)->contrlRect;

    if ( theControl == theInfo->hScrollBar )

        InsetRect ( &theRect, -kThumbTrackLengthSlop, -kThumbTrackWidthSlop );

    else

        InsetRect ( &theRect, -kThumbTrackWidthSlop, -kThumbTrackLengthSlop );

    // Assumes the port is correctly set up

    GetMouse ( &thePoint );

    if ( PtInRect ( thePoint, &theRect ) )

        theValue = CalcValueFromPoint ( theControl, thePoint );

    else

        theValue = gStartValue;

    if ( theValue != GetControlValue ( theControl ) )

    {

        EnableDrawing ( );

        gSaveValue = theValue;

        SetControlValue ( theControl, theValue );

        UpdateWindowContent ( theWindow );

        DisableDrawing ( );

    }

    return;

}

pascal void ScrollControlActionProc ( ControlRef theControl, SInt16 thePart )

{

    WindowRef       theWindow;

    tWindowInfoPtr  theInfo;

    SInt32          theValue,

                    theDistance,

                    limitValue;

    theWindow = (*theControl)->contrlOwner;

    theInfo = (tWindowInfoPtr) GetWRefCon ( theWindow );

    #if DEBUGGING

    if ( theInfo == nil ) DebugStr ( "\p theInfo == nil" );

    #endif

    switch ( thePart )

    {

        case kControlUpButtonPart:

        case kControlDownButtonPart:

            theDistance = 10;

        break;

        case kControlPageUpPart:

        case kControlPageDownPart:

            if ( theControl == theInfo->hScrollBar )

                theDistance = (theWindow->portRect.right - theWindow->portRect.left)

                                                - kScrollBarWidth - kPageOverlap;

            else

                theDistance = (theWindow->portRect.bottom - theWindow->portRect.top)

                                                - kScrollBarWidth - kPageOverlap;

        break;

    }

    theValue = GetControlValue ( theControl );

    switch ( thePart )

    {

        case kControlUpButtonPart:

        case kControlPageUpPart:

            limitValue = GetControlMinimum ( theControl );

            if ( theValue - theDistance < limitValue )

                theValue = limitValue;

            else

                theValue -= theDistance;

        break;

        case kControlDownButtonPart:

        case kControlPageDownPart:

            limitValue = GetControlMaximum ( theControl );

            if ( theValue + theDistance > limitValue )

                theValue = limitValue;

            else

                theValue += theDistance;

        break;

    }

    SetControlValue ( theControl, theValue );

    UpdateWindowContent ( theWindow );

    return;

}

static SInt32 CalcValueFromPoint ( ControlRef theControl, Point thePoint )

{

    SInt32          theValue,

                    theRange,

                    theDistance,

                    thePin;

    Rect            theRect;

    WindowRef       theWindow;

    tWindowInfoPtr  theInfo;

    theWindow = (*theControl)->contrlOwner;

    theInfo = (tWindowInfoPtr) GetWRefCon ( theWindow );

    #if DEBUGGING

    if ( theInfo == nil ) DebugStr ( "\p theInfo == nil" );

    #endif

    theRect = (*theControl)->contrlRect;

    theRange = GetControlMaximum ( theControl ) - GetControlMinimum ( theControl );

    if ( theControl == theInfo->vScrollBar )

    {

        // Scroll distance adjusted for scroll arrows and the thumb

        theDistance = theRect.bottom - theRect.top - kTotalWidthAdjust;

        // Pin thePoint to the middle of the thumb

        thePin = theRect.top + (kTotalWidthAdjust / 2);

        theValue = ((thePoint.v - thePin) * theRange) / theDistance;

    }

    else

    {

        // Scroll distance adjusted for scroll arrows and the thumb

        theDistance = theRect.right - theRect.left - kTotalWidthAdjust;

        // Pin thePoint to the middle of the thumb

        thePin = theRect.left + (kTotalWidthAdjust / 2);

        theValue = ((thePoint.h - thePin) * theRange) / theDistance;

    }

    theValue += gValueSlop;

    if ( theValue < GetControlMinimum ( theControl ) )

        theValue = GetControlMinimum ( theControl );

    else if ( theValue > GetControlMaximum ( theControl ) )

        theValue = GetControlMaximum ( theControl );

    return theValue;

}

static void DisableDrawing ( void )

{

    Rect    nullRect = { 0, 0, 0, 0 };

    GetClip ( gSaveClip );

    ClipRect ( &nullRect );

    return;

}

static void EnableDrawing ( void )

{

    SetClip ( gSaveClip );

    return;

}