//*****************************************************************************
//
// slider.c - A simple slider widget class.
//
// Copyright (c) 2008-2010 Texas Instruments Incorporated.  All rights reserved.
// Software License Agreement
// 
// Texas Instruments (TI) is supplying this software for use solely and
// exclusively on TI's microcontroller products. The software is owned by
// TI and/or its suppliers, and is protected under applicable copyright
// laws. You may not combine this software with "viral" open-source
// software in order to form a larger program.
// 
// THIS SOFTWARE IS PROVIDED "AS IS" AND WITH ALL FAULTS.
// NO WARRANTIES, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT
// NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. TI SHALL NOT, UNDER ANY
// CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
// DAMAGES, FOR ANY REASON WHATSOEVER.
// 
// This is part of revision 5821 of the Stellaris Graphics Library.
//
//*****************************************************************************

#include "driverlib/debug.h"
#include "grlib/grlib.h"
#include "grlib/widget.h"
#include "grlib/slider.h"

//*****************************************************************************
//
//! \addtogroup slider_api
//! @{
//
//*****************************************************************************

//*****************************************************************************
//
// Make sure min and max are defined.
//
//*****************************************************************************
#ifndef min
#define min(a, b)               (((a) < (b)) ? (a) : (b))
#endif

#ifndef max
#define max(a, b)               (((a) < (b)) ? (b) : (a))
#endif

//*****************************************************************************
//
// Converts a slider value to a position on the display.
//
// \param pSlider is a pointer to the slider widget for which the conversion is
// being requested.
// \param lValue is the slider value that is to be converted to a position.
//
// Converts a value within the range represented by a slider into a position
// along the slider control.  The function converts taking into account the
// slider position and style as well as its range.
//
// \return Returns the screen position (x coordinate for horizontal sliders or
// y coordinate for vertical ones) that represents the value passed.
//
//*****************************************************************************
static short
SliderValueToPosition(tSliderWidget *pSlider, long lValue)
{
    unsigned short usSize;
    long lRange;
    long lPos;

    //
    // First look for the trivial cases.  To ensure correct display and remove
    // artifacts caused by rounding errors, we specifically catch the cases
    // where the value provided is at either end of the slider range.  In these
    // cases we return values that are outside the actual widget rectangle.
    // This is detected while drawing so that the relevant bars fill the full
    // area and don't leave single pixel lines at either end even when the
    // slider is at full scale.  These cases also catch out-of-range values
    // and peg them at one end of the range or the other.
    //
    // First check for values at the top of the range.
    //
    if(lValue >= pSlider->lMax)
    {
        //
        // Is this a vertical slider?
        //
        if(pSlider->ulStyle & SL_STYLE_VERTICAL)
        {
            //
            // Vertical slider case.  Return the top position.
            //
            lPos = pSlider->sBase.sPosition.sYMin - 1;

            //
            // Adjust by 1 to move past the border if this widget has one.
            //
            if(pSlider->ulStyle & SL_STYLE_OUTLINE)
            {
                lPos++;
            }
        }
        else
        {
            //
            // Horizontal slider case.  Return the rightmost position.
            //
            lPos = pSlider->sBase.sPosition.sXMax + 1;

            //
            // Adjust by 1 to move past the border if this widget has one.
            //
            if(pSlider->ulStyle & SL_STYLE_OUTLINE)
            {
                lPos--;
            }
        }
        return((short)lPos);
    }

    //
    // Now look at the bottom end of the range.
    //
    if(lValue <= pSlider->lMin)
    {
        //
        // Is this a vertical slider?
        //
        if(pSlider->ulStyle & SL_STYLE_VERTICAL)
        {
            //
            // Vertical slider case.  Return the bottom position.
            //
            lPos = pSlider->sBase.sPosition.sYMax + 1;

            //
            // Adjust by 1 to move past the border if this widget has one.
            //
            if(pSlider->ulStyle & SL_STYLE_OUTLINE)
            {
                lPos--;
            }
        }
        else
        {
            //
            // Horizontal slider case.  Return the leftmost position.
            //
            lPos = pSlider->sBase.sPosition.sXMin - 1;

            //
            // Adjust by 1 to move past the border if this widget has one.
            //
            if(pSlider->ulStyle & SL_STYLE_OUTLINE)
            {
                lPos++;
            }
        }
        return((short)lPos);
    }

    //
    // What is the length of the whole slider?
    //
    if(pSlider->ulStyle & SL_STYLE_VERTICAL)
    {
        //
        // Vertical slider case.
        //
        usSize = (pSlider->sBase.sPosition.sYMax -
                  pSlider->sBase.sPosition.sYMin) + 1;
    }
    else
    {
        //
        // Horizontal slider case.
        //
        usSize = (pSlider->sBase.sPosition.sXMax -
                  pSlider->sBase.sPosition.sXMin) + 1;
    }

    //
    // Adjust the range if the slider has an outline (which removes 2 pixels).
    //
    if(pSlider->ulStyle & SL_STYLE_OUTLINE)
    {
        usSize -= 2;
    }

    //
    // Determine the range of the slider (the number of individual integers
    // represented by the widget).
    //
    lRange = (pSlider->lMax - pSlider->lMin) + 1;

    //
    // Now we can determine the relevant position relative to the start of the
    // slider.
    //
    lPos = ((lValue * (long)usSize) / lRange);

    //
    // Clip the calculated position to the valid range based on the slider
    // size.
    //
    lPos = max(lPos, 0);
    lPos = min(lPos, (long)usSize - 1);

    //
    // Adjust for the position of the widget relative to the screen origin.
    //
    if(pSlider->ulStyle & SL_STYLE_VERTICAL)
    {
        //
        // Vertical case - adjust the Y coordinate.
        //
        lPos = pSlider->sBase.sPosition.sYMax - lPos;
    }
    else
    {
        //
        // Horizontal case - adjust the X coordinate.
        //
        lPos += pSlider->sBase.sPosition.sXMin;
    }

    //
    // If the widget has an outline, make sure to adjust for this too.
    //
    lPos += ((pSlider->ulStyle & SL_STYLE_OUTLINE) ? 1 : 0);

    //
    // Convert to the expected return type and hand the caller the final
    // value.
    //
    return((short)lPos);
}

//*****************************************************************************
//
// Converts a slider position to a value within its range.
//
// \param pSlider is a pointer to the slider widget for which the conversion is
// being requested.
// \param usPos is a position within the slider.  This is an x coordinate for
// a horizontal slider or a y coordinate for a vertical one.  In both cases,
// the position is relative to the display origin.
//
// Converts a screen position into a value within the current range of the
// slider.  The function converts taking into account the slider position and
// style as well as its range.
//
// \return Returns the slider value represented by the position passed.
//
//*****************************************************************************
static long
SliderPositionToValue(tSliderWidget *pSlider, short sPos)
{
    short sMax;
    short sMin;
    long lValue;

    //
    // Determine the bounds of the control on the display.
    //
    if(pSlider->ulStyle & SL_STYLE_VERTICAL)
    {
        sMax = pSlider->sBase.sPosition.sYMax;
        sMin = pSlider->sBase.sPosition.sYMin;
    }
    else
    {
        sMax = pSlider->sBase.sPosition.sXMax;
        sMin = pSlider->sBase.sPosition.sXMin;
    }

    //
    // Adjust for the outline if present.
    //
    if(pSlider->ulStyle & SL_STYLE_OUTLINE)
    {
        sMax--;
        sMin--;
    }

    //
    // If the control is too narrow, this is a bug but handle it gracefully
    // rather than throwing a divide by zero later.
    //
    ASSERT(sMax > sMin);
    if(sMax <= sMin)
    {
        return(pSlider->lMin);
    }

    //
    // Clip the supplied position to the extent of the widget.
    //
    sPos = min(sMax, sPos);
    sPos = max(sMin, sPos);

    //
    // Adjust the position to make it relative to the start of the slider.
    //
    if(pSlider->ulStyle & SL_STYLE_VERTICAL)
    {
        sPos = sMax - sPos;
    }

    else
    {
        sPos -= sMin;
    }

    //
    // Calculate the value represented by this position.
    //
    lValue = ((long)sPos * ((pSlider->lMax - pSlider->lMin) + 1)) /
             (long)((sMax - sMin) + 1);

    //
    // Adjust for the bottom of the value range.
    //
    lValue += pSlider->lMin;

    //
    // Hand the conversion result back to the caller.
    //
    return(lValue);
}

//*****************************************************************************
//
//! Draws a slider.
//!
//! \param pWidget is a pointer to the slider widget to be drawn.
//! \param pDirty is the subrectangle of the widget which is to be redrawn.
//! This is expressed in screen coordinates.
//!
//! This function draws a slider on the display.  This is called in response to
//! a \b #WIDGET_MSG_PAINT message or when the slider position changes.
//!
//! \return None.
//
//*****************************************************************************
static void
SliderPaint(tWidget *pWidget, tRectangle *pDirty)
{
    tRectangle sClipRect, sValueRect, sEmptyRect, sActiveClip;
    tSliderWidget *pSlider;
    tContext sCtx;
    long lX, lY, bIntersect;
    short sPos;

    //
    // Check the arguments.
    //
    ASSERT(pWidget);

    //
    // Convert the generic widget pointer into a slider widget pointer.
    //
    pSlider = (tSliderWidget *)pWidget;

    //
    // Initialize a drawing context.
    //
    GrContextInit(&sCtx, pWidget->pDisplay);

    //
    // Initialize the clipping region based on the update rectangle passed.
    //
    bIntersect = GrRectIntersectGet(pDirty, &(pSlider->sBase.sPosition),
                                    &sClipRect);
    GrContextClipRegionSet(&sCtx, &sClipRect);

    //
    // Draw the control outline if necessary.
    //
    if(pSlider->ulStyle & SL_STYLE_OUTLINE)
    {
        //
        // Outline the slider with the outline color.
        //
        GrContextForegroundSet(&sCtx, pSlider->ulOutlineColor);
        GrRectDraw(&sCtx, &(pWidget->sPosition));

        //
        // Adjust the clipping rectangle to prevent the outline from being
        // corrupted later.
        //
        if(sClipRect.sXMin == pWidget->sPosition.sXMin)
        {
            sClipRect.sXMin++;
        }

        if(sClipRect.sYMin == pWidget->sPosition.sYMin)
        {
            sClipRect.sYMin++;
        }

        if(sClipRect.sXMax == pWidget->sPosition.sXMax)
        {
            sClipRect.sXMax--;
        }

        if(sClipRect.sYMax == pWidget->sPosition.sYMax)
        {
            sClipRect.sYMax--;
        }
    }

    //
    // Determine the position associated with the current slider value.
    //
    sPos = SliderValueToPosition(pSlider, pSlider->lValue);

    //
    // Remember this so that the dirty rectangle code in the click handler
    // draws the correct thing the first time it is called.
    //
    pSlider->sPos = sPos;

    //
    // Determine the rectangles for the active and empty portions of the
    // widget.
    //
    if(pSlider->ulStyle & SL_STYLE_VERTICAL)
    {
        //
        // Determine the rectangle corresponding to the bottom (value) portion
        // of the slider.
        //
        sValueRect.sXMin = pWidget->sPosition.sXMin;