/*

    File:       GetDragHilite.c

    Contains:   This shows how to obtain the color that the Drag Manager uses to

                hilite regions when ShowDragHilite is called.  Check out GetDragHilite.c

                for the code.  

                Please note this is only how it's done presently.  Since it is undocumented

                it can and will change in the future.

    Written by: Nitin Ganatra   

    Copyright:  Copyright © 1994-1999 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

*/

#include <Windows.h>

#include <QuickDraw.h>

#define wTitleBarColor  4

#define wTingeLight     11

#define wTingeDark      12

unsigned short BlendValues(short lightValue, short darkValue);

void SetupDragHiliteColor(WindowPtr targetWindow);

/*-------------------------------------------------------------------------------------

BlendValues

    Blend two color values by 27%.  Be careful of overflow when multiplying

    a negative number.  Output should be light + 27% of difference between light

    and dark.

*/

unsigned short BlendValues(short lightValue, short darkValue)

{

    register short blender;

    blender = darkValue - lightValue;

    if ((unsigned long)lightValue > (unsigned long)darkValue)

        blender = -blender;                     // flip if subtraction would overflow

    blender = (unsigned short)((unsigned short)blender * .27);

                                                // 27% percent multiply

    if ((unsigned long)lightValue > (unsigned long)darkValue)

        blender = -blender;                     // flip it back if it was flipped the

                                                // first time.

    return ((unsigned short)(lightValue + blender));

}

/*-------------------------------------------------------------------------------------

SetupDragHiliteColor

    Set the fore color to the color used by the Drag Manager to hilite regions.

*/

void SetupDragHiliteColor(WindowPtr targetWindow)

{

    RGBColor windowRGB, lightRGB, darkRGB;

    AuxWinHandle auxHandle;                     // the default AuxWindow data

    CTabHandle winColorTable;                       // the window color table

    short i, j;                                 // for our color table search

    windowRGB.red = 0x8000;                     // Default to 50% gray.

    windowRGB.green = 0x8000;

    windowRGB.blue = 0x8000;

    // If we're using a window which uses System 7's 3D colors

    // then set the hilite color to a tinge for that window.

    GetAuxWin(targetWindow, &auxHandle);

    // do we have an aux window handle ?

    if (auxHandle != nil) {

        winColorTable = (**auxHandle).awCTable;

        // do we have a system 7 sized window color table?

        if ((**winColorTable).ctSize > wTitleBarColor) {

            // yes, now search for the tinge color, start at the end

            // because our tinge colors are usually last in the list.

            for (i = (**winColorTable).ctSize; i > 0; i--) {

                if ((**winColorTable).ctTable[i].value == wTingeLight) {

                    // light tinge found, set the window color to it

                    // in case we can't find the dark tinge.

                    lightRGB = (**winColorTable).ctTable[i].rgb;

                    windowRGB.red = lightRGB.red;

                    windowRGB.green = lightRGB.green;

                    windowRGB.blue = lightRGB.blue;

                    // we now need the wTingeDark entry to perform a blend.

                    // again, search from the end

                    for (j = (**winColorTable).ctSize; j > 0; j--)

                        if ((**winColorTable).ctTable[j].value == wTingeDark) {

                            // dark tinge found.  now do the blend

                            darkRGB = (**winColorTable).ctTable[j].rgb;

                            windowRGB.red = BlendValues((short)lightRGB.red, (short)darkRGB.red);

                            windowRGB.green = BlendValues((short)lightRGB.green, (short)darkRGB.green);

                            windowRGB.blue = BlendValues((short)lightRGB.blue, (short)darkRGB.blue);

                            // if the Color control panel was set to "Black and White", it makes the

                            // tinge colors black and black.  Use gray in this case

                            if ((windowRGB.red | windowRGB.green | windowRGB.blue) == 0) {

                                windowRGB.red = 0x8000;

                                windowRGB.green = 0x8000;

                                windowRGB.blue = 0x8000;

                            }

                            j = 0;              // bail from inner loop

                        }

                    i = 0;                      // bail from outer loop

                }

            }

        }

    }

    RGBForeColor(&windowRGB);       // finally, set it

}