colclist.cpp

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// $Id: colclist.cpp 1282 2006-06-09 09:46:49Z alex $
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 */
// colclist.cpp - the ColourContextList class

/*
*/


#include "camtypes.h"

#include "colcontx.h"
//#include "doccolor.h" - in camtypes.h [AUTOMATICALLY REMOVED]
//#include "ensure.h" - in camtypes.h [AUTOMATICALLY REMOVED]



CC_IMPLEMENT_MEMDUMP(ColourContextList, List)

// Declare smart memory handling in Debug builds
#define new CAM_DEBUG_NEW



/*  ColContextList
 *
 *  This is a 'global' pointer to a list of colour context objects
 *  It is used to ensure that no colour contexts are ever repeated (i.e. they
 *  are shared wherever possible). Only users of this file have access to this
 *  list.
 *  Access is via the static function ColourContextList::GetList()
 */

ColourContextList *ColourContextList::ColContextList = NULL;



/********************************************************************************************

>   static BOOL ColourContextList::InitColourContexts(void)

    Author:     Jason_Williams (Xara Group Ltd) <camelotdev@xara.com>
    Created:    11/04/94
    Inputs:     -
    Outputs:    -
    Returns:    TRUE if initialisation succeeded, else FALSE
                FALSE if it failed (most likely because of lack of memory)
    Purpose:    Initialises the Colour Context system, setting up the global list
                of default colour contexts which are shared by all documents.
                Called from app.cpp (must not be called more than once)
    Errors:     -

********************************************************************************************/

BOOL ColourContextList::InitColourContexts(void)
{
    ENSURE(ColContextList == NULL, "ColourContextList::InitColourContexts called more than once!");

    // First, create the global Colour context list in which all colour contexts
    // should be registered.
    ColContextList = new ColourContextList;
    if (ColContextList == NULL)
        return(FALSE);


    // Now, create an instance of each available colour context to provide the
    // global set of default colour contexts. Add each to the CCList.
    ColourContext *tempcc;

    tempcc = new ColourContextRGBT(NULL, 1.0);          // --- RGBT
    if (tempcc == NULL)
        return(FALSE);

    ColContextList->AddContext(&tempcc);
    ColourContext::SetGlobalDefault(COLOURMODEL_RGBT, tempcc);
    

    tempcc = new ColourContextCMYK(NULL);               // --- CMYK
    if (tempcc == NULL)
        return(FALSE);

    ColContextList->AddContext(&tempcc);
    ColourContext::SetGlobalDefault(COLOURMODEL_CMYK, tempcc);

    tempcc = new ColourContextHSVT(NULL);               // --- HSVT
    if (tempcc == NULL)
        return(FALSE);

    ColContextList->AddContext(&tempcc);
    ColourContext::SetGlobalDefault(COLOURMODEL_HSVT, tempcc);


    tempcc = new ColourContextGreyT(NULL);              // --- GreyT
    if (tempcc == NULL)
        return(FALSE);

    ColContextList->AddContext(&tempcc);
    ColourContext::SetGlobalDefault(COLOURMODEL_GREYT, tempcc);


#ifndef DISABLE_WEBRGBT
    tempcc = new ColourContextWebRGBT(NULL);            // --- WebRBGT
    if (tempcc == NULL)
        return(FALSE);

    ColContextList->AddContext(&tempcc);
    ColourContext::SetGlobalDefault(COLOURMODEL_WEBRGBT, tempcc);
#endif
                                                        // --- etc...

    return(TRUE);
}



/********************************************************************************************

>   static void ColourContextList::DeinitColourContexts(void)

    Author:     Jason_Williams (Xara Group Ltd) <camelotdev@xara.com>
    Created:    11/04/94
    Inputs:     -
    Outputs:    -
    Returns:    -
    Purpose:    De-initialises the Colour Context system, deleting the global list
                of default colour contexts which are shared by all documents.
                It is assumed that by this time the contexts should not be in use!
                Called from app.cpp (must not be caled more than once)
    Errors:     If any colour contexts are still in use when this function is
                called, you may get ENSURE failures.

********************************************************************************************/

void ColourContextList::DeinitColourContexts(void)
{
    ENSURE(ColContextList != NULL, "ColourContextList::DeinitColourContexts: but I haven't been initialised yet!");

    ColourContextArray  DefaultCCA;
    ColourContext       *DefaultCC;

    ColourContext::GetGlobalDefaults(&DefaultCCA);

    // Delete any of the default colour contexts that actually exist...
    for (INT32 cm = 0; cm < MAX_COLOURMODELS; cm++)
    {
        // Get the default colour context object for this colour model number
        // I do this via a copy of the real array to avoid the GetDefaultContext()
        // call giving an ENSURE failure in the case of a NULL context pointer.
        DefaultCC = DefaultCCA.Context[cm];
    
        if (DefaultCC != NULL)
        {
            // Set the default to NULL to ensure fewer rampant pointers are
            // left lying around (just to be on the safe side)
            ColourContext::SetGlobalDefault((ColourModel) cm, NULL);

            // Remove from the list. Note that we use RemoveItem to *force*
            // removal - RemoveContext only removes it if UsageCount == 0.
            ColContextList->RemoveItem(DefaultCC);

            // Decrement usage. This *should* take it down to zero usage, as
            // it is hoped that by the time we are called, all other users will
            // have released their claims. We do this to stop the ENSURE from
            // triggering when we delete the object.
            DefaultCC->DecrementUsage();

            // And delete the object
            delete DefaultCC;
        }
    }

    ENSURE(ColContextList->IsEmpty(), "ColourContextList::DeinitColourContexts: Some ColourContext(s) have not yet been released");

    // And delete the global list of contexts
    delete ColContextList;
    ColContextList = NULL;
}




/********************************************************************************************

>   void ColourContextList::AddContext(ColourContext **NewContext)

    Author:     Jason_Williams (Xara Group Ltd) <camelotdev@xara.com>
    Created:    11/04/94
    Inputs:     -
    Outputs:    An equivalent colour context that may now be used
    Returns:    -

    Purpose:    "Adds" the given colour context to the global list of available
                contexts. Note that if an identical context is already present in
                the list, the passed context will be DELETEd and the existing
                context will be returned in the given pointer. Thus, you must 
                only ever access the context through the returned pointer, rather
                than the pointer that you originally allocated with 'new'.

                i.e. to create and use a new context, you must:
                {
                    ColourContext *MyContext;

                    MyContext = new ColourContextABCD(1.0);     // Create new context
                    if (MyContext == NULL)
                        return(FAILED_MISERABLY);

                    ColContextList->AddContext(&MyContext);     // MyContext may change!

                    MyContext->DoSomething...                   // Use the context

                    ColContextList->RemoveContext(&MyContext);  // Have finished with it

                    // MyContext is now a NULL pointer, so don't use it!
                }

    Notes:      You must NOT delete the context when you finish with it. Instead, you
                must call ColourContextList::RemoveContext() when you have finished with
                the context. The context will be automatically deleted when it is no
                longer in use by anyone.

                (Sharing of contexts is currently disabled - see the comment in the
                function for details)

    Errors:     -
    SeeAlso:    ColourContext::ConvertColour; ColourContext::ConvertColourInternal

********************************************************************************************/

void ColourContextList::AddContext(ColourContext **NewContext)
{
    ENSURE(NewContext != NULL && *NewContext != NULL,
                "ColourContextList::AddContext called with NULL parameter!");

#if FALSE
/*
    Jason 22/5/96
    We no longer merge contexts because this makes for danger with the new ColourPlate
    system - it's now too easy to change a colourcontext by altering its ColourPlate,
    in which case shared contexts will cause extreme grief.

    ColourContext *Item;

    Item = (ColourContext *) GetHead();

    while (Item)
    {
        if (!Item->IsDifferent(*NewContext))    // Have found identical context
        {
            delete *NewContext;         // Delete the new context
            Item->IncrementUsage();     // Increment the new context's usage count
            *NewContext = Item;         // And return the existing one for use
            return;
        }

        Item = (ColourContext *) GetNext(Item);
    }

    // We have searched the entore list now but still have no equivalent context
    // so it is necessary to add this context to the list, and return it.
*/
#endif

    // However, we do check that the given context is not already in the list,
    // and ignore the caller if it's already there.
    ColourContext *Item;

    Item = (ColourContext *) GetHead();

    while (Item)
    {
        if (Item == *NewContext)
        {
            Item->IncrementUsage();     // Increment the context's usage count
            return;
        }

        Item = (ColourContext *) GetNext(Item);
    }

    AddTail(*NewContext);
    (*NewContext)->Init();

    // And by leaving the contents of the passed pointer alone, we return it.
}



/********************************************************************************************

>   void ColourContextList::RemoveContext(ColourContext **OldContext)

    Author:     Jason_Williams (Xara Group Ltd) <camelotdev@xara.com>
    Created:    11/04/94
    Inputs:     -
    Outputs:    -
    Returns:    -

    Purpose:    "Removes" the given colour context to the global list of available
                contexts. If the context is now no longer in use by anyone, it will
                be 'delete'd. The context pointer passed in will be set to NULL.
    Errors:     -
    SeeAlso:    ColourContextList::AddContext; ColourContext

********************************************************************************************/

void ColourContextList::RemoveContext(ColourContext **OldContext)
{
    ENSURE(OldContext != NULL && *OldContext != NULL,
                "ColourContextList::RemoveContext called with NULL parameter!");

    if (!((*OldContext)->DecrementUsage()))     // Not still in use, so discard it
    {
        RemoveItem(*OldContext);
        delete *OldContext;
    }

    *OldContext = NULL;
}

---