fntcache.h

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// $Id: fntcache.h 1282 2006-06-09 09:46:49Z alex $
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================================XARAHEADERSTART===========================
 
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 */
/*
 * */
// Definition of the Text tools FontCache
// See FNTCACHE.DOC for an explanation




#ifndef INC_FNTCACHE
#define INC_FNTCACHE

//#include "ccobject.h" - in camtypes.h [AUTOMATICALLY REMOVED]
//#include "listitem.h" - in camtypes.h [AUTOMATICALLY REMOVED]
#include "gcache.h"
//#include "txtattr.h" - in camtypes.h [AUTOMATICALLY REMOVED]
#include <limits.h>


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

>   class FontCache

    Author:     Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com>

    Created:    16/1/95
    
    Purpose:    The FontCache maps a character description to a  path for that character. 
                There only ever needs to be a single instance of the FontCache so all
                data and methods are static.
    
    Documentation:  specs\fntcache.doc
    
    SeeAlso:    CharDescription
    SeeAlso:    PathHandleItem

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


// The simpler FontCache defined below is simply a wrapper around a CamCache

class FontCache
{
    // All data/methods must be static

public:
    // This method must be called before we can use the CamCache
    static BOOL Init();

    static BOOL InitCalled; // = FALSE, set to TRUE only if Init function has been called

    // This function must be called to destroy the font cache
    static void DeInit(); 

    // Returns path for character specified by ChDesc 
    static BOOL GetPath(CharDescription& ChDesc, INT32** Points, BYTE** Types, UINT32 *Length);
    
    // The path cache is used to map a Path Handle to path data
    static CamCache* pPathCache;

    static BOOL  GetBounds(DocRect* pBounds, CharDescription& CharDesc);
    static BOOL  CalcDefaultCharBounds(DocRect* pRect, CharDescription& CharDesc);
    static Path* CreateDefaultCharPath(CharDescription& CharDesc);
private:
    static INT32 BoundsEntries;     // number of entries in the char bounds cache


};


#endif

#if 0

//
// WE ARE NOT USING THE HI-TECH FONT CACHE AT THE MOMENT
//
//

// ------------------------------------------------------------------------------------------
// Constants

// The cache size is the maximum number of characters to cache
#define CACHE_SIZE 255

// We will allocate two arrays CacheA, CacheB each of length CACHE_LIST_SIZE. Each of these arrays
// will never be more than 1/3 full
//#define CACHE_LIST_SIZE (1.5 * CACHE_SIZE); // This MUST be prime or performance is naff
#define CACHE_LIST_SIZE 383

//#define MAX_ITEMS_IN_CACHE_LIST = (CACHE_LIST_SIZE/3)
#define MAX_ITEMS_IN_CACHE_LIST 255

// We can never allocate a path handle larger than MAX_FONT_HANDLE 
#define MAX_PATH_HANDLE (UINT32_MAX - 1)


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

>   class ClassName : public CCObject

    Author:     Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com>
    Created:    16/1/95
    Purpose:    Each character we need to render can be uniquely identified by a 16 bit 
                unicode character + various attributes which define the appearance of the 
                characters font. The CharDescription structure defined below is used to 
                identify a character. This structure is similar to the windows LOGFONT 
                structure.

    SeeAlso:    FontCache

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


class CharDescription : public CCObject
{
    // Important !!!
    // Whenever this structure is changed, you must remember to update the operator= and
    // operator== methods !!!
    CC_DECLARE_DYNAMIC(CharDescription)

    public:

    INT32 operator==(const CharDescription& ChDesc); 
    CharDescription& operator=(CharDescription& ChDesc);

    INT32 Height;
    INT32 Width;
    //INT32 lfEscapement;
    //INT32 lfOrientation;
    //INT32 lfWeight;
    BYTE Italic;
    //BYTE lfUnderline;
    //BYTE lfStrikeOut;
    //BYTE lfCharSet;
    //BYTE lfOutPrecision;
    //BYTE lfClipPrecision;
    //BYTE lfQuality;
    //BYTE lfPitchAndFamily;    
    WCHAR CharCode;             // A 16 bit unicode value
}; 


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

>   class PathHandleItem: public CCObject

    Author:     Simon_Maneggio (Xara Group Ltd) <camelotdev@xara.com>
    Created:    16/1/95
    Purpose:    We store PathHandle Items in lists pointed to by the CacheA and CacheB arrays
                within the FontCache.They associate a CharDescription with a unique path handle.

    SeeAlso:    FontCache
    SeeAlso:    CharDescription

********************************************************************************************/
/*
    Technical notes: We want to minimise the size of the PathHandleItem. This is why they are
    not derived from ListItem. Instead they store a single Next pointer so that they can be 
    linked together.

*/                                                                                                     


class PathHandleItem: public CCObject
{  
    CC_DECLARE_DYNAMIC(PathHandleItem)

    public:
    PathHandleItem(CharDescription& ChDesc, UINT32 PathHandle);

    CharDescription CharDesc;   // Identifies a character
    UINT32 PathHandle;
    // Removes this item from the specified list
    void RemoveItemFromList(PathHandleItem** pHead); 
    PathHandleItem* Next;       // pointer to the Next PathHandleItem
};




class FontCache
{
    // All data/methods must be static

    public:
    
    // This method must be called before we can use the CamCache
    static BOOL Init();

    static BOOL InitCalled; // = FALSE, set to TRUE only if Init function has been called

    // This function must be called to destroy the font cache
    static void DeInit(); 

    // Returns path for character specified by ChDesc 
    static BOOL GetPath(CharDescription& ChDesc, INT32** Points, BYTE** Types, UINT32 *Length);
    
    #ifdef _DEBUG
    static void Test1();
    #endif


    private:
    
    static UINT32 GetPathHandle(CharDescription& ChDesc); 

    // Given a CharDescription returns an integer hash key in the range 0..CACHE_LIST_SIZE
    static UINT32 GetHashKey(CharDescription& ChDesc);

    // The two caches used to map a CharacterDescription to a Path Handle 
    static PathHandleItem* CacheA   [CACHE_LIST_SIZE]; 
    static PathHandleItem* CacheB   [CACHE_LIST_SIZE]; 
    
    // Searches a PathHandleItem list for ChDesc item
    static PathHandleItem* GetPathHandleItem(PathHandleItem* ListHead, CharDescription&  ChDesc); 
    
    // Deletes all items in specified cache
    static void DeleteCacheLists(PathHandleItem** pCacheArray);
    
    static void TidyCache();

    static PathHandleItem** PrimaryC;   // Points to the current primary cache (CacheA or CacheB)
    static PathHandleItem** SecondaryC; // Points to the current secondary cache (CacheA or CacheB)


    static BOOL GetPathFromPathCache(UINT32 PathHandle, CharDescription& ChDesc, 
                                    INT32** Points, BYTE** Types, UINT32* Length);
    
    // The path cache is used to map a Path Handle to path data
    static CamCache* pPathCache;
    
    static PathHandleItem* AllocatePathHandle(UINT32 Key, CharDescription& ChDesc);

    // The next PathHandle to assign to a new CharDescPathHandleItem we add to the cache
    static UINT32 NextUniquePathHandle; 

    // The number of items stored in the primary cache
    static UINT32 NumItemsInPrimaryCache; 

    // Can be deleted
    #ifdef _DEBUG
    static UINT32 PHits;
    static UINT32 SHits;
    static UINT32 Misses;
    #endif

        
};

#endif

---