thumb.h

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// $Id: thumb.h 751 2006-03-31 15:43:49Z alex $
/* @@tag:xara-cn@@ DO NOT MODIFY THIS LINE
================================XARAHEADERSTART===========================
 
               Xara LX, a vector drawing and manipulation program.
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----------------------------------

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=================================XARAHEADEREND============================
 */

// Thumbnail cache class for the library system
// Cheap 'n' Cheesy version knocked up by Richard
/***********************************************************************/

#ifndef INC_THUMB
#define INC_THUMB

#include "bitmap.h"
//#include "pathname.h"

typedef void * LP_SGTHUMBS_MOREINFO;

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

class Library;
class PathName;

// All the types of library
enum SGLibType
{
    SGLib_Blank = 0,    // Unknown library type
    SGLib_ClipArt,      // Clipart libraries
    SGLib_Font,         // Font libraries
    SGLib_Bitmap,       // Bitmap libs
    SGLib_Texture,      // Texture libs
    SGLib_Colour,       // Colour libs
    SGLib_Fractal,      // Fractal fill libs
    SGLib_ClipArt_WebThemes
};

// All thumbnail sizes
enum SGThumbSize
{
    SGThumb_Small = 0,  // Small thumbnails
    SGThumb_Medium,
    SGThumb_Large
};  


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

class SGThumbs : public CC_CLASS_MEMDUMP
{
    CC_DECLARE_MEMDUMP(SGThumbs)

public:

    SGThumbs();

    // Destructor - calls DeleteThumbnails() - returns all memory
    ~SGThumbs();

    // Constructor which sets the Size of thumbnails as well
    SGThumbs(PathName *Dir, SGLibType Type, SGThumbSize Size);
                                    
    // Get a thumbnail from the cache, disk, or if Directory == NULL try and generate it.
    BOOL GetThumbnail(UINT32 ID, BOOL Urgent, KernelBitmap **Result, PathName *File = NULL, LP_SGTHUMBS_MOREINFO MoreInfo = NULL);
    
    // Set thumbnail size - all returned thumbnails will be this size after this call
    BOOL SetSize(SGThumbSize Size);

    // Get current thumbnail size setting
    BOOL GetSize(SGThumbSize *Size);

    // Delete all thumbnail cache entries and return the memory
    BOOL DeleteThumbnails(void);

    // Debugging stuff - do not call
    void DumpCache(char *DumpFile);

    // Called when we want to change MaxThumbnails;
    static BOOL ResizeAllThumbCaches(INT32 Entries);

    // Access to the protected members
    inline PathName *GetDirectory() {return Directory;}
    inline SGLibType GetType() {return ThumbnailsLibType;}

protected:

    // Return encrypted thumbnail filename
    BOOL GetThumbnailName(UINT32 ID, String_8 *Result);

    // Sets the internal structures to sensible values
    // Assumes pointers not pointing to NULL are not pointing to memory
    BOOL InitThumbnails(SGLibType Type, SGThumbSize Size);

    // Return TRUE and an offset if ID is in cache
    BOOL OffsetInCache(UINT32 ID, UINT32 *Offset);
    
    // Find an unused slot, if there are non, use the one with the least Usage
    BOOL FindNewSlotInBuffer(UINT32 *Slot);

    // Load a thumbnail into a given slot
    BOOL LoadThumbnailIntoSlot(UINT32 Slot, UINT32 ID, PathName *ActualFile = NULL);

private:

    // Implementation helper function to check file existence
    BOOL OpenThumbnailFile( CCDiskFile* pFile, const PathName& ThumbFileName ) const;

protected:

    // Use a more fabby data-structure when we've got CCList access
    struct TN {
        UINT32 ID;              // ID for thumbnail held below
        UINT32 Usage;           // Usage count - used for finding new slots
        BOOL Valid;             // Are buffer and ID valid ?
        SGThumbSize Size;       // Size of thumbnail
        KernelBitmap *buffer;   // Pointer to actual data
    };

    // Array of thumbnails
    TN *Thumbnails;

    // Number of thumbnails in array
    INT32 Entries;

    // Place where all the thumbnails are being stored
    PathName *Directory;
    
    // Have we initialised the data-structures yet ?
    BOOL ThumbnailsInitialised;

    // Size of thumbnail to load, cache and return
    SGThumbSize ThumbnailsSize;

    // Type of library we're dealing with here
    SGLibType ThumbnailsLibType;

public:
    // Maximum number of entries in thumbnail cache
    static INT32 MaxThumbnails;
};

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

#endif

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