sd/source/ui/slidesorter/cache/SlsGenericPageCache.hxx

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  19
  20 #ifndef INCLUDED_SD_SOURCE_UI_SLIDESORTER_CACHE_SLSGENERICPAGECACHE_HXX
  21 #define INCLUDED_SD_SOURCE_UI_SLIDESORTER_CACHE_SLSGENERICPAGECACHE_HXX
  22
  23 #include "SlsRequestQueue.hxx"
  24 #include <memory>
  25
  26 #include <vcl/bitmapex.hxx>
  27
  28 namespace sd { namespace slidesorter { namespace cache {
  29
  30 class BitmapCache;
  31 class QueueProcessor;
  32
  33 /** This basically is the implementation class for the PageCache class.
  34 */
  35 class GenericPageCache
  36 {
  37 public:
  38     /** The page cache is created with a reference to the SlideSorter and
  39         thus has access to both view and model.  This allows the cache to
  40         fill itself with requests for all pages or just the visible ones.
  41         @param rPreviewSize
  42             The size of the previews is expected in pixel values.
  43         @param bDoSuperSampling
  44             When <TRUE/> the previews are rendered larger and then scaled
  45             down to the requested size to improve image quality.
  46     */
  47     GenericPageCache (
  48         const Size& rPreviewSize,
  49         const bool bDoSuperSampling,
  50         const SharedCacheContext& rpCacheContext);
  51
  52     ~GenericPageCache();
  53
  54     /** Change the size of the preview bitmaps.  This may be caused by a
  55         resize of the slide sorter window or a change of the number of
  56         columns.
  57     */
  58     void ChangePreviewSize (
  59         const Size& rPreviewSize,
  60         const bool bDoSuperSampling);
  61
  62     /** Request a preview bitmap for the specified page object in the
  63         specified size.  The returned bitmap may be a preview of the preview,
  64         i.e. either a scaled (up or down) version of a previous preview (of
  65         the wrong size) or an empty bitmap.  In this case a request for the
  66         generation of a new preview is created and inserted into the request
  67         queue.  When the preview is available the page shape will be told to
  68         paint itself again.  When it then calls this method again if
  69         receives the correctly sized preview bitmap.
  70         @param rRequestData
  71             This data is used to determine the preview.
  72         @param bResize
  73             When <TRUE/> then when the available bitmap has not the
  74             requested size, it is scaled before it is returned.  When
  75             <FALSE/> then the bitmap is returned in the wrong size and it is
  76             the task of the caller to scale it.
  77         @return
  78             Returns a bitmap that is either empty, contains a scaled (up or
  79             down) version or is the requested bitmap.
  80     */
  81     BitmapEx GetPreviewBitmap (
  82         const CacheKey aKey,
  83         const bool bResize);
  84     BitmapEx GetMarkedPreviewBitmap (
  85         const CacheKey aKey);
  86     void SetMarkedPreviewBitmap (
  87         const CacheKey aKey,
  88         const BitmapEx& rMarkedBitmap);
  89
  90     /** When the requested preview bitmap does not yet exist or is not
  91         up-to-date then the rendering of one is scheduled.  Otherwise this
  92         method does nothing.
  93         @param rRequestData
  94             This data is used to determine the preview.
  95         @param bMayBeUpToDate
  96             This flag helps the method to determine whether an existing
  97             preview that matches the request is up to date.  If the caller
  98             knows that it is not then by passing <FALSE/> he tells us that we
  99             do not have to check the up-to-date flag a second time.  If
 100             unsure use <TRUE/>.
 101     */
 102     void RequestPreviewBitmap (
 103         const CacheKey aKey,
 104         const bool bMayBeUpToDate);
 105
 106     /** Tell the cache to replace the bitmap associated with the given
 107         request data with a new one that reflects recent changes in the
 108         content of the page object.
 109         @return
 110             When the key is known then return <TRUE/>.
 111     */
 112     bool InvalidatePreviewBitmap (const CacheKey aKey);
 113
 114     /** Call this method when all preview bitmaps have to be generated anew.
 115         This is the case when the size of the page objects on the screen has
 116         changed or when the model has changed.
 117     */
 118     void InvalidateCache ();
 119
 120     /** With the precious flag you can control whether a bitmap can be
 121         removed from the cache or reduced in size to make room for other
 122         bitmaps or is so precious that it will not be touched.  A typical
 123         use is to set the precious flag for the visible pages.
 124     */
 125     void SetPreciousFlag (const CacheKey aKey, const bool bIsPrecious);
 126
 127     void Pause();
 128     void Resume();
 129
 130 private:
 131     std::shared_ptr<BitmapCache> mpBitmapCache;
 132
 133     RequestQueue maRequestQueue;
 134
 135     std::unique_ptr<QueueProcessor> mpQueueProcessor;
 136
 137     SharedCacheContext mpCacheContext;
 138
 139     /** The current size of preview bitmaps.
 140     */
 141     Size maPreviewSize;
 142
 143     bool mbDoSuperSampling;
 144
 145     /** Both bitmap cache and queue processor are created on demand by this
 146         method.
 147     */
 148     void ProvideCacheAndProcessor();
 149 };
 150
 151 } } } // end of namespace ::sd::slidesorter::cache
 152
 153 #endif
 154
 155 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */