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| |
| #ifndef SD_SLIDESORTER_PAGE_CACHE_HXX |
| #define SD_SLIDESORTER_PAGE_CACHE_HXX |
| |
| #include "cache/SlsCacheContext.hxx" |
| #include <sal/types.h> |
| #include <tools/gen.hxx> |
| #include <boost/scoped_ptr.hpp> |
| #include <vcl/bitmap.hxx> |
| |
| |
| namespace sd { namespace slidesorter { namespace view { |
| class PageObjectViewObjectContact; |
| } } } |
| |
| namespace sd { namespace slidesorter { namespace cache { |
| |
| class GenericPageCache; |
| class RequestData; |
| |
| /** The page cache is responsible for the creation and storage of preview |
| bitmaps of pages that are shown by the slide sorter. |
| |
| <p>Bitmaps for previews and a cache are used to speed up the display |
| (painting) of the slide sorter. But, of course, we have to limit this |
| time-space-tradeoff by limiting the amount of space that can be use to |
| store bitmaps.</p> |
| |
| <p>There are several strategies employed by this class to shorten the |
| perceived time that is used to paint the slide sorter: |
| <ul> |
| <li>Rendering pages ahead of time. Additionally to rendering the |
| visible slides we try to render part or all of the slides that are not |
| (yet) visible. This, of course, makes sense only when the computer is |
| ohterwise idle while doing that.</li> |
| <li>When the size of the slides on the screen changes we mark the |
| bitmaps as needing an update but use them while the new bitmap in the |
| correct size is not available.</li> |
| <li>Give the UI the chance to handle user events between the rendering |
| of differe slides.</li> |
| <li>Limit the amount of space that may be used for storing preview |
| bitmaps and throw.</li> |
| </p> |
| |
| <p>There is another somewhat similar methods for requesting new previews: |
| GetPreviewBitmap() schedules a re-rendering (when necessary) and |
| returns the preview what is currently available, either as a preview of |
| the preview or, when nothing has changed since the last call, as the |
| final thing. |
| </p> |
| */ |
| class PageCache |
| { |
| public: |
| /** The page chache is created with a reference to the slide sorter so |
| that it has access to both the view and the model and so can fill |
| itself with requests for all or just the visible pages. |
| |
| It is the task of the PageCacheManager to create new objects of this |
| class. |
| */ |
| PageCache ( |
| const Size& rPreviewSize, |
| const bool bDoSuperSampling, |
| const SharedCacheContext& rpCacheContext); |
| |
| ~PageCache (void); |
| |
| void ChangeSize( |
| const Size& rPreviewSize, |
| const bool bDoSuperSampling); |
| |
| /** Request a preview bitmap for the specified page object in the |
| specified size. The returned bitmap may be a preview of the |
| preview, i.e. either a scaled (up or down) version of a previous |
| preview (of the wrong size) or an empty bitmap. In this case a |
| request for the generation of a new preview is created and inserted |
| into the request queue. When the preview is available in the right |
| size the page shape will be told to paint itself again. When it |
| then calls this method again if receives the correctly sized preview |
| bitmap. |
| @param rRequestData |
| This data is used to determine the preview. |
| @param bResize |
| When <TRUE/> then when the available bitmap has not the |
| requested size, it is scaled before it is returned. When |
| <FALSE/> then the bitmap is returned in the wrong size and it is |
| the task of the caller to scale it. |
| @return |
| Returns a bitmap that is either empty, contains a scaled (up or |
| down) version or is the requested bitmap. |
| */ |
| Bitmap GetPreviewBitmap ( |
| const CacheKey aKey, |
| const bool bResize); |
| |
| Bitmap GetMarkedPreviewBitmap ( |
| const CacheKey aKey, |
| const bool bResize); |
| void SetMarkedPreviewBitmap ( |
| const CacheKey aKey, |
| const Bitmap& rBitmap); |
| |
| /** When the requested preview bitmap does not yet exist or is not |
| up-to-date then the rendering of one is scheduled. Otherwise this |
| method does nothing. |
| */ |
| void RequestPreviewBitmap (const CacheKey aKey); |
| |
| /** Tell the cache that the bitmap associated with the given request |
| data is not up-to-date anymore. This will invalidate all previews |
| in other caches that represent the same page as well. |
| @param bRequestPreview |
| When <TRUE/> then a new preview is requested and will lead |
| eventually to a repaint of the associated page object. |
| */ |
| void InvalidatePreviewBitmap ( |
| const CacheKey aKey, |
| const bool bRequestPreview); |
| |
| /** Call this method when a view-object-contact object is being deleted |
| and does not need (a) its current bitmap in the cache and (b) a |
| requested new bitmap. |
| */ |
| void ReleasePreviewBitmap (const CacheKey aKey); |
| |
| /** Call this method when all preview bitmaps have to be generated anew. |
| This is the case when the size of the page objects on the screen has |
| changed or when the model has changed. |
| @param bUpdateCache |
| When this flags is <TRUE/> then requests for updated previews |
| are created. When it is <FALSE/> the existing previews are only |
| marked as not being up-to-date anymore. |
| */ |
| void InvalidateCache (const bool bUpdateCache = true); |
| |
| /** With the precious flag you can control whether a bitmap can be |
| removed or reduced in size to make room for other bitmaps or is so |
| precious that it will not touched. A typical use is to set the |
| precious flag for exactly the visible pages. |
| */ |
| void SetPreciousFlag (const CacheKey aKey, const bool bIsPrecious); |
| |
| void Pause (void); |
| void Resume (void); |
| |
| private: |
| ::boost::scoped_ptr<GenericPageCache> mpImplementation; |
| }; |
| |
| } } } // end of namespace ::sd::slidesorter::cache |
| |
| #endif |