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

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  * This file incorporates work covered by the following license notice:
  10  *
  11  *   Licensed to the Apache Software Foundation (ASF) under one or more
  12  *   contributor license agreements. See the NOTICE file distributed
  13  *   with this work for additional information regarding copyright
  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #pragma once
  21
  22 #include "SlsRequestQueue.hxx"
  23 #include <memory>
  24
  25 #include <vcl/bitmapex.hxx>
  26
  27 namespace sd::slidesorter::cache {
  28
  29 class BitmapCache;
  30 class QueueProcessor;
  31
  32 /** This basically is the implementation class for the PageCache class.
  33 */
  34 class GenericPageCache
  35 {
  36 public:
  37     /** The page cache is created with a reference to the SlideSorter and
  38         thus has access to both view and model.  This allows the cache to
  39         fill itself with requests for all pages or just the visible ones.
  40         @param rPreviewSize
  41             The size of the previews is expected in pixel values.
  42         @param bDoSuperSampling
  43             When <TRUE/> the previews are rendered larger and then scaled
  44             down to the requested size to improve image quality.
  45     */
  46     GenericPageCache (
  47         const Size& rPreviewSize,
  48         const bool bDoSuperSampling,
  49         const SharedCacheContext& rpCacheContext);
  50
  51     ~GenericPageCache();
  52
  53     /** Change the size of the preview bitmaps.  This may be caused by a
  54         resize of the slide sorter window or a change of the number of
  55         columns.
  56     */
  57     void ChangePreviewSize (
  58         const Size& rPreviewSize,
  59         const bool bDoSuperSampling);
  60
  61     /** Request a preview bitmap for the specified page object in the
  62         specified size.  The returned bitmap may be a preview of the preview,
  63         i.e. either a scaled (up or down) version of a previous preview (of
  64         the wrong size) or an empty bitmap.  In this case a request for the
  65         generation of a new preview is created and inserted into the request
  66         queue.  When the preview is available the page shape will be told to
  67         paint itself again.  When it then calls this method again if
  68         receives the correctly sized preview bitmap.
  69         @param rRequestData
  70             This data is used to determine the preview.
  71         @param bResize
  72             When <TRUE/> then when the available bitmap has not the
  73             requested size, it is scaled before it is returned.  When
  74             <FALSE/> then the bitmap is returned in the wrong size and it is
  75             the task of the caller to scale it.
  76         @return
  77             Returns a bitmap that is either empty, contains a scaled (up or
  78             down) version or is the requested bitmap.
  79     */
  80     BitmapEx GetPreviewBitmap (
  81         const CacheKey aKey,
  82         const bool bResize);
  83     BitmapEx GetMarkedPreviewBitmap (
  84         const CacheKey aKey);
  85     void SetMarkedPreviewBitmap (
  86         const CacheKey aKey,
  87         const BitmapEx& rMarkedBitmap);
  88
  89     /** When the requested preview bitmap does not yet exist or is not
  90         up-to-date then the rendering of one is scheduled.  Otherwise this
  91         method does nothing.
  92         @param rRequestData
  93             This data is used to determine the preview.
  94         @param bMayBeUpToDate
  95             This flag helps the method to determine whether an existing
  96             preview that matches the request is up to date.  If the caller
  97             knows that it is not then by passing <FALSE/> he tells us that we
  98             do not have to check the up-to-date flag a second time.  If
  99             unsure use <TRUE/>.
 100     */
 101     void RequestPreviewBitmap (
 102         const CacheKey aKey,
 103         const bool bMayBeUpToDate);
 104
 105     /** Tell the cache to replace the bitmap associated with the given
 106         request data with a new one that reflects recent changes in the
 107         content of the page object.
 108         @return
 109             When the key is known then return <TRUE/>.
 110     */
 111     bool InvalidatePreviewBitmap (const CacheKey aKey);
 112
 113     /** Call this method when all preview bitmaps have to be generated anew.
 114         This is the case when the size of the page objects on the screen has
 115         changed or when the model has changed.
 116     */
 117     void InvalidateCache ();
 118
 119     /** With the precious flag you can control whether a bitmap can be
 120         removed from the cache or reduced in size to make room for other
 121         bitmaps or is so precious that it will not be touched.  A typical
 122         use is to set the precious flag for the visible pages.
 123     */
 124     void SetPreciousFlag (const CacheKey aKey, const bool bIsPrecious);
 125
 126     void Pause();
 127     void Resume();
 128
 129 private:
 130     std::shared_ptr<BitmapCache> mpBitmapCache;
 131
 132     RequestQueue maRequestQueue;
 133
 134     std::unique_ptr<QueueProcessor> mpQueueProcessor;
 135
 136     SharedCacheContext mpCacheContext;
 137
 138     /** The current size of preview bitmaps.
 139     */
 140     Size maPreviewSize;
 141
 142     bool mbDoSuperSampling;
 143
 144     /** Both bitmap cache and queue processor are created on demand by this
 145         method.
 146     */
 147     void ProvideCacheAndProcessor();
 148 };
 149
 150 } // end of namespace ::sd::slidesorter::cache
 151
 152 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */