office-gobmx/include/drawinglayer/primitive2d/BufferedDecompositionPrimitive2D.hxx
Noel Grandin 3b83c6ac80 make BufferedDecompositionPrimitive2D store a Primitive2DReference..
.. instead of a Primitive2DContainer.

The container very frequently contains only a single item, since
the decomposition method often sticks only a single top-level node
in there, so it turns out to be a net loss overall, memory
consumption-wise.

Also, if we return a single Primitive2DReference from
a BufferedDecomposition, that maximises the sharing of
data between the BufferedDecomposition objects at the
bottom of the decomposed tree, and objects higher up.

Change-Id: Iaf272e60e2997299cc35a1bd209c51b6b79e9a8b
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/162976
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
2024-02-12 11:36:05 +01:00

113 lines
5.2 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
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* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* This file incorporates work covered by the following license notice:
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed
* with this work for additional information regarding copyright
* ownership. The ASF licenses this file to you under the Apache
* License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.apache.org/licenses/LICENSE-2.0 .
*/
#pragma once
#include <drawinglayer/drawinglayerdllapi.h>
#include <drawinglayer/primitive2d/Primitive2DContainer.hxx>
#include <drawinglayer/primitive2d/baseprimitive2d.hxx>
#include <salhelper/timer.hxx>
namespace drawinglayer::geometry
{
class ViewInformation2D;
}
namespace drawinglayer::primitive2d
{
/** BufferedDecompositionPrimitive2D class
Baseclass for all C++ implementations of css::graphic::XPrimitive2D
which want to buffer the decomposition result
Buffering the decomposition is the most-used buffering and is thus used my most
primitive implementations which support a decomposition as base class.
The buffering is done by holding the last decomposition in the local parameter
maBuffered2DDecomposition. The default implementation of get2DDecomposition checks
if maBuffered2DDecomposition is empty. If yes, it uses create2DDecomposition
to create the content. In all cases, maBuffered2DDecomposition is returned.
For view-dependent primitives derived from Primitive2DBufferDecomposition more needs
to be done when the decomposition depends on parts of the parameter ViewInformation2D.
This defines a standard method for processing these:
Implement a view-dependent get2DDecomposition doing the following steps:
(a) Locally extract needed parameters from ViewInformation2D to new, local parameters
(this may be a complete local copy of ViewInformation2D)
(b) If a buffered decomposition exists, check if one of the new local parameters
differs from the corresponding locally remembered (as member) ones. If yes,
clear maBuffered2DDecomposition
(d) call baseclass::get2DDecomposition which will use create2DDecomposition
to fill maBuffered2DDecomposition if it's empty
(e) copy the new local parameters to the corresponding locally remembered ones
to identify if a new decomposition is needed at the next call
(f) return maBuffered2DDecomposition
*/
class DRAWINGLAYERCORE_DLLPUBLIC BufferedDecompositionPrimitive2D : public BasePrimitive2D
{
private:
// exclusive helper for Primitive2DFlusher
friend void flushBufferedDecomposition(BufferedDecompositionPrimitive2D&);
/// a sequence used for buffering the last create2DDecomposition() result
Primitive2DReference maBuffered2DDecomposition;
/// offer callback mechanism to flush buffered content timer-based
::rtl::Reference<::salhelper::Timer> maCallbackTimer;
mutable std::mutex maCallbackLock;
sal_uInt16 maCallbackSeconds;
protected:
/** access methods to maBuffered2DDecomposition. The usage of this methods may allow
later thread-safe stuff to be added if needed. Only to be used by getDecomposition()
implementations for buffering the last decomposition.
*/
const Primitive2DReference& getBuffered2DDecomposition() const;
void setBuffered2DDecomposition(Primitive2DReference rNew);
/** method which is to be used to implement the local decomposition of a 2D primitive. */
virtual Primitive2DReference
create2DDecomposition(const geometry::ViewInformation2D& rViewInformation) const = 0;
// when changing from null (which is inactive) to a count of seconds, the
// callback mechanism to flush buffered content timer-based will be activated.
// it is protected since the idea is that this gets called in the constructor
// of derived classes.
void setCallbackSeconds(sal_uInt16 nNew) { maCallbackSeconds = nNew; }
public:
// constructor/destructor
BufferedDecompositionPrimitive2D();
virtual ~BufferedDecompositionPrimitive2D();
/** The getDecomposition default implementation will on demand use create2DDecomposition() if
maBuffered2DDecomposition is empty. It will set maBuffered2DDecomposition to this obtained decomposition
to buffer it. If the decomposition is also ViewInformation2D-dependent, this method needs to be
overridden and the ViewInformation2D for the last decomposition need to be remembered, too, and
be used in the next call to decide if the buffered decomposition may be reused or not.
*/
virtual void
get2DDecomposition(Primitive2DDecompositionVisitor& rVisitor,
const geometry::ViewInformation2D& rViewInformation) const override;
};
} // end of namespace drawinglayer::primitive2d
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */