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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 09:06:44 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 09:06:44 +0000
commited5640d8b587fbcfed7dd7967f3de04b37a76f26 (patch)
tree7a5f7c6c9d02226d7471cb3cc8fbbf631b415303 /include/drawinglayer/processor2d/baseprocessor2d.hxx
parentInitial commit. (diff)
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Adding upstream version 4:7.4.7.upstream/4%7.4.7upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * 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 .
+ */
+
+#ifndef INCLUDED_DRAWINGLAYER_PROCESSOR2D_BASEPROCESSOR2D_HXX
+#define INCLUDED_DRAWINGLAYER_PROCESSOR2D_BASEPROCESSOR2D_HXX
+
+#include <drawinglayer/drawinglayerdllapi.h>
+
+#include <drawinglayer/primitive2d/Primitive2DVisitor.hxx>
+#include <drawinglayer/primitive2d/baseprimitive2d.hxx>
+#include <drawinglayer/geometry/viewinformation2d.hxx>
+
+
+namespace drawinglayer::processor2d
+ {
+ /** BaseProcessor2D class
+
+ Base class for all C++ implementations of instances which process
+ primitives.
+
+ Instances which process primitives can be renderers, but also stuff
+ for HitTests, BoundRect calculations and/or animation processing. The
+ main usage are renderers, but they are supposed to handle any primitive
+ processing.
+
+ The base implementation is constructed with a ViewInformation2D which
+ is accessible throughout the processor implementations. The idea is
+ to construct any processor with a given ViewInformation2D. To be able
+ to handle primitives which need to change the current transformation
+ (as e.g. TransformPrimitive2D) it is allowed for the processor implementation
+ to change its local value using updateViewInformation.
+
+ The basic processing method is process(..) which gets handed over the
+ sequence of primitives to process. For convenience of the C++ implementations,
+ the default implementation of process(..) maps all accesses to primitives to
+ single calls to processBasePrimitive2D(..) where the primitive in question is
+ already casted to the C++ implementation class.
+
+ The process(..) implementation makes a complete iteration over the given
+ sequence of primitives. If the Primitive is not derived from BasePrimitive2D
+ and thus not part of the C++ implementations, it converts ViewInformation2D
+ to the corresponding API implementation (a uno::Sequence< beans::PropertyValue >)
+ and recursively calls the method process(..) at the primitive with the decomposition
+ derived from that primitive. This is the preparation to handle unknown implementations
+ of the css::graphic::XPrimitive2D interface in the future.
+
+ So, to implement a basic processor, it is necessary to override and implement the
+ processBasePrimitive2D(..) method. A minimal renderer has to support the
+ Basic Primitives (see baseprimitive2d.hxx) and the Grouping Primitives (see
+ groupprimitive2d.hxx). These are (currently):
+
+ Basic Primitives:
+
+ - BitmapPrimitive2D (bitmap data, possibly with transparency)
+ - PointArrayPrimitive2D (single points)
+ - PolygonHairlinePrimitive2D (hairline curves/polygons)
+ - PolyPolygonColorPrimitive2D (colored polygons)
+
+ Grouping Primitives:
+
+ - TransparencePrimitive2D (objects with freely defined transparence)
+ - InvertPrimitive2D (for XOR)
+ - MaskPrimitive2D (for masking)
+ - ModifiedColorPrimitive2D (for a stack of color modifications)
+ - TransformPrimitive2D (for a transformation stack)
+
+ A processor doing so is a minimal processor. Of course a processor may
+ handle any higher-level primitive (that has a decomposition implementation)
+ for more direct data access or performance reasons, too.
+
+ The main part of a processBasePrimitive2D implementation is a switch..case
+ construct, looking like the following:
+
+ void foo::processBasePrimitive2D(const BasePrimitive2D& rCandidate)
+ {
+ switch(rCandidate.getPrimitive2DID())
+ {
+ case PRIMITIVE2D_ID_??? :
+ {
+ // process PRIMITIVE2D_ID_??? here...
+
+ ...
+
+ break;
+ }
+
+ ...
+
+ default :
+ {
+ // process recursively
+ process(rCandidate.get2DDecomposition(getViewInformation2D()));
+ break;
+ }
+ }
+ }
+
+ The default case makes the processor work with all complex primitives
+ by recursively using their decomposition.
+
+ You can also add a case for ignoring primitives by using:
+
+ case PRIMITIVE2D_ID_...IGNORE.A.. :
+ case PRIMITIVE2D_ID_...IGNORE.B.. :
+ case PRIMITIVE2D_ID_...IGNORE.C.. :
+ {
+ // ignore these primitives by neither processing nor
+ // recursively processing their decomposition
+ break;
+ }
+
+ Another useful case is embedding the processing of a complex primitive by
+ bracketing it with some actions:
+
+ case PRIMITIVE2D_ID_SOME_TEXT :
+ {
+ // encapsulate e.g. with changing local variables, e.g.
+ // sometimes it's good to know if a basic primitive is
+ // part of a text, especially when not handling the text
+ // self but by purpose want to handle the decomposed
+ // geometries in the processor
+ startText();
+ process(rCandidate.get2DDecomposition(getViewInformation2D()));
+ endText();
+ break;
+ }
+
+ As an example a processor collecting the outlines of a sequence of primitives
+ only needs to handle some Basic Primitives and create outline and collect
+ outline polygons e.g. for primitives with area like BitmapPrimitive2D (a
+ rectangle) and PolyPolygonColorPrimitive2D. When also handling the Grouping
+ Primitives MaskPrimitive2D (e.g. ignoring its content, using the mask polyPolygon)
+ and TransformPrimitive2D (to have the correct local transformation), a processor
+ creating the outline can be written using just four (4) primitives. As a tipp, it can
+ be helpful to add many for the purpose not interesting higher level primitives
+ to not force their decomposition to be created and/or parsed.
+ */
+ class DRAWINGLAYER_DLLPUBLIC BaseProcessor2D : public drawinglayer::primitive2d::Primitive2DDecompositionVisitor
+ {
+ private:
+ /// The ViewInformation2D itself. It's private to isolate accesses to it
+ geometry::ViewInformation2D maViewInformation2D;
+
+ protected:
+ /* access method to allow the implementations to change the current
+ ViewInformation2D if needed. This allows isolating these accesses
+ later if needed
+ */
+ void updateViewInformation(const geometry::ViewInformation2D& rViewInformation2D)
+ {
+ maViewInformation2D = rViewInformation2D;
+ }
+
+ /* as tooling, the process() implementation takes over API handling and calls this
+ virtual render method when the primitive implementation is BasePrimitive2D-based.
+ Default implementation does nothing
+ */
+ virtual void processBasePrimitive2D(const primitive2d::BasePrimitive2D& rCandidate);
+
+ void process(const primitive2d::BasePrimitive2D& rCandidate);
+
+ // Primitive2DDecompositionVisitor
+ virtual void visit(const primitive2d::Primitive2DReference&) override final;
+ virtual void visit(const primitive2d::Primitive2DContainer&) override final;
+ virtual void visit(primitive2d::Primitive2DContainer&&) override final;
+
+ public:
+ /// constructor/destructor
+ explicit BaseProcessor2D(const geometry::ViewInformation2D& rViewInformation);
+ virtual ~BaseProcessor2D();
+
+ /// the central processing method
+ void process(const primitive2d::Primitive2DContainer& rSource);
+
+ /// data read access
+ const geometry::ViewInformation2D& getViewInformation2D() const { return maViewInformation2D; }
+ };
+
+} // end of namespace drawinglayer::processor2d
+
+
+#endif //INCLUDED_DRAWINGLAYER_PROCESSOR2D_BASEPROCESSOR2D_HXX
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */