AOO410/main/drawinglayer/inc/drawinglayer/processor2d/baseprocessor2d.hxx - openoffice - Git at Google

 /**************************************************************
  *
  * 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
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  *
  *   http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing,
  * software distributed under the License is distributed on an
  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  * KIND, either express or implied.  See the License for the
  * specific language governing permissions and limitations
  * under the License.
  *
  *************************************************************/


 #ifndef INCLUDED_DRAWINGLAYER_PROCESSOR2D_BASEPROCESSOR2D_HXX
 #define INCLUDED_DRAWINGLAYER_PROCESSOR2D_BASEPROCESSOR2D_HXX

 #include <drawinglayer/drawinglayerdllapi.h>
 #include <drawinglayer/primitive2d/baseprimitive2d.hxx>
 #include <drawinglayer/geometry/viewinformation2d.hxx>

 //////////////////////////////////////////////////////////////////////////////

 namespace drawinglayer
 {
 	namespace processor2d
 	{
         /** BaseProcessor2D class

             Baseclass 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 tis 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 (an 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 com::sun::star::graphic::XPrimitive2D interface in the future.

             So, to implement a basic processor, it is necessary to overload 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, evtl. with transparence)
             - 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 prmitive (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 varibles, 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 it's 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
 		{
 		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);

 		public:
             /// constructor/destructor
 			BaseProcessor2D(const geometry::ViewInformation2D& rViewInformation);
 			virtual ~BaseProcessor2D();

 			/// the central processing method
 			virtual void process(const primitive2d::Primitive2DSequence& rSource);

 			/// data read access
 			const geometry::ViewInformation2D& getViewInformation2D() const { return maViewInformation2D; }
 		};
 	} // end of namespace processor2d
 } // end of namespace drawinglayer

 //////////////////////////////////////////////////////////////////////////////

 #endif //INCLUDED_DRAWINGLAYER_PROCESSOR2D_BASEPROCESSOR2D_HXX

 // eof
	/**************************************************************
	*
	* 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
	*
	* Unless required by applicable law or agreed to in writing,
	* software distributed under the License is distributed on an
	* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
	* KIND, either express or implied. See the License for the
	* specific language governing permissions and limitations
	* under the License.
	*
	*************************************************************/



	#ifndef INCLUDED_DRAWINGLAYER_PROCESSOR2D_BASEPROCESSOR2D_HXX
	#define INCLUDED_DRAWINGLAYER_PROCESSOR2D_BASEPROCESSOR2D_HXX

	#include <drawinglayer/drawinglayerdllapi.h>
	#include <drawinglayer/primitive2d/baseprimitive2d.hxx>
	#include <drawinglayer/geometry/viewinformation2d.hxx>

	//////////////////////////////////////////////////////////////////////////////

	namespace drawinglayer
	{
	namespace processor2d
	{
	/** BaseProcessor2D class

	Baseclass 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 tis 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 (an 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 com::sun::star::graphic::XPrimitive2D interface in the future.

	So, to implement a basic processor, it is necessary to overload 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, evtl. with transparence)
	- 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 prmitive (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 varibles, 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 it's 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
	{
	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);

	public:
	/// constructor/destructor
	BaseProcessor2D(const geometry::ViewInformation2D& rViewInformation);
	virtual ~BaseProcessor2D();

	/// the central processing method
	virtual void process(const primitive2d::Primitive2DSequence& rSource);

	/// data read access
	const geometry::ViewInformation2D& getViewInformation2D() const { return maViewInformation2D; }
	};
	} // end of namespace processor2d
	} // end of namespace drawinglayer

	//////////////////////////////////////////////////////////////////////////////

	#endif //INCLUDED_DRAWINGLAYER_PROCESSOR2D_BASEPROCESSOR2D_HXX

	// eof