diff options
Diffstat (limited to 'drawinglayer/inc/drawinglayer/processor2d/baseprocessor2d.hxx')
| -rw-r--r-- | drawinglayer/inc/drawinglayer/processor2d/baseprocessor2d.hxx | 177 |
1 files changed, 172 insertions, 5 deletions
diff --git a/drawinglayer/inc/drawinglayer/processor2d/baseprocessor2d.hxx b/drawinglayer/inc/drawinglayer/processor2d/baseprocessor2d.hxx index c3889463c1de..d93fb68c932c 100644 --- a/drawinglayer/inc/drawinglayer/processor2d/baseprocessor2d.hxx +++ b/drawinglayer/inc/drawinglayer/processor2d/baseprocessor2d.hxx @@ -37,30 +37,159 @@ 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 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 + /* 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 + /// the central processing method virtual void process(const primitive2d::Primitive2DSequence& rSource); - // data access + /// data read access const geometry::ViewInformation2D& getViewInformation2D() const { return maViewInformation2D; } }; } // end of namespace processor2d @@ -68,6 +197,44 @@ namespace drawinglayer ////////////////////////////////////////////////////////////////////////////// +namespace drawinglayer +{ + namespace processor2d + { + /** CollectingProcessor2D class + + A processor which just collects all primitives given to it in + process(..) calls to maPrimitive2DSequence. This can e.g. be used to + hand around as instance over various methods where every called + method can add graphic content to it. + */ + class CollectingProcessor2D : public BaseProcessor2D + { + private: + primitive2d::Primitive2DSequence maPrimitive2DSequence; + + public: + CollectingProcessor2D(const geometry::ViewInformation2D& rViewInformation); + virtual ~CollectingProcessor2D(); + + /// the central processing method + virtual void process(const primitive2d::Primitive2DSequence& rSource); + + /// helpers for adding to local sequence + void appendPrimitive2DReference(const primitive2d::Primitive2DReference& rSource) + { + primitive2d::appendPrimitive2DReferenceToPrimitive2DSequence(maPrimitive2DSequence, rSource); + } + + /// data access and reset + const primitive2d::Primitive2DSequence& getPrimitive2DSequence() const { return maPrimitive2DSequence; } + void reset() { maPrimitive2DSequence = primitive2d::Primitive2DSequence(); } + }; + } // end of namespace processor2d +} // end of namespace drawinglayer + +////////////////////////////////////////////////////////////////////////////// + #endif //INCLUDED_DRAWINGLAYER_PROCESSOR2D_BASEPROCESSOR2D_HXX // eof |