Re: Generic Embeddable plugins.

On Tue, 2005-01-11 at 08:34 +0000, Tomas Frydrych wrote:
> Sounds good Martin. I have two suggestions:
>
> (1) Allow jpg snapshots alongside png and svg (once fjf implements the
> jpg storage in documents). JPG is more suitable for some things than
> PNG, and the plugin designer should have the option to provide JPG if
> she knows that preferable.

I can't see 1 single reason to prefer jpg.

> I suggest each plugin should provide
> getSnapshotType() method, with return value based on or-able enum for
> the types: some plugins might return PNG | JPG | SVG, some just JPG, etc.
>
> (2) Provide a preference that would allow the user to force PNG or JPG
> snapshots for everything in the document. This way if you sent a doc
> with a formula and I complain it has no formulas in it (no SVG plugin)
> you will be able to make me a usable one.

We should make this 100% portable, so this should be avoided at all cost
imo. Having png data inside the document, and with some luck svg data,
makes this senario never happen for example.

Marc

> Tomas
>
>
> msevior@physics.unimelb.edu.au wrote:
> > Hi Folks,
> > I've taken the comments of people asking for a generic
> > embeddable API on-board and now propose the following.
> >
> > The idea is to have a generic XP class with a well defined API with
> > default implementations. Plugins are subclasses of this class which
> > overide the default implementations.
> >
> > OK here is the header file for the base class:
> > -------------------------------------------------------------
> > #ifndef __gr_Abi_EmbedManager_h__
> > #define __gr_Abi_EmebdManager_h__
> > #include "ut_string_class.h"
> > #include "ut_types.h"
> > #include "pt_Types.h"
> >
> >
> > class GR_Graphics;
> > class UT_ByteBuf;
> > class PD_Document;
> > class ABI_EXPORT GR_EmbedView
> > {
> > public:
> > GR_EmbedView(PD_Document * pDoc, PT_AttrPropIndex api );
> > virtual ~GR_EmbedView(void);
> > PD_Document * m_pDoc;
> > PT_AttrPropIndex m_iAPI;
> > bool m_bHasSVGSnapshot;
> > bool m_bHasPNGSnapshot;
> > UT_ByteBuf m_SVGBuf;
> > UT_ByteBuf m_PNGBuf;
> > }
> >
> > class ABI_EXPORT GR_Abi_EmbedManager
> > {
> > public:
> > GR_Abi_EmbedManager(GR_Graphics * pG);
> > virtual ~GR_Abi_EmbedManager();
> > const char * getObjectType(void) const;
> > GR_Abi_EmbedManager * createMe(GR_Graphics * pG);
> > virtual void initialize(void);
> > GR_Graphics * getGraphics(void);
> > virtual void setGraphics(GR_Graphics * pG);
> > virtual UT_sint32 makeEmbedView(PD_Document * pDoc,
> > PT_AttrPropIndex api) ;
> > virtual void setColor(UT_sint32 uid, UT_RGBColor c);
> > virtual UT_sint32 getWidth(UT_sint32 uid);
> > virtual UT_sint32 getAscent(UT_sint32 uid) ;
> > virtual UT_sint32 getDescent(UT_sint32 uid) ;
> > virtual void loadEmbedData(UT_sint32 uid);
> >
> > virtual void setDefaultFontSize(UT_sint32 uid, UT_sint32);
> > virtual void render(UT_sint32 uid, UT_sint32 x, UT_sint32 y);
> > virtual void releaseEmbedView(UT_sint32 uid);
> > virtual void initializeEmbedView(UT_sint32 uid);
> > virtual void makeSnapShot(UT_sint32 uid);
> > virtual bool isDefault(void);
> > private:
> > GR_Graphics * m_pG;
> > UT_Vector<GR_EmbedView *> m_vecSnapshots;
> > };
> >
> > We will have two methods in the XAP_App class which are used to register
> > and discover embeddable plugins. Two register the plugin creates a copy of
> > the itself and calls:
> >
> > XAP_App::registerEmbeddable(GR_Abi_EmbedManager * pEmbed)
> >
> > Which places the pointer to this manager in a vector in XAP_App.
> >
> > We have invented a new type of piecetable object like a field or image.
> > The object type is
> > PTO_Embed.
> >
> > The PTO_Embed object has an attribute "object-type". The value of this
> > attribute is the type of embeddable object. For MathML we would have the
> > object/attribute pair "object-type:MathML"
> >
> > When the layout classes encounter a PTO_Embed object they look in
> > fl_DocLayout to see if a manager has been loaded for it. If one has they
> > use that, otherwise a new manager is created via the XAP_App method:
> >
> > GR_Abi_EmbedManager * XAP_App::getEmbeddableManager(GR_Graphics * pG,
> > const char * szObjectType)
> >
> > This method scans the vector of loaded plugins looking for a match to
> > szObjectType via the
> >
> > GR_Abi_EmbedManager::getObjectType(void)
> >
> > method.
> >
> > If a match is found a new instance of the manager is created and returned
> > to the caller via the
> >
> > GR_Abi_EmbedManager * GR_Abi_EmbedManager::createMe(GR_Graphics * pG)
> >
> > Method.
> >
> > If none are found a default implementation is created and returned to
> > fl_DocLayout which stores it in a vector as well.
> >
> > OK now we have either the default embeddable or the requested implementation.
> >
> > I'll go through the rest of the API.
> >
> > virtual void initialize(void);
> >
> > This initializes the manager.
> >
> > GR_Graphics * getGraphics(void);
> > virtual void setGraphics(GR_Graphics * pG);
> >
> > As you might expect. The setGraphics method is called when the document is
> > zoomed.
> >
> > virtual UT_sint32 makeEmbedView(PD_Document * pDoc,
> > PT_AttrPropIndex api) ;
> >
> > This method makes a specific instance of the render for the object in
> > question. It returns an integer which is an index (a "handle") to the
> > specific instance of the renderer. The PD_Document and PT_AttrPropIndex
> > index are used to determine specific attributes of the object as well as
> > being used to make snapshots of the renderer.
> >
> > virtual void setColor(UT_sint32 uid, UT_RGBColor c);
> > virtual UT_sint32 getWidth(UT_sint32 uid);
> > virtual UT_sint32 getAscent(UT_sint32 uid) ;
> > virtual UT_sint32 getDescent(UT_sint32 uid) ;
> > virtual void setDefaultFontSize(UT_sint32 uid, UT_sint32);
> >
> > These do as expected.
> >
> > virtual void loadEmbedData(UT_sint32 uid);
> >
> > OK these load the data from data-item in the associated with the object.
> > This data could be:
> >
> > MathML for a the GtkMathView plugin
> > Gnumeric XML for a Gnumeric plugin
> > Postscript text for a postscript plugin
> >
> > Some generic bonobo XML data for a generic bonobo plugin.
> > Whatever you like...
> >
> > virtual void render(UT_sint32 uid, UT_sint32 x, UT_sint32 y);
> >
> > Draw the object at locattion (x,y) in the graphics class.
> >
> > virtual void releaseEmbedView(UT_sint32 uid);
> >
> > Delete this specific renderer
> >
> > virtual void initializeEmbedView(UT_sint32 uid);
> > Initialize a specific instance of this view.
> >
> > virtual void makeSnapShot(UT_sint32 uid);
> >
> > Make a snapshot of the current view. This snapshot can be either in SVG or
> > PNG form. SVG is clearly prefered. The snapshot data is stored in the
> > PD_Document as a data item. The attribute/value is recorded for the
> > PTO_Embed object as either
> >
> > "snapshot-svg:dataitem-val#" or "snapshot-png:dataitem-val#"
> >
> > Where dataitem-val# is some unique string to identify the object.
> >
> > If idea is that if a document loaded by an instance of AbiWord without the
> > plugin, the default implementation can render the snapshot of the object.
> >
> > I will make a PNG snapshotter for which just takes a screenshot of the
> > object.
> >
> > Once the SVG backend for gnome-print is in wide use, and printable
> > document which employs gnome-print can be snapshotted.
> >
> > virtual bool isDefault(void);
> >
> > Returns true if the manager is the default implementation.
> >
> > Here is my current working of the MathML plugin header file...
> >
> > Cheers
> >
> > Martin
> >
> > -----------------------------------------------------------------------
> >
> > #include "ut_string_class.h"
> > #include "gr_Abi_EmbedManager.h"
> > #include <MathView/libxml2_MathView.hh>
> >
> > class GR_Graphics;
> > class GR_Abi_MathGraphicDevice;
> > class GR_Abi_RenderingContext;
> > class MathMLOperatorDictionary;
> > class GR_AbiMathView;
> >
> > class ABI_EXPORT GR_Abi_MathManager : pubic GR_Abi_EmbedManager
> > {
> > public:
> > GR_Abi_MathManager(GR_Graphics * pG);
> > virtual ~GR_Abi_MathManager();
> > GR_Abi_EmbedManager * createMe(GR_Graphics * pG);
> > virtual void initialize(void);
> > GR_Graphics * getGraphics(void);
> > virtual void setGraphics(GR_Graphics * pG);
> > virtual UT_sint32 makeEmbedView(PD_Document * pDoc,
> > PT_AttrPropIndex api) ;
> > virtual void setColor(UT_sint32 uid, UT_RGBColor c);
> > virtual UT_sint32 getWidth(UT_sint32 uid);
> > virtual UT_sint32 getAscent(UT_sint32 uid) ;
> > virtual UT_sint32 getDescent(UT_sint32 uid) ;
> > virtual void loadEmbedData(UT_sint32 uid, UT_UTF8String &
> > sMathBuf);
> > virtual void render(UT_sint32 uid, UT_sint32 x, UT_sint32 y);
> > virtual void releaseEmbedView(UT_sint32 uid);
> > virtual void initializeEmbedView(UT_sint32 uid);
> > virtual void makeSnapShot(UT_sint32 uid);
> > virtual bool isDefault(void);
> > private:
> > virtual UT_sint32 _makeMathView(void) ;
> > virtual void _releaseMathView(UT_sint32 uid);
> > virtual void _resetRootElement(UT_sint32 uid, void);
> > virtual void _loadMathML(UT_sint32 uid, UT_UTF8String &
> > sMathBuf);
> > UT_sint32 _getNextUID(void);
> > UT_sint32 m_CurrentUID;
> > SmartPtr<AbstractLogger> m_pLogger;
> > SmartPtr<GR_Abi_MathGraphicDevice> m_pMathGraphicDevice;
> > GR_Abi_RenderingContext * m_pAbiContext;
> > SmartPtr<MathMLOperatorDictionary> m_pOperatorDictionary;
> > UT_Vector<GR_AbiMathView *> m_vecMathView;
> > };
> >
> >
> >
> >
> >
>
Received on Tue Jan 11 13:55:15 2005