Miraplacid Publisher SDK 2009: Programming

Miraplacid Publisher SDK Programming Guide

Miraplacid Publisher is actually a collection of ActiveX objects which communicate with each other trough well-defined COM interfaces. This model allows us to keep the system highly scalabe and extensible. Every component could be developed independently and base on different technologies as long as it supports COM. All examples provided in two separate folders: "examples.vb" containing project written in VB 6.0, and "examples.net" containing projects written in C#.
There are 5 different types of software modules in Publisher:

• Driver components. These are system dll modules and settings files. This is mandatory part of Publisher.
• Core component (mp_core.exe). This is the heart of the whole system. It takes data from the driver, keeps it in internal queue and manages all other components - plug-ins and UI.
• UI (mp_ui.exe). This is User Interface component. This is COM client of Core component; it uses Core methods and receives COM events from Core. UI interacts with Core only; it have no direct access to other components. User Interface module is not required for Publisher Core and Driver, they can work fine without UI. To display transport and rendering plug-ins user interfaces, UI loads its own set of plug-ins as an ActiveX components.
• Format plug-ins. Inproc dll ActiveX modules which performs conversion from internal graphics representation into particular graphics format. Core component manages these modules.
• Transport plug-ins. Inproc dll ActiveX modules which allows to save resulting files to some locations. Core component manages these modules.

This manual describes only Core and UI interaction details and registration services.
Transport and Rendering plug-ins interfaces are still subject of change and will be presented in the next version os SDK.

For simple solutions like scripting support or object creation from VB, please, refer to Scripting manual.

Miraplacid Publisher Object Model

Publisher Core component consists of two COM objects (coclasses):

• coclass MP (MiraplacidSE.Publisher {C9828C82-2136-4e25-894F-399109583971}). This is the main part of Publisher.
  The folowing interfaces included:
  • IMP (default interface). Includes all methods and properties which control Publisher functionality, including plug-ins.
  • _IMPEvents (default, source interface). This interface is collection of COM events and provided for Core and UI interoperability.
  • Some other internal interfaces which are out of scope of current document. You do not have to learn them to build your system.
• coclass MP_Register (MiraplacidSE.PublisherRegistrator {235836F3-0079-4067-98B9-7F2E8FFE5876}). This objects includes single interface IMP_Register, which manages registration and verification services.

MP_Register object will be always created and its interface will allow calling program to verify Publisher registration status and to register Publisher. MP object will not be created successfully if trial period is expired. Unlimited version of SDK does not contain MP_Register coclass and object MP will be created always.

For C++ users: Number means long and String means BSTR in this guide.
Do not forget to add get_ (read) and put_ (write) prefixes for properties.

Miraplacid Publisher IMP Object Reference

This is a main Publisher interface. Its IID is {D5FD471D-BAEC-4dfa-8C3C-CCD09050B3AA}.

Miraplacid Publisher Properties Reference

Miraplacid Publisher Output Format (Format plug-ins) parameters

To query or modify Format plug-in parameters, use FormatParam property of Miraplacid Publisher object.
obj.FormatParam("GIF","palette")=64

Miraplacid Publisher Send To (Transport plug-ins) parameters

To query or modify Transport plug-in parameters, use TransportParam property of Miraplacid Publisher object.
obj.TransportParam("File","filename")="image_{{PAGE}}"

Miraplacid Publisher _IMPEvents Events Reference.

This is connection point interface which UI uses to catch printing events from Core component. Its IID is {BCDAF6C5-8CA2-4eea-A299-45F0FE0365F5}.

Event	Parameters	Description
OnStartJob	None	Called when Core receives start job signal from driver.
OnPagePrinted	Number	Called when Core receives next job from driver with page number as a parameter.
OnAllPagesPrinted	None	Called when Core receives end job signal from driver.
OnPageReady	Number page_id, String object	Called when Core prepared a page for displaying in responce to PreparePage method call. Page_id is a number of prepared page. Object parameter is a name of Windows FileMapping object which contains ready-to-display Windows bitmap. UI may use this object as a memory object with OpenFileMapping/MapViewOfFile API calls.
OnCancelJob	None	Called when Core finishes all activity with current job as an acknowledge for CancelJob call from UI or after SendAll process end.
OnRewindJob	None	Called instead of OnCancelJob when SendAll finished with errors.
OnUnload	None	Called when AutoSend property is set to true. UI should unload upon receiving this event.
OnProgress	String source, Number value	Called when some lengthy process is taking place. Source could be a name of transport plug-in - in this case it reflects sending progress for this particular plug-in; or special value "process" which reflects the state of image processing. Special value of "convert" reflects state of image conversion process (from internal representation to perticular image format). Value is the value of progress indicator (0 - 100).
OnError	Number code, String message	Called when some error is happened. Message is textual representation of the error. There are the folowing codes could be passed to this event: General errors - code = 1 If Value is wrong - code = 0x400 Name errors: configuration, unknown transport or format selected - code = 0x600 Range 0x100 - 0x1ff has a special meaning - these are transport plug-in errors. Source transport plug-in may be located by its index which is equal to error_code - 0x100; these errors may happen only during saving procedure.
OnSetDocName	String	Called when Core sets document name to let UI update its status line, etc.
OnChangePrinter	String	Called when Core receives print job for different printer or after initial configuration load. UI must re-read all the configuration from Core.
OnAddRemovePrinter	Number	Core monitors printers add/remove operations and default printer change in the system. When this happen, it generates this event to let UI update lists of printers. In responce to this event, UI must update its own printer lists and send update signal to its set of transport plug-ins to allow them update their printer lists, by calling CheckSettings method with appropriate parameter. Parameter may have the following values: 0 - Default printer changed. 1 - Some printer added/removed, not from Publisher family and not redirect printer. 2 - Some printer from Publisher family added/removed.

Miraplacid Publisher IMP_Register Object Reference.

When evaluation period is expired, object of the main interface (IMP) will not be created successfully. Application should use IMP_Register interface to register Publisher. Its IID is {90D08213-5B6D-4103-96A7-297AA8EC4DEB}.
Examples of registration utility are located at examples.vb\register and examples.net\MP_SE_Reg folders at this package.

Property	Type	Description
Valid	Number	(Read Only) May be used to examine current evaluation state. Has the following values: <=0 - Internal error happened in verification code. This could be caused by corrupted .key file, wrong permissions of .key file, etc. 1 - Publisher is registered. 2 - Publisher is unregistered but trial period is not expired. 3 - Trial periond is expired.
Users	String Collection	(Read / Write) List of users currently allowed to print to Publisher. Implemented in Terminal Server version only.
UserLicenses	Number	(Read Only) Maximum number of end user licenses. Implemented in Terminal Server version only.

Method	Parameters	Returns	Description
SetLicense	String FirtsName, String LastName, String Keycode	Number	This method is intended for registering Publisher. Application must provide FirstName, LastName and Keycode generated by Miraplacid to this method. Resulting value is 1 if registration succeeded, 0 if not. After 3 unsuccessful registration attempts this method will always return CLASS_E_NOTLICENSED and will not actually try to register. Application should re-create the object to continue registering.
LoadUI	None	None	Method LoadUI allows application to force loading UI which will ask user for registration information. This could be done if Valid property returns 2 or 3.

Miraplacid Publisher UI working scheme.

You can see a live custom UI examples in examples.vb\customui and examples.net\MP_SE_UI folders of SDK package.

1. UI is launched by Core when it receives a new job and AutoSend property is in false state or by user when he clicks on Publisher icon on Desktop or Programs folder.
2. UI loads MP object and obtains IMP interface pointer.
3. UI establishes a connection with Core and loads configuration (by reading properties). After initialization steps (when it will be ready to receive events), UI must set UILoaded property to 1 (true). This property counts active UIs, and, if UI was loaded and the last UI sets UILoaded=0, core will save configuration automatically.
   When Core launches UI, it looks for "WaitUILoaded" parameter in its registry folder (HKLM).
   
   If WaitUILoaded = 0 (default value), Core does not wait for UI to be loaded. So, when UI will be ready to listen events, it will appear in the middle of print job (OnStartJob + some page or whole job events may be missed).
   And, even if user starts UI from Desktop, it may connect to Core with current print job already waiting for user input (save or cancel).
   To avoid this situation and get current status correctly, there are two possibilities exists:
   • Get the current job status from core before subsribing to events, as did in .Net UI example. This is the most correct method.
   • Use UILoadedWithEvents = 1 construction. This property will feed UI with all needed events for current job automatically, if Core has active job.
     This is the most simple method, but it has one side-effect: if you use several applications listens events from Core, all them will receive print job events missed by this UI. This is the only way for applications written in languages like VB, which creates objects and subscribes to events in one operation (Dim WithEvents).
     In this case, you need to set UILoadedWithEvents right after object creation.
   We recommend to use this method for UIs intended for interactive job with user.
   
   If WaitUILoaded = 1, Core waits UI to be loaded (on StartJob) for 60 seconds maximum, then continues job processing. This method is convenient for UIs which perform job data processing in automatic mode, without significant user intervention.
   UI should use any method of events subscription and UILoaded=1 and it will not miss any events from Core.
   If you wish to use this mode, do not forget to set WaitUILoaded parameter to 1 in your installer.

Further steps (4 - 7) make an event-driven loop.
Core generates events in two modes: syncronous and asyncronous. To control this mode, installer may set "AsyncEvents" parameter in Publisher registry folder (HKLM).
When Core users asyncronous events mode, it sends events from separate thread and does not wait for UI to return. So, if your UI performs some processing on events (not just mirror Core state), we recommend you to use asyncronous mode - the printing process will be faster. Core may collect print jobs with its maximal speed, and UI will process them with its own speed.
But, please, be careful when your UI works in asyncronous mode and Core is in autosend mode. If your UI slower than Core and it makes some actions with print job (saving particular pages/all pages, etc), these actions in autosend mode may affect wrong print job because in autosend mode Core does not wait the job to be calcelled from UI - it saves a job automatically and get the next one from queue.
In this case, you need to ensure that Core is not in autosend mode.

4. OnStartJob: On this event UI may read document name and examine print job status. Job may already be completed (printed) if next job was printed on background before finalizing previous one.
5. OnPagePrinted: If the job was already completed, this event will not be generated. On this event, its possible to ask for a page by calling PreparePage method.
   Calling this method will force Core to start processing of the page. It makes sense to ask only for page which is currently displayed.
6. OnAllPagesPrinted: This is informational event which allows UI to update its internal state (and interface elements like SaveAll button).
7. OnPageReady: Core sends this event if UI asked for a page and it is ready for displaying. UI may read the picture and display it. This event may be generated not only in responce to PreparePage call; Core will fire it when it saves all job, in page-by-page or multipage mode. The order of pages may be reverse in this case, depending from image format, so page_id parameter is important.

The following stage is interactive job with end user.

8. User can change settings. Appropriate Core properties must be set by UI. During this process, OnError event might be raised in response to incorrect property change.
9. User can change active printer, save its configuration for current user or for all users.
10. User can save current page. UI shall call SendPage method.
11. User may want to save all pages. UI shall call SendAllPages method. In response to this call, Core will notify UI by raising OnCancelJob event when job is done. On this event, UI must get ready for the next job. If some transports fail, Core raises OnRewindJob event (but does not cancels the job). On this event UI can rewind the job to the first page, show some (additional) error message, etc.
12. User can cancel the job. UI must call CancelJob method. In response, Core generates OnCancelJob event.
13. During saving process, Core will generate OnProgress events or OnError if some error happened.

At any time, Core may send OnAddRemovePrinter event if some printer configuration changed in the system.
Dependent from this event argument, UI should take appropriate measures - reload printer lists, configuration, etc.

Miraplacid Publisher Format plug-ins.

Format plug-ins are Publisher components intended for image conversion from internal image representation (bitmap) to particular graphics format file.
Format plug-ins are AcitveX components which implements all standard visual ActiveX component interfaces.
Additionally, it must obey the following requirements:

• It must be included into "Miraplacid Publisher Format Plug-ins" COM category (FBFE9C5A-8D40-46bd-99C1-93F162E30AE7), but not create it.
• It must implement IMP_FPLUGIN interface (69E3226F-C540-4829-9CB4-88738766C9E4) and realize _IMP_FPlugin_Events connection point dispinterface (20B34C58-2EE5-4f87-AC73-F8080DA8ABE1).
• It must not register its own type library. Ready for use type library provided in imp_fplugin.dll.

IMP_FPLUGIN interface:

Property	Type	Description
Value	Variant	(Read/Write) Any properties that your plug-in may have. Some of them may be saved into configuration in registry and restored from it.
ValueNoCheck	Variant	(Write Only) The same as Value, but does not check value itself or against other values and does not update UI. Use to prevent update relative settings in a wrong order. When all the settings updated, call CheckSettings method.
Name	String	(Read Only) Plug-in name for internal use.
Layout	String	(Read Only) This string contains a list of properties (Values) which should be saved inconfiguration or restored from it. Format of this string is: "Bparam1,Lparam2,BParam3", where "B" and "L" are prefixes meaning type of parameter (BSTR and Long accordingly). Parameter names should be separated by commas. Spaces are not allowed.
Extension	String	(Read Only) File extension corresponding current rendering plug-in, without leading period, i.e. "gif", "bmp".
SafeForMultipage	Number	(Read Only) Returns 1 if this plug-in is able to support multipage images with pages of different dimensions. For example, TIFF, GIF and PDF have internal paged stucture, while other plug-ins assemble "multipage" images by glueing pages together, and this prevents them from accepting pages with different dimensions. Core analyses this property and prohibits saving multipage documents with this format if it does not supprt this feature.
Method	Parameters	Description
Convert	IImageCollection *images, String filename	Conversion procedure. Plug-in sohuld obtain images from images, convert it to appropriate format and save to filename.
CheckSettings	no parameterts; returns nothing	Call this method after a series of ValueNoCheck done to perform values (mutual) check and update plug-in UI state.
InitSettings	no parameterts; returns nothing	Core calls this method when there is no configuration for current printer loaded. Plug-in must update its internal settings and UI.

_IMP_FPlugin_Events interface:

Method	Parameters	Description
OnChangeParam	String plugin, String param, VARIANT val	When some plug-in parameter has changed via user interface, plug-in informs about that with OnChangeParam event. "plugin" is internal name of plug-in, "param" is a name of changed parameter, "val" is a new value of parameter.
OnProgress	String plugin, long value	During conversion process, plug-in may fire this event to provide information about the progress of image conversion.

IImageCollection Core interface:

Property	Type	Description
Count	Number	(Read Only) Number of images in image set.
Method	Parameters	Description
Item	Number index; returns String	With this method, plug-in receives page content identified by "index". Method returns name of system filemapping object containing image for conversion.

Format plug-in working scheme

1. UI starts and loads plug-ins. It subscribes to _IMP_FPlugin_Events events interface.
2. UI gets Layout property. According to Layout parameters, it reads appropriate FormatParam properties from Core and sets as a Values of plug-in (using ValueNoCheck property and calls CheckSettings).
3. Core creates plug-ins too and subscribes to their events (to get OnProgress event).
4. Core gets Layout property. According to Layout parameters, it reads saved values from configuration (registry) and sets as Values of plug-in (using ValueNoCheck property and calls CheckSettings). If configuration for current printer does not exist, Core calls InitSettings.

Remark: UI and Core may start each other, but the final situation does not change: Core reads settings and sets plug-in properties first, then UI reads these properties and sets them to its "own" plug-ins.
There are two sets of plug-ins exists in the scheme, because UI and Core are separate processes.

Interactive job cycle:

5. User changes settings of plug-in. Plug-in updates its internal state and raises OnChangeParam to UI.
6. In responce, UI sets appropriate Core property with FormatParam. In result, all parameters are in sync.

Rendering job cycle. Job of rendering plug-in is page-oriented.

7. When Core needs to convert (and save) current page or all pages in a single miltipage file, it calls Convert method.
8. Plug-in calls Count property of IImageCollection imterface provided as paramter. If count = 1, plug-in calls Item method and get a name of filemapping obect.
   Then, it just converts an image containing in this object to appropriate image fomat and saves it to file.
   Format of filemapping image is bitmap (BimapInfoHeader + bitmap bits, in 24-bit format).
9. If count > 1, that means plug-in need to save several images to a single multipage file. Formats which support multipage images (TIFF, animated GIF) may use these possibilities; other formats should just make one lenghty contiuous image file.

Miraplacid Publisher Transport plug-ins.

Transport plug-ins are Publisher components intended for saving converted images to some destination (file, URL) using some transport protocol (file, FTP, HTTP).
Transport plug-ins are AcitveX components which implements all standard visual ActiveX component interfaces.
Additionally, it must obey the following requirements:

• It must be included into "Miraplacid Publisher Transport Plug-ins" COM category (92D23852-D793-4251-83C2-9D577A779DFB), but not create it.
• It must implement IMP_TPLUGIN interface (A24B0942-EDCC-47c5-AF3C-82A6A2E4FD11) and realize _IMP_TPlugin_Events connection point dispinterface (DD69A786-C884-410a-B27B-DECA265042C9).
• It must not register its own type library. Ready for use type library provided in imp_tplugin.dll.
• Default write-only properies docname and extension may be used in transport plug-in to capture this setting from UI.

IMP_TPLUGIN interface:

Property	Type	Description
Value	Variant	(Read/Write) Any properties that your plug-in may have. Some of them may be saved into configuration in registry and restored from it.
ValueNoCheck	Variant	(Write Only) The same as Value, but does not check value itself or against other values and does not update UI. Use to prevent update relative settings in a wrong order. When all the settings updated, call CheckSettings method.
Name	String	(Read Only) Plug-in name (short).
Layout	String	(Read Only) This string contains a list of properties (Values) which should be saved inconfiguration or restored from it. Format of this string is: "Bparam1,Lparam2,BParam3", where "B" and "L" are prefixes meaning type of parameter (BSTR and Long accordingly). Parameter names should be separated by commas. Spaces are not allowed.
UsesRawImage	Number	(Read Only) Plug-in should return 1 if it does not need to convert image to particular format; it uses internal representation (bitmap) directly. Example of such a plug-in could be printer plug-in which prints bitmap to a printer and does not need converted image.
Method	Parameters	Description
Start	None	Publisher Core call this member when it begins saving text page(s). Plug-in may update its internal state and prepare resources.
Process	ITransportHelper object	Publisher Core calls this method when it needs to send converted file to selected location. "object" parameter is an interface provided by Core which allows plug-in to retrieve input file name needed for save and translate strings.
End	None	Publisher Core call this member on end of saving to let plug-in free used resources and update its state.
CheckSettings	Number	Call this method with parameter = 0 after a series of ValueNoCheck done to perform values (mutual) check and update plug-in UI state. Other values of parameter is for plug-ins which deals with printers. If some plug-in will not need this information, it may ignore calls with values other than 0 and return immediately. If parameter = 1 - default printer changed. Plug-in may just update visual representation of its printer list. If parameter = 2 - some printer added/removed. Plug-in must reload printer list and update all settings.
InitSettings	no parameterts; returns nothing	Core calls this method when there is no configuration for current printer loaded. Plug-in must update its internal settings and UI.

_IMP_TPlugin_Events interface:

Method	Parameters	Description
OnChangeParam	String plugin, String param, VARIANT val	When some plug-in parameter has changed via user interface, plug-in informs about that with OnChangeParam event. "plugin" is internal name of plug-in, "param" is a name of changed parameter, "val" is a new value of parameter.
OnError	String plugin, Number error_code, String error_message	When some error happens during saving the text, plug-in should raise OnError event. "error_code" provided mainly for debugging purposes, to watch this value in Publisher log file; "error_message" is what user will see as an error description.
OnProgress	String plugin, Number value	Plug-in should raise this event periodically during saving process. Value is the value of progress indicator (0 - 100).

ITransportHelper Core interface:

Property	Type	Description
Source	String	(Read Only) Name of the source object to save. For raw plug-ins (UsesRawImage == 1) this will be a name of file mapping object; for other plug-ins this is a name of graphics file.
Method	Parameters	Description
TranslateString	String input; Number translate_flag; returns String output	Translates string possibly containing special tags and replaces these tags with their actual values. If translate_flag is not 0, this method changes unsafe characters (which cannot be used in filenames) to underscores when replaces tags.

Transport plug-in working scheme

1. UI starts and loads plug-ins. It subscribes to _IMP_TPlugin_Events events interface.
2. UI gets Layout property. According to Layout parameters, it reads appropriate TransportParam properties from Core and sets as a Values of plug-in (using ValueNoCheck property and calls CheckSettings).
3. Core creates plug-ins and subscribes to events. UI listens OnParamChange event; Core listens other events: OnError and OnProgress.
4. Core gets Layout property. According to Layout parameters, it reads saved values from configuration (registry) and sets as Values of plug-in (using ValueNoCheck property and calls CheckSettings). If configuration for current printer does not exist, Core calls InitSettings.

Remark: UI and Core may start each other, but the final situation does not change: Core reads settings and sets plug-in properties first, then UI reads these properties and sets them to its "own" plug-ins.
There are two sets of plug-ins exists in the scheme, because UI and Core are separate processes.

Interactive job cycle:

5. User changes settings of plug-in. Plug-in updates its internal state and raises OnChangeParam to UI.
6. In responce, UI sets appropriate Core property with TrandportParam. In result, all parameters are in sync.

Saving job cycle.

7. In response to Save or SaveAll method call, Core initiates saving procedure. Several plug-ins may work at the same time.
   Care calls Start method of each plug-in.
8. After that, it calls Process method with appropriate parameters. During this call, plug-ins may call TranslateString method provided by Core.
9. Finally, Core calls End method.

See also:

• About Miraplacid Publisher 2009 SDK
• Miraplacid Publisher 2009 SDK: Installation
• Miraplacid Publisher 2009 SDK: SetupMaker
• Miraplacid Publisher 2009 SDK: Installation Component
• Miraplacid Publisher 2009 SDK: Programming Guide
• Miraplacid Publisher SDK 2009 Main Page