#  |

# How to add your own mesher

# (as a set of hypotheses and algorithms)

# to the application.

## Table of contents

- 1. Introduction
- 2. Implementation steps

- 2.1. Mesher plugin package
- 2.2. List of available hypotheses and algorithms
- 2.3. Build server plugin library

- 2.3.1. Define interface to your hypotheses and algorithms
- 2.3.2. Implement functionality of your hypotheses and algorithms
- 2.3.3. Implement interface to your hypotheses and algorithms
- 2.3.4. Implement being exported method

- 2.4. Build client (GUI) plugin library

- 2.4.1. Implement the required GUI
- 2.4.2. Provide icons and messages for your GUI
- 2.4.3. Implement your hypotheses creator and being exported method

- 2.5. Provide icons for Object Browser
- 2.6. Setup SALOME environment

- 2.6.1. Set LD_LIBRARY_PATH, PYTHONPATH, PATH environment variables
- 2.6.2. Set mesher plugin resources environment variable

## 1. Introduction

All hypotheses and algorithms are available in SMESH module via plugin mechanism. Such approach allows easily to introduce new hypotheses and algorithms types to the application. Also, it makes possible the customization of available hypotheses and algorithms list for different users without recompilation of sources.
The goal of this document is to describe the process of creation external mesher plugins.

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## 2. Implementation steps

###

### 2.1. Mesher plugin package

Create your mesher plugin package which will contain the sources files, e.g. MyMesherPlugin.
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### 2.2. List of available hypotheses and algorithms

Create XML file to describe all algorithms and hypotheses, provided by your plugin package (see SMESH_SRC/resources/SMESH_Meshers.xml for example).

> `<meshers-group name="MyName"
> resources="MyResourceKey"
> server-lib="libMyServerLib.so"
> gui-lib="libMyClientLib.so">
> <hypotheses>
> <hypothesis type="MyHypType1"
> label-id="My beautiful hypothesis name"
> icon-id="my_hypo_1_icon.png"/>
> </hypotheses>
> <algorithms>
> <algorithm type="MyAlgType1"
> label-id="My beautiful algorithm name"
> icon-id="my_algo_1_icon.png"/>
> </algorithms>
> </meshers-group>
> `
> - Attributes of <meshers-group> tag:

> > - value of <name> attribute is used to collect hypotheses/algoritms in groups; you can also use this attribute for short description of your mesher plugin.
> > - value of <resources> attribute (MyResourceKey) is used to access resources (messages and icons) from GUI (see paragraphs 2.4.2 and 2.5); in the current implementation it should coincide with the name of plugin package; this limitation will be eliminated in the further development.
> > - value of <server-lib> attribute describes the name of your mesher's server plugin library (See paragraph 2.3)
> > - value of <gui-lib> attribute describes the name of your mesher's client plugin library (See paragraph 2.4)

> - Attributes of <hypothesis/algorithm> tag:

> > - value of <type> attribute is an unique name of the hypothesis/algorithm
> > - It is a value of _name field of your hypothesis class (see paragraph 2.3, implementation of constructor of StdMeshers_LocalLength class: _name = "LocalLength")
> > - It is a key to each certain hypothesis class (see paragraph 2.3, implementation of "GetHypothesisCreator()" method in StdMeshers_i.cxx)
> > - It is a key to each certain hypothesis GUI (see paragraph 2.4, implementation of "StdMeshersGUI_HypothesisCreator::CreateHypothesis()" and "StdMeshersGUI_HypothesisCreator::EditHypothesis()" methods in StdMeshersGUI.cxx)
> > - It is a key to each certain hypothesis icon in Object Browser (see paragraph 2.4.2.1)

> > - value of <label-id> attribute is displayed in the GUI in the list of available hypotheses/algorithms ("Create Hypothesis/Algorithm" dialog)
> > - value of <icon-id> attribute is a name of icon file, which is displayed in GUI in the list of available hypotheses/algorithms ("Create Hypothesis/Algorithm" dialog)

> Note: All attributes values are accessible in your GUI via HypothesisData class (see paragraph 2.4.1)
> Note: The environment variable SMESH_MeshersList contains the list of plugins names, separated by colon (":") symbol, e.g.:
> `setenv SMESH_MeshersList StdMeshers:NETGENPlugin`
> Please, pay attention that StdMeshers should also be included into this environment variable, if you want to use standard hypotheses/algorithms, provided with SMESH module.
> The SALOME automatically locates XML files, searching them in the following directories:
> `
> ${<PLUGINNAME>_ROOT_DIR}/share/salome/resources
> ${SALOME_<PluginName>Resources}
> ${HOME}/.salome/resources
> ${KERNEL_ROOT_DIR}/share/salome/resources`
> where <PluginName> is a name of each mesher plugin package

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### 2.3. Build server plugin library <libMyServerLib.so>.

#### 2.3.1. Define interface to your hypotheses and algorithms.

> `Example: SMESH_SRC/idl/SMESH_BasicHypothesis.idl
> NETGENPLUGIN_SRC/src/NETGENPlugin_Algorithm.idl
> ` ``

#### 2.3.2. Implement functionality of your hypotheses and algorithms.

> Inherit corresponding classes from SMESH.

> `Example: SMESH_SRC/src/StdMeshers/StdMeshers_*
> NETGENPLUGIN_SRC/src/NETGENPlugin_NETGEN_3D
> ` ``

#### 2.3.3.Implement interface to your hypotheses and algorithms.

> `Inherit corresponding classes from SMESH_I.`

> `Example: SMESH_SRC/src/StdMeshers_I/SMESH_*_i
> NETGENPLUGIN_SRC/src/NETGENPlugin_NETGEN_3D_i
> ` ``

#### 2.3.4. Implement being exported method.

> `GenericHypothesisCreator_i* GetHypothesisCreator (const char* aHypType)`

> <aHypType> is a value of <type> attribute in the XML-description file

> `Example: SMESH_SRC/src/StdMeshers_I/StdMeshers_i.cxx
> NETGENPLUGIN_SRC/src/NETGENPlugin_i.cxx
> ` ``

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### 2.4. Build client (GUI) plugin library <libMyClientLib.so>.

> This step is required only if your hypotheses/algorithms need specific GUI for their construction.

#### 2.4.1. Implement the required GUI (e.g. construction dialog boxes).

> `Example: SMESH_SRC/src/StdMeshersGUI/StdMeshersGUI_*Dlg`

> Note: all data from XML-description files is accessible in your GUI via HypothesisData class (mySMESHGUI->GetHypothesisData (aHypType), see SMESHGUI_Hypotheses.h for HypothesisData definition)

#### 2.4.2. Provide icons and messages for your GUI.

##### 2.4.2.1. Implement resource files

> `MyResourceKey_icons.po and MyResourceKey_msg_en.po`

> `Example: SMESH_SRC/src/StdMeshersGUI/StdMeshers_*.po
> NETGENPLUGIN_SRC/src/NETGENPlugin_icons.po
> `
> Note: ICON_SMESH_TREE_HYPO_MyHypType1 is ID of icon for Object Browser for hypothesis with type="MyHypType1"; ICON_SMESH_TREE_ALGO_MyAlgType1 is ID of icon for Object Browser for algorithm with type="MyAlgType1".
> See paragraph 2 for definition of MyResourceKey, MyHypType1, MyAlgType1.`
> `

##### 2.4.2.2. Define environment variable SALOME_<MyResourceKey>Resources

> It should point to the directory where resources are situated.

> `Example: setenv SALOME_StdMeshersResources ${SMESH_ROOT_DIR}/share/salome/resources`

#### 2.4.3. Implement your Hypothesis Creator and being exported method

> `SMESHGUI_GenericHypothesisCreator* GetHypothesisCreator`
> `(QString aHypType, QString aServerLibName, SMESHGUI* aSMESHGUI)`

> <aHypType> is to pass a value of <type> attribute in XML-description file;
> <aServerLibName> is to pass a value of <server-lib> attribute in XML-description file.

> `Example: SMESH_SRC/src/StdMeshersGUI/StdMeshersGUI.cxx`

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### 2.5. Provide icons for object browser.

> If your hypotheses/algorithms do not need specific GUI, but you want to provide icons for object browser, see 2.4.2 paragrath.

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### 2.6. Setup your SALOME environment.

#### 2.6.1. Add your plugin to the LD_LIBRARY_PATH, PYTHONPATH (and maybe PATH) environment variables.

> `setenv PATH <path-to-my-plugin>/bin/salome:${PATH}
> setenv LD_LIBRARY_PATH <path-to-my-plugin>/lib/salome:${LD_LIBRARY_PATH}
> Setenv PYTHONPATH <path-to-my-plugin>/lib/python2.2/site-packages/salome:${PYTHONPATH}
> `

#### 2.6.2. Set mesher plugin resources environment variable

> This enviroment variable is used to set meshers plugins which should be loaded by SMESH module (see 2.4.2.2 paragraph). Add your plugin to this variable. All plugins are separated by colon (":") symbol.
> Note: If you use runSalome.py script from KERNEL package to launch SALOME, you may not to set environment variables, because this script sets them itself. All what you should do is to add <plugin> section to your ${HOME}/.salome/salome.launch file for SMESH module section:
> `
> ...
> <modules-list>
> ...
> <module name="SMESH">
> <plugin name="MyMesher"/>
> </module>
> ...
> </modules-list>
> ...`

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