Modularize virtual keyboard and add an extension interface

With the extension interface it is possible to add new input
method and/or languages without recompiling the Qt Virtual
Keyboard plugin itself.

The existing input methods are now isolated into plugins.
So installing a new input method is a matter of copying the
corresponding extension plugin to the plugins/virtualkeyboard
directory (and any collateral required by the extension plugin
itself).

This change also renames the HunspellInputMethod to
DefaultInputMethod. This change is necessary because some other
extension plugin may want to provide the default input method
instead.

Implementation plan
===================
[x] Create virtualkeyboard-private module
[x] Create plugin library
[x] Define interface for input method plugin
[x] Define interface for keyboard layouts
[x] Move existing input methods and layouts to plugins
    [x] HangulInputMethod
    [x] HunspellInputMethod
        [x] Maybe create a private library for sharing
            between HunspellInputMethod and LipiInputMethod
    [x] LipiInputMethod
    [x] OpenWnnInputMethod
    [x] PinyinInputMethod
    [x] T9WriteInputMethod
    [x] TCInputMethod
[o] Rename some C++ classes (too generic name?)
[x] Think again replacing the QtVirtualKeyboard namespace
[x] Update documentation
    [x] General instructions for creating a plugin
    [x] For the C++ interfaces too (previously removed)

[ChangeLog][Important Behavior Changes] Introduce an extension
interface for the virtual keyboard. All the current input methods and
some special keyboard layouts (e.g. Hunspell, OpenWnn, etc.) have been
moved to extensions. The extension interface allows third party to
create a new input method without having to modify or rebuild the
virtual keyboard. In addition, this change makes it possible to add
features and languages independently by copying the desired extension
to the system.

[ChangeLog][Important Behavior Changes] Introduce a virtualkeyboard
module, which can be linked against an extension plugin. This module
provides the C++ API necessary for creating an input method.

[ChangeLog][Important Behavior Changes] Wrap the entire virtual
keyboard API into Qt namespace (e.g. QT_BEGIN_NAMESPACE/QT_END_NAMESPACE).

Task-number: QTBUG-57602
Change-Id: I449f4429109f596a7a1df7517c81f97d4aada27c
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

1 files changed, 102 insertions, 0 deletions

diff --git a/src/plugins/lipi-toolkit/3rdparty/lipi-toolkit/src/reco/shaperec/featureextractor/common/LTKShapeFeatureExtractor.h b/src/plugins/lipi-toolkit/3rdparty/lipi-toolkit/src/reco/shaperec/featureextractor/common/LTKShapeFeatureExtractor.h
new file mode 100644
index 00000000..51ab4b57
--- /dev/null
+++ b/src/plugins/lipi-toolkit/3rdparty/lipi-toolkit/src/reco/shaperec/featureextractor/common/LTKShapeFeatureExtractor.h
@@ -0,0 +1,102 @@
+/*****************************************************************************************
+* Copyright (c) 2006 Hewlett-Packard Development Company, L.P.
+* Permission is hereby granted, free of charge, to any person obtaining a copy of 
+* this software and associated documentation files (the "Software"), to deal in 
+* the Software without restriction, including without limitation the rights to use, 
+* copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the 
+* Software, and to permit persons to whom the Software is furnished to do so, 
+* subject to the following conditions:
+*
+* The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+*
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
+* INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A 
+* PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT 
+* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
+* CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE 
+* OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 
+*****************************************************************************************/
+
+/************************************************************************
+ * SVN MACROS
+ *
+ * $LastChangedDate: 2008-07-10 15:23:21 +0530 (Thu, 10 Jul 2008) $
+ * $Revision: 556 $
+ * $Author: sharmnid $
+ *
+ ************************************************************************/
+/************************************************************************
+ * FILE DESCR: Function prototype for feature extraction module
+ *
+ * CONTENTS:   
+ *
+ * AUTHOR:     Nidhi Sharma
+ *
+ * DATE:       07-FEB-2007
+ * CHANGE HISTORY:
+ * Author		Date			Description of change
+ ************************************************************************/
+
+#ifndef __LTKFEATUREEXTRACTOR_H
+#define __LTKFEATUREEXTRACTOR_H
+
+
+#include "LTKTypes.h"
+#include "LTKShapeFeatureMacros.h"
+
+// Forward class declarations
+class LTKTraceGroup;
+class LTKShapeFeature;
+
+/**
+* @ingroup feature_extractor
+* @brief An abstract class which is extended by all the feature extractors.
+* @class LTKShapeFeatureExtractor
+* 
+*/
+class LTKShapeFeatureExtractor
+{
+public:
+	/**
+	* <b>Responsibility</b><br>
+	* Extract features from the input TraceGroup passed a parameter.
+	*
+	* <b>Description</b>
+	* <p>
+	* Every feature representation class has a feature extractor associated with it. The feature extractor
+	* extracts the features from the trace group passed as parameter.
+	* </p>
+	*
+	* <p>This function is based on run-time polymorphism.
+	* The pointer to the derived class instances are stored in a vector of base class (<i>LTKShapeFeature</i>) pointers.
+	* </p>
+	*
+	* @return Pointer to the vector of LTKShapeFeature pointers.
+	*/
+	virtual int extractFeatures(const LTKTraceGroup& inTraceGroup,
+	                              vector<LTKShapeFeaturePtr>& outFeatureVec)=0;
+
+	/**
+	* <b>Responsibility</b><br>
+	* Returns the instance of the shape feature class associated with the feature extractor.
+	*
+	* @return Pointer to the shape feature class. 
+	*
+	*/
+	virtual LTKShapeFeaturePtr getShapeFeatureInstance()=0;
+
+
+	/**
+	* <b>Responsibility</b><br>
+	* Constructs traceGroup based on input LTKShapeFeaturePtr 
+	*
+	* @return Pointer to Trace Group. 
+	*
+	*/
+	virtual int convertFeatVecToTraceGroup(
+	                            const vector<LTKShapeFeaturePtr>& shapeFeature, 
+	                            LTKTraceGroup& outTraceGroup);
+};
+
+
+#endif