Mesh transform by expression (#44873)

[feature] [mesh] allows the user to make geom transformation of mesh frame by changing the vertices coordinates by expression. Each coordinates (X,Y,Z) of selected vertices can be calculated with an expression allowing transformation of the mesh while the mesh is still valid. Co-authored-by: Harrissou Sant-anna <delazj@gmail.com>
qgis · Sep 3, 2021 · 9ce295e · 9ce295e
1 parent 8b18399
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diff --git a/images/images.qrc b/images/images.qrc
@@ -925,6 +925,7 @@
         <file>themes/default/mActionMeshDigitizing.svg</file>
         <file>themes/default/mActionMeshSelectPolygon.svg</file>
         <file>themes/default/mActionNewMeshLayer.svg</file>
+        <file>themes/default/mActionMeshTransformByExpression.svg</file>
         <file>themes/default/mIconGeometryCollectionLayer.svg</file>
         <file>themes/default/mIconGps.svg</file>
         <file>themes/default/mActionNewGpx.svg</file>

diff --git a/images/themes/default/mActionMeshTransformByExpression.svg b/images/themes/default/mActionMeshTransformByExpression.svg
diff --git a/python/core/auto_generated/mesh/qgsmeshadvancedediting.sip.in b/python/core/auto_generated/mesh/qgsmeshadvancedediting.sip.in
@@ -83,6 +83,69 @@ Constructor
 };
 
 
+class QgsMeshTransformVerticesByExpression : QgsMeshAdvancedEditing
+{
+%Docstring(signature="appended")
+
+Class that can transform vertices of a mesh by expression
+
+Each coordinates are associated with an expression that can be defined with function
+returning the current coordinates (see :py:func:`~QgsMeshEditRefineFaces.setExpressions`):
+
+- $vertex_x
+- $vertex_y
+- $vertex_z
+
+Example:
+Transposing a mesh and translate following axe X with a distance of 50 and increase the level of the mesh
+with an height of 80 when previous X coordinate is under 100 and de crease the level of 150 when X is under 100:
+
+expressionX: "$vertex_y + 50"
+expressionY: "$vertex_x"
+expressionZ: "if( $vertex_x <= 100 , $vertex_z + 80 , $vertex_z - 150)"
+
+.. versionadded:: 3.22
+%End
+
+%TypeHeaderCode
+#include "qgsmeshadvancedediting.h"
+%End
+  public:
+
+    QgsMeshTransformVerticesByExpression();
+%Docstring
+Constructor
+%End
+
+    void setExpressions( const QString &expressionX, const QString &expressionY, const QString &expressionZ );
+%Docstring
+Sets the expressions for the coordinates transformation.
+
+.. note::
+
+   Expressions are optional for each coordinate, the coordinate will not be transformed if the string is void.
+%End
+
+    bool calculate( QgsMeshLayer *layer );
+%Docstring
+Calculates the transformed vertices of the mesh ``layer``, returns ``False`` if this leads to topological or geometrical errors.
+The mesh layer must be in edit mode.
+
+.. note::
+
+   this method not apply new vertices to the mesh layer but only store the calculated transformation
+   that can be apply later with :py:func:`QgsMeshEditor.advancedEdit()`
+%End
+
+    QgsMeshVertex transformedVertex( QgsMeshLayer *layer, int vertexIndex ) const;
+%Docstring
+Returns the transformed vertex from its index ``vertexIndex`` for the mesh ``layer``
+
+If ``layer`` is not the same than the one used to make the calculation, this will create an undefined behavior
+%End
+
+};
+
 /************************************************************************
  * This file has been generated automatically from                      *
  *                                                                      *

diff --git a/python/core/auto_generated/mesh/qgsmesheditor.sip.in b/python/core/auto_generated/mesh/qgsmesheditor.sip.in
@@ -171,7 +171,7 @@ Returns whether the mesh has been modified
 %End
 
 
-    QList<int> freeVerticesIndexes();
+    QList<int> freeVerticesIndexes() const;
 %Docstring
 Returns all the free vertices indexes
 %End

diff --git a/src/app/CMakeLists.txt b/src/app/CMakeLists.txt
@@ -248,6 +248,7 @@ set(QGIS_APP_SRCS
   mesh/qgsmeshcalculatordialog.cpp
   mesh/qgsnewmeshlayerdialog.cpp
   mesh/qgsmaptooleditmeshframe.cpp
+  mesh/qgsmeshtransformcoordinatesdockwidget.cpp
 )
 
 if (WITH_SPATIALITE)