Implement platform-specific coordinate conversion functions

Generic wxDC::DeviceToLogical{X|Y}() and wxDC::LogicalToDevice{X|Y}()
functions don't take into account transformations applied with
wxDC::SetTransformMatrix() so conversion results are invalid if wxDC is
transformed with both e.g. wxDC::SetUserScale() and
wxDC::SetTransformMatrix().
We need to implement functions in wxDCImpl and its platform-specific
derivates to do this conversion with taking into account all applied
transformations.

See #18916.

src/common/dcbase.cpp

@@ -502,6 +502,16 @@ wxCoord wxDCImpl::LogicalToDeviceYRel(wxCoord y) const
     return wxRound((double)(y) * m_scaleY);
 }
 
+wxPoint wxDCImpl::DeviceToLogical(wxCoord x, wxCoord y) const
+{
+    return wxPoint(DeviceToLogicalX(x), DeviceToLogicalY(y));
+}
+
+wxPoint wxDCImpl::LogicalToDevice(wxCoord x, wxCoord y) const
+{
+    return wxPoint(LogicalToDeviceX(x), LogicalToDeviceY(y));
+}
+
 void wxDCImpl::ComputeScaleAndOrigin()
 {
     m_scaleX = m_logicalScaleX * m_userScaleX;