QGIS/python/core/qgsmaplayerrenderer.sip

/************************************************************************
 * This file has been generated automatically from                      *
 *                                                                      *
 * src/core/qgsmaplayerrenderer.h                                       *
 *                                                                      *
 * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
 ************************************************************************/





class QgsMapLayerRenderer
{
%Docstring
 Base class for utility classes that encapsulate information necessary
 for rendering of map layers. The rendering is typically done in a background
 thread, so it is necessary to keep all structures required for rendering away
 from the original map layer because it may change any time.

 Because the data needs to be copied (to avoid the need for locking),
 is is highly desirable to use copy-on-write where possible. This way,
 the overhead of copying (both memory and CPU) will be kept low.
 Qt containers and various Qt classes use implicit sharing.

 The scenario will be:
 1. renderer job (doing preparation in the GUI thread) calls
    QgsMapLayer.createMapRenderer() and gets instance of this class.
    The instance is initialized at that point and should not need
    additional calls to QgsVectorLayer.
 2. renderer job (still in GUI thread) stores the renderer for later use.
 3. renderer job (in worker thread) calls QgsMapLayerRenderer.render()
 4. renderer job (again in GUI thread) will check errors() and report them

.. versionadded:: 2.4
%End

%TypeHeaderCode
#include "qgsmaplayerrenderer.h"
%End
  public:
    QgsMapLayerRenderer( const QString &layerID );
    virtual ~QgsMapLayerRenderer();

    virtual bool render() = 0;
%Docstring
Do the rendering (based on data stored in the class)
 :rtype: bool
%End

    virtual QgsFeedback *feedback() const;
%Docstring
 Access to feedback object of the layer renderer (may be null)
.. versionadded:: 3.0
 :rtype: QgsFeedback
%End

    QStringList errors() const;
%Docstring
Return list of errors (problems) that happened during the rendering
 :rtype: list of str
%End

    QString layerId() const;
%Docstring
Get access to the ID of the layer rendered by this class
 :rtype: str
%End

  protected:
};

/************************************************************************
 * This file has been generated automatically from                      *
 *                                                                      *
 * src/core/qgsmaplayerrenderer.h                                       *
 *                                                                      *
 * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
 ************************************************************************/