QGIS API Documentation
3.0.2-Girona (307d082)
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Base class for utility classes that encapsulate information necessary for rendering of map layers. More...
#include <qgsmaplayerrenderer.h>
Public Member Functions | |
QgsMapLayerRenderer (const QString &layerID) | |
virtual | ~QgsMapLayerRenderer ()=default |
QStringList | errors () const |
Return list of errors (problems) that happened during the rendering. More... | |
virtual QgsFeedback * | feedback () const |
Access to feedback object of the layer renderer (may be null) More... | |
QString | layerId () const |
Get access to the ID of the layer rendered by this class. More... | |
virtual bool | render ()=0 |
Do the rendering (based on data stored in the class) More... | |
Protected Attributes | |
QStringList | mErrors |
QString | mLayerID |
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), it 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:
Definition at line 48 of file qgsmaplayerrenderer.h.
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inline |
Definition at line 51 of file qgsmaplayerrenderer.h.
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virtualdefault |
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inline |
Return list of errors (problems) that happened during the rendering.
Definition at line 64 of file qgsmaplayerrenderer.h.
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inlinevirtual |
Access to feedback object of the layer renderer (may be null)
Reimplemented in QgsRasterLayerRenderer.
Definition at line 61 of file qgsmaplayerrenderer.h.
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inline |
Get access to the ID of the layer rendered by this class.
Definition at line 67 of file qgsmaplayerrenderer.h.
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pure virtual |
Do the rendering (based on data stored in the class)
Implemented in QgsVectorLayerRenderer, and QgsRasterLayerRenderer.
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protected |
Definition at line 70 of file qgsmaplayerrenderer.h.
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protected |
Definition at line 71 of file qgsmaplayerrenderer.h.