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127 lines
4.1 KiB
Plaintext
127 lines
4.1 KiB
Plaintext
/************************************************************************
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* This file has been generated automatically from *
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* *
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* src/core/qgsmaplayerrenderer.h *
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* *
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* Do not edit manually ! Edit header and run scripts/sipify.pl again *
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************************************************************************/
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class QgsMapLayerRenderer
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{
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%Docstring
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Base class for utility classes that encapsulate information necessary
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for rendering of map layers.
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The rendering is typically done in a background
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thread, so it is necessary to keep all structures required for rendering away
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from the original map layer because it may change any time.
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Because the data needs to be copied (to avoid the need for locking),
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it is highly desirable to use copy-on-write where possible. This way,
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the overhead of copying (both memory and CPU) will be kept low.
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Qt containers and various Qt classes use implicit sharing.
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The scenario will be:
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# renderer job (doing preparation in the GUI thread) calls
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:py:func:`QgsMapLayer.createMapRenderer()` and gets instance of this class.
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The instance is initialized at that point and should not need
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additional calls to :py:class:`QgsVectorLayer`.
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# renderer job (still in GUI thread) stores the renderer for later use.
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# renderer job (in worker thread) calls :py:func:`QgsMapLayerRenderer.render()`
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# renderer job (again in GUI thread) will check :py:func:`~errors` and report them
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.. versionadded:: 2.4
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%End
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%TypeHeaderCode
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#include "qgsmaplayerrenderer.h"
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%End
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public:
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QgsMapLayerRenderer( const QString &layerID, QgsRenderContext *context = 0 );
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%Docstring
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Constructor for QgsMapLayerRenderer, with the associated ``layerID`` and render ``context``.
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%End
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virtual ~QgsMapLayerRenderer();
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virtual bool render() = 0;
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%Docstring
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Do the rendering (based on data stored in the class).
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Returns ``True`` if the layer was completely rendered successfully (i.e. the render
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was not canceled early).
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%End
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virtual bool forceRasterRender() const;
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%Docstring
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Returns ``True`` if the renderer must be rendered to a raster paint device (e.g. QImage).
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Some layer settings require layers to be effectively "flattened" while rendering maps,
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which is achieved by first rendering the layer onto a raster paint device and then compositing
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the resultant image onto the final map render.
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E.g. if a layer contains features with transparency or alternative blending modes, and
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the effects of these opacity or blending modes should be restricted to only affect other
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features within the SAME layer, then a flattened raster based render is required.
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Subclasses should return ``True`` whenever their corresponding layer settings require the
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layer to always be rendered using a raster paint device.
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.. versionadded:: 3.18
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%End
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virtual QgsFeedback *feedback() const;
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%Docstring
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Access to feedback object of the layer renderer (may be ``None``)
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.. versionadded:: 3.0
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%End
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QStringList errors() const;
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%Docstring
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Returns list of errors (problems) that happened during the rendering
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%End
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QString layerId() const;
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%Docstring
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Gets access to the ID of the layer rendered by this class
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%End
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QgsRenderContext *renderContext();
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%Docstring
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Returns the render context associated with the renderer.
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.. versionadded:: 3.10
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%End
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bool isReadyToCompose() const;
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%Docstring
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Returns whether the renderer has already drawn (at
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least partially) some data
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.. versionadded:: 3.18
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%End
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protected:
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};
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/************************************************************************
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* This file has been generated automatically from *
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* *
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* src/core/qgsmaplayerrenderer.h *
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* *
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* Do not edit manually ! Edit header and run scripts/sipify.pl again *
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************************************************************************/
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