QGIS API Documentation  3.21.0-Master (564c892cfd)
Public Member Functions | List of all members
QgsVectorTileLayerRenderer Class Reference

This class provides map rendering functionality for vector tile layers. More...

#include <qgsvectortilelayerrenderer.h>

Inheritance diagram for QgsVectorTileLayerRenderer:
Inheritance graph
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Public Member Functions

 QgsVectorTileLayerRenderer (QgsVectorTileLayer *layer, QgsRenderContext &context)
 Creates the renderer. Always called from main thread, should copy whatever necessary from the layer. More...
 
virtual QgsFeedbackfeedback () const override
 Access to feedback object of the layer renderer (may be nullptr) More...
 
bool forceRasterRender () const override
 Returns true if the renderer must be rendered to a raster paint device (e.g. More...
 
virtual bool render () override
 Do the rendering (based on data stored in the class). More...
 
- Public Member Functions inherited from QgsMapLayerRenderer
 QgsMapLayerRenderer (const QString &layerID, QgsRenderContext *context=nullptr)
 Constructor for QgsMapLayerRenderer, with the associated layerID and render context. More...
 
virtual ~QgsMapLayerRenderer ()=default
 
QStringList errors () const
 Returns list of errors (problems) that happened during the rendering. More...
 
bool isReadyToCompose () const
 Returns whether the renderer has already drawn (at least partially) some data. More...
 
QString layerId () const
 Gets access to the ID of the layer rendered by this class. More...
 
QgsRenderContextrenderContext ()
 Returns the render context associated with the renderer. More...
 
const QgsRenderContextrenderContext () const
 Returns the render context associated with the renderer. More...
 
virtual void setLayerRenderingTimeHint (int time)
 Sets approximate render time (in ms) for the layer to render. More...
 

Additional Inherited Members

- Protected Attributes inherited from QgsMapLayerRenderer
QStringList mErrors
 
QString mLayerID
 
bool mReadyToCompose = true
 The flag must be set to false in renderer's constructor if wants to use the smarter map redraws functionality https://github.com/qgis/QGIS-Enhancement-Proposals/issues/181. More...
 
- Static Protected Attributes inherited from QgsMapLayerRenderer
static constexpr int MAX_TIME_TO_USE_CACHED_PREVIEW_IMAGE = 3000
 Maximum time (in ms) to allow display of a previously cached preview image while rendering layers, before switching to a progressive rendering display. More...
 

Detailed Description

This class provides map rendering functionality for vector tile layers.

In render() function (assumed to be run in a worker thread) it will:

fetch vector tiles using QgsVectorTileLoader

decode raw tiles into QgsFeature objects using QgsVectorTileDecoder

render tiles using a class derived from QgsVectorTileRenderer

Since
QGIS 3.14

Definition at line 41 of file qgsvectortilelayerrenderer.h.

Constructor & Destructor Documentation

◆ QgsVectorTileLayerRenderer()

QgsVectorTileLayerRenderer::QgsVectorTileLayerRenderer ( QgsVectorTileLayer layer,
QgsRenderContext context 
)

Creates the renderer. Always called from main thread, should copy whatever necessary from the layer.

Definition at line 33 of file qgsvectortilelayerrenderer.cpp.

Member Function Documentation

◆ feedback()

virtual QgsFeedback* QgsVectorTileLayerRenderer::feedback ( ) const
inlineoverridevirtual

Access to feedback object of the layer renderer (may be nullptr)

Since
QGIS 3.0

Reimplemented from QgsMapLayerRenderer.

Definition at line 48 of file qgsvectortilelayerrenderer.h.

◆ forceRasterRender()

bool QgsVectorTileLayerRenderer::forceRasterRender ( ) const
overridevirtual

Returns true if the renderer must be rendered to a raster paint device (e.g.

QImage).

Some layer settings require layers to be effectively "flattened" while rendering maps, which is achieved by first rendering the layer onto a raster paint device and then compositing the resultant image onto the final map render.

E.g. if a layer contains features with transparency or alternative blending modes, and the effects of these opacity or blending modes should be restricted to only affect other features within the SAME layer, then a flattened raster based render is required.

Subclasses should return true whenever their corresponding layer settings require the layer to always be rendered using a raster paint device.

Since
QGIS 3.18

Reimplemented from QgsMapLayerRenderer.

Definition at line 196 of file qgsvectortilelayerrenderer.cpp.

◆ render()

bool QgsVectorTileLayerRenderer::render ( )
overridevirtual

Do the rendering (based on data stored in the class).

Returns true if the layer was completely rendered successfully (i.e. the render was not canceled early).

Implements QgsMapLayerRenderer.

Definition at line 65 of file qgsvectortilelayerrenderer.cpp.


The documentation for this class was generated from the following files: