QGIS API Documentation 3.27.0-Master (1d7a28cfd2)
qgsannotationlayerrenderer.cpp
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1/***************************************************************************
2 qgsannotationlayerrenderer.cpp
3 ------------------
4 copyright : (C) 2019 by Sandro Mani
5 email : smani at sourcepole dot ch
6 ***************************************************************************/
7
8/***************************************************************************
9 * *
10 * This program is free software; you can redistribute it and/or modify *
11 * it under the terms of the GNU General Public License as published by *
12 * the Free Software Foundation; either version 2 of the License, or *
13 * (at your option) any later version. *
14 * *
15 ***************************************************************************/
16
18#include "qgsannotationlayer.h"
19#include "qgsfeedback.h"
21#include "qgspainteffect.h"
22#include "qgsrendercontext.h"
23#include <optional>
24
26 : QgsMapLayerRenderer( layer->id(), &context )
27 , mFeedback( std::make_unique< QgsFeedback >() )
28 , mLayerOpacity( layer->opacity() )
29{
30 // Clone items from layer which fall inside the rendered extent
31 // Because some items have scale dependent bounds, we have to accept some limitations here.
32 // first, we can use the layer's spatial index to very quickly retrieve items we know will fall within the visible
33 // extent. This will ONLY apply to items which have a non-scale-dependent bounding box though.
34
35 const QStringList itemsList = layer->queryIndex( context.extent() );
36 QSet< QString > items( itemsList.begin(), itemsList.end() );
37
38 // we also have NO choice but to clone ALL non-indexed items (i.e. those with a scale-dependent bounding box)
39 // since these won't be in the layer's spatial index, and it's too expensive to determine their actual bounding box
40 // upfront (we are blocking the main thread right now!)
41
42 // TODO -- come up with some brilliant way to avoid this and also index scale-dependent items ;)
43 items.unite( layer->mNonIndexedItems );
44
45 mItems.reserve( items.size() );
46 std::transform( items.begin(), items.end(), std::back_inserter( mItems ),
47 [layer]( const QString & id ) ->std::pair< QString, std::unique_ptr< QgsAnnotationItem > >
48 {
49 return std::make_pair( id, std::unique_ptr< QgsAnnotationItem >( layer->item( id )->clone() ) );
50 } );
51
52 std::sort( mItems.begin(), mItems.end(), [](
53 const std::pair< QString, std::unique_ptr< QgsAnnotationItem > > &a,
54 const std::pair< QString, std::unique_ptr< QgsAnnotationItem > > &b )
55 { return a.second->zIndex() < b.second->zIndex(); } );
56
57 if ( layer->paintEffect() && layer->paintEffect()->enabled() )
58 {
59 mPaintEffect.reset( layer->paintEffect()->clone() );
60 }
61}
62
64
66{
67 return mFeedback.get();
68}
69
71{
72 QgsRenderContext &context = *renderContext();
73
74 if ( mPaintEffect )
75 {
76 mPaintEffect->begin( context );
77 }
78
79 bool canceled = false;
80 for ( const std::pair< QString, std::unique_ptr< QgsAnnotationItem > > &item : std::as_const( mItems ) )
81 {
82 if ( mFeedback->isCanceled() )
83 {
84 canceled = true;
85 break;
86 }
87
88 std::optional< QgsScopedRenderContextReferenceScaleOverride > referenceScaleOverride;
89 if ( item.second->useSymbologyReferenceScale() )
90 {
91 referenceScaleOverride.emplace( QgsScopedRenderContextReferenceScaleOverride( context, item.second->symbologyReferenceScale() ) );
92 }
93
94 const QgsRectangle bounds = item.second->boundingBox( context );
95 if ( bounds.intersects( context.extent() ) )
96 {
97 item.second->render( context, mFeedback.get() );
98 std::unique_ptr< QgsRenderedAnnotationItemDetails > details = std::make_unique< QgsRenderedAnnotationItemDetails >( mLayerID, item.first );
99 details->setBoundingBox( bounds );
100 appendRenderedItemDetails( details.release() );
101 }
102 }
103
104 if ( mPaintEffect )
105 {
106 mPaintEffect->end( context );
107 }
108
109 return !canceled;
110}
111
113{
114 return renderContext()->testFlag( Qgis::RenderContextFlag::UseAdvancedEffects ) && ( !qgsDoubleNear( mLayerOpacity, 1.0 ) );
115}
@ UseAdvancedEffects
Enable layer opacity and blending effects.
bool forceRasterRender() const override
Returns true if the renderer must be rendered to a raster paint device (e.g.
~QgsAnnotationLayerRenderer() override
bool render() override
Do the rendering (based on data stored in the class).
QgsFeedback * feedback() const override
Access to feedback object of the layer renderer (may be nullptr)
QgsAnnotationLayerRenderer(QgsAnnotationLayer *layer, QgsRenderContext &context)
Constructor for a QgsAnnotationLayerRenderer, for the specified layer.
Represents a map layer containing a set of georeferenced annotations, e.g.
QgsPaintEffect * paintEffect() const
Returns the current paint effect for the layer.
Base class for feedback objects to be used for cancellation of something running in a worker thread.
Definition: qgsfeedback.h:45
Base class for utility classes that encapsulate information necessary for rendering of map layers.
void appendRenderedItemDetails(QgsRenderedItemDetails *details)
Appends the details of a rendered item to the renderer.
QgsRenderContext * renderContext()
Returns the render context associated with the renderer.
bool enabled() const
Returns whether the effect is enabled.
virtual QgsPaintEffect * clone() const =0
Duplicates an effect by creating a deep copy of the effect.
A rectangle specified with double values.
Definition: qgsrectangle.h:42
bool intersects(const QgsRectangle &rect) const SIP_HOLDGIL
Returns true when rectangle intersects with other rectangle.
Definition: qgsrectangle.h:349
Contains information about the context of a rendering operation.
double symbologyReferenceScale() const
Returns the symbology reference scale.
const QgsRectangle & extent() const
When rendering a map layer, calling this method returns the "clipping" extent for the layer (in the l...
bool testFlag(Qgis::RenderContextFlag flag) const
Check whether a particular flag is enabled.
Scoped object for temporary override of the symbologyReferenceScale property of a QgsRenderContext.
bool qgsDoubleNear(double a, double b, double epsilon=4 *std::numeric_limits< double >::epsilon())
Compare two doubles (but allow some difference)
Definition: qgis.h:2507