QGIS API Documentation  3.21.0-Master (5b68dc587e)
qgsrasterrenderer.cpp
Go to the documentation of this file.
1 /***************************************************************************
2  qgsrasterrenderer.cpp
3  ---------------------
4  begin : December 2011
5  copyright : (C) 2011 by Marco Hugentobler
6  email : marco at sourcepole dot ch
7  ***************************************************************************/
8 
9 /***************************************************************************
10  * *
11  * This program is free software; you can redistribute it and/or modify *
12  * it under the terms of the GNU General Public License as published by *
13  * the Free Software Foundation; either version 2 of the License, or *
14  * (at your option) any later version. *
15  * *
16  ***************************************************************************/
17 
18 #include "qgsrasterrenderer.h"
19 #include "qgsrastertransparency.h"
20 
21 #include "qgssymbollayerutils.h"
23 
24 #include <QCoreApplication>
25 #include <QDomDocument>
26 #include <QDomElement>
27 #include <QImage>
28 #include <QPainter>
29 
30 // See #9101 before any change of NODATA_COLOR!
31 const QRgb QgsRasterRenderer::NODATA_COLOR = qRgba( 0, 0, 0, 0 );
32 
34  : QgsRasterInterface( input )
35  , mType( type )
36 {
37 }
38 
40 {
41  delete mRasterTransparency;
42 }
43 
45 {
46  if ( mOn ) return 1;
47 
48  if ( mInput ) return mInput->bandCount();
49 
50  return 0;
51 }
52 
54 {
55  QgsDebugMsgLevel( QStringLiteral( "Entered" ), 4 );
56 
58 
59  if ( mInput ) return mInput->dataType( bandNo );
60 
62 }
63 
65 {
66  // Renderer can only work with numerical values in at least 1 band
67  if ( !input ) return false;
68 
69  if ( !mOn )
70  {
71  // In off mode we can connect to anything
72  mInput = input;
73  return true;
74  }
75 
76  for ( int i = 1; i <= input->bandCount(); i++ )
77  {
78  const Qgis::DataType bandType = input->dataType( i );
79  // we always allow unknown data types to connect - otherwise invalid layers cannot setup
80  // their original rendering pipe and this information is lost
81  if ( bandType != Qgis::DataType::UnknownDataType && !QgsRasterBlock::typeIsNumeric( bandType ) )
82  {
83  return false;
84  }
85  }
86  mInput = input;
87  return true;
88 }
89 
91 {
92  if ( !mInput )
93  {
94  return true;
95  }
96  return ( mAlphaBand > 0 || ( mRasterTransparency && !mRasterTransparency->isEmpty() ) || !qgsDoubleNear( mOpacity, 1.0 ) );
97 }
98 
100 {
101  delete mRasterTransparency;
103 }
104 
105 QList< QPair< QString, QColor > > QgsRasterRenderer::legendSymbologyItems() const
106 {
107  return QList< QPair< QString, QColor > >();
108 }
109 
110 QList<QgsLayerTreeModelLegendNode *> QgsRasterRenderer::createLegendNodes( QgsLayerTreeLayer *nodeLayer )
111 {
112  QList<QgsLayerTreeModelLegendNode *> nodes;
113 
114  const QList< QPair< QString, QColor > > rasterItemList = legendSymbologyItems();
115  if ( rasterItemList.isEmpty() )
116  return nodes;
117 
118  // Paletted raster may have many colors, for example UInt16 may have 65536 colors
119  // and it is very slow, so we limit max count
120  int count = 0;
121  const int max_count = 1000;
122 
123  for ( auto itemIt = rasterItemList.constBegin(); itemIt != rasterItemList.constEnd(); ++itemIt, ++count )
124  {
125  nodes << new QgsRasterSymbolLegendNode( nodeLayer, itemIt->second, itemIt->first );
126 
127  if ( count == max_count )
128  {
129  const QString label = tr( "following %1 items\nnot displayed" ).arg( rasterItemList.size() - max_count );
130  nodes << new QgsSimpleLegendNode( nodeLayer, label );
131  break;
132  }
133  }
134 
135  return nodes;
136 }
137 
138 void QgsRasterRenderer::_writeXml( QDomDocument &doc, QDomElement &rasterRendererElem ) const
139 {
140  if ( rasterRendererElem.isNull() )
141  {
142  return;
143  }
144 
145  rasterRendererElem.setAttribute( QStringLiteral( "type" ), mType );
146  rasterRendererElem.setAttribute( QStringLiteral( "opacity" ), QString::number( mOpacity ) );
147  rasterRendererElem.setAttribute( QStringLiteral( "alphaBand" ), mAlphaBand );
148  rasterRendererElem.setAttribute( QStringLiteral( "nodataColor" ), mNodataColor.isValid() ? QgsSymbolLayerUtils::encodeColor( mNodataColor ) : QString() );
149 
150  if ( mRasterTransparency )
151  {
152  mRasterTransparency->writeXml( doc, rasterRendererElem );
153  }
154 
155  QDomElement minMaxOriginElem = doc.createElement( QStringLiteral( "minMaxOrigin" ) );
156  mMinMaxOrigin.writeXml( doc, minMaxOriginElem );
157  rasterRendererElem.appendChild( minMaxOriginElem );
158 }
159 
161 {
162  if ( !mNodataColor.isValid() )
163  return NODATA_COLOR;
164  else
165  return mNodataColor.rgba();
166 }
167 
168 void QgsRasterRenderer::readXml( const QDomElement &rendererElem )
169 {
170  if ( rendererElem.isNull() )
171  {
172  return;
173  }
174 
175  mType = rendererElem.attribute( QStringLiteral( "type" ) );
176  mOpacity = rendererElem.attribute( QStringLiteral( "opacity" ), QStringLiteral( "1.0" ) ).toDouble();
177  mAlphaBand = rendererElem.attribute( QStringLiteral( "alphaBand" ), QStringLiteral( "-1" ) ).toInt();
178  const QString colorEncoded = rendererElem.attribute( QStringLiteral( "nodataColor" ) );
179  mNodataColor = !colorEncoded.isEmpty() ? QgsSymbolLayerUtils::decodeColor( colorEncoded ) : QColor();
180 
181  const QDomElement rasterTransparencyElem = rendererElem.firstChildElement( QStringLiteral( "rasterTransparency" ) );
182  if ( !rasterTransparencyElem.isNull() )
183  {
184  delete mRasterTransparency;
186  mRasterTransparency->readXml( rasterTransparencyElem );
187  }
188 
189  const QDomElement minMaxOriginElem = rendererElem.firstChildElement( QStringLiteral( "minMaxOrigin" ) );
190  if ( !minMaxOriginElem.isNull() )
191  {
192  mMinMaxOrigin.readXml( minMaxOriginElem );
193  }
194 }
195 
196 void QgsRasterRenderer::copyCommonProperties( const QgsRasterRenderer *other, bool copyMinMaxOrigin )
197 {
198  if ( !other )
199  return;
200 
201  setOpacity( other->opacity() );
202  setAlphaBand( other->alphaBand() );
203  setRasterTransparency( other->rasterTransparency() ? new QgsRasterTransparency( *other->rasterTransparency() ) : nullptr );
204  setNodataColor( other->nodataColor() );
205  if ( copyMinMaxOrigin )
206  setMinMaxOrigin( other->minMaxOrigin() );
207 }
208 
209 void QgsRasterRenderer::toSld( QDomDocument &doc, QDomElement &element, const QVariantMap & ) const
210 {
211  QDomElement rasterSymbolizerElem = doc.createElement( QStringLiteral( "sld:RasterSymbolizer" ) );
212  element.appendChild( rasterSymbolizerElem );
213 
214  // add opacity only is different from default
215  if ( !qgsDoubleNear( opacity(), 1.0 ) )
216  {
217  QDomElement opacityElem = doc.createElement( QStringLiteral( "sld:Opacity" ) );
218  opacityElem.appendChild( doc.createTextNode( QString::number( opacity() ) ) );
219  rasterSymbolizerElem.appendChild( opacityElem );
220  }
221 }
222 
224 {
225  return true;
226 }
DataType
Raster data types.
Definition: qgis.h:120
@ ARGB32_Premultiplied
Color, alpha, red, green, blue, 4 bytes the same as QImage::Format_ARGB32_Premultiplied.
@ UnknownDataType
Unknown or unspecified type.
Layer tree node points to a map layer.
static bool typeIsNumeric(Qgis::DataType type)
Returns true if data type is numeric.
Base class for processing filters like renderers, reprojector, resampler etc.
virtual Qgis::DataType dataType(int bandNo) const =0
Returns data type for the band specified by number.
virtual QgsRasterInterface * input() const
Current input.
virtual int bandCount() const =0
Gets number of bands.
QgsRasterInterface * mInput
void writeXml(QDomDocument &doc, QDomElement &parentElem) const
Serialize object.
void readXml(const QDomElement &elem)
Deserialize object.
Raster renderer pipe that applies colors to a raster.
QColor nodataColor() const
Returns the color to use for shading nodata pixels.
QgsRasterRenderer(QgsRasterInterface *input=nullptr, const QString &type=QString())
Constructor for QgsRasterRenderer.
const QgsRasterTransparency * rasterTransparency() const
double mOpacity
Global alpha value (0-1)
bool setInput(QgsRasterInterface *input) override
Set input.
void setMinMaxOrigin(const QgsRasterMinMaxOrigin &origin)
Sets origin of min/max values.
~QgsRasterRenderer() override
int mAlphaBand
Read alpha value from band.
QRgb renderColorForNodataPixel() const
Returns the color for the renderer to use to represent nodata pixels.
void _writeXml(QDomDocument &doc, QDomElement &rasterRendererElem) const
Write upper class info into rasterrenderer element (called by writeXml method of subclasses)
int bandCount() const override
Gets number of bands.
double opacity() const
Returns the opacity for the renderer, where opacity is a value between 0 (totally transparent) and 1....
void setAlphaBand(int band)
void setOpacity(double opacity)
Sets the opacity for the renderer, where opacity is a value between 0 (totally transparent) and 1....
QgsRasterMinMaxOrigin mMinMaxOrigin
Origin of min/max values.
QgsRasterTransparency * mRasterTransparency
Raster transparency per color or value. Overwrites global alpha value.
virtual QList< QgsLayerTreeModelLegendNode * > createLegendNodes(QgsLayerTreeLayer *nodeLayer)
Creates a set of legend nodes representing the renderer.
void setRasterTransparency(QgsRasterTransparency *t)
virtual bool accept(QgsStyleEntityVisitorInterface *visitor) const
Accepts the specified symbology visitor, causing it to visit all symbols associated with the renderer...
bool usesTransparency() const
void copyCommonProperties(const QgsRasterRenderer *other, bool copyMinMaxOrigin=true)
Copies common properties like opacity / transparency data from other renderer.
static const QRgb NODATA_COLOR
const QgsRasterMinMaxOrigin & minMaxOrigin() const
Returns const reference to origin of min/max values.
virtual void toSld(QDomDocument &doc, QDomElement &element, const QVariantMap &props=QVariantMap()) const
Used from subclasses to create SLD Rule elements following SLD v1.0 specs.
void setNodataColor(const QColor &color)
Sets the color to use for shading nodata pixels.
virtual QList< QPair< QString, QColor > > legendSymbologyItems() const
Returns symbology items if provided by renderer.
void readXml(const QDomElement &rendererElem) override
Sets base class members from xml. Usually called from create() methods of subclasses.
Qgis::DataType dataType(int bandNo) const override
Returns data type for the band specified by number.
Implementation of legend node interface for displaying raster legend entries.
Defines the list of pixel values to be considered as transparent or semi transparent when rendering r...
void writeXml(QDomDocument &doc, QDomElement &parentElem) const
Writes the transparency information to an XML document.
bool isEmpty() const
True if there are no entries in the pixel lists except the nodata value.
void readXml(const QDomElement &elem)
Reads the transparency information from an XML document.
Implementation of legend node interface for displaying arbitrary label with icon.
An interface for classes which can visit style entity (e.g.
static QColor decodeColor(const QString &str)
static QString encodeColor(const QColor &color)
bool qgsDoubleNear(double a, double b, double epsilon=4 *std::numeric_limits< double >::epsilon())
Compare two doubles (but allow some difference)
Definition: qgis.h:1234
#define QgsDebugMsgLevel(str, level)
Definition: qgslogger.h:39