wms convert color to value following mapTiler encoding scheme

qgis · Jan 8, 2022 · 1ab5432 · 1ab5432
1 parent 50748cd
commit 1ab5432
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Showing 16 changed files with 382 additions and 43 deletions.
diff --git a/src/providers/wms/qgswmscapabilities.cpp b/src/providers/wms/qgswmscapabilities.cpp
@@ -55,6 +55,11 @@ bool QgsWmsSettings::parseUri( const QString &uriString )
   mAuth.mReferer = uri.param( QStringLiteral( "referer" ) );
   mXyz = false;  // assume WMS / WMTS
 
+  if ( uri.hasParam( QStringLiteral( "encodingScheme" ) ) )
+  {
+    mEncodingScheme = uri.param( QStringLiteral( "encodingScheme" ) );
+  }
+
   if ( uri.param( QStringLiteral( "type" ) ) == QLatin1String( "xyz" ) ||
        uri.param( QStringLiteral( "type" ) ) == QLatin1String( "mbtiles" ) )
   {
@@ -69,7 +74,7 @@ bool QgsWmsSettings::parseUri( const QString &uriString )
     mBaseUrl = mHttpUri;
     mIgnoreGetMapUrl = false;
     mIgnoreGetFeatureInfoUrl = false;
-    mSmoothPixmapTransform = true;
+    mSmoothPixmapTransform = mEncodingScheme.isEmpty();
     mDpiMode = DpiNone; // does not matter what we set here
     mActiveSubLayers = QStringList( QStringLiteral( "xyz" ) );  // just a placeholder to have one sub-layer
     mActiveSubStyles = QStringList( QStringLiteral( "xyz" ) );  // just a placeholder to have one sub-style

diff --git a/src/providers/wms/qgswmscapabilities.h b/src/providers/wms/qgswmscapabilities.h
@@ -858,6 +858,8 @@ class QgsWmsSettings
 
     bool mEnableContextualLegend;
 
+    QString mEncodingScheme;
+
     friend class QgsWmsProvider;
 };
 

diff --git a/src/providers/wms/qgswmsprovider.cpp b/src/providers/wms/qgswmsprovider.cpp
@@ -221,6 +221,9 @@ QgsWmsProvider::QgsWmsProvider( QString const &uri, const ProviderOptions &optio
   // 2) http://xxx.xxx.xx/yyy/yyy?
   // 3) http://xxx.xxx.xx/yyy/yyy?zzz=www
 
+
+  mConverter.reset( QgsWmsConverter::createConverter( mSettings.mEncodingScheme ) );
+
   mValid = true;
   QgsDebugMsgLevel( QStringLiteral( "exiting constructor." ), 4 );
 }
@@ -884,7 +887,7 @@ QImage *QgsWmsProvider::draw( QgsRectangle const &viewExtent, int pixelWidth, in
                     r.rect.width() / cr,
                     r.rect.height() / cr );
         // if image size is "close enough" to destination size, don't smooth it out. Instead try for pixel-perfect placement!
-        bool disableSmoothing = ( qgsDoubleNear( dst.width(), tm->tileWidth, 2 ) && qgsDoubleNear( dst.height(), tm->tileHeight, 2 ) );
+        bool disableSmoothing = ( qgsDoubleNear( dst.width(), tm->tileWidth, 2 ) && qgsDoubleNear( dst.height(), tm->tileHeight, 2 ) ) || mConverter ;
         tileImages << TileImage( dst, localImage, !disableSmoothing );
       }
       else
@@ -1018,7 +1021,25 @@ bool QgsWmsProvider::readBlock( int bandNo, QgsRectangle  const &viewExtent, int
   if ( ptr )
   {
     // If image is too large, ptr can be NULL
-    memcpy( block, ptr, myExpectedSize );
+    if ( mConverter && ( image->format() == QImage::Format_ARGB32 || image->format() == QImage::Format_RGB32 ) )
+    {
+      std::vector<float> data;
+      data.resize( myImageSize );
+      const QRgb *inputPtr = reinterpret_cast<const QRgb *>( image->constBits() );
+      float *outputPtr = data.data();
+      for ( int i = 0; i < pixelWidth * pixelHeight; ++i )
+      {
+        mConverter->convert( *inputPtr, outputPtr );
+        inputPtr++;
+        outputPtr++;
+      }
+
+      memcpy( block, data.data(), myExpectedSize );
+
+    }
+    else
+      memcpy( block, ptr, myExpectedSize );
+
     return true;
   }
   else
@@ -1600,7 +1621,10 @@ Qgis::DataType QgsWmsProvider::dataType( int bandNo ) const
 Qgis::DataType QgsWmsProvider::sourceDataType( int bandNo ) const
 {
   Q_UNUSED( bandNo )
-  return Qgis::DataType::ARGB32;
+  if ( mConverter )
+    return mConverter->dataType();
+  else
+    return Qgis::DataType::ARGB32;
 }
 
 int QgsWmsProvider::bandCount() const
@@ -3673,6 +3697,22 @@ QgsLayerMetadata QgsWmsProvider::layerMetadata() const
   return mLayerMetadata;
 }
 
+QgsRasterBandStats QgsWmsProvider::bandStatistics( int, int, const QgsRectangle &, int, QgsRasterBlockFeedback * )
+{
+  if ( mConverter )
+    return mConverter->statistics();
+  else
+    return QgsRasterBandStats();
+}
+
+QgsRasterHistogram QgsWmsProvider::histogram( int, int, double, double, const QgsRectangle &, int, bool, QgsRasterBlockFeedback * )
+{
+  if ( mConverter )
+    return mConverter->histogram();
+  else
+    return QgsRasterHistogram();
+}
+
 QVector<QgsWmsSupportedFormat> QgsWmsProvider::supportedFormats()
 {
   QVector<QgsWmsSupportedFormat> formats;
@@ -4787,3 +4827,39 @@ QGISEXTERN QgsProviderMetadata *providerMetadataFactory()
   return new QgsWmsProviderMetadata();
 }
 #endif
+
+Qgis::DataType QgsWmsConverter::dataType() const
+{
+  return Qgis::DataType::Float32;
+}
+
+QgsWmsConverter *QgsWmsConverter::createConverter( const QString &key )
+{
+  if ( key == QgsWmsConverterMapTilerTerrainRGB::encodingSchemeKey() )
+    return new QgsWmsConverterMapTilerTerrainRGB();
+
+  return nullptr;
+}
+
+void QgsWmsConverterMapTilerTerrainRGB::convert( const QRgb &color, float *converted ) const
+{
+  int R = qRed( color );
+  int G = qGreen( color );
+  int B = qBlue( color );
+
+  *converted = -10000 + ( ( R * 256 * 256 + G * 256 + B ) ) * 0.1;
+}
+
+QgsRasterBandStats QgsWmsConverterMapTilerTerrainRGB::statistics() const
+{
+  QgsRasterBandStats stat;
+  stat.minimumValue = 0;
+  stat.maximumValue = 9000;
+  stat.statsGathered = QgsRasterBandStats::Min | QgsRasterBandStats::Max;
+  return stat;
+}
+
+QgsRasterHistogram QgsWmsConverterMapTilerTerrainRGB::histogram() const
+{
+  return QgsRasterHistogram();
+}
diff --git a/src/providers/wms/qgswmsprovider.h b/src/providers/wms/qgswmsprovider.h
@@ -99,6 +99,41 @@ class QgsCachedImageFetcher: public QgsImageFetcher
     }
 };
 
+//! Abstract class to convert color to float value following encoding scheme
+class QgsWmsConverter
+{
+  public:
+    virtual ~QgsWmsConverter() = default;
+
+    //! Convert the \a color to a value pointed by float
+    virtual void convert( const QRgb &color, float *converted ) const = 0;
+
+    //! Returns the output datatype of this converter
+    virtual Qgis::DataType dataType() const;
+
+    //! Returns statistics related to converted values
+    virtual QgsRasterBandStats statistics() const = 0;
+
+    //! Returns the histogram related to converted values
+    virtual QgsRasterHistogram histogram() const = 0;
+
+    //! Creates a converter instance corresponding to the \a key
+    static QgsWmsConverter *createConverter( const QString &key );
+};
+
+
+//! Abstract class to convert color to float value following the mapTiler terrain RGB encoding scheme
+class QgsWmsConverterMapTilerTerrainRGB : public QgsWmsConverter
+{
+  public:
+    void convert( const QRgb &color, float *converted ) const override;
+
+    QgsRasterBandStats statistics() const override;
+    QgsRasterHistogram histogram() const override;
+
+    static QString displayName() {return QObject::tr( "MapTiler Terrain RGB" );}
+    static QString encodingSchemeKey() {return QStringLiteral( "maptilerterrain" );}
+};
 
 /**
  *
@@ -219,6 +254,21 @@ class QgsWmsProvider final: public QgsRasterDataProvider
     QList< double > nativeResolutions() const override;
     QgsLayerMetadata layerMetadata() const override;
 
+    //! Statitics could be available if the provider has a converter from colors to other value type, the returned statistics depend on the converter
+    QgsRasterBandStats bandStatistics( int bandNo,
+                                       int stats = QgsRasterBandStats::All,
+                                       const QgsRectangle &extent = QgsRectangle(),
+                                       int sampleSize = 0, QgsRasterBlockFeedback *feedback = nullptr ) override;
+
+    virtual QgsRasterHistogram histogram( int bandNo,
+                                          int binCount = 0,
+                                          double minimum = std::numeric_limits<double>::quiet_NaN(),
+                                          double maximum = std::numeric_limits<double>::quiet_NaN(),
+                                          const QgsRectangle &extent = QgsRectangle(),
+                                          int sampleSize = 0,
+                                          bool includeOutOfRange = false,
+                                          QgsRasterBlockFeedback *feedback = nullptr ) override;
+
     static QVector<QgsWmsSupportedFormat> supportedFormats();
 
     static void showMessageBox( const QString &title, const QString &text );
@@ -492,6 +542,8 @@ class QgsWmsProvider final: public QgsRasterDataProvider
 
     QList< double > mNativeResolutions;
 
+    std::unique_ptr<QgsWmsConverter> mConverter;
+
     friend class TestQgsWmsProvider;
 
 };

diff --git a/src/providers/wms/qgswmssourceselect.cpp b/src/providers/wms/qgswmssourceselect.cpp
@@ -143,6 +143,9 @@ QgsWMSSourceSelect::QgsWMSSourceSelect( QWidget *parent, Qt::WindowFlags fl, Qgs
     tabLayers->layout()->removeWidget( gbCRS );
   }
 
+  mEncodingSchemeWidget = new QgsWMSEncodingSchemeWidget( this );
+  mEncodingSchemeLayout->addWidget( mEncodingSchemeWidget );
+
   clear();
 
   // set up the WMS connections we already know about
@@ -284,6 +287,8 @@ void QgsWMSSourceSelect::clear()
   }
 
   mFeatureCount->setEnabled( false );
+
+  mEncodingSchemeWidget->setEncodingScheme( QString() );
 }
 
 bool QgsWMSSourceSelect::populateLayerList( const QgsWmsCapabilities &capabilities )
@@ -599,6 +604,9 @@ void QgsWMSSourceSelect::addButtonClicked()
     uri.setParam( QStringLiteral( "featureCount" ), mFeatureCount->text() );
   }
 
+  if ( tabTilesets->isEnabled() && !mEncodingSchemeWidget->encodingScheme().isEmpty() )
+    uri.setParam( QStringLiteral( "encodingScheme" ), mEncodingSchemeWidget->encodingScheme() );
+
   uri.setParam( QStringLiteral( "contextualWMSLegend" ), mContextualLegendCheckbox->isChecked() ? "1" : "0" );
 
   emit addRasterLayer( uri.encodedUri(),
@@ -1308,3 +1316,54 @@ void QgsWMSSourceSelect::showHelp()
 {
   QgsHelp::openHelp( QStringLiteral( "working_with_ogc/ogc_client_support.html" ) );
 }
+
+QgsWMSEncodingSchemeWidget::QgsWMSEncodingSchemeWidget( QWidget *parent ): QWidget( parent )
+{
+  QHBoxLayout *lay = new QHBoxLayout( this );
+  lay->setContentsMargins( 0, 0, 0, 0 );
+  setLayout( lay );
+  mCheckBox = new QCheckBox( this );
+  mCheckBox->setText( tr( "Convert to single band raster" ) );
+  mCheckBox->setChecked( false );
+  layout()->addWidget( mCheckBox );
+
+  mCombo = new QComboBox( this );
+  mCombo->setEnabled( false );
+  layout()->addWidget( mCombo );
+
+  connect( mCheckBox, &QAbstractButton::toggled, mCombo, &QComboBox::setEnabled );
+
+  populateEncodingScheme();
+}
+
+void QgsWMSEncodingSchemeWidget::populateEncodingScheme()
+{
+  mCombo->addItem( QgsWmsConverterMapTilerTerrainRGB::displayName(), QgsWmsConverterMapTilerTerrainRGB::encodingSchemeKey() );
+}
+
+void QgsWMSEncodingSchemeWidget::setEncodingScheme( const QString &encodingSchemeKey )
+{
+  bool checked = false;
+  if ( ! encodingSchemeKey.isEmpty() )
+  {
+    int index = mCombo->findData( encodingSchemeKey );
+    if ( index != -1 )
+    {
+      checked = true;
+      mCombo->setCurrentIndex( index );
+    }
+    else
+      checked = false;
+  }
+
+  mCheckBox->setChecked( checked );
+  mCombo->setEnabled( checked );
+}
+
+QString QgsWMSEncodingSchemeWidget::encodingScheme() const
+{
+  if ( mCheckBox->isChecked() )
+    return mCombo->currentData().toString();
+
+  return QString();
+}
diff --git a/src/providers/wms/qgswmssourceselect.h b/src/providers/wms/qgswmssourceselect.h
@@ -33,6 +33,7 @@ class QgsTreeWidgetItem;
 class QDomDocument;
 class QDomElement;
 class QgsWmsCapabilities;
+class QgsWMSEncodingSchemeWidget;
 
 /*!
  * \brief   Dialog to create connections and add layers from WMS, etc.
@@ -128,7 +129,6 @@ class QgsWMSSourceSelect : public QgsAbstractDataSourceWidget, private Ui::QgsWM
     //! Map mime types to supported formats
     QMap<QString, int> mMimeMap;
 
-
     // Clear layers list, crs, encodings ...
     void clear();
 
@@ -193,6 +193,8 @@ class QgsWMSSourceSelect : public QgsAbstractDataSourceWidget, private Ui::QgsWM
     // save the current status of the layer true
     QMap<QTreeWidgetItem *, bool> mTreeInitialExpand = QMap<QTreeWidgetItem *, bool>();
 
+    QgsWMSEncodingSchemeWidget *mEncodingSchemeWidget = nullptr;
+
   private slots:
     void lstTilesets_itemClicked( QTableWidgetItem *item );
     void mLayerUpButton_clicked();
@@ -201,5 +203,29 @@ class QgsWMSSourceSelect : public QgsAbstractDataSourceWidget, private Ui::QgsWM
     void showHelp();
 };
 
+/*!
+ * \brief  Widget that embeds a check box and a combo box to select an encoding scheme to convert image to a single band raster
+ */
+class QgsWMSEncodingSchemeWidget : public QWidget
+{
+  public:
+    //! Contructor
+    QgsWMSEncodingSchemeWidget( QWidget *parent = nullptr );
+
+    /**
+     * Sets the current encoding scheme from its key \a encodingSchemeKey,
+     * leading to checked the check box if the encoding scheme exists or unchecked if the key is empty or the scheme does not exist
+     */
+    void setEncodingScheme( const QString &encodingSchemeKey );
+
+    //! Returns the key of the current selected scheme, returns empty string if the check box is unchecked
+    QString encodingScheme() const;
+
+  private:
+    QCheckBox *mCheckBox = nullptr;
+    QComboBox *mCombo = nullptr;
+
+    void populateEncodingScheme();
+};
 
 #endif // QGSWMSSOURCESELECT_H
diff --git a/src/providers/wms/qgsxyzconnection.cpp b/src/providers/wms/qgsxyzconnection.cpp
@@ -38,6 +38,8 @@ QString QgsXyzConnection::encodedUri() const
     uri.setParam( QStringLiteral( "referer" ), referer );
   if ( tilePixelRatio != 0 )
     uri.setParam( QStringLiteral( "tilePixelRatio" ), QString::number( tilePixelRatio ) );
+  if ( !encodingScheme.isEmpty() )
+    uri.setParam( QStringLiteral( "encodingScheme" ), encodingScheme );
   return uri.encodedUri();
 }
 
@@ -94,6 +96,7 @@ QgsXyzConnection QgsXyzConnectionUtils::connection( const QString &name )
   conn.referer = settings.value( QStringLiteral( "referer" ) ).toString();
   conn.tilePixelRatio = settings.value( QStringLiteral( "tilePixelRatio" ), 0 ).toDouble();
   conn.hidden = settings.value( QStringLiteral( "hidden" ) ).toBool();
+  conn.encodingScheme = settings.value( QStringLiteral( "encodingScheme" ), conn.encodingScheme ).toString();
   return conn;
 }
 
@@ -136,6 +139,7 @@ void QgsXyzConnectionUtils::addConnection( const QgsXyzConnection &conn )
   settings.setValue( QStringLiteral( "password" ), conn.password );
   settings.setValue( QStringLiteral( "referer" ), conn.referer );
   settings.setValue( QStringLiteral( "tilePixelRatio" ), conn.tilePixelRatio );
+  settings.setValue( QStringLiteral( "encodingScheme" ), conn.encodingScheme );
   if ( addHiddenProperty )
   {
     settings.setValue( QStringLiteral( "hidden" ), false );

diff --git a/src/providers/wms/qgsxyzconnection.h b/src/providers/wms/qgsxyzconnection.h
@@ -36,6 +36,9 @@ struct QgsXyzConnection
   double tilePixelRatio = 0;
   bool hidden = false;
 
+  // Encoding scheme key related to the converter from color to value, empty if none
+  QString encodingScheme;
+
   QString encodedUri() const;
 };