[FEATURE] Preview for WMTS + added XYZ tile layers

This is a port of the functionality from master (to be QGIS 3.0) to 2.x that keeps backward API compatibility. - added support for XYZ tile layers to WMS provider - rendering of raster layers can be interrupted, support in WMS provider - temporary preview of tiled layers (WMTS / XYZ) in WMS provider WMTS improvements funded by Land Information New Zealand. XYZ tile layer funded by Lutra Consulting.
qgis · Sep 16, 2016 · f5b657d · f5b657d
1 parent 85b6cba
commit f5b657d
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diff --git a/python/core/core.sip b/python/core/core.sip
@@ -54,6 +54,7 @@
 %Include qgsfeaturefilterprovider.sip
 %Include qgsfeatureiterator.sip
 %Include qgsfeaturerequest.sip
+%Include qgsfeedback.sip
 %Include qgsfield.sip
 %Include qgsgeometrysimplifier.sip
 %Include qgsgeometryvalidator.sip

diff --git a/python/core/qgsfeedback.sip b/python/core/qgsfeedback.sip
@@ -0,0 +1,43 @@
+
+/** \ingroup core
+ * Base class for feedback objects to be used for cancellation of something running in a worker thread.
+ * The class may be used as is or it may be subclassed for extended functionality
+ * for a particular operation (e.g. report progress or pass some data for preview).
+ *
+ * When cancel() is called, the internal code has two options to check for cancellation state:
+ * - if the worker thread uses an event loop (e.g. for network communication), the code can
+ *   make a queued connection to cancelled() signal and handle the cancellation in its slot.
+ * - if the worker thread does not use an event loop, it can poll isCancelled() method regularly
+ *   to see if the operation should be cancelled.
+ *
+ * The class is meant to be created and destroyed in the main thread.
+ *
+ * For map rendering, the object may be created in constructor of a QgsMapLayerRenderer
+ * subclass and available with QgsMapLayerRenderer::feedback() method. When a map rendering job
+ * gets cancelled, the cancel() method is called on the feedback object of all layers.
+ *
+ * @note added in QGIS 2.18
+ */
+class QgsFeedback : QObject
+{
+%TypeHeaderCode
+#include <qgsfeedback.h>
+%End
+
+  public:
+    //! Construct a feedback object
+    QgsFeedback( QObject* parent /TransferThis/ = nullptr );
+
+    virtual ~QgsFeedback();
+
+    //! Tells the internal routines that the current operation should be cancelled. This should be run by the main thread
+    void cancel();
+
+    //! Tells whether the operation has been cancelled already
+    bool isCancelled() const;
+
+  signals:
+    //! Internal routines can connect to this signal if they use event loop
+    void cancelled();
+
+};
diff --git a/python/core/qgsmaplayerrenderer.sip b/python/core/qgsmaplayerrenderer.sip
@@ -12,6 +12,10 @@ class QgsMapLayerRenderer
     //! Do the rendering (based on data stored in the class)
     virtual bool render() = 0;
 
+    //! Access to feedback object of the layer renderer (may be null)
+    //! @note added in QGIS 2.18
+    virtual QgsFeedback* feedback() const;
+
     //! Return list of errors (problems) that happened during the rendering
     QStringList errors() const;
 

diff --git a/python/core/qgsmapsettings.sip b/python/core/qgsmapsettings.sip
@@ -116,7 +116,8 @@ class QgsMapSettings
       UseRenderingOptimization,   //!< Enable vector simplification and other rendering optimizations
       DrawSelection,              //!< Whether vector selections should be shown in the rendered map
       DrawSymbolBounds,           //!< Draw bounds of symbols (for debugging/testing)
-      RenderMapTile               //!< Draw map such that there are no problems between adjacent tiles
+      RenderMapTile,              //!< Draw map such that there are no problems between adjacent tiles
+      RenderPartialOutput,        //!< Whether to make extra effort to update map image with partially rendered layers (better for interactive map canvas). Added in QGIS 2.18
     };
     typedef QFlags<QgsMapSettings::Flag> Flags;
 

diff --git a/python/core/qgsrendercontext.sip b/python/core/qgsrendercontext.sip
@@ -23,6 +23,7 @@ class QgsRenderContext
       DrawSymbolBounds,         //!< Draw bounds of symbols (for debugging/testing)
       RenderMapTile,            //!< Draw map such that there are no problems between adjacent tiles
       Antialiasing,             //!< Use antialiasing while drawing
+      RenderPartialOutput,      //!< Whether to make extra effort to update map image with partially rendered layers (better for interactive map canvas). Added in QGIS 2.18
     };
     typedef QFlags<QgsRenderContext::Flag> Flags;
 

diff --git a/python/core/raster/qgsbrightnesscontrastfilter.sip b/python/core/raster/qgsbrightnesscontrastfilter.sip
@@ -15,7 +15,8 @@ class QgsBrightnessContrastFilter : QgsRasterInterface
 
     bool setInput( QgsRasterInterface* input );
 
-    QgsRasterBlock *block( int bandNo, const QgsRectangle &extent, int width, int height );
+    QgsRasterBlock *block( int bandNo, const QgsRectangle &extent, int width, int height ) /Factory/;
+    QgsRasterBlock *block2( int bandNo, const QgsRectangle &extent, int width, int height, QgsRasterBlockFeedback* feedback = nullptr ) /Factory/;
 
     void setBrightness( int brightness );
     int brightness() const;

diff --git a/python/core/raster/qgshillshaderenderer.sip b/python/core/raster/qgshillshaderenderer.sip
@@ -32,6 +32,7 @@ class QgsHillshadeRenderer : QgsRasterRenderer
     static QgsRasterRenderer* create( const QDomElement& elem, QgsRasterInterface* input ) /Factory/;
 
     QgsRasterBlock *block( int bandNo, const QgsRectangle & extent, int width, int height ) /Factory/;
+    QgsRasterBlock *block2( int bandNo, const QgsRectangle & extent, int width, int height, QgsRasterBlockFeedback* feedback = nullptr ) /Factory/;
 
     void writeXML( QDomDocument& doc, QDomElement& parentElem ) const;
 

diff --git a/python/core/raster/qgshuesaturationfilter.sip b/python/core/raster/qgshuesaturationfilter.sip
@@ -25,7 +25,8 @@ class QgsHueSaturationFilter : QgsRasterInterface
 
     bool setInput( QgsRasterInterface* input );
 
-    QgsRasterBlock *block( int bandNo, const QgsRectangle &extent, int width, int height );
+    QgsRasterBlock *block( int bandNo, const QgsRectangle &extent, int width, int height ) /Factory/;
+    QgsRasterBlock *block2( int bandNo, const QgsRectangle &extent, int width, int height, QgsRasterBlockFeedback* feedback = nullptr ) /Factory/;
 
     void setSaturation( int saturation );
     int saturation() const;

diff --git a/python/core/raster/qgsmultibandcolorrenderer.sip b/python/core/raster/qgsmultibandcolorrenderer.sip
@@ -13,6 +13,7 @@ class QgsMultiBandColorRenderer: QgsRasterRenderer
     static QgsRasterRenderer* create( const QDomElement& elem, QgsRasterDataProvider* provider ) /Factory/;
 
     QgsRasterBlock* block( int bandNo, const QgsRectangle & extent, int width, int height ) /Factory/;
+    QgsRasterBlock* block2( int bandNo, const QgsRectangle & extent, int width, int height, QgsRasterBlockFeedback* feedback = nullptr ) /Factory/;
 
     int redBand() const;
     void setRedBand( int band );

diff --git a/python/core/raster/qgspalettedrasterrenderer.sip b/python/core/raster/qgspalettedrasterrenderer.sip
@@ -11,6 +11,7 @@ class QgsPalettedRasterRenderer : QgsRasterRenderer
     static QgsRasterRenderer* create( const QDomElement& elem, QgsRasterInterface* input ) /Factory/;
 
     QgsRasterBlock *block( int bandNo, const QgsRectangle & extent, int width, int height ) /Factory/;
+    QgsRasterBlock *block2( int bandNo, const QgsRectangle & extent, int width, int height, QgsRasterBlockFeedback* feedback = nullptr ) /Factory/;
 
     /** Returns number of colors*/
     int nColors() const;

diff --git a/python/core/raster/qgsrasterdataprovider.sip b/python/core/raster/qgsrasterdataprovider.sip
@@ -103,6 +103,7 @@ class QgsRasterDataProvider : QgsDataProvider, QgsRasterInterface
 
     /** Read block of data using given extent and size. */
     virtual QgsRasterBlock *block( int theBandNo, const QgsRectangle &theExtent, int theWidth, int theHeight ) / Factory /;
+    virtual QgsRasterBlock *block2( int theBandNo, const QgsRectangle &theExtent, int theWidth, int theHeight, QgsRasterBlockFeedback* feedback = nullptr ) / Factory /;
 
     /** Return true if source band has no data value */
     virtual bool srcHasNoDataValue( int bandNo ) const;
@@ -306,7 +307,7 @@ class QgsRasterDataProvider : QgsDataProvider, QgsRasterInterface
     /** Read block of data using give extent and size
      * @note not available in python bindings
      */
-    //virtual void readBlock( int bandNo, QgsRectangle  const & viewExtent, int width, int height, void *data );
+    //virtual void readBlock( int bandNo, QgsRectangle  const & viewExtent, int width, int height, void *data, QgsRasterBlockFeedback* feedback = nullptr );
 
     /** Returns true if user no data contains value */
     bool userNoDataValuesContains( int bandNo, double value ) const;

diff --git a/python/core/raster/qgsrasterdrawer.sip b/python/core/raster/qgsrasterdrawer.sip
@@ -14,8 +14,9 @@ class QgsRasterDrawer
      * @param viewPort viewport to render
      * @param theQgsMapToPixel map to pixel convertor
      * @param ctx render context
+     * @param feedback optional raster feedback object for cancellation/preview. Added in QGIS 2.18.
      */
-    void draw( QPainter* p, QgsRasterViewPort* viewPort, const QgsMapToPixel* theQgsMapToPixel, const QgsRenderContext *ctx = nullptr );
+    void draw( QPainter* p, QgsRasterViewPort* viewPort, const QgsMapToPixel* theQgsMapToPixel, const QgsRenderContext *ctx = nullptr, QgsRasterBlockFeedback* feedback = nullptr );
 
   protected:
     /** Draws raster part

diff --git a/python/core/raster/qgsrasterinterface.sip b/python/core/raster/qgsrasterinterface.sip
@@ -1,4 +1,41 @@
 
+/** \ingroup core
+ * Feedback object tailored for raster block reading.
+ *
+ * @note added in QGIS 2.18
+ */
+class QgsRasterBlockFeedback : QgsFeedback
+{
+%TypeHeaderCode
+#include <qgsrasterinterface.h>
+%End
+
+  public:
+    //! Construct a new raster block feedback object
+    QgsRasterBlockFeedback( QObject* parent = nullptr );
+
+    //! May be emitted by raster data provider to indicate that some partial data are available
+    //! and a new preview image may be produced
+    virtual void onNewData();
+
+    //! Whether the raster provider should return only data that are already available
+    //! without waiting for full result. By default this flag is not enabled.
+    //! @see setPreviewOnly()
+    bool isPreviewOnly() const;
+    //! set flag whether the block request is for preview purposes only
+    //! @see isPreviewOnly()
+    void setPreviewOnly( bool preview );
+
+    //! Whether our painter is drawing to a temporary image used just by this layer
+    //! @see setRenderPartialOutput()
+    bool renderPartialOutput() const;
+    //! Set whether our painter is drawing to a temporary image used just by this layer
+    //! @see renderPartialOutput()
+    void setRenderPartialOutput( bool enable );
+
+};
+
+
 /** Base class for processing modules.
  *
  */
@@ -132,6 +169,19 @@ class QgsRasterInterface
      */
     virtual QgsRasterBlock *block( int bandNo, const QgsRectangle &extent, int width, int height ) = 0 /Factory/;
 
+    /** Read block of data using given extent and size.
+     *  Returns pointer to data.
+     *  Caller is responsible to free the memory returned.
+     * @param bandNo band number
+     * @param extent extent of block
+     * @param width pixel width of block
+     * @param height pixel height of block
+     * @param feedback optional raster feedback object for cancellation/preview
+     * @note This is extended version of block() method. Default implementation falls back to calling block().
+     * @note Added in QGIS 2.18
+     */
+    virtual QgsRasterBlock *block2( int bandNo, const QgsRectangle &extent, int width, int height, QgsRasterBlockFeedback* feedback = nullptr ) /Factory/;
+
     /** Set input.
       * Returns true if set correctly, false if cannot use that input */
     virtual bool setInput( QgsRasterInterface* input );
@@ -241,5 +291,6 @@ class QgsRasterInterface
                          int theStats = QgsRasterBandStats::All,
                          const QgsRectangle & theExtent = QgsRectangle(),
                          int theBinCount = 0 );
+
 };
 
diff --git a/python/core/raster/qgsrasteriterator.sip b/python/core/raster/qgsrasteriterator.sip
@@ -12,8 +12,9 @@ class QgsRasterIterator
       @param nCols number of columns
       @param nRows number of rows
       @param extent area to read
+      @param feedback optional raster feedback object for cancellation/preview. Added in QGIS 2.18
      */
-    void startRasterRead( int bandNumber, int nCols, int nRows, const QgsRectangle& extent );
+    void startRasterRead( int bandNumber, int nCols, int nRows, const QgsRectangle& extent, QgsRasterBlockFeedback* feedback = nullptr );
 
     /** Fetches next part of raster data, caller takes ownership of the block and
        caller should delete the block.

diff --git a/python/core/raster/qgsrasternuller.sip b/python/core/raster/qgsrasternuller.sip
@@ -20,6 +20,7 @@ class QgsRasterNuller : QgsRasterInterface
     QGis::DataType dataType( int bandNo ) const;
 
     QgsRasterBlock *block( int bandNo, const QgsRectangle &extent, int width, int height ) / Factory /;
+    QgsRasterBlock *block2( int bandNo, const QgsRectangle &extent, int width, int height, QgsRasterBlockFeedback* feedback = nullptr ) / Factory /;
 
     void setNoData( int bandNo, const QgsRasterRangeList& noData );
 

diff --git a/python/core/raster/qgsrasterprojector.sip b/python/core/raster/qgsrasterprojector.sip
@@ -1,6 +1,10 @@
 
-/** Raster projector */
-
+/** \ingroup core
+ * \brief QgsRasterProjector implements approximate projection support for
+ * it calculates grid of points in source CRS for target CRS + extent
+ * which are used to calculate affine transformation matrices.
+ * \class QgsRasterProjector
+ */
 class QgsRasterProjector : QgsRasterInterface
 {
 %TypeHeaderCode
@@ -18,11 +22,7 @@ class QgsRasterProjector : QgsRasterInterface
       Exact,   //!< Exact, precise but slow
     };
 
-    /** \brief QgsRasterProjector implements approximate projection support for
-     * it calculates grid of points in source CRS for target CRS + extent
-     * which are used to calculate affine transformation matrices.
-     */
-
+    //! @deprecated since 2.18: use default constructor
     QgsRasterProjector( const QgsCoordinateReferenceSystem& theSrcCRS,
                         const QgsCoordinateReferenceSystem& theDestCRS,
                         int theSrcDatumTransform,
@@ -31,20 +31,21 @@ class QgsRasterProjector : QgsRasterInterface
                         int theDestRows, int theDestCols,
                         double theMaxSrcXRes, double theMaxSrcYRes,
                         const QgsRectangle& theExtent
-                      );
-
+                      ) /Deprecated/;
+    //! @deprecated since 2.18: use default constructor
     QgsRasterProjector( const QgsCoordinateReferenceSystem& theSrcCRS,
                         const QgsCoordinateReferenceSystem& theDestCRS,
                         const QgsRectangle& theDestExtent,
                         int theDestRows, int theDestCols,
                         double theMaxSrcXRes, double theMaxSrcYRes,
                         const QgsRectangle& theExtent
-                      );
+                      ) /Deprecated/;
+    //! @deprecated since 2.18: use default constructor
     QgsRasterProjector( const QgsCoordinateReferenceSystem& theSrcCRS,
                         const QgsCoordinateReferenceSystem& theDestCRS,
                         double theMaxSrcXRes, double theMaxSrcYRes,
                         const QgsRectangle& theExtent
-                      );
+                      ) /Deprecated/;
     QgsRasterProjector();
 
     /** \brief The destructor */
@@ -66,15 +67,16 @@ class QgsRasterProjector : QgsRasterInterface
     /** \brief Get destination CRS */
     QgsCoordinateReferenceSystem destCrs() const;
 
-    /** \brief set maximum source resolution */
-    void setMaxSrcRes( double theMaxSrcXRes, double theMaxSrcYRes );
+    /** @deprecated since 2.18, does nothing */
+    void setMaxSrcRes( double theMaxSrcXRes, double theMaxSrcYRes ) /Deprecated/;
 
     Precision precision() const;
     void setPrecision( Precision precision );
     // Translated precision mode, for use in ComboBox etc.
     static QString precisionLabel( Precision precision );
 
     QgsRasterBlock *block( int bandNo, const QgsRectangle & extent, int width, int height ) / Factory /;
+    QgsRasterBlock *block2( int bandNo, const QgsRectangle & extent, int width, int height, QgsRasterBlockFeedback* feedback = nullptr ) / Factory /;
 
     /** Calculate destination extent and size from source extent and size */
     bool destExtentSize( const QgsRectangle& theSrcExtent, int theSrcXSize, int theSrcYSize,

diff --git a/python/core/raster/qgsrasterrenderer.sip b/python/core/raster/qgsrasterrenderer.sip
@@ -38,8 +38,6 @@ class QgsRasterRenderer : QgsRasterInterface
 
     virtual bool setInput( QgsRasterInterface* input );
 
-    virtual QgsRasterBlock *block( int bandNo, const QgsRectangle &extent, int width, int height ) = 0 / Factory /;
-
     bool usesTransparency() const;
 
     void setOpacity( double opacity );

diff --git a/python/core/raster/qgsrasterresamplefilter.sip b/python/core/raster/qgsrasterresamplefilter.sip
@@ -20,6 +20,7 @@ class QgsRasterResampleFilter : QgsRasterInterface
     bool setInput( QgsRasterInterface* input );
 
     QgsRasterBlock *block( int bandNo, const QgsRectangle &extent, int width, int height ) /Factory/;
+    QgsRasterBlock *block2( int bandNo, const QgsRectangle &extent, int width, int height, QgsRasterBlockFeedback* feedback = nullptr ) /Factory/;
 
     /** Set resampler for zoomed in scales. Takes ownership of the object*/
     void setZoomedInResampler( QgsRasterResampler* r /Transfer/ );

diff --git a/python/core/raster/qgssinglebandcolordatarenderer.sip b/python/core/raster/qgssinglebandcolordatarenderer.sip
@@ -13,6 +13,7 @@ class QgsSingleBandColorDataRenderer: QgsRasterRenderer
     bool setInput( QgsRasterInterface* input );
 
     QgsRasterBlock* block( int bandNo, const QgsRectangle & extent, int width, int height ) / Factory /;
+    QgsRasterBlock* block2( int bandNo, const QgsRectangle & extent, int width, int height, QgsRasterBlockFeedback* feedback = nullptr ) / Factory /;
 
     void writeXML( QDomDocument& doc, QDomElement& parentElem ) const;
 

diff --git a/python/core/raster/qgssinglebandgrayrenderer.sip b/python/core/raster/qgssinglebandgrayrenderer.sip
@@ -17,6 +17,7 @@ class QgsSingleBandGrayRenderer: QgsRasterRenderer
     static QgsRasterRenderer* create( const QDomElement& elem, QgsRasterDataProvider* provider ) /Factory/;
 
     QgsRasterBlock *block( int bandNo, const QgsRectangle & extent, int width, int height ) / Factory /;
+    QgsRasterBlock *block2( int bandNo, const QgsRectangle & extent, int width, int height, QgsRasterBlockFeedback* feedback = nullptr ) / Factory /;
 
     int grayBand() const;
     void setGrayBand( int band );

diff --git a/python/core/raster/qgssinglebandpseudocolorrenderer.sip b/python/core/raster/qgssinglebandpseudocolorrenderer.sip
@@ -12,6 +12,7 @@ class QgsSingleBandPseudoColorRenderer: QgsRasterRenderer
     static QgsRasterRenderer* create( const QDomElement& elem, QgsRasterDataProvider* provider ) /Factory/;
 
     QgsRasterBlock* block( int bandNo, const QgsRectangle & extent, int width, int height ) / Factory /;
+    QgsRasterBlock* block2( int bandNo, const QgsRectangle & extent, int width, int height, QgsRasterBlockFeedback* feedback = nullptr ) / Factory /;
 
     /** Takes ownership of the shader*/
     void setShader( QgsRasterShader* shader /Transfer/ );

diff --git a/src/app/main.cpp b/src/app/main.cpp
@@ -194,6 +194,14 @@ static void dumpBacktrace( unsigned int depth )
     depth = 20;
 
 #if ((defined(linux) || defined(__linux__)) && !defined(ANDROID)) || defined(__FreeBSD__)
+  // Below there is a bunch of operations that are not safe in multi-threaded
+  // environment (dup()+close() combo, wait(), juggling with file descriptors).
+  // Maybe some problems could be resolved with dup2() and waitpid(), but it seems
+  // that if the operations on descriptors are not serialized, things will get nasty.
+  // That's why there's this lovely mutex here...
+  static QMutex mutex;
+  QMutexLocker locker( &mutex );
+
   int stderr_fd = -1;
   if ( access( "/usr/bin/c++filt", X_OK ) < 0 )
   {