QGIS API Documentation  2.99.0-Master (9fdd060)
qgsrasterlayerrenderer.cpp
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1 /***************************************************************************
2  qgsrasterlayerrenderer.cpp
3  --------------------------------------
4  Date : December 2013
5  Copyright : (C) 2013 by Martin Dobias
6  Email : wonder dot sk at gmail dot com
7  ***************************************************************************
8  * *
9  * This program is free software; you can redistribute it and/or modify *
10  * it under the terms of the GNU General Public License as published by *
11  * the Free Software Foundation; either version 2 of the License, or *
12  * (at your option) any later version. *
13  * *
14  ***************************************************************************/
15 
16 #include "qgsrasterlayerrenderer.h"
17 
18 #include "qgsmessagelog.h"
19 #include "qgsrasterdataprovider.h"
20 #include "qgsrasterdrawer.h"
21 #include "qgsrasteriterator.h"
22 #include "qgsrasterlayer.h"
23 #include "qgsrasterprojector.h"
24 #include "qgsrendercontext.h"
25 #include "qgsproject.h"
26 #include "qgsexception.h"
27 
28 
30 
31 QgsRasterLayerRendererFeedback::QgsRasterLayerRendererFeedback( QgsRasterLayerRenderer *r )
32  : mR( r )
33  , mMinimalPreviewInterval( 250 )
34 {
35  setRenderPartialOutput( r->mContext.testFlag( QgsRenderContext::RenderPartialOutput ) );
36 }
37 
38 void QgsRasterLayerRendererFeedback::onNewData()
39 {
40  if ( !renderPartialOutput() )
41  return; // we were not asked for partial renders and we may not have a temporary image for overwriting...
42 
43  // update only once upon a time
44  // (preview itself takes some time)
45  if ( mLastPreview.isValid() && mLastPreview.msecsTo( QTime::currentTime() ) < mMinimalPreviewInterval )
46  return;
47 
48  // TODO: update only the area that got new data
49 
50  QgsDebugMsg( QString( "new raster preview! %1" ).arg( mLastPreview.msecsTo( QTime::currentTime() ) ) );
51  QTime t;
52  t.start();
53  QgsRasterBlockFeedback feedback;
54  feedback.setPreviewOnly( true );
55  feedback.setRenderPartialOutput( true );
56  QgsRasterIterator iterator( mR->mPipe->last() );
57  QgsRasterDrawer drawer( &iterator );
58  drawer.draw( mR->mPainter, mR->mRasterViewPort, mR->mMapToPixel, &feedback );
59  QgsDebugMsg( QString( "total raster preview time: %1 ms" ).arg( t.elapsed() ) );
60  mLastPreview = QTime::currentTime();
61 }
62 
66  : QgsMapLayerRenderer( layer->id() )
67  , mContext( rendererContext )
68  , mFeedback( new QgsRasterLayerRendererFeedback( this ) )
69 {
70  mPainter = rendererContext.painter();
71  const QgsMapToPixel &qgsMapToPixel = rendererContext.mapToPixel();
72  mMapToPixel = &qgsMapToPixel;
73 
74  QgsMapToPixel mapToPixel = qgsMapToPixel;
75  if ( mapToPixel.mapRotation() )
76  {
77  // unset rotation for the sake of local computations.
78  // Rotation will be handled by QPainter later
79  // TODO: provide a method of QgsMapToPixel to fetch map center
80  // in geographical units
81  QgsPointXY center = mapToPixel.toMapCoordinates(
82  mapToPixel.mapWidth() / 2.0,
83  mapToPixel.mapHeight() / 2.0
84  );
85  mapToPixel.setMapRotation( 0, center.x(), center.y() );
86  }
87 
88  QgsRectangle myProjectedViewExtent;
89  QgsRectangle myProjectedLayerExtent;
90 
91  if ( rendererContext.coordinateTransform().isValid() )
92  {
93  QgsDebugMsgLevel( "coordinateTransform set -> project extents.", 4 );
94  try
95  {
96  myProjectedViewExtent = rendererContext.coordinateTransform().transformBoundingBox( rendererContext.extent() );
97  }
98  catch ( QgsCsException &cs )
99  {
100  QgsMessageLog::logMessage( QObject::tr( "Could not reproject view extent: %1" ).arg( cs.what() ), QObject::tr( "Raster" ) );
101  myProjectedViewExtent.setMinimal();
102  }
103 
104  try
105  {
106  myProjectedLayerExtent = rendererContext.coordinateTransform().transformBoundingBox( layer->extent() );
107  }
108  catch ( QgsCsException &cs )
109  {
110  QgsMessageLog::logMessage( QObject::tr( "Could not reproject layer extent: %1" ).arg( cs.what() ), QObject::tr( "Raster" ) );
111  myProjectedLayerExtent.setMinimal();
112  }
113  }
114  else
115  {
116  QgsDebugMsgLevel( "coordinateTransform not set", 4 );
117  myProjectedViewExtent = rendererContext.extent();
118  myProjectedLayerExtent = layer->extent();
119  }
120 
121  // clip raster extent to view extent
122  QgsRectangle myRasterExtent = myProjectedViewExtent.intersect( &myProjectedLayerExtent );
123  if ( myRasterExtent.isEmpty() )
124  {
125  QgsDebugMsg( "draw request outside view extent." );
126  // nothing to do
127  return;
128  }
129 
130  QgsDebugMsgLevel( "theViewExtent is " + rendererContext.extent().toString(), 4 );
131  QgsDebugMsgLevel( "myProjectedViewExtent is " + myProjectedViewExtent.toString(), 4 );
132  QgsDebugMsgLevel( "myProjectedLayerExtent is " + myProjectedLayerExtent.toString(), 4 );
133  QgsDebugMsgLevel( "myRasterExtent is " + myRasterExtent.toString(), 4 );
134 
135  //
136  // The first thing we do is set up the QgsRasterViewPort. This struct stores all the settings
137  // relating to the size (in pixels and coordinate system units) of the raster part that is
138  // in view in the map window. It also stores the origin.
139  //
140  //this is not a class level member because every time the user pans or zooms
141  //the contents of the rasterViewPort will change
142  mRasterViewPort = new QgsRasterViewPort();
143 
144  mRasterViewPort->mDrawnExtent = myRasterExtent;
145  if ( rendererContext.coordinateTransform().isValid() )
146  {
147  mRasterViewPort->mSrcCRS = layer->crs();
148  mRasterViewPort->mDestCRS = rendererContext.coordinateTransform().destinationCrs();
149  mRasterViewPort->mSrcDatumTransform = rendererContext.coordinateTransform().sourceDatumTransform();
150  mRasterViewPort->mDestDatumTransform = rendererContext.coordinateTransform().destinationDatumTransform();
151  }
152  else
153  {
154  mRasterViewPort->mSrcCRS = QgsCoordinateReferenceSystem(); // will be invalid
155  mRasterViewPort->mDestCRS = QgsCoordinateReferenceSystem(); // will be invalid
156  mRasterViewPort->mSrcDatumTransform = -1;
157  mRasterViewPort->mDestDatumTransform = -1;
158  }
159 
160  // get dimensions of clipped raster image in device coordinate space (this is the size of the viewport)
161  mRasterViewPort->mTopLeftPoint = mapToPixel.transform( myRasterExtent.xMinimum(), myRasterExtent.yMaximum() );
162  mRasterViewPort->mBottomRightPoint = mapToPixel.transform( myRasterExtent.xMaximum(), myRasterExtent.yMinimum() );
163 
164  // align to output device grid, i.e. std::floor/ceil to integers
165  // TODO: this should only be done if paint device is raster - screen, image
166  // for other devices (pdf) it can have floating point origin
167  // we could use floating point for raster devices as well, but respecting the
168  // output device grid should make it more effective as the resampling is done in
169  // the provider anyway
170  mRasterViewPort->mTopLeftPoint.setX( std::floor( mRasterViewPort->mTopLeftPoint.x() ) );
171  mRasterViewPort->mTopLeftPoint.setY( std::floor( mRasterViewPort->mTopLeftPoint.y() ) );
172  mRasterViewPort->mBottomRightPoint.setX( std::ceil( mRasterViewPort->mBottomRightPoint.x() ) );
173  mRasterViewPort->mBottomRightPoint.setY( std::ceil( mRasterViewPort->mBottomRightPoint.y() ) );
174  // recalc myRasterExtent to aligned values
175  myRasterExtent.set(
176  mapToPixel.toMapCoordinatesF( mRasterViewPort->mTopLeftPoint.x(),
177  mRasterViewPort->mBottomRightPoint.y() ),
178  mapToPixel.toMapCoordinatesF( mRasterViewPort->mBottomRightPoint.x(),
179  mRasterViewPort->mTopLeftPoint.y() )
180  );
181 
182  //raster viewport top left / bottom right are already rounded to int
183  mRasterViewPort->mWidth = static_cast<int>( mRasterViewPort->mBottomRightPoint.x() - mRasterViewPort->mTopLeftPoint.x() );
184  mRasterViewPort->mHeight = static_cast<int>( mRasterViewPort->mBottomRightPoint.y() - mRasterViewPort->mTopLeftPoint.y() );
185 
186  //the drawable area can start to get very very large when you get down displaying 2x2 or smaller, this is because
187  //mapToPixel.mapUnitsPerPixel() is less then 1,
188  //so we will just get the pixel data and then render these special cases differently in paintImageToCanvas()
189 
190  QgsDebugMsgLevel( QString( "mapUnitsPerPixel = %1" ).arg( mapToPixel.mapUnitsPerPixel() ), 3 );
191  QgsDebugMsgLevel( QString( "mWidth = %1" ).arg( layer->width() ), 3 );
192  QgsDebugMsgLevel( QString( "mHeight = %1" ).arg( layer->height() ), 3 );
193  QgsDebugMsgLevel( QString( "myRasterExtent.xMinimum() = %1" ).arg( myRasterExtent.xMinimum() ), 3 );
194  QgsDebugMsgLevel( QString( "myRasterExtent.xMaximum() = %1" ).arg( myRasterExtent.xMaximum() ), 3 );
195  QgsDebugMsgLevel( QString( "myRasterExtent.yMinimum() = %1" ).arg( myRasterExtent.yMinimum() ), 3 );
196  QgsDebugMsgLevel( QString( "myRasterExtent.yMaximum() = %1" ).arg( myRasterExtent.yMaximum() ), 3 );
197 
198  QgsDebugMsgLevel( QString( "mTopLeftPoint.x() = %1" ).arg( mRasterViewPort->mTopLeftPoint.x() ), 3 );
199  QgsDebugMsgLevel( QString( "mBottomRightPoint.x() = %1" ).arg( mRasterViewPort->mBottomRightPoint.x() ), 3 );
200  QgsDebugMsgLevel( QString( "mTopLeftPoint.y() = %1" ).arg( mRasterViewPort->mTopLeftPoint.y() ), 3 );
201  QgsDebugMsgLevel( QString( "mBottomRightPoint.y() = %1" ).arg( mRasterViewPort->mBottomRightPoint.y() ), 3 );
202 
203  QgsDebugMsgLevel( QString( "mWidth = %1" ).arg( mRasterViewPort->mWidth ), 3 );
204  QgsDebugMsgLevel( QString( "mHeight = %1" ).arg( mRasterViewPort->mHeight ), 3 );
205 
206  // /\/\/\ - added to handle zoomed-in rasters
207 
208  // TODO R->mLastViewPort = *mRasterViewPort;
209 
210  // TODO: is it necessary? Probably WMS only?
211  layer->dataProvider()->setDpi( 25.4 * rendererContext.scaleFactor() );
212 
213 
214  // copy the whole raster pipe!
215  mPipe = new QgsRasterPipe( *layer->pipe() );
216  QgsRasterRenderer *rasterRenderer = mPipe->renderer();
217  if ( rasterRenderer )
218  layer->refreshRendererIfNeeded( rasterRenderer, rendererContext.extent() );
219 }
220 
222 {
223  delete mFeedback;
224 
225  delete mRasterViewPort;
226  delete mPipe;
227 }
228 
230 {
231  if ( !mRasterViewPort )
232  return true; // outside of layer extent - nothing to do
233 
234  //R->draw( mPainter, mRasterViewPort, &mMapToPixel );
235 
236  QTime time;
237  time.start();
238  //
239  //
240  // The goal here is to make as many decisions as possible early on (outside of the rendering loop)
241  // so that we can maximise performance of the rendering process. So now we check which drawing
242  // procedure to use :
243  //
244 
245  QgsRasterProjector *projector = mPipe->projector();
246 
247  // TODO add a method to interface to get provider and get provider
248  // params in QgsRasterProjector
249  if ( projector )
250  {
251  projector->setCrs( mRasterViewPort->mSrcCRS, mRasterViewPort->mDestCRS, mRasterViewPort->mSrcDatumTransform, mRasterViewPort->mDestDatumTransform );
252  }
253 
254  // Drawer to pipe?
255  QgsRasterIterator iterator( mPipe->last() );
256  QgsRasterDrawer drawer( &iterator );
257  drawer.draw( mPainter, mRasterViewPort, mMapToPixel, mFeedback );
258 
259  QgsDebugMsgLevel( QString( "total raster draw time (ms): %1" ).arg( time.elapsed(), 5 ), 4 );
260 
261  return true;
262 }
263 
265 {
266  return mFeedback;
267 }
268 
int width() const
Accessor that returns the width of the (unclipped) raster.
virtual QgsFeedback * feedback() const override
Access to feedback object of the layer renderer (may be null)
A rectangle specified with double values.
Definition: qgsrectangle.h:39
void setMapRotation(double degrees, double cx, double cy)
Set map rotation in degrees (clockwise)
void setMinimal()
Set a rectangle so that min corner is at max and max corner is at min.
Base class for processing modules.
Definition: qgsrasterpipe.h:46
Iterator for sequentially processing raster cells.
QgsRasterRenderer * renderer() const
#define QgsDebugMsg(str)
Definition: qgslogger.h:37
This class provides qgis with the ability to render raster datasets onto the mapcanvas.
double y
Definition: qgspointxy.h:48
QgsRasterPipe * pipe()
Get raster pipe.
A class to represent a 2D point.
Definition: qgspointxy.h:43
QgsRasterProjector * projector() const
QgsRasterInterface * last() const
QgsRectangle transformBoundingBox(const QgsRectangle &rectangle, TransformDirection direction=ForwardTransform, const bool handle180Crossover=false) const
Transforms a rectangle from the source CRS to the destination CRS.
QgsCoordinateReferenceSystem destinationCrs() const
Returns the destination coordinate reference system, which the transform will transform coordinates t...
QgsRectangle intersect(const QgsRectangle *rect) const
Return the intersection with the given rectangle.
void setRenderPartialOutput(bool enable)
Set whether our painter is drawing to a temporary image used just by this layer.
int height() const
Accessor that returns the height of the (unclipped) raster.
Implementation of threaded rendering for raster layers.
virtual bool render() override
Do the rendering (based on data stored in the class)
bool isValid() const
Returns true if the coordinate transform is valid, ie both the source and destination CRS have been s...
virtual QgsRectangle extent() const
Returns the extent of the layer.
double mapRotation() const
Return current map rotation in degrees.
QgsCoordinateReferenceSystem mDestCRS
Target coordinate system.
QString what() const
Definition: qgsexception.h:49
void setCrs(const QgsCoordinateReferenceSystem &srcCRS, const QgsCoordinateReferenceSystem &destCRS, int srcDatumTransform=-1, int destDatumTransform=-1)
set source and destination CRS
Base class for feedback objects to be used for cancelation of something running in a worker thread...
Definition: qgsfeedback.h:44
Perform transforms between map coordinates and device coordinates.
Definition: qgsmaptopixel.h:36
The drawing pipe for raster layers.
QgsPointXY transform(const QgsPointXY &p) const
Transform the point from map (world) coordinates to device coordinates.
QgsRasterDataProvider * dataProvider() override
int mapWidth() const
Return current map width in pixels The information is only known if setRotation was used...
QString id() const
Returns the layer&#39;s unique ID, which is used to access this layer from QgsProject.
int mapHeight() const
Return current map height in pixels.
void setPreviewOnly(bool preview)
set flag whether the block request is for preview purposes only
#define QgsDebugMsgLevel(str, level)
Definition: qgslogger.h:38
bool isEmpty() const
Returns true if the rectangle is empty.
const QgsRectangle & extent() const
QgsRasterLayerRenderer(QgsRasterLayer *layer, QgsRenderContext &rendererContext)
QString toString(int precision=16) const
Returns a string representation of form xmin,ymin : xmax,ymax Coordinates will be truncated to the sp...
QgsCoordinateReferenceSystem crs() const
Returns the layer&#39;s spatial reference system.
QgsCoordinateTransform coordinateTransform() const
Returns the current coordinate transform for the context, or an invalid transform is no coordinate tr...
double mapUnitsPerPixel() const
Return current map units per pixel.
void setX(double x)
Sets the x value of the point.
Definition: qgspointxy.h:105
double x
Definition: qgspointxy.h:47
double yMinimum() const
Returns the y minimum value (bottom side of rectangle).
Definition: qgsrectangle.h:119
QgsCoordinateReferenceSystem mSrcCRS
Source coordinate system.
double xMaximum() const
Returns the x maximum value (right side of rectangle).
Definition: qgsrectangle.h:104
QgsRasterProjector implements approximate projection support for it calculates grid of points in sour...
static void logMessage(const QString &message, const QString &tag=QString(), MessageLevel level=QgsMessageLog::WARNING)
add a message to the instance (and create it if necessary)
Contains information about the context of a rendering operation.
QPainter * painter()
Returns the destination QPainter for the render operation.
const QgsMapToPixel & mapToPixel() const
Whether to make extra effort to update map image with partially rendered layers (better for interacti...
This class represents a coordinate reference system (CRS).
double xMinimum() const
Returns the x minimum value (left side of rectangle).
Definition: qgsrectangle.h:109
Base class for utility classes that encapsulate information necessary for rendering of map layers...
double yMaximum() const
Returns the y maximum value (top side of rectangle).
Definition: qgsrectangle.h:114
void refreshRendererIfNeeded(QgsRasterRenderer *rasterRenderer, const QgsRectangle &extent)
Refresh renderer with new extent, if needed.
Custom exception class for Coordinate Reference System related exceptions.
Definition: qgsexception.h:66
This class provides details of the viewable area that a raster will be rendered into.
bool testFlag(Flag flag) const
Check whether a particular flag is enabled.
double scaleFactor() const
Returns the scaling factor for the render to convert painter units to physical sizes.
Feedback object tailored for raster block reading.
QgsPointXY toMapCoordinatesF(double x, double y) const
Transform device coordinates to map (world) coordinates.
QgsPointXY toMapCoordinates(int x, int y) const
Raster renderer pipe that applies colors to a raster.
void setDpi(int dpi)
Sets the output device resolution.
void set(const QgsPointXY &p1, const QgsPointXY &p2)
Sets the rectangle from two QgsPoints.