QGIS API Documentation  2.99.0-Master (0a63d1f)
qgsrasterdrawer.cpp
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1 /***************************************************************************
2  qgsrasterdrawer.cpp
3  ---------------------
4  begin : June 2012
5  copyright : (C) 2012 by Radim Blazek
6  email : radim dot blazek at gmail.com
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 "qgslogger.h"
19 #include "qgsrasterblock.h"
20 #include "qgsrasterdrawer.h"
21 #include "qgsrasterinterface.h"
22 #include "qgsrasteriterator.h"
23 #include "qgsrasterviewport.h"
24 #include "qgsmaptopixel.h"
25 #include "qgsrendercontext.h"
26 #include <QImage>
27 #include <QPainter>
28 #include <QPrinter>
29 
30 QgsRasterDrawer::QgsRasterDrawer( QgsRasterIterator* iterator ): mIterator( iterator )
31 {
32 }
33 
34 void QgsRasterDrawer::draw( QPainter* p, QgsRasterViewPort* viewPort, const QgsMapToPixel* theQgsMapToPixel, QgsRasterBlockFeedback* feedback )
35 {
36  QgsDebugMsgLevel( "Entered", 4 );
37  if ( !p || !mIterator || !viewPort || !theQgsMapToPixel )
38  {
39  return;
40  }
41 
42  // last pipe filter has only 1 band
43  int bandNumber = 1;
44  mIterator->startRasterRead( bandNumber, viewPort->mWidth, viewPort->mHeight, viewPort->mDrawnExtent, feedback );
45 
46  //number of cols/rows in output pixels
47  int nCols = 0;
48  int nRows = 0;
49  //shift to top left point for the raster part
50  int topLeftCol = 0;
51  int topLeftRow = 0;
52 
53  // We know that the output data type of last pipe filter is QImage data
54 
55  QgsRasterBlock *block;
56 
57  // readNextRasterPart calcs and resets nCols, nRows, topLeftCol, topLeftRow
58  while ( mIterator->readNextRasterPart( bandNumber, nCols, nRows,
59  &block, topLeftCol, topLeftRow ) )
60  {
61  if ( !block )
62  {
63  QgsDebugMsg( "Cannot get block" );
64  continue;
65  }
66 
67  QImage img = block->image();
68 
69 #ifndef QT_NO_PRINTER
70  // Because of bug in Acrobat Reader we must use "white" transparent color instead
71  // of "black" for PDF. See #9101.
72  QPrinter *printer = dynamic_cast<QPrinter *>( p->device() );
73  if ( printer && printer->outputFormat() == QPrinter::PdfFormat )
74  {
75  QgsDebugMsgLevel( "PdfFormat", 4 );
76 
77  img = img.convertToFormat( QImage::Format_ARGB32 );
78  QRgb transparentBlack = qRgba( 0, 0, 0, 0 );
79  QRgb transparentWhite = qRgba( 255, 255, 255, 0 );
80  for ( int x = 0; x < img.width(); x++ )
81  {
82  for ( int y = 0; y < img.height(); y++ )
83  {
84  if ( img.pixel( x, y ) == transparentBlack )
85  {
86  img.setPixel( x, y, transparentWhite );
87  }
88  }
89  }
90  }
91 #endif
92 
93  if ( feedback && feedback->renderPartialOutput() )
94  {
95  // there could have been partial preview written before
96  // so overwrite anything with the resulting image.
97  // (we are guaranteed to have a temporary image for this layer, see QgsMapRendererJob::needTemporaryImage)
98  p->setCompositionMode( QPainter::CompositionMode_Source );
99  }
100 
101  drawImage( p, viewPort, img, topLeftCol, topLeftRow, theQgsMapToPixel );
102 
103  delete block;
104 
105  p->setCompositionMode( QPainter::CompositionMode_SourceOver ); // go back to the default composition mode
106 
107  // ok this does not matter much anyway as the tile size quite big so most of the time
108  // there would be just one tile for the whole display area, but it won't hurt...
109  if ( feedback && feedback->isCancelled() )
110  break;
111  }
112 }
113 
114 void QgsRasterDrawer::drawImage( QPainter* p, QgsRasterViewPort* viewPort, const QImage& img, int topLeftCol, int topLeftRow, const QgsMapToPixel* theQgsMapToPixel ) const
115 {
116  if ( !p || !viewPort )
117  {
118  return;
119  }
120 
121  //top left position in device coords
122  QPoint tlPoint = QPoint( viewPort->mTopLeftPoint.x() + topLeftCol, viewPort->mTopLeftPoint.y() + topLeftRow );
123  p->save();
124  p->setRenderHint( QPainter::Antialiasing, false );
125 
126  // Blending problem was reported with PDF output if background color has alpha < 255
127  // in #7766, it seems to be a bug in Qt, setting a brush with alpha 255 is a workaround
128  // which should not harm anything
129  p->setBrush( QBrush( QColor( Qt::white ), Qt::NoBrush ) );
130 
131  if ( theQgsMapToPixel )
132  {
133  int w = theQgsMapToPixel->mapWidth();
134  int h = theQgsMapToPixel->mapHeight();
135 
136  double rotation = theQgsMapToPixel->mapRotation();
137  if ( rotation )
138  {
139  // both viewPort and image sizes are dependent on scale
140  double cx = w / 2.0;
141  double cy = h / 2.0;
142  p->translate( cx, cy );
143  p->rotate( rotation );
144  p->translate( -cx, -cy );
145  }
146  }
147 
148  p->drawImage( tlPoint, img );
149 
150 #if 0
151  // For debugging:
152  QRectF br = QRectF( tlPoint, img.size() );
153  QPointF c = br.center();
154  double rad = std::max( br.width(), br.height() ) / 10;
155  p->drawRoundedRect( br, rad, rad );
156  p->drawLine( QLineF( br.x(), br.y(), br.x() + br.width(), br.y() + br.height() ) );
157  p->drawLine( QLineF( br.x() + br.width(), br.y(), br.x(), br.y() + br.height() ) );
158 
159  double nw = br.width() * 0.5;
160  double nh = br.height() * 0.5;
161  br = QRectF( c - QPointF( nw / 2, nh / 2 ), QSize( nw, nh ) );
162  p->drawRoundedRect( br, rad, rad );
163 
164  nw = br.width() * 0.5;
165  nh = br.height() * 0.5;
166  br = QRectF( c - QPointF( nw / 2, nh / 2 ), QSize( nw, nh ) );
167  p->drawRoundedRect( br, rad, rad );
168 #endif
169 
170  p->restore();
171 }
172 
void drawImage(QPainter *p, QgsRasterViewPort *viewPort, const QImage &img, int topLeftCol, int topLeftRow, const QgsMapToPixel *mapToPixel=nullptr) const
Draws raster part.
double y
Definition: qgspoint.h:148
bool renderPartialOutput() const
Whether our painter is drawing to a temporary image used just by this layer.
Iterator for sequentially processing raster cells.
#define QgsDebugMsg(str)
Definition: qgslogger.h:36
int mWidth
Width, number of columns to be rendered.
bool isCancelled() const
Tells whether the operation has been cancelled already.
Definition: qgsfeedback.h:62
double mapRotation() const
Return current map rotation in degrees.
Perform transforms between map coordinates and device coordinates.
Definition: qgsmaptopixel.h:34
int mapWidth() const
Return current map width in pixels The information is only known if setRotation was used...
int mapHeight() const
Return current map height in pixels.
Raster data container.
#define QgsDebugMsgLevel(str, level)
Definition: qgslogger.h:37
QgsRasterDrawer(QgsRasterIterator *iterator)
bool readNextRasterPart(int bandNumber, int &nCols, int &nRows, QgsRasterBlock **block, int &topLeftCol, int &topLeftRow)
Fetches next part of raster data, caller takes ownership of the block and caller should delete the bl...
double ANALYSIS_EXPORT max(double x, double y)
Returns the maximum of two doubles or the first argument if both are equal.
Definition: MathUtils.cc:437
QImage image() const
Get image if type is color.
int mHeight
Distance in map units from bottom edge to top edge for the part of the raster that is to be rendered...
void draw(QPainter *p, QgsRasterViewPort *viewPort, const QgsMapToPixel *theQgsMapToPixel, QgsRasterBlockFeedback *feedback=nullptr)
Draws raster data.
QgsPoint mTopLeftPoint
Coordinate (in output device coordinate system) of top left corner of the part of the raster that is ...
This class provides details of the viewable area that a raster will be rendered into.
Feedback object tailored for raster block reading.
void startRasterRead(int bandNumber, int nCols, int nRows, const QgsRectangle &extent, QgsRasterBlockFeedback *feedback=nullptr)
Start reading of raster band.
QgsRectangle mDrawnExtent
Intersection of current map extent and layer extent.
double x
Definition: qgspoint.h:147