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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 "qgsrasterdrawer.h"
20 #include "qgsrasteriterator.h"
21 #include "qgsrasterviewport.h"
22 #include "qgsmaptopixel.h"
23 #include <QImage>
24 #include <QPainter>
25 #include <QPrinter>
26 
27 QgsRasterDrawer::QgsRasterDrawer( QgsRasterIterator* iterator ): mIterator( iterator )
28 {
29 }
30 
32 {
33 }
34 
35 void QgsRasterDrawer::draw( QPainter* p, QgsRasterViewPort* viewPort, const QgsMapToPixel* theQgsMapToPixel )
36 {
37  QgsDebugMsg( "Entered" );
38  if ( !p || !mIterator || !viewPort || !theQgsMapToPixel )
39  {
40  return;
41  }
42 
43  // last pipe filter has only 1 band
44  int bandNumber = 1;
45  mIterator->startRasterRead( bandNumber, viewPort->mWidth, viewPort->mHeight, viewPort->mDrawnExtent );
46 
47  //number of cols/rows in output pixels
48  int nCols = 0;
49  int nRows = 0;
50  //shift to top left point for the raster part
51  int topLeftCol = 0;
52  int topLeftRow = 0;
53 
54  // We know that the output data type of last pipe filter is QImage data
55 
56  QgsRasterBlock *block;
57 
58  // readNextRasterPart calcs and resets nCols, nRows, topLeftCol, topLeftRow
59  while ( mIterator->readNextRasterPart( bandNumber, nCols, nRows,
60  &block, topLeftCol, topLeftRow ) )
61  {
62  if ( !block )
63  {
64  QgsDebugMsg( "Cannot get block" );
65  continue;
66  }
67 
68  QImage img = block->image();
69 
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  QgsDebugMsg( "PdfFormat" );
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 
92  drawImage( p, viewPort, img, topLeftCol, topLeftRow );
93 
94  delete block;
95  }
96 }
97 
98 void QgsRasterDrawer::drawImage( QPainter* p, QgsRasterViewPort* viewPort, const QImage& img, int topLeftCol, int topLeftRow ) const
99 {
100  if ( !p || !viewPort )
101  {
102  return;
103  }
104 
105  //top left position in device coords
106  QPoint tlPoint = QPoint( viewPort->mTopLeftPoint.x() + topLeftCol, viewPort->mTopLeftPoint.y() + topLeftRow );
107  p->save();
108  p->setRenderHint( QPainter::Antialiasing, false );
109 
110  // Blending problem was reported with PDF output if background color has alpha < 255
111  // in #7766, it seems to be a bug in Qt, setting a brush with alpha 255 is a workaround
112  // which should not harm anything
113  p->setBrush( QBrush( QColor( Qt::white ), Qt::NoBrush ) );
114 
115  p->drawImage( tlPoint, img );
116  p->restore();
117 }
118 
Iterator for sequentially processing raster cells.
void startRasterRead(int bandNumber, int nCols, int nRows, const QgsRectangle &extent)
Start reading of raster band.
#define QgsDebugMsg(str)
Definition: qgslogger.h:33
int mWidth
Width, number of columns to be rendered.
void drawImage(QPainter *p, QgsRasterViewPort *viewPort, const QImage &img, int topLeftCol, int topLeftRow) const
Draws raster part.
double x() const
Definition: qgspoint.h:126
void draw(QPainter *p, QgsRasterViewPort *viewPort, const QgsMapToPixel *theQgsMapToPixel)
Perform transforms between map coordinates and device coordinates.
Definition: qgsmaptopixel.h:33
Raster data container.
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...
int mHeight
Distance in map units from bottom edge to top edge for the part of the raster that is to be rendered...
double y() const
Definition: qgspoint.h:134
QImage image() const
Get image if type is color.
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.
QgsRectangle mDrawnExtent
Intersection of current map extent and layer extent.