add rendering tests for HiDPI (device pixel ratio)

src/core/qgsrenderchecker.cpp

@@ -182,7 +182,7 @@ bool QgsRenderChecker::runTest( const QString &testName,
   //
   mMapSettings.setBackgroundColor( qRgb( 152, 219, 249 ) );
   mMapSettings.setFlag( QgsMapSettings::Antialiasing );
-  mMapSettings.setOutputSize( QSize( myExpectedImage.width(), myExpectedImage.height() ) );
+  mMapSettings.setOutputSize( QSize( myExpectedImage.width(), myExpectedImage.height() ) / mMapSettings.devicePixelRatio() );
 
   QTime myTime;
   myTime.start();
@@ -194,6 +194,7 @@ bool QgsRenderChecker::runTest( const QString &testName,
   mElapsedTime = myTime.elapsed();
 
   QImage myImage = job.renderedImage();
+  Q_ASSERT( myImage.devicePixelRatioF() == mMapSettings.devicePixelRatio() );
 
   //
   // Save the pixmap to disk so the user can make a

tests/src/core/CMakeLists.txt

@@ -147,6 +147,7 @@ SET(TESTS
  testqgslegendrenderer.cpp
  testqgscentroidfillsymbol.cpp
  testqgslinefillsymbol.cpp
+ testqgsmapdevicepixelratio.cpp
  testqgsmaplayerstylemanager.cpp
  testqgsmaplayer.cpp
  testqgsmaprendererjob.cpp

tests/src/core/testqgsmapdevicepixelratio.cpp

@@ -0,0 +1,136 @@
+/***************************************************************************
+     TestQgsMapDevicePixelRatio.cpp
+     --------------------------------------
+    Date                 : October 2018
+    Copyright            : (C) 2018 by Denis Rouzaud
+    Email                : denis@opengis.ch
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include <QObject>
+#include <QString>
+#include <QStringList>
+#include <QApplication>
+#include <QFileInfo>
+#include <QDir>
+#include <QFile>
+#include <QIODevice>
+
+#include "qgstest.h"
+#include "qgsvectorlayer.h"
+#include "qgsfontutils.h"
+#include "qgsmapsettings.h"
+
+//qgis unit test includes
+#include <qgsrenderchecker.h>
+
+/**
+ * \ingroup UnitTests
+ * This is a unit test for the map rotation feature
+ */
+class TestQgsMapDevicePixelRatio : public QObject
+{
+    Q_OBJECT
+  public:
+    TestQgsMapDevicePixelRatio()
+    {
+      mTestDataDir = QStringLiteral( TEST_DATA_DIR ) + '/';
+    }
+
+    ~TestQgsMapDevicePixelRatio() override;
+
+  private slots:
+    void initTestCase();// will be called before the first testfunction is executed.
+    void cleanupTestCase();// will be called after the last testfunction was executed.
+    void init() {} // will be called before each testfunction is executed.
+    void cleanup() {} // will be called after every testfunction.
+
+    void pointsLayer();
+
+  private:
+    bool render( const QString &fileName, float dpr );
+
+    QString mTestDataDir;
+    QgsVectorLayer *mPointsLayer = nullptr;
+    QgsMapSettings *mMapSettings = nullptr;
+    QString mReport;
+};
+
+//runs before all tests
+void TestQgsMapDevicePixelRatio::initTestCase()
+{
+  // init QGIS's paths - true means that all path will be inited from prefix
+  QgsApplication::init();
+  QgsApplication::initQgis();
+
+  mMapSettings = new QgsMapSettings();
+
+  //create a point layer that will be used in all tests...
+  QString myPointsFileName = mTestDataDir + "points.shp";
+  QFileInfo myPointFileInfo( myPointsFileName );
+  mPointsLayer = new QgsVectorLayer( myPointFileInfo.filePath(),
+                                     myPointFileInfo.completeBaseName(), QStringLiteral( "ogr" ) );
+
+  mReport += QLatin1String( "<h1>Map Device Pixel Ratio Tests</h1>\n" );
+
+  QgsFontUtils::loadStandardTestFonts( QStringList() << QStringLiteral( "Bold" ) );
+}
+
+TestQgsMapDevicePixelRatio::~TestQgsMapDevicePixelRatio() = default;
+
+//runs after all tests
+void TestQgsMapDevicePixelRatio::cleanupTestCase()
+{
+  delete mMapSettings;
+  delete mPointsLayer;
+  QgsApplication::exitQgis();
+
+  QString myReportFile = QDir::tempPath() + "/qgistest.html";
+  QFile myFile( myReportFile );
+  if ( myFile.open( QIODevice::WriteOnly | QIODevice::Append ) )
+  {
+    QTextStream myQTextStream( &myFile );
+    myQTextStream << mReport;
+    myFile.close();
+  }
+}
+
+void TestQgsMapDevicePixelRatio::pointsLayer()
+{
+  mMapSettings->setLayers( QList<QgsMapLayer *>() << mPointsLayer );
+
+  QString qml = mTestDataDir + "points.qml";
+  bool success = false;
+  mPointsLayer->loadNamedStyle( qml, success );
+  QVERIFY( success );
+  QVERIFY( render( "dpr-normal", 1 ) );
+  QVERIFY( render( "dpr-2", 2 ) );
+  QVERIFY( render( "dpr-float", 2.5 ) );
+}
+
+
+bool TestQgsMapDevicePixelRatio::render( const QString &testType, float dpr )
+{
+  mReport += "<h2>" + testType + "</h2>\n";
+  mMapSettings->setOutputSize( QSize( 256, 256 ) );
+  mMapSettings->setOutputDpi( 96 );
+  mMapSettings->setDevicePixelRatio( dpr );
+  mMapSettings->setExtent( QgsRectangle( -105.5, 37, -97.5, 45 ) );
+  qDebug() << "scale" << QString::number( mMapSettings->scale(), 'f' );
+  QgsRenderChecker checker;
+  checker.setControlPathPrefix( QStringLiteral( "mapdevicepixelratio" ) );
+  checker.setControlName( "expected_" + testType );
+  checker.setMapSettings( *mMapSettings );
+  bool result = checker.runTest( testType );
+  mReport += "\n\n\n" + checker.report();
+  return result;
+}
+
+QGSTEST_MAIN( TestQgsMapDevicePixelRatio )
+#include "testqgsmapdevicepixelratio.moc"