Allow passing {width,height}-only size to the image cache

nirvn · nirvn · commit ce5636afedcf · 2018-12-05T11:14:13.000+07:00
diff --git a/src/core/qgsimagecache.cpp b/src/core/qgsimagecache.cpp
@@ -115,8 +115,8 @@ QImage QgsImageCache::pathAsImage( const QString &file, const QSize size, const
   if ( currentEntry->image.isNull() )
   {
     long cachedDataSize = 0;
-    cachedDataSize += currentEntry->size.width() * currentEntry->size.height() * 32;
     result = renderImage( file, size, keepAspectRatio );
+    cachedDataSize += result.width() * result.height() * 32;
     if ( cachedDataSize > mMaxCacheSize / 2 )
     {
       fitsInCache = false;
@@ -214,6 +214,12 @@ QImage QgsImageCache::renderImage( const QString &path, QSize size, const bool k
   // render image at desired size -- null size means original size
   if ( !size.isValid() || size.isNull() || im.size() == size )
     return im;
+  // when original aspect ratio is respected and provided height value is 0, automatically compute height
+  else if ( keepAspectRatio && size.height() == 0 )
+    return im.scaledToWidth( size.width(), Qt::SmoothTransformation );
+  // when original aspect ratio is respected and provided width value is 0, automatically compute width
+  else if ( keepAspectRatio && size.width() == 0 )
+    return im.scaledToHeight( size.height(), Qt::SmoothTransformation );
   else
     return im.scaled( size, keepAspectRatio ? Qt::KeepAspectRatio : Qt::IgnoreAspectRatio, Qt::SmoothTransformation );
 }
diff --git a/tests/src/core/testqgsimagecache.cpp b/tests/src/core/testqgsimagecache.cpp
@@ -49,7 +49,8 @@ class TestQgsImageCache : public QObject
     void cleanup() {} // will be called after every testfunction.
     void fillCache();
     void threadSafeImage();
-    void changeImage(); //check that cache is updated if image source file changes
+    void changeImage(); // check that cache is updated if image source file changes
+    void size(); // check various size-specific handling
     void base64();
 
 };
@@ -193,6 +194,29 @@ void TestQgsImageCache::changeImage()
   QVERIFY( imageCheck( "imagecache_changed_before", img, 30 ) );
 }
 
+void TestQgsImageCache::size()
+{
+  QgsImageCache cache;
+  QImage img;
+  bool inCache;
+  QString originalImage = TEST_DATA_DIR + QStringLiteral( "/sample_image.png" );
+
+  // null size should return image using original size
+  img = cache.pathAsImage( originalImage, QSize(), true, 1.0, inCache );
+  QCOMPARE( img.width(), 511 );
+  QCOMPARE( img.height(), 800 );
+
+  // a size with an height set to 0 while keep aspect ratio is true should return an image with automatically computed height
+  img = cache.pathAsImage( originalImage, QSize( 100, 0 ), true, 1.0, inCache );
+  QCOMPARE( img.width(), 100 );
+  QCOMPARE( img.height(), 157 );
+
+  // a size with an width set to 0 while keep aspect ratio is true should return an image with automatically computed width
+  img = cache.pathAsImage( originalImage, QSize( 0, 100 ), true, 1.0, inCache );
+  QCOMPARE( img.width(), 64 );
+  QCOMPARE( img.height(), 100 );
+}
+
 void TestQgsImageCache::base64()
 {
   // test rendering images encoded in base 64
