Merge pull request #291 from aws-lumberyard-dev/Atom/guthadam/ATOM-15326

ATOM-15326 support for image thumbnails in asset browser and thumbnail widget

Code/Framework/AzToolsFramework/AzToolsFramework/AssetBrowser/Views/EntryDelegate.cpp

@@ -139,8 +139,11 @@ namespace AzToolsFramework
             }
             else
             {
-                QPixmap pixmap = thumbnail->GetPixmap(size);
-                painter->drawPixmap(point, pixmap.scaled(size, Qt::IgnoreAspectRatio, Qt::SmoothTransformation));
+                // Scaling and centering pixmap within bounds to preserve aspect ratio
+                const QPixmap pixmap = thumbnail->GetPixmap(size).scaled(size, Qt::KeepAspectRatio, Qt::SmoothTransformation);
+                const QSize sizeDelta = size - pixmap.size();
+                const QPoint pointDelta = QPoint(sizeDelta.width() / 2, sizeDelta.height() / 2);
+                painter->drawPixmap(point + pointDelta, pixmap);
             }
             return m_iconSize;
         }

Code/Framework/AzToolsFramework/AzToolsFramework/Thumbnails/ThumbnailWidget.cpp

@@ -71,20 +71,12 @@ namespace AzToolsFramework
                 SharedThumbnail thumbnail;
                 ThumbnailerRequestsBus::BroadcastResult(thumbnail, &ThumbnailerRequests::GetThumbnail, m_key, m_contextName.c_str());
                 QPainter painter(this);
-                QPixmap pixmap = thumbnail->GetPixmap();
-                // preserve thumbnail image's ratio, if the widget is wider than the image, center the image hotizontally
-                float aspectRatio = aznumeric_cast<float>(pixmap.width()) / pixmap.height();
-                int originalWidth = width();
-                int originalHeight = height();
-                int realHeight = qMin(aznumeric_cast<int>(originalWidth /aspectRatio), originalHeight);
-                int realWidth = aznumeric_cast<int>(realHeight * aspectRatio);
-                int x = (originalWidth - realWidth) / 2;
-                // pixmap needs to be manually scaled to produce smoother result and avoid looking pixelated
-                // using painter.setRenderHint(QPainter::SmoothPixmapTransform); does not seem to work
-                // Note: there is a potential issue with pixmap.scaled:
-                // it is multithreaded (using global threadPool) and blocking until finished.
-                // A deadlock will happen if global threadPool has no free threads available.
-                painter.drawPixmap(QPoint(x, 0), pixmap.scaled(realWidth, realHeight, Qt::IgnoreAspectRatio, Qt::SmoothTransformation));
+
+                // Scaling and centering pixmap within bounds to preserve aspect ratio
+                const QPixmap pixmap = thumbnail->GetPixmap().scaled(size(), Qt::KeepAspectRatio, Qt::SmoothTransformation);
+                const QSize sizeDelta = size() - pixmap.size();
+                const QPoint pointDelta = QPoint(sizeDelta.width() / 2, sizeDelta.height() / 2);
+                painter.drawPixmap(pointDelta, pixmap);
             }
             QWidget::paintEvent(event);
         }