Add logging for QPlatformBackingStore::composeAndFlush

Change-Id: I96778296480d2aaad5e01ed15353106bc90d4d2b
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

2 files changed, 9 insertions, 2 deletions

diff --git a/src/gui/painting/qplatformbackingstore.cpp b/src/gui/painting/qplatformbackingstore.cpp
index cc8d850689..373722cdb4 100644
--- a/src/gui/painting/qplatformbackingstore.cpp
+++ b/src/gui/painting/qplatformbackingstore.cpp
@@ -80,6 +80,8 @@
 
 QT_BEGIN_NAMESPACE
 
+Q_LOGGING_CATEGORY(lcQpaBackingStore, "qt.qpa.backingstore", QtWarningMsg);
+
 class QPlatformBackingStorePrivate
 {
 public:
@@ -331,16 +333,19 @@ void QPlatformBackingStore::composeAndFlush(QWindow *window, const QRegion &regi
         d_ptr->context->setScreen(d_ptr->window->screen());
         d_ptr->context->setShareContext(qt_window_private(d_ptr->window)->shareContext());
         if (!d_ptr->context->create()) {
-            qWarning("composeAndFlush: QOpenGLContext creation failed");
+            qCWarning(lcQpaBackingStore, "composeAndFlush: QOpenGLContext creation failed");
             return;
         }
     }
 
     if (!d_ptr->context->makeCurrent(window)) {
-        qWarning("composeAndFlush: makeCurrent() failed");
+        qCWarning(lcQpaBackingStore, "composeAndFlush: makeCurrent() failed");
         return;
     }
 
+    qCDebug(lcQpaBackingStore) << "Composing and flushing" << region << "of" << window
+        << "at offset" << offset << "with" << textures->count() << "texture(s) in" << textures;
+
     QWindowPrivate::get(window)->lastComposeTime.start();
 
     QOpenGLFunctions *funcs = d_ptr->context->functions();
diff --git a/src/gui/painting/qplatformbackingstore.h b/src/gui/painting/qplatformbackingstore.h
index 381c564079..de5ba964dc 100644
--- a/src/gui/painting/qplatformbackingstore.h
+++ b/src/gui/painting/qplatformbackingstore.h
@@ -50,6 +50,7 @@
 //
 
 #include <QtGui/qtguiglobal.h>
+#include <QtCore/qloggingcategory.h>
 #include <QtCore/qrect.h>
 #include <QtCore/qobject.h>
 
@@ -59,6 +60,7 @@
 
 QT_BEGIN_NAMESPACE
 
+Q_GUI_EXPORT Q_DECLARE_LOGGING_CATEGORY(lcQpaBackingStore)
 
 class QRegion;
 class QRect;