Modernize QML SceneGrabber

Use PMF syntax for signal/slot connections, and categorized logging
rather than preprocessor defines for diagnostics. Add more and fix
some debug output.

Change-Id: I388904fd0caa474bff137b59358489e962ccf955
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>
(cherry picked from commit 82f6e4c3f7efe7c1bef1b389fafc812de00d466a)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 18 insertions, 20 deletions

diff --git a/tests/baseline/scenegraph/scenegrabber/main.cpp b/tests/baseline/scenegraph/scenegrabber/main.cpp
index f830b2a3a4..046c535e24 100644
--- a/tests/baseline/scenegraph/scenegrabber/main.cpp
+++ b/tests/baseline/scenegraph/scenegrabber/main.cpp
@@ -7,6 +7,7 @@
 #include <QtCore/QHashFunctions>
 #include <QtGui/QGuiApplication>
 #include <QtGui/QImage>
+#include <QtCore/QLoggingCategory>
 
 #include <QtQuick/QQuickView>
 #include <QtQuick/QQuickItem>
@@ -29,6 +30,7 @@
 #define SCENE_TIMEOUT     6000
 
 //#define GRABBERDEBUG
+Q_LOGGING_CATEGORY(lcGrabber, "qt.baseline.scenegrabber")
 
 static const QSize DefaultGrabSize(320, 480);
 
@@ -45,15 +47,17 @@ public:
         grabTimer = new QTimer(this);
         grabTimer->setSingleShot(true);
         grabTimer->setInterval(SCENE_STABLE_TIME);
-        connect(grabTimer, SIGNAL(timeout()), SLOT(grab()));
+        connect(grabTimer, &QTimer::timeout, this, &GrabbingView::grab);
 
         if (!preferAppWindow)
             QObject::connect(this, &QQuickWindow::afterRendering, this, &GrabbingView::startGrabbing);
 
-        QTimer::singleShot(SCENE_TIMEOUT, this, SLOT(timedOut()));
+        QTimer::singleShot(SCENE_TIMEOUT, this, &GrabbingView::timedOut);
     }
 
     void setApplicationWindow(QWindow* window) {
+        qCDebug(lcGrabber) << "Using ApplicationWindow as visual parent" << this;
+
         appwindow = qobject_cast<QQuickApplicationWindow *>(window);
         if (preferAppWindow)
             QObject::connect(this, &QQuickWindow::afterRendering, this, &GrabbingView::startGrabbing);
@@ -63,6 +67,7 @@ public:
 private slots:
     void startGrabbing()
     {
+        qCDebug(lcGrabber) << "Starting to grab";
         if (!initDone) {
             initDone = true;
             grabTimer->start();
@@ -71,13 +76,15 @@ private slots:
 
     void grab()
     {
-        if (isGrabbing)
+        if (isGrabbing) {
+            qCDebug(lcGrabber) << "Already grabbing, skipping";
             return;
-        isGrabbing = true;
+        }
+
+        QScopedValueRollback grabGuard(isGrabbing, true);
+
         grabNo++;
-#ifdef GRABBERDEBUG
-        printf("grab no. %i\n", grabNo);
-#endif
+        qCDebug(lcGrabber) << "grab no." << grabNo;
         QImage img;
         img = appwindow ? appwindow->grabWindow() : grabWindow();
         if (!img.isNull() && img == lastGrab) {
@@ -86,15 +93,11 @@ private slots:
             lastGrab = img;
             grabTimer->start();
         }
-
-        isGrabbing = false;
     }
 
     void sceneStabilized()
     {
-#ifdef GRABBERDEBUG
-        printf("...sceneStabilized IN\n");
-#endif
+        qCDebug(lcGrabber) << "...sceneStabilized IN";
         if (QGuiApplication::platformName() == QLatin1String("eglfs")) {
             QSize grabSize = initialSize().isEmpty() ? DefaultGrabSize : initialSize();
             lastGrab = lastGrab.copy(QRect(QPoint(0, 0), grabSize));
@@ -119,9 +122,7 @@ private slots:
             }
         }
         QGuiApplication::exit(0);
-#ifdef GRABBERDEBUG
-        printf("...sceneStabilized OUT\n");
-#endif
+        qCDebug(lcGrabber) << "...sceneStabilized OUT";
     }
 
     void timedOut()
@@ -181,7 +182,6 @@ int main(int argc, char *argv[])
             }
         }
         else if (arg == "-useAppWindow") {
-            qWarning() << "Using ApplicationWindow as visual parent";
             useAppWindow = true;
         }
         else if (ifile.isEmpty()) {
@@ -229,7 +229,7 @@ int main(int argc, char *argv[])
             auto *appWindow = qobject_cast<QQuickApplicationWindow *>(appWndComp.create());
 
             if (!appWindow) {
-                qWarning() << "Error: failed to grab application window.";
+                qWarning() << "Error: failed to create application window.";
                 QGuiApplication::exit(2);
             }
 
@@ -259,9 +259,7 @@ int main(int argc, char *argv[])
     }
 
     int retVal = a.exec();
-#ifdef GRABBERDEBUG
-    printf("...retVal=%i\n", retVal);
-#endif
+    qCDebug(lcGrabber) << "...retVal=" << retVal;
 
     return retVal;
 }