Windows clipboard: Deny CF_DIB support for images with alpha.

Support CF_DIBV5 for these images so that transparency is preserved.

Task-number: QTBUG-11463
Change-Id: I51881ae8bfbd05b92abd309766f4da9a7ea26c2d
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>

src/plugins/platforms/windows/qwindowsmime.cpp

@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
 ** Contact: http://www.qt-project.org/legal
 **
 ** This file is part of the plugins of the Qt Toolkit.
@@ -1035,17 +1035,14 @@ bool QWindowsMimeImage::canConvertToMime(const QString &mimeType, IDataObject *p
 bool QWindowsMimeImage::canConvertFromMime(const FORMATETC &formatetc, const QMimeData *mimeData) const
 {
     int cf = getCf(formatetc);
-    if (mimeData->hasImage()) {
-        if (cf == CF_DIB)
-            return true;
-        else if (cf == CF_DIBV5) {
-            //support DIBV5 conversion only if the image has alpha channel
-            QImage image = qvariant_cast<QImage>(mimeData->imageData());
-            if (!image.isNull() && image.hasAlphaChannel())
-                return true;
-        }
-    }
-    return false;
+    if (!mimeData->hasImage())
+        return false;
+    const QImage image = qvariant_cast<QImage>(mimeData->imageData());
+    if (image.isNull())
+        return false;
+    // QTBUG-11463, deny CF_DIB support for images with alpha to prevent loss of
+    // transparency in conversion.
+    return cf == CF_DIBV5 || (cf == CF_DIB && !image.hasAlphaChannel());
 }
 
 bool QWindowsMimeImage::convertFromMime(const FORMATETC &formatetc, const QMimeData *mimeData, STGMEDIUM * pmedium) const

tests/auto/gui/kernel/qclipboard/paster/main.cpp

@@ -40,20 +40,59 @@
 ****************************************************************************/
 #include <QtGui/QGuiApplication>
 #include <QtGui/QClipboard>
+#include <QtGui/QImage>
+#include <QtGui/QColor>
 #include <QtCore/QStringList>
+#include <QtCore/QCommandLineParser>
 
 int main(int argc, char **argv)
 {
     QGuiApplication app(argc, argv);
-    QString expected = QStringLiteral("testString.!");
-#ifndef Q_OS_WINCE
-    const QStringList arguments = app.arguments();
-    if (arguments.size() > 1)
-        expected = arguments.at(1);
-#endif
-    QString actual;
+    QCommandLineParser parser;
+    parser.addHelpOption();
+    QCommandLineOption textOption(QStringLiteral("text"),
+                                  QStringLiteral("Text to compare"),
+                                  QStringLiteral("text"));
+    parser.addOption(textOption);
+    QCommandLineOption imageOption(QStringLiteral("image"),
+                                   QStringLiteral("Perform image check"));
+    parser.addOption(imageOption);
+    parser.process(QCoreApplication::arguments());
+
+    if (parser.isSet(imageOption)) {
 #ifndef QT_NO_CLIPBOARD
-    actual = QGuiApplication::clipboard()->text();
+        const QImage actual = QGuiApplication::clipboard()->image();
+#else
+        const QImage actual;
 #endif
-    return actual == expected ? 0 : 1;
+        // Perform hard-coded checks on copied image (size, pixel 0,0: transparent,
+        // pixel 1,0: blue). Note: Windows sets RGB of transparent to 0xFF when converting
+        // to DIB5.
+        if (actual.size() != QSize(100, 100))
+            return 1;
+        const QRgb pixel00 = actual.pixel(QPoint(0, 0));
+        if (qAlpha(pixel00))
+            return 2;
+        const QRgb pixel01 = actual.pixel(QPoint(1, 0));
+        if (pixel01 != QColor(Qt::blue).rgba())
+            return 3;
+        return 0;
+    }
+
+#ifndef Q_OS_WINCE
+    QString expected;
+    if (parser.isSet(textOption))
+        expected = parser.value(textOption);
+#else // !Q_OS_WINCE
+    const QString expected = QStringLiteral("testString.!");
+#endif // Q_OS_WINCE
+    if (!expected.isEmpty()) {
+#ifndef QT_NO_CLIPBOARD
+        const QString actual = QGuiApplication::clipboard()->text();
+#else
+        const QString actual;
+#endif
+        return actual == expected ? 0 : 1;
+    }
+    return -2;
 }

tests/auto/gui/kernel/qclipboard/tst_qclipboard.cpp

@@ -46,6 +46,8 @@
 #include <QtCore/QDir>
 #include <QtGui/QGuiApplication>
 #include <QtGui/QClipboard>
+#include <QtGui/QImage>
+#include <QtGui/QColor>
 #include "../../../shared/platformclipboard.h"
 
 class tst_QClipboard : public QObject
@@ -59,6 +61,7 @@ private slots:
     void init();
 #if defined(Q_OS_WIN) || defined(Q_OS_MAC) || defined(Q_OS_QNX)
     void copy_exit_paste();
+    void copyImage();
 #endif
     void capabilityFunctions();
     void modes();
@@ -278,18 +281,42 @@ void tst_QClipboard::copy_exit_paste()
     // ### It's still possible to test copy/paste - just keep the apps running
     if (!PlatformClipboard::isAvailable())
         QSKIP("Native clipboard not working in this setup");
-    const QStringList stringArgument(QStringLiteral("Test string."));
+    const QString stringArgument(QStringLiteral("Test string."));
     QByteArray errorMessage;
-    QVERIFY2(runHelper(QStringLiteral("copier/copier"), stringArgument, &errorMessage),
+    QVERIFY2(runHelper(QStringLiteral("copier/copier"), QStringList(stringArgument), &errorMessage),
              errorMessage.constData());
 #ifdef Q_OS_MAC
     // The Pasteboard needs a moment to breathe (at least on older Macs).
     QTest::qWait(100);
 #endif // Q_OS_MAC
-    QVERIFY2(runHelper(QStringLiteral("paster/paster"), stringArgument, &errorMessage),
+    QVERIFY2(runHelper(QStringLiteral("paster/paster"),
+                       QStringList() << QStringLiteral("--text") << stringArgument,
+                       &errorMessage),
              errorMessage.constData());
 #endif // QT_NO_PROCESS
 }
+
+void tst_QClipboard::copyImage()
+{
+#ifndef QT_NO_PROCESS
+    if (!PlatformClipboard::isAvailable())
+        QSKIP("Native clipboard not working in this setup");
+    QImage image(100, 100, QImage::Format_ARGB32);
+    image.fill(QColor(Qt::transparent));
+    image.setPixel(QPoint(1, 0), QColor(Qt::blue).rgba());
+    QGuiApplication::clipboard()->setImage(image);
+#ifdef Q_OS_OSX
+    // The Pasteboard needs a moment to breathe (at least on older Macs).
+    QTest::qWait(100);
+#endif // Q_OS_OSX
+    // paster will perform hard-coded checks on the copied image.
+    QByteArray errorMessage;
+    QVERIFY2(runHelper(QStringLiteral("paster/paster"),
+                       QStringList(QStringLiteral("--image")), &errorMessage),
+             errorMessage.constData());
+#endif // QT_NO_PROCESS
+}
+
 #endif // Q_OS_WIN || Q_OS_MAC || Q_OS_QNX
 
 void tst_QClipboard::setMimeData()