Deprecate and remove all uses of AA_UseHighDpiPixmaps

High-DPI pixmaps are always enabled, and cannot be disabled.

Change-Id: I01a006b404e5431582b64ef812974c1c022b39ae
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

7 files changed, 17 insertions, 42 deletions

diff --git a/src/corelib/global/qnamespace.h b/src/corelib/global/qnamespace.h
index dbd0c20282..86afa623a9 100644
--- a/src/corelib/global/qnamespace.h
+++ b/src/corelib/global/qnamespace.h
@@ -458,7 +458,11 @@ namespace Qt {
         // AA_X11InitThreads = 10,
         AA_SynthesizeTouchForUnhandledMouseEvents = 11,
         AA_SynthesizeMouseForUnhandledTouchEvents = 12,
-        AA_UseHighDpiPixmaps = 13,
+#if QT_DEPRECATED_SINCE(6, 0)
+        AA_UseHighDpiPixmaps Q_DECL_ENUMERATOR_DEPRECATED_X(
+            "High-DPI pixmaps are always enabled. " \
+            "This attribute no longer has any effect.") = 13,
+#endif
         AA_ForceRasterWidgets = 14,
         AA_UseDesktopOpenGL = 15,
         AA_UseOpenGLES = 16,
diff --git a/src/corelib/global/qnamespace.qdoc b/src/corelib/global/qnamespace.qdoc
index b8c9854555..b96d8e0656 100644
--- a/src/corelib/global/qnamespace.qdoc
+++ b/src/corelib/global/qnamespace.qdoc
@@ -172,13 +172,6 @@
            to left button mouse events instead. This attribute is enabled
            by default.
 
-    \value AA_UseHighDpiPixmaps Make QIcon::pixmap() generate high-dpi pixmaps
-           that can be larger than the requested size. Such pixmaps will have
-           \l {QPixmap::devicePixelRatio}{devicePixelRatio()} set to a value higher than 1.
-           After setting this attribute, application code that uses pixmap
-           sizes in layout geometry calculations should typically divide by
-           \l {QPixmap::devicePixelRatio}{devicePixelRatio()} to get device-independent layout geometry.
-
     \value AA_ForceRasterWidgets Make top-level widgets use pure raster surfaces,
            and do not support non-native GL-based child widgets.
 
@@ -297,6 +290,7 @@
 
     \omitvalue AA_AttributeCount
     \omitvalue AA_EnableHighDpiScaling
+    \omitvalue AA_UseHighDpiPixmaps
 */
 
 /*!
diff --git a/src/corelib/kernel/qcoreapplication.cpp b/src/corelib/kernel/qcoreapplication.cpp
index 3bda921820..f9bd7bb63b 100644
--- a/src/corelib/kernel/qcoreapplication.cpp
+++ b/src/corelib/kernel/qcoreapplication.cpp
@@ -350,8 +350,7 @@ QAbstractEventDispatcher *QCoreApplicationPrivate::eventDispatcher = nullptr;
 QCoreApplication *QCoreApplication::self = nullptr;
 uint QCoreApplicationPrivate::attribs =
     (1 << Qt::AA_SynthesizeMouseForUnhandledTouchEvents) |
-    (1 << Qt::AA_SynthesizeMouseForUnhandledTabletEvents) |
-    (1 << Qt::AA_UseHighDpiPixmaps);
+    (1 << Qt::AA_SynthesizeMouseForUnhandledTabletEvents);
 
 struct QCoreApplicationData {
     QCoreApplicationData() noexcept {
diff --git a/src/gui/image/qicon.cpp b/src/gui/image/qicon.cpp
index a4f6369fd2..2278eb8201 100644
--- a/src/gui/image/qicon.cpp
+++ b/src/gui/image/qicon.cpp
@@ -128,15 +128,9 @@ static void qt_cleanup_icon_cache()
 
     Returns the effective device pixel ratio, using
     the provided window pointer if possible.
-
-    if Qt::AA_UseHighDpiPixmaps is not set this function
-    returns 1.0 to keep non-hihdpi aware code working.
 */
 static qreal qt_effective_device_pixel_ratio(QWindow *window = nullptr)
 {
-    if (!qApp->testAttribute(Qt::AA_UseHighDpiPixmaps))
-        return qreal(1.0);
-
     if (window)
         return window->devicePixelRatio();
 
@@ -190,11 +184,8 @@ QPixmapIconEngine::~QPixmapIconEngine()
 
 void QPixmapIconEngine::paint(QPainter *painter, const QRect &rect, QIcon::Mode mode, QIcon::State state)
 {
-    qreal dpr = 1.0;
-    if (QCoreApplication::testAttribute(Qt::AA_UseHighDpiPixmaps)) {
-      auto paintDevice = painter->device();
-      dpr = paintDevice ? paintDevice->devicePixelRatioF() : qApp->devicePixelRatio();
-    }
+    auto paintDevice = painter->device();
+    qreal dpr = paintDevice ? paintDevice->devicePixelRatioF() : qApp->devicePixelRatio();
     const QSize pixmapSize = rect.size() * dpr;
     QPixmap px = pixmap(pixmapSize, mode, state);
     painter->drawPixmap(rect, px);
@@ -800,11 +791,8 @@ qint64 QIcon::cacheKey() const
 /*!
   Returns a pixmap with the requested \a size, \a mode, and \a
   state, generating one if necessary. The pixmap might be smaller than
-  requested, but never larger.
-
-  Setting the Qt::AA_UseHighDpiPixmaps application attribute enables this
-  function to return pixmaps that are larger than the requested size. Such
-  images will have a devicePixelRatio larger than 1.
+  requested, but never larger, unless the device-pixel ratio of the returned
+  pixmap is larger than 1.
 
   \sa actualSize(), paint()
 */
@@ -822,11 +810,8 @@ QPixmap QIcon::pixmap(const QSize &size, Mode mode, State state) const
     \overload
 
     Returns a pixmap of size QSize(\a w, \a h). The pixmap might be smaller than
-    requested, but never larger.
-
-    Setting the Qt::AA_UseHighDpiPixmaps application attribute enables this
-    function to return pixmaps that are larger than the requested size. Such
-    images will have a devicePixelRatio larger than 1.
+    requested, but never larger, unless the device-pixel ratio of the returned
+    pixmap is larger than 1.
 */
 
 /*!
@@ -835,11 +820,8 @@ QPixmap QIcon::pixmap(const QSize &size, Mode mode, State state) const
     \overload
 
     Returns a pixmap of size QSize(\a extent, \a extent). The pixmap might be smaller
-    than requested, but never larger.
-
-    Setting the Qt::AA_UseHighDpiPixmaps application attribute enables this
-    function to return pixmaps that are larger than the requested size. Such
-    images will have a devicePixelRatio larger than 1.
+    than requested, but never larger, unless the device-pixel ratio of the returned
+    pixmap is larger than 1.
 */
 
 /*!
diff --git a/src/gui/image/qiconloader.cpp b/src/gui/image/qiconloader.cpp
index 250e695574..51a9632dcc 100644
--- a/src/gui/image/qiconloader.cpp
+++ b/src/gui/image/qiconloader.cpp
@@ -641,10 +641,7 @@ void QIconLoaderEngine::ensureLoaded()
 void QIconLoaderEngine::paint(QPainter *painter, const QRect &rect,
                              QIcon::Mode mode, QIcon::State state)
 {
-    const qreal dpr = !qApp->testAttribute(Qt::AA_UseHighDpiPixmaps) ?
-                qreal(1.0) : painter->device()->devicePixelRatioF();
-
-    QSize pixmapSize = rect.size() * dpr;
+    QSize pixmapSize = rect.size() * painter->device()->devicePixelRatioF();
     painter->drawPixmap(rect, pixmap(pixmapSize, mode, state));
 }
 
diff --git a/src/gui/image/qimagereader.cpp b/src/gui/image/qimagereader.cpp
index 0702e2bb23..611cbb1df1 100644
--- a/src/gui/image/qimagereader.cpp
+++ b/src/gui/image/qimagereader.cpp
@@ -102,7 +102,7 @@
     \c QT_HIGHDPI_DISABLE_2X_IMAGE_LOADING.
 
     \sa QImageWriter, QImageIOHandler, QImageIOPlugin, QMimeDatabase, QColorSpace
-    \sa QImage::devicePixelRatio(), QPixmap::devicePixelRatio(), QIcon, QPainter::drawPixmap(), QPainter::drawImage(), Qt::AA_UseHighDpiPixmaps
+    \sa QImage::devicePixelRatio(), QPixmap::devicePixelRatio(), QIcon, QPainter::drawPixmap(), QPainter::drawImage()
 */
 
 /*!
diff --git a/src/testlib/qtest.h b/src/testlib/qtest.h
index 935fbf9b05..fa439130d9 100644
--- a/src/testlib/qtest.h
+++ b/src/testlib/qtest.h
@@ -466,7 +466,6 @@ bool compareSequence(ActualIterator actualIt, ActualIterator actualEnd,
 void disableHighDpi()
 {
     QCoreApplication::setAttribute(Qt::AA_DisableHighDpiScaling);
-    QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps, false);
 }
 Q_CONSTRUCTOR_FUNCTION(disableHighDpi);
 #endif