Parse Xft.dpi with fraction

Some versions of GNOME 3 would set Xft.dpi with fraction though that
is technically not valid.

Change-Id: Ib1027283cc78fd5d9869cd337864a92e28cd7e88
Fixes: QTBUG-64738
Reviewed-by: Gatis Paeglis <gatis.paeglis@qt.io>

1 files changed, 12 insertions, 2 deletions

diff --git a/src/plugins/platforms/xcb/qxcbscreen.cpp b/src/plugins/platforms/xcb/qxcbscreen.cpp
index 7c60ca06f9..44d0bb3f55 100644
--- a/src/plugins/platforms/xcb/qxcbscreen.cpp
+++ b/src/plugins/platforms/xcb/qxcbscreen.cpp
@@ -320,12 +320,22 @@ bool QXcbVirtualDesktop::xResource(const QByteArray &identifier,
 
 static bool parseXftInt(const QByteArray& stringValue, int *value)
 {
-    Q_ASSERT(value != 0);
+    Q_ASSERT(value);
     bool ok;
     *value = stringValue.toInt(&ok);
     return ok;
 }
 
+static bool parseXftDpi(const QByteArray& stringValue, int *value)
+{
+    Q_ASSERT(value);
+    bool ok = parseXftInt(stringValue, value);
+    // Support GNOME 3 bug that wrote DPI with fraction:
+    if (!ok)
+        *value = qRound(stringValue.toDouble(&ok));
+    return ok;
+}
+
 static QFontEngine::HintStyle parseXftHintStyle(const QByteArray& stringValue)
 {
     if (stringValue == "hintfull")
@@ -391,7 +401,7 @@ void QXcbVirtualDesktop::readXResources()
         int value;
         QByteArray stringValue;
         if (xResource(r, "Xft.dpi:\t", stringValue)) {
-            if (parseXftInt(stringValue, &value))
+            if (parseXftDpi(stringValue, &value))
                 m_forcedDpi = value;
         } else if (xResource(r, "Xft.hintstyle:\t", stringValue)) {
             m_hintStyle = parseXftHintStyle(stringValue);