Reintroduce -geometry command line argument for X11/XCB.

Add parsing for the window geometry specification to
QGuiApplicationPrivate. Enable the argument under a different
name for the other platforms as well.

Task-number: QTBUG-27349
Change-Id: I973b2c69f5172f7d0bc983b8ba4b0d164649ef02
Reviewed-by: David Faure <david.faure@kdab.com>
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>

3 files changed, 125 insertions, 4 deletions

diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index e1d0b1c01f..dd111be0eb 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -101,6 +101,8 @@
 #  include <QtCore/QLibraryInfo>
 #endif // Q_OS_WIN && !Q_OS_WINCE
 
+#include <ctype.h>
+
 QT_BEGIN_NAMESPACE
 
 Q_GUI_EXPORT bool qt_is_gui_used = true;
@@ -215,6 +217,106 @@ static inline bool isPopupWindow(const QWindow *w)
     return (w->flags() & Qt::WindowType_Mask) == Qt::Popup;
 }
 
+// Geometry specification for top level windows following the convention of the
+// -geometry command line arguments in X11 (see XParseGeometry).
+struct QWindowGeometrySpecification
+{
+    QWindowGeometrySpecification() : corner(Qt::TopLeftCorner), xOffset(-1), yOffset(-1), width(-1), height(-1) {}
+    static QWindowGeometrySpecification fromArgument(const QByteArray &a);
+    QRect apply(const QRect &windowGeometry, const QSize &windowMinimumSize, const QSize &windowMaximumSize, const QRect &availableGeometry) const;
+    inline QRect apply(const QRect &windowGeometry, const QWindow *window) const
+    { return apply(windowGeometry, window->minimumSize(), window->maximumSize(), window->screen()->virtualGeometry()); }
+
+    Qt::Corner corner;
+    int xOffset;
+    int yOffset;
+    int width;
+    int height;
+};
+
+// Parse a token of a X11 geometry specification "200x100+10-20".
+static inline int nextGeometryToken(const QByteArray &a, int &pos, char *op)
+{
+    *op = 0;
+    const int size = a.size();
+    if (pos >= size)
+        return -1;
+
+    *op = a.at(pos);
+    if (*op == '+' || *op == '-' || *op == 'x')
+        pos++;
+    else if (isdigit(*op))
+        *op = 'x'; // If it starts with a digit, it is supposed to be a width specification.
+    else
+        return -1;
+
+    const int numberPos = pos;
+    for ( ; pos < size && isdigit(a.at(pos)); ++pos) ;
+
+    bool ok;
+    const int result = a.mid(numberPos, pos - numberPos).toInt(&ok);
+    return ok ? result : -1;
+}
+
+QWindowGeometrySpecification QWindowGeometrySpecification::fromArgument(const QByteArray &a)
+{
+    QWindowGeometrySpecification result;
+    int pos = 0;
+    for (int i = 0; i < 4; ++i) {
+        char op;
+        const int value = nextGeometryToken(a, pos, &op);
+        if (value < 0)
+            break;
+        switch (op) {
+        case 'x':
+            (result.width >= 0 ? result.height : result.width) = value;
+            break;
+        case '+':
+        case '-':
+            if (result.xOffset >= 0) {
+                result.yOffset = value;
+                if (op == '-')
+                    result.corner = result.corner == Qt::TopRightCorner ? Qt::BottomRightCorner : Qt::BottomLeftCorner;
+            } else {
+                result.xOffset = value;
+                if (op == '-')
+                    result.corner = Qt::TopRightCorner;
+            }
+        }
+    }
+    return result;
+}
+
+QRect QWindowGeometrySpecification::apply(const QRect &windowGeometry, const QSize &windowMinimumSize, const QSize &windowMaximumSize, const QRect &availableGeometry) const
+{
+    QRect result = windowGeometry;
+    if (width >= 0 || height >= 0) {
+        QSize size = windowGeometry.size();
+        if (width >= 0)
+            size.setWidth(qBound(windowMinimumSize.width(), width, windowMaximumSize.width()));
+        if (height >= 0)
+            size.setHeight(qBound(windowMinimumSize.height(), height, windowMaximumSize.height()));
+        result.setSize(size);
+    }
+    if (xOffset >= 0 || yOffset >= 0) {
+        QPoint topLeft = windowGeometry.topLeft();
+        if (xOffset >= 0) {
+            topLeft.setX(corner == Qt::TopLeftCorner || corner == Qt::BottomLeftCorner ?
+                         xOffset :
+                         qMax(availableGeometry.right() - result.width() - xOffset, availableGeometry.left()));
+        }
+        if (yOffset >= 0) {
+            topLeft.setY(corner == Qt::TopLeftCorner || corner == Qt::TopRightCorner ?
+                         yOffset :
+                         qMax(availableGeometry.bottom() - result.height() - yOffset, availableGeometry.top()));
+        }
+        result.moveTopLeft(topLeft);
+    }
+    return result;
+}
+
+static QWindowGeometrySpecification windowGeometrySpecification;
+
 /*!
     \class QGuiApplication
     \brief The QGuiApplication class manages the GUI application's control
@@ -910,6 +1012,9 @@ void QGuiApplicationPrivate::createPlatformIntegration()
         } else if (arg == "-platform") {
             if (++i < argc)
                 platformName = argv[i];
+        } else if (arg == "-qwindowgeometry" || (platformName == "xcb" && arg == "-geometry")) {
+            if (++i < argc)
+                windowGeometrySpecification = QWindowGeometrySpecification::fromArgument(argv[i]);
         } else {
             argv[j++] = argv[i];
         }
@@ -2398,6 +2503,11 @@ void QGuiApplication::setPalette(const QPalette &pal)
     applicationResourceFlags |= ApplicationPaletteExplicitlySet;
 }
 
+QRect QGuiApplicationPrivate::applyWindowGeometrySpecification(const QRect &windowGeometry, const QWindow *window)
+{
+    return windowGeometrySpecification.apply(windowGeometry, window);
+}
+
 /*!
     Returns the default application font.
 
diff --git a/src/gui/kernel/qguiapplication_p.h b/src/gui/kernel/qguiapplication_p.h
index 3a4b692b69..11f68ba2ff 100644
--- a/src/gui/kernel/qguiapplication_p.h
+++ b/src/gui/kernel/qguiapplication_p.h
@@ -275,6 +275,8 @@ public:
     // hook reimplemented in QApplication to apply the QStyle function on the QIcon
     virtual QPixmap applyQIconStyleHelper(QIcon::Mode, const QPixmap &basePixmap) const { return basePixmap; }
 
+    static QRect applyWindowGeometrySpecification(const QRect &windowGeometry, const QWindow *window);
+
 protected:
     virtual void notifyThemeChanged();
 #ifndef QT_NO_DRAGANDDROP
diff --git a/src/widgets/kernel/qwidget.cpp b/src/widgets/kernel/qwidget.cpp
index 869362654c..ac649b4bdf 100644
--- a/src/widgets/kernel/qwidget.cpp
+++ b/src/widgets/kernel/qwidget.cpp
@@ -7268,10 +7268,19 @@ void QWidget::setVisible(bool visible)
             create();
         }
 
-#if defined(Q_WS_X11)
-        if (windowType() == Qt::Window)
-            QApplicationPrivate::applyX11SpecificCommandLineArguments(this);
-#endif
+        // Handling of the -qwindowgeometry, -geometry command line arguments
+        if (windowType() == Qt::Window && windowHandle()) {
+            static bool done = false;
+            if (!done) {
+                done = true;
+                const QRect oldGeometry = frameGeometry();
+                const QRect geometry = QGuiApplicationPrivate::applyWindowGeometrySpecification(oldGeometry, windowHandle());
+                if (oldGeometry.size() != geometry.size())
+                    resize(geometry.size());
+                if (geometry.topLeft() != oldGeometry.topLeft())
+                    move(geometry.topLeft());
+            } // done
+        }
 
         bool wasResized = testAttribute(Qt::WA_Resized);
         Qt::WindowStates initialWindowState = windowState();