Move min/max size constrain logic to QPlatformWindow.

This increases the uniformity of the to/fromNativePixels
functions by removing a special case, and avoids pulling
the qwindow_p.h details into qhihgdpiscaling.cpp.

Keep the logic of constraining the device-independent
size.

Change-Id: Id0dae30a7c0170ff2e5d21b94d56719cc900c726
Reviewed-by: Morten Johan Sørvig <morten.sorvig@theqtcompany.com>

src/gui/kernel/qhighdpiscaling.cpp

@@ -40,7 +40,6 @@
 ****************************************************************************/
 
 #include "qhighdpiscaling_p.h"
-#include "qwindow_p.h" // for QWINDOWSIZE_MAX
 #include "qguiapplication.h"
 #include "qscreen.h"
 #include "qplatformintegration.h"
@@ -228,15 +227,4 @@ QPoint QHighDpiScaling::origin(const QPlatformScreen *platformScreen)
     return platformScreen->geometry().topLeft();
 }
 
-
-Q_GUI_EXPORT QSize QHighDpi::toNativePixelsConstrained(const QSize &size, const QWindow *window)
-{
-    const int width = size.width();
-    const int height = size.height();
-    return QSize(width > 0 && width < QWINDOWSIZE_MAX ?
-                 QHighDpi::toNativePixels(width, window) : width,
-                 height > 0 && height < QWINDOWSIZE_MAX ?
-                 QHighDpi::toNativePixels(height, window) : height);
-}
-
 QT_END_NAMESPACE

src/gui/kernel/qhighdpiscaling_p.h

@@ -284,9 +284,6 @@ inline QSize fromNativePixels(const QSize &pixelSize, const QWindow *window)
     return pixelSize / QHighDpiScaling::factor(window);
 }
 
-// For converting minimum/maximum sizes of QWindow, limits to 0..QWINDOWSIZE_MAX
-Q_GUI_EXPORT QSize toNativePixelsConstrained(const QSize &size, const QWindow *window);
-
 inline QSize toNativePixels(const QSize &pointSize, const QWindow *window)
 {
     return pointSize * QHighDpiScaling::factor(window);

src/gui/kernel/qplatformwindow.cpp

@@ -496,6 +496,14 @@ QPlatformScreen *QPlatformWindow::screenForGeometry(const QRect &newGeometry) co
     return fallback;
 }
 
+/*!
+    Returns a size with both dimentions bounded to [0, QWINDOWSIZE_MAX]
+*/
+QSize QPlatformWindow::constrainWindowSize(const QSize &size)
+{
+    return size.boundedTo(QSize(0, 0)).boundedTo(QSize(QWINDOWSIZE_MAX, QWINDOWSIZE_MAX));
+}
+
 /*!
     Reimplement this method to set whether the window demands attention
     (for example, by flashing the taskbar icon) depending on \a enabled.
@@ -637,7 +645,7 @@ void QPlatformWindow::requestUpdate()
 */
 QSize QPlatformWindow::windowMinimumSize() const
 {
-    return QHighDpi::toNativePixelsConstrained(window()->minimumSize(), window());
+    return QHighDpi::toNativePixels(constrainWindowSize(window()->minimumSize()), window());
 }
 
 /*!
@@ -645,7 +653,7 @@ QSize QPlatformWindow::windowMinimumSize() const
 */
 QSize QPlatformWindow::windowMaximumSize() const
 {
-    return QHighDpi::toNativePixelsConstrained(window()->maximumSize(), window());
+    return QHighDpi::toNativePixels(constrainWindowSize(window()->maximumSize()), window());
 }
 
 /*!

src/gui/kernel/qplatformwindow.h

@@ -141,6 +141,7 @@ public:
 protected:
     static QString formatWindowTitle(const QString &title, const QString &separator);
     QPlatformScreen *screenForGeometry(const QRect &newGeometry) const;
+    static QSize constrainWindowSize(const QSize &size);
 
     QScopedPointer<QPlatformWindowPrivate> d_ptr;
 private: