Reset static sizes when DPI changes

include/wx/private/window.h

@@ -11,6 +11,7 @@
 #define _WX_PRIVATE_WINDOW_H_
 
 #include "wx/gdicmn.h"
+#include "wx/dynlib.h"
 
 namespace wxPrivate
 {
@@ -33,6 +34,67 @@ inline wxSize GetAverageASCIILetterSize(const T& of_what)
     return s;
 }
 
+namespace
+{
+
+inline bool SupportsPerMonitorDPI()
+{
+    static bool s_checkDPI =
+#if defined(__WXMSW__) && wxUSE_DYNLIB_CLASS
+        // Only check the DPI when GetDpiForWindow is available because the old
+        // method (GetDeviceCaps) is a lot slower (about 1500 times).
+        // And when GetDpiForWindow is not available (for example older Windows
+        // versions), per-monitor DPI (V2) is also not available.
+        wxLoadedDLL("user32.dll").HasSymbol("GetDpiForWindow");
+#else
+        false;
+#endif
+    return s_checkDPI;
+}
+
+}
+
+template <typename T>
+class DpiDependentValue
+{
+public:
+    // Explicit initialization is needed if T is a primitive type.
+    DpiDependentValue()
+        : m_value(), m_dpi()
+    { }
+
+    bool HasChanged(const wxWindowBase* win)
+    {
+        if ( win && SupportsPerMonitorDPI() )
+        {
+            const wxSize dpi = win->GetDPI();
+            if ( dpi != m_dpi )
+            {
+                m_dpi = dpi;
+                return true;
+            }
+        }
+
+        // Ensure that we return true the first time we're called,
+        // asuming that the value will always be set to a non-default value.
+        return m_value == T();
+    }
+
+    void SetAtNewDPI(const T& value)
+    {
+        m_value = value;
+    }
+
+    T& Get()
+    {
+        return m_value;
+    }
+
+private:
+    T m_value;
+    wxSize m_dpi;
+};
+
 } // namespace wxPrivate
 
 #endif // _WX_PRIVATE_WINDOW_H_

include/wx/sizer.h

@@ -120,13 +120,7 @@ public:
         // current DPI, do it once (and cache the result) in another function.
         #define wxNEEDS_BORDER_IN_PX
 
-        // We don't react to dynamic DPI changes, so we can cache the values of
+        return DoGetDefaultBorderInPx();
-        // the border in on-screen pixels after computing it once. This
-        // could/should change in the future.
-        if ( !ms_defaultBorderInPx )
-            ms_defaultBorderInPx = DoGetDefaultBorderInPx();
-
-        return ms_defaultBorderInPx;
     #endif
 #else
         return 0;
@@ -230,8 +224,6 @@ public:
 private:
 #ifdef wxNEEDS_BORDER_IN_PX
     static int DoGetDefaultBorderInPx();
-
-    static int ms_defaultBorderInPx;
 #endif // wxNEEDS_BORDER_IN_PX
 
     int m_proportion;

src/common/sizer.cpp

@@ -28,11 +28,13 @@
     #include "wx/button.h"
     #include "wx/statbox.h"
     #include "wx/toplevel.h"
+    #include "wx/app.h"
 #endif // WX_PRECOMP
 
 #include "wx/display.h"
 #include "wx/vector.h"
 #include "wx/listimpl.cpp"
+#include "wx/private/window.h"
 
 
 //---------------------------------------------------------------------------
@@ -90,8 +92,6 @@ WX_DEFINE_EXPORTED_LIST( wxSizerItemList )
 
 #ifdef wxNEEDS_BORDER_IN_PX
 
-int wxSizerFlags::ms_defaultBorderInPx = 0;
-
 /* static */
 int wxSizerFlags::DoGetDefaultBorderInPx()
 {
@@ -103,11 +103,14 @@ int wxSizerFlags::DoGetDefaultBorderInPx()
     // between related and unrelated controls, as explained at the above URL,
     // but we don't have a way to specify this in our API currently.
     //
-    // We also have to use the DPI for the primary monitor here as we don't
+    // We also have to use the DPI for the monitor showing the top window here
-    // have any associated window, so this is wrong on systems using multiple
+    // as we don't have any associated window -- but, again, without changes
-    // monitors with different resolutions too -- but, again, without changes
     // in the API, there is nothing we can do about this.
-    return wxWindow::FromDIP(5, NULL);
+    const wxWindow* const win = wxTheApp ? wxTheApp->GetTopWindow() : NULL;
+    static wxPrivate::DpiDependentValue<int> s_defaultBorderInPx;
+    if ( s_defaultBorderInPx.HasChanged(win) )
+        s_defaultBorderInPx.SetAtNewDPI(wxWindow::FromDIP(5, win));
+    return s_defaultBorderInPx.Get();
 }
 
 #endif // wxNEEDS_BORDER_IN_PX

src/common/wincmn.cpp

@@ -2921,7 +2921,7 @@ wxWindowBase::ToDIP(const wxSize& sz, const wxWindowBase* w)
 // using them.
 wxSize wxWindowBase::GetDlgUnitBase() const
 {
-    const wxWindowBase * const parent = wxGetTopLevelParent((wxWindow*)this);
+    const wxWindowBase* const parent = wxGetTopLevelParent((wxWindow*)this);
 
     wxCHECK_MSG( parent, wxDefaultSize, wxS("Must have TLW parent") );
 
@@ -2929,10 +2929,10 @@ wxSize wxWindowBase::GetDlgUnitBase() const
     {
         // Default GUI font is used. This is the most common case, so
         // cache the results.
-        static wxSize s_defFontSize;
+        static wxPrivate::DpiDependentValue<wxSize> s_defFontSize;
-        if ( s_defFontSize.x == 0 )
+        if ( s_defFontSize.HasChanged(parent) )
-            s_defFontSize = wxPrivate::GetAverageASCIILetterSize(*parent);
+            s_defFontSize.SetAtNewDPI(wxPrivate::GetAverageASCIILetterSize(*parent));
-        return s_defFontSize;
+        return s_defFontSize.Get();
     }
     else
     {

src/msw/button.cpp

@@ -162,12 +162,25 @@ WXDWORD wxButton::MSWGetStyle(long style, WXDWORD *exstyle) const
 /* static */
 wxSize wxButtonBase::GetDefaultSize()
 {
-    static wxSize s_sizeBtn;
+    wxWindow* win = wxTheApp ? wxTheApp->GetTopWindow() : NULL;
 
-    if ( s_sizeBtn.x == 0 )
+    static wxPrivate::DpiDependentValue<wxSize> s_sizeBtn;
+
+    if ( s_sizeBtn.HasChanged(win) )
     {
-        wxScreenDC dc;
+        wxSize base;
-        dc.SetFont(wxSystemSettings::GetFont(wxSYS_DEFAULT_GUI_FONT));
+        if ( win )
+        {
+            wxClientDC dc(win);
+            dc.SetFont(wxSystemSettings::GetFont(wxSYS_DEFAULT_GUI_FONT));
+            base = wxPrivate::GetAverageASCIILetterSize(dc);
+        }
+        else
+        {
+            wxScreenDC dc;
+            dc.SetFont(wxSystemSettings::GetFont(wxSYS_DEFAULT_GUI_FONT));
+            base = wxPrivate::GetAverageASCIILetterSize(dc);
+        }
 
         // The size of a standard button in the dialog units is 50x14,
         // translate this to pixels.
@@ -180,12 +193,11 @@ wxSize wxButtonBase::GetDefaultSize()
         //
         // NB: wxMulDivInt32() is used, because it correctly rounds the result
 
-        const wxSize base = wxPrivate::GetAverageASCIILetterSize(dc);
+        s_sizeBtn.SetAtNewDPI(wxSize(wxMulDivInt32(50, base.x, 4),
-        s_sizeBtn.x = wxMulDivInt32(50, base.x, 4);
+                                     wxMulDivInt32(14, base.y, 8)));
-        s_sizeBtn.y = wxMulDivInt32(14, base.y, 8);
     }
 
-    return s_sizeBtn;
+    return s_sizeBtn.Get();
 }
 
 // ----------------------------------------------------------------------------

src/msw/checkbox.cpp

@@ -28,15 +28,14 @@
 #include "wx/checkbox.h"
 
 #ifndef WX_PRECOMP
-    #include "wx/brush.h"
     #include "wx/dcclient.h"
-    #include "wx/dcscreen.h"
     #include "wx/settings.h"
 #endif
 
 #include "wx/renderer.h"
 #include "wx/msw/uxtheme.h"
 #include "wx/msw/private/button.h"
+#include "wx/private/window.h"
 #include "wx/msw/missing.h"
 
 // ============================================================================
@@ -98,16 +97,17 @@ WXDWORD wxCheckBox::MSWGetStyle(long style, WXDWORD *exstyle) const
 
 wxSize wxCheckBox::DoGetBestClientSize() const
 {
-    static int s_checkSize = 0;
+    static wxPrivate::DpiDependentValue<wxCoord> s_checkSize;
 
-    if ( !s_checkSize )
+    if ( s_checkSize.HasChanged(this) )
     {
-        wxScreenDC dc;
+        wxClientDC dc(const_cast<wxCheckBox*>(this));
         dc.SetFont(wxSystemSettings::GetFont(wxSYS_DEFAULT_GUI_FONT));
 
-        s_checkSize = dc.GetCharHeight();
+        s_checkSize.SetAtNewDPI(dc.GetCharHeight());
     }
 
+    wxCoord& checkSize = s_checkSize.Get();
     wxString str = wxGetWindowText(GetHWND());
 
     int wCheckbox, hCheckbox;
@@ -116,7 +116,7 @@ wxSize wxCheckBox::DoGetBestClientSize() const
         wxClientDC dc(const_cast<wxCheckBox *>(this));
         dc.SetFont(GetFont());
         dc.GetMultiLineTextExtent(GetLabelText(str), &wCheckbox, &hCheckbox);
-        wCheckbox += s_checkSize + GetCharWidth();
+        wCheckbox += checkSize + GetCharWidth();
 
         if ( ::GetWindowLong(GetHwnd(), GWL_STYLE) & BS_MULTILINE )
         {
@@ -128,16 +128,16 @@ wxSize wxCheckBox::DoGetBestClientSize() const
             // label appears on 3 lines, not 2, under Windows 2003 using
             // classic look and feel (although it works fine under Windows 7,
             // with or without themes).
-            wCheckbox += s_checkSize;
+            wCheckbox += checkSize;
         }
 
-        if ( hCheckbox < s_checkSize )
+        if ( hCheckbox < checkSize )
-            hCheckbox = s_checkSize;
+            hCheckbox = checkSize;
     }
     else
     {
-        wCheckbox = s_checkSize;
+        wCheckbox = checkSize;
-        hCheckbox = s_checkSize;
+        hCheckbox = checkSize;
     }
 
     return wxSize(wCheckbox, hCheckbox);

src/msw/cursor.cpp

@@ -63,9 +63,6 @@ public:
 
 private:
     bool m_destroyCursor;
-
-    // standard cursor size, computed on first use
-    static wxSize ms_sizeStd;
 };
 
 // ----------------------------------------------------------------------------
@@ -110,28 +107,17 @@ public:
 // wxCursorRefData
 // ----------------------------------------------------------------------------
 
-wxSize wxCursorRefData::ms_sizeStd;
 
 wxCoord wxCursorRefData::GetStandardWidth()
 {
-    if ( !ms_sizeStd.x )
+    const wxWindow* win = wxTheApp ? wxTheApp->GetTopWindow() : NULL;
-    {
+    return wxSystemSettings::GetMetric(wxSYS_CURSOR_X, win);
-        wxWindow* win = wxTheApp ? wxTheApp->GetTopWindow() : NULL;
-        ms_sizeStd.x = wxSystemSettings::GetMetric(wxSYS_CURSOR_X, win);
-    }
-
-    return ms_sizeStd.x;
 }
 
 wxCoord wxCursorRefData::GetStandardHeight()
 {
-    if ( !ms_sizeStd.y )
+    const wxWindow* win = wxTheApp ? wxTheApp->GetTopWindow() : NULL;
-    {
+    return wxSystemSettings::GetMetric(wxSYS_CURSOR_Y, win);
-        wxWindow* win = wxTheApp ? wxTheApp->GetTopWindow() : NULL;
-        ms_sizeStd.y = wxSystemSettings::GetMetric(wxSYS_CURSOR_Y, win);
-    }
-
-    return ms_sizeStd.y;
 }
 
 wxCursorRefData::wxCursorRefData(HCURSOR hcursor, bool destroy)

src/msw/radiobut.cpp

@@ -29,11 +29,11 @@
 
 #ifndef WX_PRECOMP
     #include "wx/settings.h"
-    #include "wx/dcscreen.h"
+    #include "wx/dcclient.h"
-    #include "wx/toplevel.h"
 #endif
 
 #include "wx/msw/private.h"
+#include "wx/private/window.h"
 #include "wx/renderer.h"
 #include "wx/msw/uxtheme.h"
 
@@ -238,31 +238,32 @@ bool wxRadioButton::MSWCommand(WXUINT param, WXWORD WXUNUSED(id))
 
 wxSize wxRadioButton::DoGetBestSize() const
 {
-    static int s_radioSize = 0;
+    static wxPrivate::DpiDependentValue<wxCoord> s_radioSize;
 
-    if ( !s_radioSize )
+    if ( s_radioSize.HasChanged(this) )
     {
-        wxScreenDC dc;
+        wxClientDC dc(const_cast<wxRadioButton*>(this));
         dc.SetFont(wxSystemSettings::GetFont(wxSYS_DEFAULT_GUI_FONT));
 
-        s_radioSize = dc.GetCharHeight();
+        s_radioSize.SetAtNewDPI(dc.GetCharHeight());
     }
 
+    wxCoord& radioSize = s_radioSize.Get();
     wxString str = GetLabel();
 
     int wRadio, hRadio;
     if ( !str.empty() )
     {
         GetTextExtent(GetLabelText(str), &wRadio, &hRadio);
-        wRadio += s_radioSize + GetCharWidth();
+        wRadio += radioSize + GetCharWidth();
 
-        if ( hRadio < s_radioSize )
+        if ( hRadio < radioSize )
-            hRadio = s_radioSize;
+            hRadio = radioSize;
     }
     else
     {
-        wRadio = s_radioSize;
+        wRadio = radioSize;
-        hRadio = s_radioSize;
+        hRadio = radioSize;
     }
 
     return wxSize(wRadio, hRadio);