Fix setting frame icon when using non-standard icon sizes in wxMSW.

Set the closest (and larger, if possible) icon if the icon of exactly the
system icon size is not available. This fixes setting the icons when using
custom DPI settings under MSW as the standard icon size may be different from
the standard 32*32 in this case.

This also improves wxIconBundle::GetIcon() to make its behaviour when the icon
with exactly the given size is not found more flexible as a side effect.

Closes #13891.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70455 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/iconbndl.cpp

@@ -193,49 +193,91 @@ void wxIconBundle::AddIcon(wxInputStream& stream, wxBitmapType type)
 
 #endif // wxUSE_STREAMS && wxUSE_IMAGE
 
-wxIcon wxIconBundle::GetIcon(const wxSize& size) const
+wxIcon wxIconBundle::GetIcon(const wxSize& size, int flags) const
 {
+    wxASSERT( size == wxDefaultSize || (size.x >= 0 && size.y > 0) );
+
+    // We need the standard system icon size when using FALLBACK_SYSTEM.
+    wxCoord sysX = 0,
+            sysY = 0;
+    if ( flags & FALLBACK_SYSTEM )
+    {
+        sysX = wxSystemSettings::GetMetric(wxSYS_ICON_X);
+        sysY = wxSystemSettings::GetMetric(wxSYS_ICON_Y);
+    }
+
+    // If size == wxDefaultSize, we use system default icon size by convention.
+    wxCoord sizeX = size.x;
+    wxCoord sizeY = size.y;
+    if ( size == wxDefaultSize )
+    {
+        wxASSERT_MSG( flags == FALLBACK_SYSTEM,
+                      wxS("Must have valid size if not using FALLBACK_SYSTEM") );
+
+        sizeX = sysX;
+        sizeY = sysY;
+    }
+
+    // Iterate over all icons searching for the exact match or the closest icon
+    // for FALLBACK_NEAREST_LARGER.
+    wxIcon iconBest;
+    int bestDiff = 0;
+    bool bestIsLarger = false;
+    bool bestIsSystem = false;
+
     const size_t count = GetIconCount();
 
-    // optimize for the common case of icon bundles containing one icon only
-    wxIcon iconBest;
-    switch ( count )
+    const wxIconArray& iconArray = M_ICONBUNDLEDATA->m_icons;
+    for ( size_t i = 0; i < count; i++ )
     {
-        case 0:
-            // nothing to do, iconBest is already invalid
+        const wxIcon& icon = iconArray[i];
+        if ( !icon.IsOk() )
+            continue;
+        wxCoord sx = icon.GetWidth(),
+                sy = icon.GetHeight();
+
+        // Exact match ends search immediately in any case.
+        if ( sx == sizeX && sy == sizeY )
+        {
+            iconBest = icon;
             break;
+        }
 
-        case 1:
-            iconBest = M_ICONBUNDLEDATA->m_icons[0];
-            break;
-
-        default:
-            // there is more than one icon, find the best match:
-            wxCoord sysX = wxSystemSettings::GetMetric( wxSYS_ICON_X ),
-                    sysY = wxSystemSettings::GetMetric( wxSYS_ICON_Y );
-
-            const wxIconArray& iconArray = M_ICONBUNDLEDATA->m_icons;
-            for ( size_t i = 0; i < count; i++ )
+        if ( flags & FALLBACK_SYSTEM )
+        {
+            if ( sx == sysX && sy == sysY )
             {
-                const wxIcon& icon = iconArray[i];
-                wxCoord sx = icon.GetWidth(),
-                        sy = icon.GetHeight();
-
-                // if we got an icon of exactly the requested size, we're done
-                if ( sx == size.x && sy == size.y )
-                {
-                    iconBest = icon;
-                    break;
-                }
-
-                // the best icon is by default (arbitrarily) the first one but
-                // if we find a system-sized icon, take it instead
-                if ((sx == sysX && sy == sysY) || !iconBest.IsOk())
-                    iconBest = icon;
+                iconBest = icon;
+                bestIsSystem = true;
+                continue;
             }
+        }
+
+        if ( !bestIsSystem && (flags & FALLBACK_NEAREST_LARGER) )
+        {
+            bool iconLarger = (sx >= sizeX) && (sy >= sizeY);
+            int iconDiff = abs(sx - sizeX) + abs(sy - sizeY);
+
+            // Use current icon as candidate for the best icon, if either:
+            // - we have no candidate yet
+            // - we have no candidate larger than desired size and current icon is
+            // - current icon is closer to desired size than candidate
+            if ( !iconBest.IsOk() ||
+                    (!bestIsLarger && iconLarger) ||
+                        (iconLarger && (iconDiff < bestDiff)) )
+            {
+                iconBest = icon;
+                bestIsLarger = iconLarger;
+                bestDiff = iconDiff;
+                continue;
+            }
+        }
     }
 
 #if defined( __WXMAC__ ) && wxOSX_USE_CARBON
+    if (!iconBest.IsOk())
+        return wxNullIcon;
+
     return wxIcon(iconBest.GetHICON(), size);
 #else
     return iconBest;
@@ -244,14 +286,7 @@ wxIcon wxIconBundle::GetIcon(const wxSize& size) const
 
 wxIcon wxIconBundle::GetIconOfExactSize(const wxSize& size) const
 {
-    wxIcon icon = GetIcon(size);
-    if ( icon.IsOk() &&
-            (icon.GetWidth() != size.x || icon.GetHeight() != size.y) )
-    {
-        icon = wxNullIcon;
-    }
-
-    return icon;
+    return GetIcon(size, FALLBACK_NONE);
 }
 
 void wxIconBundle::AddIcon(const wxIcon& icon)