Allow suppressing warnings from wxImage::LoadFile()

Add wxImage::SetLoadFlags() and static SetDefaultLoadFlags() to allow
suppressing the warning messages that can be logged when loading some files,
notably PNG ones with invalid sRGB profiles which, unfortunately, seem to be
rather common and result in annoying warnings about them with libpng 1.6+.

Closes #15331.

src/common/image.cpp

@@ -87,6 +87,10 @@ public:
     // same as m_static but for m_alpha
     bool            m_staticAlpha;
 
+    // global and per-object flags determining LoadFile() behaviour
+    int             m_loadFlags;
+    static int      sm_defaultLoadFlags;
+
 #if wxUSE_PALETTE
     wxPalette       m_palette;
 #endif // wxUSE_PALETTE
@@ -97,6 +101,9 @@ public:
     wxDECLARE_NO_COPY_CLASS(wxImageRefData);
 };
 
+// For compatibility, if nothing else, loading is verbose by default.
+int wxImageRefData::sm_defaultLoadFlags = wxImage::Load_Verbose;
+
 wxImageRefData::wxImageRefData()
 {
     m_width = 0;
@@ -113,6 +120,8 @@ wxImageRefData::wxImageRefData()
     m_ok = false;
     m_static =
     m_staticAlpha = false;
+
+    m_loadFlags = sm_defaultLoadFlags;
 }
 
 wxImageRefData::~wxImageRefData()
@@ -2341,6 +2350,30 @@ bool wxImage::HasOption(const wxString& name) const
 // image I/O
 // ----------------------------------------------------------------------------
 
+/* static */
+void wxImage::SetDefaultLoadFlags(int flags)
+{
+    wxImageRefData::sm_defaultLoadFlags = flags;
+}
+
+/* static */
+int wxImage::GetDefaultLoadFlags()
+{
+    return wxImageRefData::sm_defaultLoadFlags;
+}
+
+void wxImage::SetLoadFlags(int flags)
+{
+    AllocExclusive();
+
+    M_IMGDATA->m_loadFlags = flags;
+}
+
+int wxImage::GetLoadFlags() const
+{
+    return M_IMGDATA ? M_IMGDATA->m_loadFlags : wxImageRefData::sm_defaultLoadFlags;
+}
+
 // Under Windows we can load wxImage not only from files but also from
 // resources.
 #if defined(__WINDOWS__) && wxUSE_WXDIB && wxUSE_IMAGE
@@ -2629,7 +2662,8 @@ bool wxImage::DoLoad(wxImageHandler& handler, wxInputStream& stream, int index)
     if ( stream.IsSeekable() )
         posOld = stream.TellI();
 
-    if ( !handler.LoadFile(this, stream, true/*verbose*/, index) )
+    if ( !handler.LoadFile(this, stream,
+                           (M_IMGDATA->m_loadFlags & Load_Verbose) != 0, index) )
     {
         if ( posOld != wxInvalidOffset )
             stream.SeekI(posOld);