Merge branch 'gc-get-text-extent'

Micro-optimization in wxGDIPlusContext::GetTextExtent() and minor
printing sample cleanup.

See https://github.com/wxWidgets/wxWidgets/pull/1220

samples/printing/printing.cpp

@@ -38,6 +38,7 @@
 
 #if wxUSE_GRAPHICS_CONTEXT
     #include "wx/graphics.h"
+    #include "wx/scopedptr.h"
 #endif
 
 #ifdef __WXMAC__
@@ -219,7 +220,7 @@ void MyApp::Draw(wxDC&dc)
         dc.DrawBitmap( m_bitmap, 10, 10 );
 
 #if wxUSE_GRAPHICS_CONTEXT
-    wxGraphicsContext *gc = wxGraphicsContext::CreateFromUnknownDC(dc);
+    wxScopedPtr<wxGraphicsContext> gc(wxGraphicsContext::CreateFromUnknownDC(dc));
 
     if (gc)
     {
@@ -243,12 +244,10 @@ void MyApp::Draw(wxDC&dc)
         gc->DrawText(text, 25.0, 60.0);
 
         // draw rectangle around the text
-        double w, h, d, el;
-        gc->GetTextExtent(text, &w, &h, &d, &el);
+        double w, h;
+        gc->GetTextExtent(text, &w, &h);
         gc->SetPen( *wxBLACK_PEN );
         gc->DrawRectangle(25.0, 60.0, w, h);
-
-        delete gc;
     }
 #endif
 

src/msw/graphics.cpp

@@ -2111,9 +2111,12 @@ void wxGDIPlusContext::GetTextExtent( const wxString &str, wxDouble *width, wxDo
     wxCHECK_RET( !m_font.IsNull(), wxT("wxGDIPlusContext::GetTextExtent - no valid font set") );
 
     wxWCharBuffer s = str.wc_str( *wxConvUI );
-    FontFamily ffamily ;
     Font* f = ((wxGDIPlusFontData*)m_font.GetRefData())->GetGDIPlusFont();
 
+    // Get the font metrics if we actually need them.
+    if ( descent || externalLeading || (height && str.empty()) )
+    {
+        FontFamily ffamily ;
         f->GetFamily(&ffamily) ;
 
         REAL factorY = m_fontScaleRatio;
@@ -2127,17 +2130,21 @@ void wxGDIPlusContext::GetTextExtent( const wxString &str, wxDouble *width, wxDo
         REAL rAscent = ffamily.GetCellAscent(style) * size / emHeight;
         REAL rHeight = ffamily.GetLineSpacing(style) * size / emHeight;
 
-    if ( height )
+        if ( height && str.empty() )
             *height = rHeight * factorY;
         if ( descent )
             *descent = rDescent * factorY;
         if ( externalLeading )
             *externalLeading = (rHeight - rAscent - rDescent) * factorY;
+    }
+
     // measuring empty strings is not guaranteed, so do it by hand
     if ( str.IsEmpty())
     {
         if ( width )
             *width = 0 ;
+
+        // Height already assigned above if necessary.
     }
     else
     {