Optimize selecting font in generated PostScript code

Emit code to select PostScript font only if it is needed (not at every call to SetFont(), but only if font has been really changed prior to a text drawing operation).

include/wx/generic/dcpsg.h

@@ -139,6 +139,8 @@ protected:
 
     // Common part of DoDrawText() and DoDrawRotatedText()
     void DrawAnyText(const wxWX2MBbuf& textbuf, wxCoord testDescent, double lineHeight);
+    // Actually set PostScript font
+    void SetPSFont();
 
     FILE*             m_pstream;    // PostScript output stream
     unsigned char     m_currentRed;
@@ -151,6 +153,7 @@ protected:
     wxPrintData       m_printData;
     double            m_pageHeight;
     wxArrayString     m_definedPSFonts;
+    bool              m_isFontChanged;
 
 private:
     wxDECLARE_DYNAMIC_CLASS(wxPostScriptDCImpl);

interface/wx/dcps.h

@@ -12,6 +12,13 @@
     can write PostScript files on any platform. See wxDC for descriptions of
     the member functions.
 
+    @section start_doc Starting a document
+
+    Document should be started with call to StartDoc() prior to calling any
+    function to execute a drawing operation.
+    However, some functions, like SetFont(), may be legitimately called even
+    before StartDoc().
+
     @library{wxbase}
     @category{dc}
 */

src/generic/dcpsg.cpp

@@ -323,6 +323,7 @@ void wxPostScriptDCImpl::Init()
     m_underlinePosition = 0.0;
     m_underlineThickness = 0.0;
 
+    m_isFontChanged = false;
 }
 
 wxPostScriptDCImpl::~wxPostScriptDCImpl ()
@@ -1038,13 +1039,27 @@ void wxPostScriptDCImpl::SetFont( const wxFont& font )
 
     if (!font.IsOk())  return;
 
+    // Note that we may legitimately call SetFont even before BeginDoc.
+    if ( font == m_font ) // No change
+        return;
+
     m_font = font;
+    m_isFontChanged = true;
+}
+
+// Actually set PostScript font.
+void wxPostScriptDCImpl::SetPSFont()
+{
+    wxASSERT_MSG( m_font.IsOk(), wxS("Font is not yet set") );
+
+    if ( !m_isFontChanged )
+        return;
 
     wxFontStyle Style = m_font.GetStyle();
     wxFontWeight Weight = m_font.GetWeight();
 
-    const char *name;
+    wxString name;
-    switch (m_font.GetFamily())
+    switch ( m_font.GetFamily() )
     {
         case wxTELETYPE:
         case wxMODERN:
@@ -1052,16 +1067,16 @@ void wxPostScriptDCImpl::SetFont( const wxFont& font )
             if (Style == wxFONTSTYLE_ITALIC)
             {
                 if (Weight == wxFONTWEIGHT_BOLD)
-                    name = "/Courier-BoldOblique";
+                    name = wxS("/Courier-BoldOblique");
                 else
-                    name = "/Courier-Oblique";
+                    name = wxS("/Courier-Oblique");
             }
             else
             {
                 if (Weight == wxFONTWEIGHT_BOLD)
-                    name = "/Courier-Bold";
+                    name = wxS("/Courier-Bold");
                 else
-                    name = "/Courier";
+                    name = wxS("/Courier");
             }
             break;
         }
@@ -1070,22 +1085,22 @@ void wxPostScriptDCImpl::SetFont( const wxFont& font )
             if (Style == wxFONTSTYLE_ITALIC)
             {
                 if (Weight == wxFONTWEIGHT_BOLD)
-                    name = "/Times-BoldItalic";
+                    name = wxS("/Times-BoldItalic");
                 else
-                    name = "/Times-Italic";
+                    name = wxS("/Times-Italic");
             }
             else
             {
                 if (Weight == wxFONTWEIGHT_BOLD)
-                    name = "/Times-Bold";
+                    name = wxS("/Times-Bold");
                 else
-                    name = "/Times-Roman";
+                    name = wxS("/Times-Roman");
             }
             break;
         }
         case wxSCRIPT:
         {
-            name = "/ZapfChancery-MediumItalic";
+            name = wxS("/ZapfChancery-MediumItalic");
             break;
         }
         case wxSWISS:
@@ -1094,42 +1109,37 @@ void wxPostScriptDCImpl::SetFont( const wxFont& font )
             if (Style == wxFONTSTYLE_ITALIC)
             {
                 if (Weight == wxFONTWEIGHT_BOLD)
-                    name = "/Helvetica-BoldOblique";
+                    name = wxS("/Helvetica-BoldOblique");
                 else
-                    name = "/Helvetica-Oblique";
+                    name = wxS("/Helvetica-Oblique");
             }
             else
             {
                 if (Weight == wxFONTWEIGHT_BOLD)
-                    name = "/Helvetica-Bold";
+                    name = wxS("/Helvetica-Bold");
                 else
-                    name = "/Helvetica";
+                    name = wxS("/Helvetica");
             }
             break;
         }
     }
 
-    // We may legitimately call SetFont before BeginDoc
+    wxString buffer;
-    if (!m_pstream)
-        return;
-
     // Generate PS code to register the font only once.
     if ( m_definedPSFonts.Index(name) == wxNOT_FOUND )
     {
-        PsPrint( name );
+        buffer.Printf( "%s reencodeISO def\n", name.c_str() );
-        PsPrint( " reencodeISO def\n" );
+        PsPrint( buffer );
         m_definedPSFonts.Add(name);
     }
-    PsPrint( name );
-    PsPrint( " findfont\n" );
 
-
+    // Select font
-    float size = float(m_font.GetPointSize());
+    float size = (float)m_font.GetPointSize() * GetFontPointSizeAdjustment(DPI);
-    size = size * GetFontPointSizeAdjustment(DPI);
+    buffer.Printf( "%s findfont %f scalefont setfont\n", name.c_str(), size * m_scaleX );
-    wxString buffer;
-    buffer.Printf( "%f scalefont setfont\n", size * m_scaleX );
     buffer.Replace( ",", "." );
     PsPrint( buffer );
+
+    m_isFontChanged = false;
 }
 
 void wxPostScriptDCImpl::SetPen( const wxPen& pen )
@@ -1425,7 +1435,7 @@ void wxPostScriptDCImpl::DoDrawText( const wxString& text, wxCoord x, wxCoord y
     if ( !textbuf )
         return;
 
-    SetFont( m_font );
+    SetPSFont();
 
     wxCoord text_descent;
     GetOwner()->GetTextExtent(text, NULL, NULL, &text_descent);
@@ -1463,7 +1473,7 @@ void wxPostScriptDCImpl::DoDrawRotatedText( const wxString& text, wxCoord x, wxC
     if ( !textbuf )
         return;
 
-    SetFont( m_font );
+    SetPSFont();
 
     // Calculate bottom-left coordinates of the rotated text
     wxCoord text_descent;
@@ -1626,11 +1636,13 @@ void wxPostScriptDCImpl::ComputeScaleAndOrigin()
     wxDCImpl::ComputeScaleAndOrigin();
 
     // If scale has changed call SetPen to recalculate the line width
-    // and SetFont to recalculate font size
+    // and request for recalculating the font size at nearest opportunity.
-    if ( wxRealPoint(m_scaleX, m_scaleY) != origScale && m_pen.IsOk() )
+    if ( wxRealPoint(m_scaleX, m_scaleY) != origScale )
     {
-        SetPen( m_pen );
+        if ( m_pen.IsOk() )
-        SetFont( m_font  );
+            SetPen( m_pen );
+
+        m_isFontChanged = true;
     }
 }