From 4d4e3e71a51c967970410f97d52a9b3b278fb219 Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Wed, 13 Nov 2019 19:12:34 +0100
Subject: [PATCH] Use helper function for applying scaled font to PangoLayout

Don't scale, or even copy, the font object unnecessarily in the common
case when the font scaling factor is 1.0 anyhow.

No real changes, just make the code slightly more efficient and also a
bit more concise after the changes of the previous commit.
---
 src/generic/graphicc.cpp | 49 ++++++++++++++++++++++++++++------------
 1 file changed, 34 insertions(+), 15 deletions(-)

diff --git a/src/generic/graphicc.cpp b/src/generic/graphicc.cpp
index 6f3480fbc7..363ef12356 100644
--- a/src/generic/graphicc.cpp
+++ b/src/generic/graphicc.cpp
@@ -527,7 +527,32 @@ protected:
     int m_mswStateSavedDC;
 #endif
 #ifdef __WXGTK__
+    // This factor must be applied to the font before actually using it, for
+    // consistency with the text drawn by GTK itself.
     float m_fontScalingFactor;
+
+    // Tiny helper actually applying the font. It's convenient because it can
+    // be called with a temporary wxFont, as we're going to make a copy of its
+    // Pango font description inside this function before the font object is
+    // destroyed.
+    static void DoApplyFont(PangoLayout* layout, const wxFont& font)
+    {
+        pango_layout_set_font_description
+        (
+            layout,
+            font.GetNativeFontInfo()->description
+        );
+    }
+
+    // Function applying the Pango font description for the given font scaled by
+    // the font scaling factor if necessary to the specified layout.
+    void ApplyFont(PangoLayout* layout, const wxFont& font) const
+    {
+        // Only scale the font if we really need to do it.
+        DoApplyFont(layout, m_fontScalingFactor == 1.0f
+                                ? font
+                                : font.Scaled(m_fontScalingFactor));
+    }
 #endif
 
 private:
@@ -2671,15 +2696,15 @@ void wxCairoContext::DoDrawText(const wxString& str, wxDouble x, wxDouble y)
     fontData->Apply(this);
 
 #ifdef __WXGTK__
-    wxFont font = fontData->GetFont();
+    const wxFont& font = fontData->GetFont();
     if ( font.IsOk() )
     {
-        // Apply GDK font scaling factor.
-        font.Scale(m_fontScalingFactor);
-
         wxGtkObject<PangoLayout> layout(pango_cairo_create_layout (m_context));
-        pango_layout_set_font_description(layout, font.GetNativeFontInfo()->description);
+        ApplyFont(layout, font);
         pango_layout_set_text(layout, data, data.length());
+
+        // Note that Pango attributes don't depend on font size, so we don't
+        // need to use the scaled font here.
         font.GTKSetPangoAttrs(layout);
 
         cairo_move_to(m_context, x, y);
@@ -2724,7 +2749,7 @@ void wxCairoContext::GetTextExtent( const wxString &str, wxDouble *width, wxDoub
 
 #ifdef __WXGTK__
     // Use Pango instead of Cairo toy font API if we have the font.
-    wxFont font = fontData->GetFont();
+    const wxFont& font = fontData->GetFont();
     if ( font.IsOk() )
     {
         // Note that there is no need to call Apply() at all in this case, it
@@ -2732,11 +2757,8 @@ void wxCairoContext::GetTextExtent( const wxString &str, wxDouble *width, wxDoub
         // measuring its extent.
         int w, h;
 
-        // Apply GDK font scaling factor.
-        font.Scale(m_fontScalingFactor);
-
         wxGtkObject<PangoLayout> layout(pango_cairo_create_layout (m_context));
-        pango_layout_set_font_description(layout, font.GetNativeFontInfo()->description);
+        ApplyFont(layout, font);
         const wxCharBuffer data = str.utf8_str();
         if ( !data )
         {
@@ -2804,12 +2826,9 @@ void wxCairoContext::GetPartialTextExtents(const wxString& text, wxArrayDouble&
     if (data.length())
     {
         wxGtkObject<PangoLayout> layout(pango_cairo_create_layout(m_context));
-        wxFont font = static_cast<wxCairoFontData*>(m_font.GetRefData())->GetFont();
+        const wxFont& font = static_cast<wxCairoFontData*>(m_font.GetRefData())->GetFont();
 
-        // Apply GDK font scaling factor.
-        font.Scale(m_fontScalingFactor);
-
-        pango_layout_set_font_description(layout, font.GetNativeFontInfo()->description);
+        ApplyFont(layout, font);
         pango_layout_set_text(layout, data, data.length());
         PangoLayoutIter* iter = pango_layout_get_iter(layout);
         PangoRectangle rect;