Don't use LCD antialiasing if Fontconfig doesn't support hinting

core/fxge/ge/fx_ge_text.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include <limits>
 
 #include "core/fxcodec/include/fx_codec.h"
 #include "core/fxge/ge/fx_text_int.h"
@@ skipping 239 matching lines @@
   FX_BOOL bNormal = FALSE;
   if ((text_flags & FXTEXT_NOSMOOTH) == 0) {
     if (m_DeviceClass == FXDC_DISPLAY && m_bpp > 1) {
       FX_BOOL bClearType;
       if (!pFont->GetFace() &&
           !(pFont->GetSubstFont()->m_SubstFlags & FXFONT_SUBST_CLEARTYPE)) {
         bClearType = FALSE;
       } else {
         bClearType = text_flags & FXTEXT_CLEARTYPE;
       }
-      if ((m_RenderCaps & (FXRC_ALPHA_OUTPUT | FXRC_CMYK_OUTPUT))) {
+      if (!CFX_GEModule::Get()->GetFontMgr()->FTLibrarySupportsHinting()) {
+        // Some Freetype implementations (like the one packaged with Fedora) do
+        // not support hinting due to patents 6219025, 6239783, 6307566,
+        // 6225973, 6243070, 6393145, 6421054, 6282327, and 6624828; the latest
+        // one expires 10/7/19.  This makes LCD antialiasing very ugly, so we
+        // instead fall back on NORMAL antialiasing.
+        anti_alias = FXFT_RENDER_MODE_NORMAL;
+      } else if ((m_RenderCaps & (FXRC_ALPHA_OUTPUT | FXRC_CMYK_OUTPUT))) {
         anti_alias = FXFT_RENDER_MODE_LCD;
         bNormal = TRUE;
       } else if (m_bpp < 16) {
         anti_alias = FXFT_RENDER_MODE_NORMAL;
       } else {
         if (bClearType == FALSE) {
           anti_alias = FXFT_RENDER_MODE_LCD;
           bNormal = TRUE;
         } else {
           anti_alias = FXFT_RENDER_MODE_LCD;
@@ skipping 1636 matching lines @@
 void _CFX_UniqueKeyGen::Generate(int count, ...) {
   va_list argList;
   va_start(argList, count);
   for (int i = 0; i < count; i++) {
     int p = va_arg(argList, int);
     ((uint32_t*)m_Key)[i] = p;
   }
   va_end(argList);
   m_KeyLen = count * sizeof(uint32_t);
 }