Fix build failure with Poppler ≥ 0.31.

Author: jwilk

doc/changelog

@@ -1,8 +1,10 @@
 pdf2djvu (0.7.19) UNRELEASED; urgency=low
 
-  * 
+  * Fix build failure with Poppler ≥ 0.31.
+    Thanks to David Evans for the bug report.
+    https://code.google.com/p/pdf2djvu/issues/detail?id=99
 
- -- Jakub Wilk <[email protected]>  Fri, 06 Feb 2015 12:06:22 +0100
+ -- Jakub Wilk <[email protected]>  Fri, 06 Feb 2015 12:39:06 +0100
 
 pdf2djvu (0.7.18) unstable; urgency=low
 

pdf-backend.cc

@@ -126,10 +126,13 @@ pdf::Environment::Environment(const char *argv0)
 
 void pdf::Environment::set_antialias(bool value)
 {
+  this->antialias = value;
+#if POPPLER_VERSION < 3100
   if (!globalParams->setAntialias(const_cast<char*>(value ? "yes" : "no")))
     throw UnableToSetParameter(_("Unable to set antialias parameter"));
   if (!globalParams->setVectorAntialias(const_cast<char*>(value ? "yes" : "no")))
     throw UnableToSetParameter(_("Unable to set vector antialias parameter"));
+#endif
 }
 
 
@@ -454,6 +457,17 @@ void pdf::set_color(splash::Color &result, uint8_t r, uint8_t g, uint8_t b)
  * ===============================================
  */
 
+bool pdf::Environment::antialias = false;
+
+pdf::Renderer::Renderer(pdf::splash::Color &paper_color, bool monochrome)
+: pdf::splash::OutputDevice(monochrome ? splashModeMono1 : splashModeRGB8, 4, false, paper_color)
+{
+#if POPPLER_VERSION >= 3100
+      this->setFontAntialias(pdf::Environment::antialias);
+      this->setVectorAntialias(pdf::Environment::antialias);
+#endif
+}
+
 void pdf::Renderer::drawLink(pdf::link::Link *link, pdf::Catalog *catalog)
 {
   std::string border_color;

pdf-backend.hh

@@ -118,9 +118,7 @@ namespace pdf
   class Renderer : public pdf::splash::OutputDevice
   {
   public:
-    Renderer(pdf::splash::Color &paper_color, bool monochrome = false) :
-      pdf::splash::OutputDevice(monochrome ? splashModeMono1 : splashModeRGB8, 4, false, paper_color)
-    { }
+    Renderer(pdf::splash::Color &paper_color, bool monochrome = false);
 
 #if POPPLER_VERSION < 1900
     void processLink(pdf::link::Link *link, pdf::Catalog *catalog)
@@ -301,6 +299,7 @@ namespace pdf
   {
   public:
     Environment(const char *argv0);
+    static bool antialias;
     void set_antialias(bool value);
     class UnableToSetParameter : public std::runtime_error
     {