Detect XRender support

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@10622 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

FL/x.H

@@ -161,6 +161,7 @@ public:
   static void x(Fl_Window* wi, int X) {wi->x(X);}
   static void y(Fl_Window* wi, int Y) {wi->y(Y);}
   static int ewmh_supported();
+  static int xrender_supported();
   static void activate_window(Window w);
 };
 

configh.in

@@ -123,6 +123,14 @@
 
 #define HAVE_XCURSOR 0
 
+/*
+ * HAVE_XRENDER:
+ *
+ * Do we have the X render library?
+ */
+
+#define HAVE_XRENDER 0
+
 /*
  * __APPLE_QUARTZ__:
  *

configure.in

@@ -1018,6 +1018,16 @@ case $host_os_gui in
 		LIBS="-lXcursor $LIBS")
 	fi
 
+	dnl Check for the Xrender library unless disabled...
+        AC_ARG_ENABLE(xrender, [  --enable-xrender        turn on Xrender support [[default=yes]]])
+
+	if test x$enable_xrender != xno; then
+	    AC_CHECK_HEADER(X11/extensions/Xrender.h, AC_DEFINE(HAVE_XRENDER),,
+	        [#include <X11/Xlib.h>])
+	    AC_CHECK_LIB(Xrender, XRenderQueryVersion,
+		LIBS="-lXrender $LIBS")
+	fi
+
 	dnl Check for overlay visuals...
 	AC_PATH_PROG(XPROP, xprop)
 	AC_CACHE_CHECK(for X overlay visuals, ac_cv_have_overlay,

src/Fl_x.cxx

@@ -69,6 +69,9 @@ static bool have_xfixes = false;
 #  if HAVE_XCURSOR
 #    include <X11/Xcursor/Xcursor.h>
 #  endif
+#  if HAVE_XRENDER
+#    include <X11/extensions/Xrender.h>
+#  endif
 static Fl_Xlib_Graphics_Driver fl_xlib_driver;
 static Fl_Display_Device fl_xlib_display(&fl_xlib_driver);
 Fl_Display_Device *Fl_Display_Device::_display = &fl_xlib_display;// the platform display
@@ -2230,6 +2233,19 @@ int Fl_X::ewmh_supported() {
   return result;
 }
 
+int Fl_X::xrender_supported() {
+  static int result = -1;
+
+  if (result == -1) {
+    fl_open_display();
+
+    int nop1, nop2;
+    result = XRenderQueryExtension(fl_display, &nop1, &nop2);
+  }
+
+  return result;
+}
+
 extern Fl_Window *fl_xfocus;
 
 void Fl_X::activate_window(Window w) {