boilerplate: Add a describe vfunc

This function is supposed to describe the backend in use. The describe
function is optional - and therefore initialized as NULL everywhere.
Note:
It is well known that the xlib backend uses X. What is not known is what
version the server supports or what graphics card it is running on. That
is the information the describe vfunc is supposed to provide.

20 files changed, 71 insertions, 34 deletions

diff --git a/boilerplate/Makefile.win32.features b/boilerplate/Makefile.win32.features
index fd0e9c735..d79fe2f26 100644
--- a/boilerplate/Makefile.win32.features
+++ b/boilerplate/Makefile.win32.features
@@ -209,6 +209,14 @@ enabled_cairo_boilerplate_private += $(cairo_boilerplate_png_private)
 enabled_cairo_boilerplate_sources += $(cairo_boilerplate_png_sources)
 endif
 
+supported_cairo_boilerplate_headers += $(cairo_boilerplate_glew_headers)
+all_cairo_boilerplate_headers += $(cairo_boilerplate_glew_headers)
+all_cairo_boilerplate_private += $(cairo_boilerplate_glew_private)
+all_cairo_boilerplate_sources += $(cairo_boilerplate_glew_sources)
+enabled_cairo_boilerplate_headers += $(cairo_boilerplate_glew_headers)
+enabled_cairo_boilerplate_private += $(cairo_boilerplate_glew_private)
+enabled_cairo_boilerplate_sources += $(cairo_boilerplate_glew_sources)
+
 unsupported_cairo_boilerplate_headers += $(cairo_boilerplate_gl_headers)
 all_cairo_boilerplate_headers += $(cairo_boilerplate_gl_headers)
 all_cairo_boilerplate_private += $(cairo_boilerplate_gl_private)
diff --git a/boilerplate/cairo-boilerplate-directfb.c b/boilerplate/cairo-boilerplate-directfb.c
index 39252aca9..6b657f1d7 100644
--- a/boilerplate/cairo-boilerplate-directfb.c
+++ b/boilerplate/cairo-boilerplate-directfb.c
@@ -217,7 +217,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	_cairo_boilerplate_get_image_surface,
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_directfb_cleanup,
-	NULL, TRUE, FALSE, FALSE
+	NULL, NULL, TRUE, FALSE, FALSE
     },
     {
 	"directfb-bitmap", "directfb", NULL, NULL,
@@ -228,7 +228,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	_cairo_boilerplate_get_image_surface,
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_directfb_cleanup,
-	NULL, FALSE, FALSE, FALSE
+	NULL, NULL, FALSE, FALSE, FALSE
     },
 };
 CAIRO_BOILERPLATE (directfb, targets);
diff --git a/boilerplate/cairo-boilerplate-drm.c b/boilerplate/cairo-boilerplate-drm.c
index 5d5d17f77..40c7049d8 100644
--- a/boilerplate/cairo-boilerplate-drm.c
+++ b/boilerplate/cairo-boilerplate-drm.c
@@ -85,6 +85,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	NULL,
 	_cairo_boilerplate_drm_synchronize,
+        NULL,
 	TRUE, FALSE, FALSE
     },
     {
@@ -97,6 +98,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	NULL,
 	_cairo_boilerplate_drm_synchronize,
+        NULL,
 	FALSE, FALSE, FALSE
     },
 };
diff --git a/boilerplate/cairo-boilerplate-egl.c b/boilerplate/cairo-boilerplate-egl.c
index 0bf285598..75439a9b3 100644
--- a/boilerplate/cairo-boilerplate-egl.c
+++ b/boilerplate/cairo-boilerplate-egl.c
@@ -139,6 +139,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_egl_cleanup,
 	_cairo_boilerplate_egl_synchronize,
+        NULL,
 	TRUE, FALSE, FALSE
     }
 };
diff --git a/boilerplate/cairo-boilerplate-glx.c b/boilerplate/cairo-boilerplate-glx.c
index a3e0338db..3fe7149ea 100644
--- a/boilerplate/cairo-boilerplate-glx.c
+++ b/boilerplate/cairo-boilerplate-glx.c
@@ -357,6 +357,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_gl_cleanup,
 	_cairo_boilerplate_gl_synchronize,
+        NULL,
 	TRUE, FALSE, FALSE
     },
     {
@@ -369,6 +370,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_gl_cleanup,
 	_cairo_boilerplate_gl_synchronize,
+        NULL,
 	FALSE, FALSE, FALSE
     },
     {
@@ -382,6 +384,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_gl_cleanup,
 	_cairo_boilerplate_gl_synchronize,
+        NULL,
 	FALSE, FALSE, FALSE
     },
     {
@@ -395,6 +398,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_gl_cleanup,
 	_cairo_boilerplate_gl_synchronize,
+        NULL,
 	FALSE, FALSE, FALSE
     },
 };
diff --git a/boilerplate/cairo-boilerplate-pdf.c b/boilerplate/cairo-boilerplate-pdf.c
index 9d83b937b..6f4afe977 100644
--- a/boilerplate/cairo-boilerplate-pdf.c
+++ b/boilerplate/cairo-boilerplate-pdf.c
@@ -249,7 +249,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	_cairo_boilerplate_pdf_get_image_surface,
 	_cairo_boilerplate_pdf_surface_write_to_png,
 	_cairo_boilerplate_pdf_cleanup,
-	NULL, FALSE, TRUE, TRUE
+	NULL, NULL, FALSE, TRUE, TRUE
     },
     {
 	"pdf", "pdf", ".pdf", NULL,
@@ -261,7 +261,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	_cairo_boilerplate_pdf_get_image_surface,
 	_cairo_boilerplate_pdf_surface_write_to_png,
 	_cairo_boilerplate_pdf_cleanup,
-	NULL, FALSE, TRUE, TRUE
+	NULL, NULL, FALSE, TRUE, TRUE
     },
 #endif
 };
diff --git a/boilerplate/cairo-boilerplate-ps.c b/boilerplate/cairo-boilerplate-ps.c
index de5a6eaba..09dce6e1d 100644
--- a/boilerplate/cairo-boilerplate-ps.c
+++ b/boilerplate/cairo-boilerplate-ps.c
@@ -310,7 +310,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	_cairo_boilerplate_ps_get_image_surface,
 	_cairo_boilerplate_ps_surface_write_to_png,
 	_cairo_boilerplate_ps_cleanup,
-	NULL, FALSE, TRUE, TRUE
+	NULL, NULL, FALSE, TRUE, TRUE
     },
     {
 	"ps2", "ps", ".ps", NULL,
@@ -322,7 +322,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	_cairo_boilerplate_ps_get_image_surface,
 	_cairo_boilerplate_ps_surface_write_to_png,
 	_cairo_boilerplate_ps_cleanup,
-	NULL, FALSE, TRUE, TRUE
+	NULL, NULL, FALSE, TRUE, TRUE
     },
     {
 	"ps3", "ps", ".ps", NULL,
@@ -335,7 +335,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	_cairo_boilerplate_ps_get_image_surface,
 	_cairo_boilerplate_ps_surface_write_to_png,
 	_cairo_boilerplate_ps_cleanup,
-	NULL, FALSE, TRUE, TRUE
+	NULL, NULL, FALSE, TRUE, TRUE
     },
     {
 	"ps3", "ps", ".ps", NULL,
@@ -347,7 +347,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	_cairo_boilerplate_ps_get_image_surface,
 	_cairo_boilerplate_ps_surface_write_to_png,
 	_cairo_boilerplate_ps_cleanup,
-	NULL, FALSE, TRUE, TRUE
+	NULL, NULL, FALSE, TRUE, TRUE
     },
 #endif
 };
diff --git a/boilerplate/cairo-boilerplate-quartz.c b/boilerplate/cairo-boilerplate-quartz.c
index 19d5928d0..67bd5bbb7 100644
--- a/boilerplate/cairo-boilerplate-quartz.c
+++ b/boilerplate/cairo-boilerplate-quartz.c
@@ -57,7 +57,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	NULL, NULL,
 	_cairo_boilerplate_get_image_surface,
 	cairo_surface_write_to_png,
-	NULL, NULL,
+	NULL, NULL, NULL,
 	TRUE, FALSE, FALSE
     },
     {
@@ -68,7 +68,8 @@ static const cairo_boilerplate_target_t targets[] = {
 	NULL, NULL,
 	_cairo_boilerplate_get_image_surface,
 	cairo_surface_write_to_png,
-	NULL, NULL, FALSE, FALSE, FALSE
+	NULL, NULL, NULL,
+        FALSE, FALSE, FALSE
     },
 };
 CAIRO_BOILERPLATE (quartz, targets)
diff --git a/boilerplate/cairo-boilerplate-script.c b/boilerplate/cairo-boilerplate-script.c
index 535ca5407..f84594d36 100644
--- a/boilerplate/cairo-boilerplate-script.c
+++ b/boilerplate/cairo-boilerplate-script.c
@@ -136,6 +136,6 @@ static const cairo_boilerplate_target_t target[] = {{
     _cairo_boilerplate_script_get_image_surface,
     _cairo_boilerplate_script_surface_write_to_png,
     _cairo_boilerplate_script_cleanup,
-    NULL, FALSE, FALSE, FALSE
+    NULL, NULL, FALSE, FALSE, FALSE
 }};
 CAIRO_BOILERPLATE (script, target)
diff --git a/boilerplate/cairo-boilerplate-skia.c b/boilerplate/cairo-boilerplate-skia.c
index 34c19f15a..eb3d44062 100644
--- a/boilerplate/cairo-boilerplate-skia.c
+++ b/boilerplate/cairo-boilerplate-skia.c
@@ -38,7 +38,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	NULL, NULL,
 	_cairo_boilerplate_get_image_surface,
 	cairo_surface_write_to_png,
-	NULL, NULL, TRUE, FALSE, FALSE
+	NULL, NULL, NULL, TRUE, FALSE, FALSE
     },
     {
 	"skia", "skia", NULL, NULL,
@@ -48,7 +48,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	NULL, NULL,
 	_cairo_boilerplate_get_image_surface,
 	cairo_surface_write_to_png,
-	NULL, NULL, FALSE, FALSE, FALSE
+	NULL, NULL, NULL, FALSE, FALSE, FALSE
     },
 };
 CAIRO_BOILERPLATE (skia, targets)
diff --git a/boilerplate/cairo-boilerplate-svg.c b/boilerplate/cairo-boilerplate-svg.c
index a7d6c797d..a0bbba6f6 100644
--- a/boilerplate/cairo-boilerplate-svg.c
+++ b/boilerplate/cairo-boilerplate-svg.c
@@ -286,7 +286,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	_cairo_boilerplate_svg_get_image_surface,
 	_cairo_boilerplate_svg_surface_write_to_png,
 	_cairo_boilerplate_svg_cleanup,
-	NULL, FALSE, TRUE, TRUE
+	NULL, NULL, FALSE, TRUE, TRUE
     },
     {
 	"svg11", "svg", NULL, NULL,
@@ -298,7 +298,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	_cairo_boilerplate_svg_get_image_surface,
 	_cairo_boilerplate_svg_surface_write_to_png,
 	_cairo_boilerplate_svg_cleanup,
-	NULL, FALSE, TRUE, TRUE
+	NULL, NULL, FALSE, TRUE, TRUE
     },
     {
 	"svg12", "svg", NULL, NULL,
@@ -310,7 +310,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	_cairo_boilerplate_svg_get_image_surface,
 	_cairo_boilerplate_svg_surface_write_to_png,
 	_cairo_boilerplate_svg_cleanup,
-	NULL, FALSE, TRUE, TRUE
+	NULL, NULL, FALSE, TRUE, TRUE
     },
     {
 	"svg12", "svg", NULL, NULL,
@@ -322,7 +322,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	_cairo_boilerplate_svg_get_image_surface,
 	_cairo_boilerplate_svg_surface_write_to_png,
 	_cairo_boilerplate_svg_cleanup,
-	NULL, FALSE, TRUE, TRUE
+	NULL, NULL, FALSE, TRUE, TRUE
     },
 #endif
 };
diff --git a/boilerplate/cairo-boilerplate-test-surfaces.c b/boilerplate/cairo-boilerplate-test-surfaces.c
index d3572ec58..993e211d2 100644
--- a/boilerplate/cairo-boilerplate-test-surfaces.c
+++ b/boilerplate/cairo-boilerplate-test-surfaces.c
@@ -238,7 +238,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	NULL, NULL,
 	_cairo_boilerplate_get_image_surface,
 	cairo_surface_write_to_png,
-	NULL, NULL, FALSE, FALSE, FALSE
+	NULL, NULL, NULL, FALSE, FALSE, FALSE
     },
     {
 	"test-fallback", "image", NULL, NULL,
@@ -249,7 +249,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	NULL, NULL,
 	_cairo_boilerplate_get_image_surface,
 	cairo_surface_write_to_png,
-	NULL, NULL, FALSE, FALSE, FALSE
+	NULL, NULL, NULL, FALSE, FALSE, FALSE
     },
     {
 	"test-fallback16", "image", NULL, NULL,
@@ -260,7 +260,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	NULL, NULL,
 	NULL, /* _cairo_boilerplate_get_image_surface, */
 	cairo_surface_write_to_png,
-	NULL, NULL, FALSE, FALSE, FALSE
+	NULL, NULL, NULL, FALSE, FALSE, FALSE
     },
     {
 	"test-fallback16", "image", NULL, NULL,
@@ -271,7 +271,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	NULL, NULL,
 	NULL, /* _cairo_boilerplate_get_image_surface, */
 	cairo_surface_write_to_png,
-	NULL, NULL, FALSE, FALSE, FALSE
+	NULL, NULL, NULL, FALSE, FALSE, FALSE
     },
 #if CAIRO_HAS_TEST_PAGINATED_SURFACE
     {
@@ -284,7 +284,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	_cairo_boilerplate_test_paginated_get_image_surface,
 	_cairo_boilerplate_test_paginated_surface_write_to_png,
 	_cairo_boilerplate_test_paginated_cleanup,
-	NULL, FALSE, TRUE, FALSE
+	NULL, NULL, FALSE, TRUE, FALSE
     },
     {
 	"test-paginated", "image", NULL, NULL,
@@ -296,7 +296,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	_cairo_boilerplate_test_paginated_get_image_surface,
 	_cairo_boilerplate_test_paginated_surface_write_to_png,
 	_cairo_boilerplate_test_paginated_cleanup,
-	NULL, FALSE, TRUE, FALSE
+	NULL, NULL, FALSE, TRUE, FALSE
     },
 #endif
 #if CAIRO_HAS_TEST_WRAPPING_SURFACE
@@ -309,7 +309,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	NULL, NULL,
 	_cairo_boilerplate_get_image_surface,
 	cairo_surface_write_to_png,
-	NULL, NULL, FALSE, FALSE, FALSE
+	NULL, NULL, NULL, FALSE, FALSE, FALSE
     },
 #endif
 #if CAIRO_HAS_TEST_NULL_SURFACE
@@ -321,7 +321,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	_cairo_boilerplate_test_null_create_surface,
 	NULL, NULL,
 	NULL, NULL, NULL,
-	NULL,
+	NULL, NULL,
 	TRUE, TRUE, FALSE
     },
 #endif
diff --git a/boilerplate/cairo-boilerplate-vg.c b/boilerplate/cairo-boilerplate-vg.c
index 9803dcc15..d5a137298 100644
--- a/boilerplate/cairo-boilerplate-vg.c
+++ b/boilerplate/cairo-boilerplate-vg.c
@@ -312,6 +312,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_vg_cleanup_glx,
 	_cairo_boilerplate_vg_synchronize,
+        NULL,
 	TRUE, FALSE, FALSE
     },
     {
@@ -324,6 +325,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_vg_cleanup_glx,
 	_cairo_boilerplate_vg_synchronize,
+        NULL,
 	FALSE, FALSE, FALSE
     },
 #endif
@@ -338,6 +340,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_vg_cleanup_egl,
 	_cairo_boilerplate_vg_synchronize,
+        NULL,
 	TRUE, FALSE, FALSE
     },
     {
@@ -350,6 +353,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_vg_cleanup_egl,
 	_cairo_boilerplate_vg_synchronize,
+        NULL,
 	FALSE, FALSE, FALSE
     },
 #endif
diff --git a/boilerplate/cairo-boilerplate-wgl.c b/boilerplate/cairo-boilerplate-wgl.c
index 35e317eb7..2215659ff 100644
--- a/boilerplate/cairo-boilerplate-wgl.c
+++ b/boilerplate/cairo-boilerplate-wgl.c
@@ -218,6 +218,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_wgl_cleanup,
 	_cairo_boilerplate_wgl_synchronize,
+        NULL,
 	TRUE, FALSE, FALSE
     },
     {
@@ -231,6 +232,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_wgl_cleanup,
 	_cairo_boilerplate_wgl_synchronize,
+        NULL,
 	FALSE, FALSE, FALSE
     },
 };
diff --git a/boilerplate/cairo-boilerplate-win32-printing.c b/boilerplate/cairo-boilerplate-win32-printing.c
index e1509951b..0d7062045 100644
--- a/boilerplate/cairo-boilerplate-win32-printing.c
+++ b/boilerplate/cairo-boilerplate-win32-printing.c
@@ -354,7 +354,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	_cairo_boilerplate_win32_printing_get_image_surface,
 	_cairo_boilerplate_win32_printing_surface_write_to_png,
 	_cairo_boilerplate_win32_printing_cleanup,
-	NULL, FALSE, TRUE, TRUE
+	NULL, NULL, FALSE, TRUE, TRUE
     },
     {
 	"win32-printing", "win32", ".ps", NULL,
@@ -365,7 +365,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	_cairo_boilerplate_win32_printing_get_image_surface,
 	_cairo_boilerplate_win32_printing_surface_write_to_png,
 	_cairo_boilerplate_win32_printing_cleanup,
-	NULL, FALSE, TRUE, TRUE
+	NULL, NULL, FALSE, TRUE, TRUE
     },
 #endif
 };
diff --git a/boilerplate/cairo-boilerplate-win32.c b/boilerplate/cairo-boilerplate-win32.c
index 72176c872..5194befc2 100644
--- a/boilerplate/cairo-boilerplate-win32.c
+++ b/boilerplate/cairo-boilerplate-win32.c
@@ -57,7 +57,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	NULL, NULL,
 	_cairo_boilerplate_get_image_surface,
 	cairo_surface_write_to_png,
-	NULL, NULL, TRUE, FALSE, FALSE
+	NULL, NULL, NULL, TRUE, FALSE, FALSE
     },
     /* Testing the win32 surface isn't interesting, since for
      * ARGB images it just chains to the image backend
@@ -70,7 +70,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	NULL, NULL,
 	_cairo_boilerplate_get_image_surface,
 	cairo_surface_write_to_png,
-	NULL, NULL, FALSE, FALSE, FALSE
+	NULL, NULL, NULL, FALSE, FALSE, FALSE
     },
 };
 CAIRO_BOILERPLATE (win32, targets)
diff --git a/boilerplate/cairo-boilerplate-xcb.c b/boilerplate/cairo-boilerplate-xcb.c
index b16b19984..0cac82b18 100644
--- a/boilerplate/cairo-boilerplate-xcb.c
+++ b/boilerplate/cairo-boilerplate-xcb.c
@@ -623,6 +623,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_xcb_cleanup,
 	_cairo_boilerplate_xcb_synchronize,
+        NULL,
 	TRUE, FALSE, FALSE
     },
     {
@@ -636,6 +637,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_xcb_cleanup,
 	_cairo_boilerplate_xcb_synchronize,
+        NULL,
 	FALSE, FALSE, FALSE
     },
     {
@@ -649,6 +651,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_xcb_cleanup,
 	_cairo_boilerplate_xcb_synchronize,
+        NULL,
 	FALSE, FALSE, FALSE
     },
     {
@@ -662,6 +665,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_xcb_cleanup,
 	_cairo_boilerplate_xcb_synchronize,
+        NULL,
 	FALSE, FALSE, FALSE
     },
     {
@@ -675,6 +679,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_xcb_cleanup,
 	_cairo_boilerplate_xcb_synchronize,
+        NULL,
 	FALSE, FALSE, FALSE
     },
     {
@@ -688,6 +693,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_xcb_cleanup,
 	_cairo_boilerplate_xcb_synchronize,
+        NULL,
 	FALSE, FALSE, FALSE
     },
     {
@@ -701,6 +707,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_xcb_cleanup,
 	_cairo_boilerplate_xcb_synchronize,
+        NULL,
 	FALSE, FALSE, FALSE
     },
 };
diff --git a/boilerplate/cairo-boilerplate-xlib.c b/boilerplate/cairo-boilerplate-xlib.c
index 906b5548b..db42d67f1 100644
--- a/boilerplate/cairo-boilerplate-xlib.c
+++ b/boilerplate/cairo-boilerplate-xlib.c
@@ -495,6 +495,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_xlib_cleanup,
 	_cairo_boilerplate_xlib_synchronize,
+        NULL,
 	TRUE, FALSE, FALSE
     },
     {
@@ -507,6 +508,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_xlib_cleanup,
 	_cairo_boilerplate_xlib_synchronize,
+        NULL,
 	FALSE, FALSE, FALSE
     },
     {
@@ -519,6 +521,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_xlib_cleanup,
 	_cairo_boilerplate_xlib_synchronize,
+        NULL,
 	FALSE, FALSE, FALSE
     },
 #endif
@@ -535,6 +538,7 @@ static const cairo_boilerplate_target_t targets[] = {
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_xlib_cleanup,
 	_cairo_boilerplate_xlib_synchronize,
+        NULL,
 	FALSE, FALSE, FALSE
     },
 #endif
diff --git a/boilerplate/cairo-boilerplate.c b/boilerplate/cairo-boilerplate.c
index 7bbc1e6ed..529a4f21c 100644
--- a/boilerplate/cairo-boilerplate.c
+++ b/boilerplate/cairo-boilerplate.c
@@ -326,7 +326,7 @@ static const cairo_boilerplate_target_t builtin_targets[] = {
 	NULL, NULL,
 	_cairo_boilerplate_get_image_surface,
 	cairo_surface_write_to_png,
-	NULL, NULL,
+	NULL, NULL, NULL,
 	TRUE, FALSE, FALSE
     },
     {
@@ -336,7 +336,7 @@ static const cairo_boilerplate_target_t builtin_targets[] = {
 	NULL, NULL,
 	_cairo_boilerplate_get_image_surface,
 	cairo_surface_write_to_png,
-	NULL, NULL,
+	NULL, NULL, NULL,
 	FALSE, FALSE, FALSE
     },
     {
@@ -346,7 +346,7 @@ static const cairo_boilerplate_target_t builtin_targets[] = {
 	NULL, NULL,
 	_cairo_boilerplate_get_image_surface,
 	cairo_surface_write_to_png,
-	NULL, NULL,
+	NULL, NULL, NULL,
 	TRUE, FALSE, FALSE
     },
 #if CAIRO_HAS_RECORDING_SURFACE
@@ -359,7 +359,7 @@ static const cairo_boilerplate_target_t builtin_targets[] = {
 	_cairo_boilerplate_get_image_surface,
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_recording_surface_cleanup,
-	NULL,
+	NULL, NULL,
 	FALSE, FALSE, TRUE
     },
     {
@@ -371,7 +371,7 @@ static const cairo_boilerplate_target_t builtin_targets[] = {
 	_cairo_boilerplate_get_image_surface,
 	cairo_surface_write_to_png,
 	_cairo_boilerplate_recording_surface_cleanup,
-	NULL,
+	NULL, NULL,
 	FALSE, FALSE, TRUE
     },
 #endif
diff --git a/boilerplate/cairo-boilerplate.h b/boilerplate/cairo-boilerplate.h
index 38df3b9bb..dae17ea45 100644
--- a/boilerplate/cairo-boilerplate.h
+++ b/boilerplate/cairo-boilerplate.h
@@ -149,6 +149,9 @@ typedef void
 typedef void
 (*cairo_boilerplate_wait_t) (void *closure);
 
+typedef char *
+(*cairo_boilerplate_describe_t) (void *closure);
+
 typedef struct _cairo_boilerplate_target {
     const char					*name;
     const char					*basename;
@@ -165,6 +168,7 @@ typedef struct _cairo_boilerplate_target {
     cairo_boilerplate_write_to_png_t		 write_to_png;
     cairo_boilerplate_cleanup_t 		 cleanup;
     cairo_boilerplate_wait_t			 synchronize;
+    cairo_boilerplate_describe_t                 describe;
     cairo_bool_t				 is_measurable;
     cairo_bool_t				 is_vector;
     cairo_bool_t				 is_recording;