Fix poppler version requirement, add loader check

This fixes the poppler-glib version requirement to version 0.16, which
is the lowest version that compiles and works properly with pdfload.

Also added a check for pdfload and enabled testing on Travis CI.

.travis.yml

@@ -8,7 +8,7 @@ before_install:
   - sudo apt-get install libpng12-dev libwebp-dev libtiff4-dev libxml2-dev 
   - sudo apt-get install swig libmagick++-dev bc 
   - sudo apt-get install libcfitsio3-dev libgsl0-dev libmatio-dev
-  - sudo apt-get install liborc-0.4-dev liblcms2-dev 
+  - sudo apt-get install liborc-0.4-dev liblcms2-dev libpoppler-glib-dev
 before_script:
   - ./bootstrap.sh
   - ./configure 

configure.ac

@@ -563,12 +563,12 @@ AC_ARG_WITH([poppler],
   AS_HELP_STRING([--without-poppler], [build without poppler (default: test)]))
 
 if test x"$with_poppler" != x"no"; then
-  PKG_CHECK_MODULES(POPPLER, [poppler-glib >= 0.30.0 cairo >= 1.2],
-    [AC_DEFINE(HAVE_POPPLER,1,[define if you have poppler-glib >= 0.30.0 and cairo >= 1.2 installed.])
+  PKG_CHECK_MODULES(POPPLER, [poppler-glib >= 0.16.0 cairo >= 1.2],
+    [AC_DEFINE(HAVE_POPPLER,1,[define if you have poppler-glib >= 0.16.0 and cairo >= 1.2 installed.])
      with_poppler=yes
      PACKAGES_USED="$PACKAGES_USED poppler-glib cairo"
     ],
-    [AC_MSG_WARN([poppler-glib >= 0.30.0 or cairo >= 1.2 not found; disabling PDF load via poppler])
+    [AC_MSG_WARN([poppler-glib >= 0.16.0 or cairo >= 1.2 not found; disabling PDF load via poppler])
      with_poppler=no
     ]
   )
@@ -961,7 +961,7 @@ file import with OpenSlide:		$with_openslide
   (requires openslide-3.3.0 or later)
 file import with matio: 		$with_matio
 PDF import with poppler-glib: 		$with_poppler
-  (requires poppler-glib 0.30.0 or later)
+  (requires poppler-glib 0.16.0 or later)
 SVG import with librsvg-2.0: 		$with_rsvg
   (requires librsvg-2.0 2.40.0 or later)
 file import with cfitsio: 		$with_cfitsio

test/images/blankpage.pdf

@@ -0,0 +1,37 @@
+%PDF-1.1
+%âãÏÓ
+1 0 obj 
+<<
+/Pages 2 0 R
+/Type /Catalog
+>>
+endobj 
+2 0 obj 
+<<
+/MediaBox [0 0 595 842]
+/Kids [3 0 R]
+/Count 1
+/Type /Pages
+>>
+endobj 
+3 0 obj 
+<<
+/Parent 2 0 R
+/MediaBox [0 0 595 842]
+/Type /Page
+>>
+endobj xref
+0 4
+0000000000 65535 f 
+0000000015 00000 n 
+0000000066 00000 n 
+0000000149 00000 n 
+trailer
+
+<<
+/Root 1 0 R
+/Size 4
+>>
+startxref
+221
+%%EOF

test/test_formats.sh

@@ -7,6 +7,10 @@
 
 . ./variables.sh
 
+# poppler / pdfload reference image
+poppler=$test_images/blankpage.pdf
+poppler_ref=$test_images/blankpage.png
+
 # the matlab image and reference image
 matlab=$test_images/sample.mat
 matlab_ref=$test_images/sample.png
@@ -215,6 +219,10 @@ test_rad $rad
 test_raw $mono 
 test_raw $image 
 
+if test_supported pdfload; then
+	test_loader $poppler_ref $poppler pdfload
+fi
+
 if test_supported matload; then
 	test_loader $matlab_ref $matlab matlab
 fi