Handle first_page greater than last_page (#66)

pdf2image/pdf2image.py

@@ -67,6 +67,9 @@ def convert_from_path(pdf_path, dpi=200, output_folder=None, first_page=None, la
     if last_page is None or last_page > page_count:
         last_page = page_count
 
+    if first_page > last_page:
+        return []
+
     auto_temp_dir = False
     if output_folder is None and use_pdfcairo:
         auto_temp_dir = True

setup.py

@@ -12,7 +12,7 @@
 setup(
     name='pdf2image',
 
-    version='1.5.3',
+    version='1.5.4',
 
     description='A wrapper around the pdftoppm and pdftocairo command line tools to convert PDF to a PIL Image list.',
     long_description=long_description,

tests.py

@@ -721,5 +721,23 @@ def test_use_poppler_path_with_trailing_slash(self):
         [im.close() for im in images_from_path]
         print('test_conversion_from_path_using_poppler_path_with_trailing_slash: {} sec'.format((time.time() - start_time)))
 
+    ## Test first page greater or equal to last_page
+
+    @profile
+    @unittest.skipIf(not POPPLER_INSTALLED, "Poppler is not installed!")
+    def test_conversion_from_path_14_first_page_1_last_page_1(self):
+        start_time = time.time()
+        images_from_path = convert_from_path('./tests/test_14.pdf', first_page=1, last_page=1)
+        self.assertTrue(len(images_from_path) == 1)
+        print('test_conversion_from_path_14: {} sec'.format((time.time() - start_time) / 14.))
+
+    @profile
+    @unittest.skipIf(not POPPLER_INSTALLED, "Poppler is not installed!")
+    def test_conversion_from_path_14_first_page_12_last_page_1(self):
+        start_time = time.time()
+        images_from_path = convert_from_path('./tests/test_14.pdf', first_page=12, last_page=1)
+        self.assertTrue(len(images_from_path) == 0)
+        print('test_conversion_from_path_14: {} sec'.format((time.time() - start_time) / 14.))
+
 if __name__=='__main__':
     unittest.main()