Prevent custom LAParams from raising exception

Issue #168 / PR #169. Many thanks to @frascuchon for submitting the PR,
which is the source for the code/idea in this commit.

README.md

@@ -375,6 +375,7 @@ Many thanks to the following users who've contributed ideas, features, and fixes
 - [@meldonization](https://github.com/meldonization)
 - [Oisín Moran](https://github.com/OisinMoran)
 - [Samkit Jain](https://github.com/samkit-jain)
+- [Francisco Aranda](https://github.com/frascuchon)
 
 ## Contributing
 

pdfplumber/page.py

@@ -81,20 +81,6 @@ class Page(Container):
                 h - d(y)
             )
 
-        IGNORE = [
-            "bbox",
-            "matrix",
-            "_text",
-            "_objs",
-            "groups",
-            "stream",
-            "colorspace",
-            "ncs",
-            "graphicstate",
-            "imagemask",
-            "pts",
-        ]
-
         noop = lambda x: x
         str_conv = lambda x: str(x or "")
 
@@ -135,10 +121,12 @@ class Page(Container):
             "stroking_color": noop,
         }
 
+        CONVERSIONS_KEYS = set(CONVERSIONS.keys())
+
         def process_object(obj):
             attr = dict((k, CONVERSIONS[k](resolve_all(v)))
                 for k, v in obj.__dict__.items()
-                    if k not in IGNORE)
+                    if k in CONVERSIONS_KEYS)
 
             kind = re.sub(lt_pat, "", obj.__class__.__name__).lower()
             attr["object_type"] = kind

tests/test-basics.py

@@ -53,13 +53,18 @@ class Test(unittest.TestCase):
 
     def test_password(self):
         path = os.path.join(HERE, "pdfs/password-example.pdf")
-        pdf = pdfplumber.open(path, password = "test")
-        assert(len(pdf.chars) > 0)
-        pdf.close()
+        with pdfplumber.open(path, password = "test") as pdf:
+            assert(len(pdf.chars) > 0)
 
     def test_colors(self):
         path = os.path.join(HERE, "pdfs/nics-background-checks-2015-11.pdf")
-        pdf = pdfplumber.open(path)
-        rect = pdf.pages[0].rects[0]
-        assert rect['non_stroking_color'] == [0.8, 1, 1]
-        pdf.close()
+        with pdfplumber.open(path) as pdf:
+            rect = pdf.pages[0].rects[0]
+            assert rect['non_stroking_color'] == [0.8, 1, 1]
+
+    def test_load_with_custom_laparams(self):
+        # See https://github.com/jsvine/pdfplumber/issues/168
+        path = os.path.join(HERE, "pdfs/cupertino_usd_4-6-16.pdf")
+        laparams = dict(line_margin = 0.2)
+        with pdfplumber.open(path, laparams = laparams) as pdf:
+            assert float(pdf.pages[0].chars[0]["top"]) == 61.656