Fix to set color space from color convenience ops

CHANGELOG.md

@@ -18,6 +18,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - `TypeError` when getting default width of font ([#720](https://github.com/pdfminer/pdfminer.six/issues/720))
 - Installing typing-extensions on Python 3.6 and 3.7 ([#775](https://github.com/pdfminer/pdfminer.six/pull/775))
 - `TypeError` in cmapdb.py when parsing null characters ([#768](https://github.com/pdfminer/pdfminer.six/pull/768))
+- Color "convenience operators" now (per spec) also set color space ([#779](https://github.com/pdfminer/pdfminer.six/issues/779))
 
 ### Deprecated
 

pdfminer/pdfinterp.py

@@ -652,21 +652,25 @@ def do_cs(self, name: PDFStackT) -> None:
     def do_G(self, gray: PDFStackT) -> None:
         """Set gray level for stroking operations"""
         self.graphicstate.scolor = cast(float, gray)
+        self.scs = self.csmap["DeviceGray"]
         return
 
     def do_g(self, gray: PDFStackT) -> None:
         """Set gray level for nonstroking operations"""
         self.graphicstate.ncolor = cast(float, gray)
+        self.ncs = self.csmap["DeviceGray"]
         return
 
     def do_RG(self, r: PDFStackT, g: PDFStackT, b: PDFStackT) -> None:
         """Set RGB color for stroking operations"""
         self.graphicstate.scolor = (cast(float, r), cast(float, g), cast(float, b))
+        self.scs = self.csmap["DeviceRGB"]
         return
 
     def do_rg(self, r: PDFStackT, g: PDFStackT, b: PDFStackT) -> None:
         """Set RGB color for nonstroking operations"""
         self.graphicstate.ncolor = (cast(float, r), cast(float, g), cast(float, b))
+        self.ncs = self.csmap["DeviceRGB"]
         return
 
     def do_K(self, c: PDFStackT, m: PDFStackT, y: PDFStackT, k: PDFStackT) -> None:
@@ -677,6 +681,7 @@ def do_K(self, c: PDFStackT, m: PDFStackT, y: PDFStackT, k: PDFStackT) -> None:
             cast(float, y),
             cast(float, k),
         )
+        self.scs = self.csmap["DeviceCMYK"]
         return
 
     def do_k(self, c: PDFStackT, m: PDFStackT, y: PDFStackT, k: PDFStackT) -> None:
@@ -687,6 +692,7 @@ def do_k(self, c: PDFStackT, m: PDFStackT, y: PDFStackT, k: PDFStackT) -> None:
             cast(float, y),
             cast(float, k),
         )
+        self.ncs = self.csmap["DeviceCMYK"]
         return
 
     def do_SCN(self) -> None:

tests/test_converter.py

@@ -1,9 +1,10 @@
 import io
 from tempfile import TemporaryFile
 
+from helpers import absolute_sample_path
 from pdfminer.converter import PDFLayoutAnalyzer, PDFConverter
 from pdfminer.high_level import extract_pages
-from pdfminer.layout import LTContainer, LTRect, LTLine, LTCurve
+from pdfminer.layout import LTChar, LTContainer, LTRect, LTLine, LTCurve
 from pdfminer.pdfinterp import PDFGraphicState
 
 
@@ -225,6 +226,31 @@ def test_paint_path_without_starting_m(self):
         assert len(analyzer.cur_item._objs) == 0
 
 
+def get_chars(el):
+    if isinstance(el, LTContainer):
+        for item in el:
+            yield from get_chars(item)
+    elif isinstance(el, LTChar):
+        yield el
+    else:
+        pass
+
+
+class TestColorSpace:
+    def test_do_rg(self):
+        path = absolute_sample_path("contrib/issue-00352-hash-twos-complement.pdf")
+        for page in extract_pages(path):
+            for char in get_chars(page):
+                cs = char.ncs.name
+                color = char.graphicstate.ncolor
+                if cs == "DeviceGray":
+                    assert isinstance(color, (float, int))
+                elif cs == "DeviceRGB":
+                    assert len(color) == 3
+                elif cs == "DeviceCMYK":
+                    assert len(color) == 4
+
+
 class TestBinaryDetector:
     def test_stringio(self):
         assert not PDFConverter._is_binary_stream(io.StringIO())