Allow alternate colors for the pens

pyproject.toml

@@ -9,6 +9,7 @@ readme = "README.md"
 
 [tool.poetry.dependencies]
 python = "^3.7"
+colour = "^0.1.5"
 pdfrw = "^0.4"
 reportlab = "^3.5.59"
 svglib = "^1.0.1"

rmrl/__main__.py

@@ -19,16 +19,22 @@
 import zipfile
 
 from . import render
-from .constants import VERSION
+from .constants import VERSION, HIGHLIGHT_DEFAULT_COLOR
+from .render import InvalidColor
 from .sources import ZipSource
 
 def main():
-    parser = argparse.ArgumentParser(description="Render a PDF file from a Remarkable document.")
+    parser = argparse.ArgumentParser(description="Render a PDF file from a Remarkable document.",
+                                     epilog='The colors may be specified as hex strings ("#AABBCC", "#ABC") or well-known names ("black", "red").  If no gray color is given, the program will use an average of the white and black colors.  A fixed amount of transparency will be applied to the color given for the highlighter.')
     parser.add_argument('input', help="Filename of zip file, or root-level unpacked file of document.  Use '-' to read zip file from stdin.")
     parser.add_argument('output', nargs='?', default='', help="Filename where PDF file should be written.  Omit to write to stdout.")
     parser.add_argument('--alpha', default=0.3, help="Opacity for template background (0 for no background).")
     parser.add_argument('--no-expand', action='store_true', help="Don't expand pages to margins on device.")
     parser.add_argument('--only-annotated', action='store_true', help="Only render pages with annotations.")
+    parser.add_argument('--black', default='black', help='Color for "black" pen.')
+    parser.add_argument('--white', default='white', help='Color for "white" pen.')
+    parser.add_argument('--gray', '--grey', default=None, help='Color for "gray" pen.')
+    parser.add_argument('--highlight', '--hilight', '--hl', default=HIGHLIGHT_DEFAULT_COLOR, help='Color for the highlighter.')
     parser.add_argument('--version', action='version', version=VERSION)
     args = parser.parse_args()
 
@@ -41,13 +47,21 @@ def main():
     else:
         fout = sys.stdout.buffer
 
-    stream = render(source,
-                    template_alpha=float(args.alpha),
-                    expand_pages=not args.no_expand,
-                    only_annotated=args.only_annotated)
-    fout.write(stream.read())
-    fout.close()
-    return 0
+    try:
+        stream = render(source,
+                        template_alpha=float(args.alpha),
+                        expand_pages=not args.no_expand,
+                        only_annotated=args.only_annotated,
+                        black=args.black,
+                        white=args.white,
+                        gray=args.gray,
+                        highlight=args.highlight)
+        fout.write(stream.read())
+        fout.close()
+        return 0
+    except InvalidColor as e:
+        print(str(e), file=sys.stderr)
+        return 1
 
 if __name__ == '__main__':
     sys.exit(main())

rmrl/constants.py

@@ -23,3 +23,6 @@
 TEMPLATE_PATH = xdg_data_home() / 'rmrl' / 'templates'
 
 VERSION = pkg_resources.get_distribution('rmrl').version
+
+HIGHLIGHT_DEFAULT_COLOR = '#FFE949'
+HIGHLIGHT_ALPHA = 0.392

rmrl/document.py

@@ -29,10 +29,11 @@
 
 class DocumentPage:
     # A single page in a document
-    def __init__(self, source, pid, pagenum):
+    def __init__(self, source, pid, pagenum, colors):
         # Page 0 is the first page!
         self.source = source
         self.num = pagenum
+        self.colors = colors
 
         # On disk, these files are named by a UUID
         self.rmpath = f'{{ID}}/{pid}.rm'
@@ -103,7 +104,7 @@ def load_layers(self):
             except:
                 name = 'Layer ' + str(i + 1)
 
-            layer = DocumentPageLayer(self, name=name)
+            layer = DocumentPageLayer(self, name=name, colors=self.colors)
             layer.strokes = layerstrokes
             self.layers.append(layer)
 
@@ -152,17 +153,15 @@ def render_to_painter(self, canvas, vector, template_alpha):
 class DocumentPageLayer:
     pen_widths = []
 
-    def __init__(self, page, name=None):
+    def __init__(self, page, colors, name=None):
         self.page = page
         self.name = name
 
         self.colors = [
-            #QSettings().value('pane/notebooks/export_pdf_blackink'),
-            #QSettings().value('pane/notebooks/export_pdf_grayink'),
-            #QSettings().value('pane/notebooks/export_pdf_whiteink')
-            (0, 0, 0),
-            (0.5, 0.5, 0.5),
-            (1, 1, 1)
+            colors.black.rgb,
+            colors.gray.rgb,
+            colors.white.rgb,
+            colors.highlight.rgb,
         ]
 
         # Set this from the calling func
@@ -233,6 +232,10 @@ def paint_strokes(self, canvas, vector):
                 log.error("Unknown pen code %d" % pen)
                 penclass = pens.GenericPen
 
+            # Hack to get the right color for the highlighter.
+            if penclass == pens.HighlighterPen:
+                color = -1
+
             qpen = penclass(vector=vector,
                             layer=self,
                             color=self.colors[color])

rmrl/pens/highlighter.py

@@ -14,6 +14,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
+from ..constants import HIGHLIGHT_ALPHA
 from .generic import GenericPen
 
 class HighlighterPen(GenericPen):
@@ -28,7 +29,7 @@ def paint_stroke(self, canvas, stroke):
         canvas.setLineCap(2)  # Square
         canvas.setLineJoin(1)  # Round
         #canvas.setDash ?? for solid line
-        canvas.setStrokeColor((1.000, 0.914, 0.290), alpha=0.392)
+        canvas.setStrokeColor(self.color, alpha=HIGHLIGHT_ALPHA)
         canvas.setLineWidth(stroke.width)
 
         path = canvas.beginPath()

rmrl/render.py

@@ -19,25 +19,38 @@
 from pathlib import Path
 import json
 import re
+from collections import namedtuple
+
+from colour import Color
 
 from pdfrw import PdfReader, PdfWriter, PageMerge, PdfDict, PdfArray, PdfName, \
     IndirectPdfDict, uncompress, compress
 
 from reportlab.pdfgen import canvas
 
 from . import document, sources
-from .constants import PDFHEIGHT, PDFWIDTH, PTPERPX, SPOOL_MAX
+from .constants import PDFHEIGHT, PDFWIDTH, PTPERPX, SPOOL_MAX, HIGHLIGHT_DEFAULT_COLOR
 
 
 log = logging.getLogger(__name__)
 
+Colors = namedtuple('Colors', ['black', 'white', 'gray', 'highlight'])
+
+class InvalidColor(Exception):
+    """Raised when an invalid string is passed as a color."""
+    pass
+
+
 def render(source, *,
            progress_cb=lambda x: None,
            expand_pages=True,
            template_alpha=0.3,
-           only_annotated=False):
-    """
-    Render a source document as a PDF file.
+           only_annotated=False,
+           black='black',
+           white='white',
+           gray=None,
+           highlight=HIGHLIGHT_DEFAULT_COLOR):
+    """Render a source document as a PDF file.
 
     source: The reMarkable document to be rendered.  This may be
               - A filename or pathlib.Path to a zip file containing the
@@ -59,8 +72,19 @@ def render(source, *,
                     makes the templates invisible, 1 makes them fully dark.
     only_annotated: Boolean value (default False) indicating whether only
                     pages with annotations should be output.
+    black: A string giving the color to use as "black" in the document.
+           Can be a color name or a hex string.  Default: 'black'
+    white: A string giving the color to use as "white" in the document.
+           See `black` parameter for format.  Default: 'white'
+    gray: A string giving the color to use as "gray" in the document.
+          See `black` parameter for format.  Default: None, which means to
+          pick an average between the "white" and "black" values.
+    highlight: A string giving the color to use for the highlighter.
+               See `black` parameter for format.
     """
 
+    colors = parse_colors(black, white, gray, highlight)
+
     vector=True  # TODO: Different rendering styles
     source = sources.get_source(source)
 
@@ -89,7 +113,7 @@ def render(source, *,
     changed_pages = []
     annotations = []
     for i in range(0, len(pages)):
-        page = document.DocumentPage(source, pages[i], i)
+        page = document.DocumentPage(source, pages[i], i, colors=colors)
         if source.exists(page.rmpath):
             changed_pages.append(i)
         page.render_to_painter(pdf_canvas, vector, template_alpha)
@@ -177,6 +201,35 @@ def render(source, *,
     return stream
 
 
+def parse_colors(black, white, gray, highlight):
+    black_color = parse_color(black, 'black')
+    white_color = parse_color(white, 'white')
+    highlight_color = parse_color(highlight, 'highlight')
+
+    if gray is not None:
+        # Use the explicit gray value.
+        gray_color = parse_color(gray, 'gray')
+    elif black_color.saturation == 0 or white_color.saturation == 0:
+        # One or the other of the color endpoints is a shade of gray (or
+        # white or black).  Use average in RGB space.  This keeps the hue
+        # from the saturated endpoint and just lets the other endpoint
+        # either darken or lighten it.
+        gray_color = Color(rgb=((b + w) / 2 for b, w in zip(black_color.rgb, white_color.rgb)))
+    else:
+        # Both "black" and "white" have color elements to them.  Use
+        # Color.range_to, which more or less averages in HSL space.
+        gray_color = list(black_color.range_to(white_color, 3))[1]
+
+    return Colors(black=black_color, white=white_color, gray=gray_color, highlight=highlight_color)
+
+
+def parse_color(color_string, name):
+    try:
+        return Color(color_string)
+    except Exception as e:
+        raise InvalidColor('"{}" color was passed an invalid string: {}'.format(name, str(e)))
+
+
 def do_apply_ocg(basepage, rmpage, i, uses_base_pdf, ocgprop, annotations):
     ocgpage = IndirectPdfDict(
         Type=PdfName('OCG'),