Take arbitrary PDF saving parameters (#1)

README.md

@@ -56,7 +56,7 @@ convert(
 ## Behaviour
 
 sla2pdf uses lossy image compression by default, to prevent the resulting files from getting too large.
-Quality settings can be controlled precisely using command-line options.
+Quality settings can be controlled using the `--params` option.
 
 
 ## Development

TASKS.md

@@ -3,9 +3,7 @@
 
 # Tasks
 
-* add ability to set any attribute on the Scribus PDFFile object using a key-value sequence and `setattr()`
-* avoid parsing arguments twice and pass options to scribus in a single key-value string
-* runner/converter: handle parameters on a per-document basis
-* make downsampling optional, also think about making conversion lossless by default
-* add tests and documentation
-* cli: use argparse choices parameter
+* runner/converter: handle parameters on a per-dcument basis, at least in the Python API
+* consider making conversion lossless by default
+* improve the readme
+* add tests and sphinx documentation

src/sla2pdf/__main__.py

@@ -2,10 +2,10 @@
 # SPDX-FileCopyrightText: 2022 geisserml <geisserml@gmail.com>
 # SPDX-License-Identifier: MPL-2.0
 
+import ast
 import logging
 import argparse
 from sla2pdf.runner import convert
-from sla2pdf._parser import extend_parser
 from sla2pdf._version import V_SLA2PDF
 
 try:
@@ -22,43 +22,75 @@ def parse_args():
         prog = "sla2pdf",
         description = "Export Scribus SLA documents to PDF from the command line",
     )
-
     parser.add_argument(
         "--version", "-v",
         action = "version",
         version = "sla2pdf %s" % V_SLA2PDF,
     )
+
+    parser.add_argument(
+        "inputs",
+        nargs = "+",
+    )
     parser.add_argument(
         "--outputs", "-o",
         nargs = "+",
-        help = "Either an output directory, or a sequence of explicit output paths. Defaults to the current directory.",
+        help = "An output directory, or a sequence of explicit output paths. Defaults to the current directory.",
     )
     parser.add_argument(
         "--show-gui",
         action = "store_true",
         help = "Show the Scribus GUI",
     )
-    extend_parser(parser)
+    parser.add_argument(
+        "--params", "-p",
+        nargs = "+",
+        default = [],
+        help = "A sequence of Scribus key=value PDF saving paramters (see the Scribus Scripter docs).",
+    )
 
     if argcomplete is not None:
         argcomplete.autocomplete(parser)
 
     return parser.parse_args()
 
 
+def _parse_params(params_list):
+
+    params_dict = {}
+
+    for param in params_list:
+
+        key, value = param.split("=", maxsplit=1)
+        key, value = key.strip(), value.strip()
+        value_lc = value.lower()
+
+        if value.isnumeric():
+            value = int(value)
+        elif value_lc == "true":
+            value = True
+        elif value_lc == "false":
+            value = False
+        elif value_lc == "none":
+            value = None
+        elif not value.isalnum():
+            value = ast.literal_eval(value)
+
+        params_dict[key] = value
+
+    return params_dict
+
+
 def main():
 
     logger.addHandler( logging.StreamHandler() )
     logger.setLevel(logging.DEBUG)
 
     args = parse_args()
-
     convert(
         args.inputs, args.outputs,
         hide_gui = not args.show_gui,
-        quality = args.quality,
-        compression = args.compression,
-        downsample = args.downsample,
+        params = _parse_params(args.params),
     )
 
 

src/sla2pdf/_converter.py

@@ -3,12 +3,11 @@
 # -- This code needs to remain compatible with Py2 --
 
 import sys
+import ast
 import argparse
 from os.path import dirname
 sys.path.insert(0, dirname(dirname(__file__)))
 
-from sla2pdf._parser import extend_parser
-
 try:
     import scribus
 except ImportError:
@@ -18,12 +17,20 @@
 def parse_args(argv=sys.argv[1:]):
 
     parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "inputs",
+        nargs = "+",
+    )
     parser.add_argument(
         "--outputs", "-o",
         required = True,
         nargs = "+",
     )
-    extend_parser(parser)
+    parser.add_argument(
+        "--params", "-p",
+        required = True,
+        type = ast.literal_eval,
+    )
 
     return parser.parse_args(argv)
 
@@ -33,16 +40,14 @@ def sla_to_pdf(args):
     for in_path, out_path in zip(args.inputs, args.outputs):
 
         scribus.openDoc(in_path)
-
         pdf = scribus.PDFfile()
-        pdf.compress = True
-        pdf.compressmtd = args.compression.value
-        pdf.quality = args.quality.value
-        pdf.resolution = args.downsample
-        pdf.downsample = args.downsample
+
+        for key, value in args.params.items():
+            if value is not None:
+                setattr(pdf, key, value)
+
         pdf.file = out_path
         pdf.save()
-
         scribus.closeDoc()
 
 

src/sla2pdf/runner.py

@@ -8,14 +8,9 @@
 import logging
 import subprocess
 from pathlib import Path
-from sla2pdf.constants import (
-    ImageQuality,
-    ImageCompression,
-)
 
 logger = logging.getLogger(__name__)
 
-
 Converter = Path(__file__).resolve().parent / "_converter.py"
 Scribus = shutil.which("scribus")
 
@@ -26,14 +21,34 @@ def _run_command(command):
     subprocess.run(command, check=True, cwd=os.getcwd())
 
 
+#: Default PDF saving parameters.
+DefaultParams = dict(
+    compress = True,
+    compressmtd = 0,  # automatic
+    quality = 1,      # high
+    resolution = 300,
+    downsample = 300,
+)
+
+
 def convert(
         inputs,
         outputs = None,
         hide_gui = True,
-        quality = ImageQuality.HIGH,
-        compression = ImageCompression.JPEG,
-        downsample = 400,
+        params = {},
     ):
+    """
+    Parameters:
+        inputs (typing.Sequence[str|pathlib.Path]):
+            List of input file paths (Scribus SLA documents).
+        outputs (str | pathlib.Path | typing.Sequence[str|pathlib.Path]):
+            Output directory or list of explicit output paths for the PDF files to generate.
+        hide_gui (bool):
+            If True, the Scribus GUI will be hidden using ``QT_QPA_PLATFORM=offscreen``.
+            Otherwise, it will be shown.
+        params (dict):
+            Dictionary of saving parameters (see the Scribus Scripter PDFfile API).
+    """
 
     if Scribus is None:
         raise RuntimeError("Scribus could not be found.")
@@ -57,16 +72,17 @@ def convert(
     if len(input_paths) != len(output_paths):
         raise ValueError("Length of inputs and outputs does not match (%s != %s)" % (len(input_paths), len(output_paths)))
 
+    conv_params = DefaultParams.copy()
+    conv_params.update(params)
+
     command = [Scribus, "--no-gui", "--no-splash"]
     if hide_gui:
         command += ["-platform", "offscreen"]
 
     command += ["--python-script", Converter]
     command += input_paths
     command += ["-o"] + output_paths
-    command += ["--compression", compression.name]
-    command += ["--quality", quality.name]
-    command += ["--downsample", downsample]
+    command += ["-p", conv_params]
 
     _run_command(command)