From 6bc8e8c9e37ce1d9db318b9a7641b8df0d23868c Mon Sep 17 00:00:00 2001
From: Lertsenem <lertsenem@lertsenem.com>
Date: Wed, 6 Jan 2021 09:33:36 +0100
Subject: [PATCH] Add new export-options and svg_embed_png option

New set of options to tweak the export, and the first one: a way to
embed PNG images inside the resulting SVG file.
---
 lokrez/__init__.py |  8 ++++++
 lokrez/export.py   | 65 ++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 71 insertions(+), 2 deletions(-)

diff --git a/lokrez/__init__.py b/lokrez/__init__.py
index af0e5df..77caf7a 100644
--- a/lokrez/__init__.py
+++ b/lokrez/__init__.py
@@ -146,6 +146,7 @@ def generate_pic(
             outform,
             log = log,
             cachedir = dir_cache,
+            options = { "svg_embed_png": options.get("svg_embed_png",False) },
             )
 
     if pic is None:
@@ -247,6 +248,12 @@ def main():
             default = [],
             help = "Template-specific options",
             )
+    top8_parser.add_argument(
+            "--export-options", "-E",
+            action = "append",
+            default = [],
+            help = "Export options (like svg_embed_png)",
+            )
 
     top8_parser.add_argument(
             "--lkrz-file", "-f",
@@ -463,6 +470,7 @@ def main():
                 args.outfile,
                 log = log,
                 cachedir = args.cachedir,
+                options={"svg_embed_png": "svg_embed_png" in args.export_options},
                 )
 
         if rv is None:
diff --git a/lokrez/export.py b/lokrez/export.py
index b5936c9..5129954 100644
--- a/lokrez/export.py
+++ b/lokrez/export.py
@@ -1,7 +1,9 @@
+import base64
 import io
 import os
 import subprocess
 import tempfile
+import urllib
 
 import jinja2
 
@@ -13,12 +15,14 @@ def generate_outfile(
         outfilename,
         log = None,
         cachedir = None,
+        options = {},
         ):
 
     # Template rendering
     # -------------------------------------------------------------------------
     log.info("Generating SVG using '{}' template".format(templatename))
     log.debug("Context : {}".format(context))
+    log.debug("Options : {}".format(options))
 
     log.debug(
             "Initializing jinja2 with template dir '{}'" \
@@ -43,7 +47,34 @@ def generate_outfile(
     # To SVG
     # -------------------------------------------------------------------------
     if outfilename.suffix == ".svg":
-        jj2_tpl.stream(context).dump( str(outfilename) )
+
+        if options.get("svg_embed_png", False):
+            log.debug("embedding png images")
+
+            with open(outfilename, "w") as out:
+                for line in jj2_tpl.render(context).splitlines():
+                    l = line.strip()
+
+                    if (     l.startswith("xlink:href=\"file://")
+                         and l.endswith(".png\"") ):
+                        image_url = urllib.parse.urlparse(
+                                "=".join( l.split("=")[1:] )[1:-1],
+                                )
+                        log.debug("embedding image '{}'".format(image_url.path))
+                        with open(image_url.path, "rb") as image:
+                            line = "xlink:href=\"data:image/png;base64,{d}\"" \
+                                    .format(
+                                            d = base64 \
+                                                    .b64encode(image.read()) \
+                                                    .decode("ascii"),
+                                                    )
+
+                    out.write(line)
+                    out.write("\n")
+
+        else:
+            jj2_tpl.stream(context).dump( str(outfilename) )
+
         return outfilename
 
     # To PNG with inkscape
@@ -156,6 +187,7 @@ def generate_pic(
         outform="svg",
         log = None,
         cachedir = None,
+        options = {},
         ):
 
     if outform not in ["svg", "png"]:
@@ -191,7 +223,36 @@ def generate_pic(
     # To SVG
     # -------------------------------------------------------------------------
     if outform == "svg":
-        return jj2_tpl.render(context)
+
+        out = io.StringIO()
+
+        if options.get("svg_embed_png", False):
+            log.debug("embedding png images")
+
+            for line in jj2_tpl.render(context).splitlines():
+                l = line.strip()
+
+                if (     l.startswith("xlink:href=\"")
+                     and l.endswith(".png\"") ):
+                    image_url = urllib.parse.urlparse(
+                            "=".join( l.split("=")[1:] )[1:-1],
+                            )
+                    log.debug("embedding image '{}'".format(image_url.path))
+                    with open(image_url.path, "rb") as image:
+                        line = "xlink:href=\"data:image/png;base64,{d}\"" \
+                                .format(
+                                        d = base64 \
+                                                .b64encode(image.read()) \
+                                                .decode("ascii"),
+                                                )
+
+                out.write(line)
+                out.write("\n")
+        else:
+            out.write(jj2_tpl.render(context))
+
+        out.seek(0)
+        return out
 
     # To PNG with inkscape
     # -------------------------------------------------------------------------