From: Scott Worley <scottworley@scottworley.com>
Date: Mon, 1 Jan 2024 06:11:25 +0000 (-0800)
Subject: Learning TeX: Do Layouts with TeX macros
X-Git-Url: http://git.scottworley.com/paperdoorknob/commitdiff_plain/1fac41bf2d403d35d43dd532a37a8225f682bae2?ds=inline

Learning TeX: Do Layouts with TeX macros

This is more elegant and reduces the size of the .tex output by 33%

h/t https://tex.stackexchange.com/a/537222 by Steven B. Segletes
for the \ifnotempty technique
---

diff --git a/args.py b/args.py
index ede8471..de6fc01 100644
--- a/args.py
+++ b/args.py
@@ -16,7 +16,7 @@ from xdg_base_dirs import xdg_cache_home
 
 from domfilter import ApplyDOMFilters, DOMFilters
 from fetch import CachingFetcher
-from glowfic import BesideIconLayout, BelowIconLayout, Layout
+from glowfic import BesideIconLayout, BelowIconLayout
 from htmlfilter import ApplyHTMLFilters, HTMLFilters
 from texfilter import ApplyTexFilters, TexFilters
 from images import DiskImageStore
@@ -87,11 +87,11 @@ See https://faculty.bard.edu/bloch/geometry.pdf for details
 def spec_from_commandline_args() -> Iterator[Spec]:
     args = _command_line_parser().parse_args()
     texifier = PandocTexifier(args.pandoc or 'pandoc')
-    layout: Layout
+    layout: bytes
     if args.layout == 'below':
-        layout = BelowIconLayout(texifier)
+        layout = BelowIconLayout
     elif args.layout == 'beside':
-        layout = BesideIconLayout(texifier)
+        layout = BesideIconLayout
     else:
         raise ValueError(f'Unknown layout: {args.layout}')
     log = (lambda _: None) if args.quiet else _print_status
diff --git a/glowfic.py b/glowfic.py
index b7e7ba7..012bd06 100644
--- a/glowfic.py
+++ b/glowfic.py
@@ -5,7 +5,6 @@
 # Free Software Foundation, version 3.
 
 
-from abc import ABC, abstractmethod
 from dataclasses import dataclass
 import itertools
 from urllib.parse import parse_qsl, urlencode, urlparse, urlunparse
@@ -111,36 +110,27 @@ def makeChunk(chunk_dom: Tag, image_store: ImageStore) -> Chunk:
                  content)
 
 
-class Layout(ABC):
+def renderChunk(texifier: Texifier, chunk: Chunk) -> bytes:
+    return b''.join([
+        br'\glowhead{',
+        br'\glowicon{%s}' % chunk.icon.encode('UTF-8') if chunk.icon else b'',
+        b'}{',
+        texifier.texify(chunk.character) if chunk.character else b'',
+        b'}{',
+        texifier.texify(chunk.screen_name) if chunk.screen_name else b'',
+        b'}{',
+        texifier.texify(chunk.author) if chunk.author else b'',
+        b'}',
+        texifier.texify(chunk.content)])
 
-    @abstractmethod
-    def renderChunk(self, chunk: Chunk) -> bytes:
-        raise NotImplementedError()
 
+ContentOnlyLayout = br'''
+\newcommand{\glowhead}[4]{}
+'''
 
-class ContentOnlyLayout(Layout):
 
-    def __init__(self, texifier: Texifier) -> None:
-        self._texifier = texifier
-
-    def renderChunk(self, chunk: Chunk) -> bytes:
-        return self._texifier.texify(chunk.content) + b'\n'
-
-
-class BelowIconLayout(Layout):
-
-    def __init__(self, texifier: Texifier) -> None:
-        self._texifier = texifier
-
-    def renderChunk(self, chunk: Chunk) -> bytes:
-        meta = []
-        if chunk.icon:
-            meta += [br'\glowicon{%s}' % chunk.icon.encode('UTF-8')]
-        meta += [self._texifier.texify(x)
-                 for x in [chunk.character, chunk.screen_name, chunk.author]
-                 if x is not None]
-
-        return br'''\wrapstuffclear
+BelowIconLayout = br'''
+\newcommand{\glowhead}[4]{\wrapstuffclear
 \begin{wrapstuff}[l]
 \fbox{
 \begin{varwidth}{0.5\textwidth}
@@ -152,7 +142,10 @@ class BelowIconLayout(Layout):
   }\\*}
   \vspace{-1em}
 \begin{center}
-%s
+#1\ifnotempty
+{#1}{\\*}#2\ifnotempty
+{#2}{\\*}#3\ifnotempty
+{#3}{\\*}#4
 \end{center}
 \end{varwidth}
 }
@@ -160,40 +153,25 @@ class BelowIconLayout(Layout):
 
 \strut
 
-\noindent %s
-''' % (
-            br'\\*'.join(meta),
-            self._texifier.texify(chunk.content))
+\noindent}'''
 
 
-class BesideIconLayout(Layout):
+# Why is \textwidth not the width of the text?
+# Why is the width of the text .765\textwidth?
+BesideIconLayout = br'''
+\newcommand{\glowhead}[4]{
 
-    def __init__(self, texifier: Texifier) -> None:
-        self._texifier = texifier
-
-    def renderChunk(self, chunk: Chunk) -> bytes:
-        meta = [
-            chunk.character,
-            chunk.screen_name,
-            chunk.author,
-        ]
+\strut
 
-        # Why is \textwidth not the width of the text?
-        # Why is the width of the text .765\textwidth?
-        return br'''\noindent\fbox{
-%s
+\noindent\fbox{
+#1
 \parbox[b]{.765\textwidth}{
 \begin{center}
-%s
+#2\ifnotempty
+{#2}{\\*}#3\ifnotempty
+{#3}{\\*}#4
 \end{center}
 }
 }\\*
 \vspace{-0.75em}\\*
-\noindent %s
-
-\strut
-
-''' % (
-            br'\glowicon{%s}' % chunk.icon.encode('UTF-8') if chunk.icon else b'',
-            br'\\*'.join(self._texifier.texify(x) for x in meta if x is not None),
-            self._texifier.texify(chunk.content))
+\noindent}'''
diff --git a/paperdoorknob.py b/paperdoorknob.py
index 0fb3fe1..86b8766 100644
--- a/paperdoorknob.py
+++ b/paperdoorknob.py
@@ -9,7 +9,7 @@ from typing import Any, Iterable
 from bs4 import BeautifulSoup
 
 from args import spec_from_commandline_args
-from glowfic import chunkDOMs, flatURL, makeChunk
+from glowfic import chunkDOMs, flatURL, makeChunk, renderChunk
 from spec import Spec
 
 
@@ -40,7 +40,10 @@ def process(spec: Spec) -> None:
 \newcommand{\glowicon}[1]{\includegraphics[
   width=\glowiconsize,height=\glowiconsize,keepaspectratio
 ]{#1}}
-''' % spec.icon_size)
+\newcommand{\ifnotempty}[2]{\expandafter\ifx\expandafter\relax
+  \detokenize{#1}\relax\else #2\fi}
+%s
+''' % (spec.icon_size, spec.layout))
     url = flatURL(spec.url)
     spec.log('Fetching HTML...\r')
     html = spec.fetcher.fetch(url)
@@ -53,7 +56,7 @@ def process(spec: Spec) -> None:
         spec.log(f'Processing chunk {i} of {num_chunks} ({percent:.1f}%)\r')
         spec.domfilter(r)
         chunk = makeChunk(r, spec.images)
-        spec.texout.write(spec.texfilter(spec.layout.renderChunk(chunk)))
+        spec.texout.write(spec.texfilter(renderChunk(spec.texifier, chunk)))
     spec.log('')
     spec.texout.write(b'\\end{document}\n')
 
diff --git a/paperdoorknob_test.py b/paperdoorknob_test.py
index 28408d6..f2cd5f1 100644
--- a/paperdoorknob_test.py
+++ b/paperdoorknob_test.py
@@ -45,7 +45,7 @@ class BaseTestProcess(ABC):
             texifier,
             lambda x: x,
             20,
-            ContentOnlyLayout(texifier),
+            ContentOnlyLayout,
             'margin=20mm',
             buf,
             lambda _: None)
@@ -54,12 +54,9 @@ class BaseTestProcess(ABC):
 (\\usepackage{[a-z]+}\n)+\\usepackage\[margin=20mm\]{geometry}
 \\begin{document}
 (.|\n)*
-This is \\href{https://glowfic.com}{glowfic}
-
-You \\emph{sure}\?
-
-Pretty sure.
-
+\\glowhead{}{}{}{}This is \\href{https://glowfic.com}{glowfic}
+\\glowhead{}{}{}{}You \\emph{sure}\?
+\\glowhead{}{}{}{}Pretty sure.
 \\end{document}
 ''', buf.getvalue())
 
@@ -76,7 +73,7 @@ Pretty sure.
             texifier,
             lambda x: x,
             20,
-            ContentOnlyLayout(texifier),
+            ContentOnlyLayout,
             None,
             buf,
             lambda _: None)
@@ -94,7 +91,7 @@ Pretty sure.
                 texifier,
                 lambda x: x,
                 20,
-                BesideIconLayout(texifier),
+                BesideIconLayout,
                 None,
                 out,
                 lambda _: None)
diff --git a/spec.py b/spec.py
index 3aa7292..5d708e2 100644
--- a/spec.py
+++ b/spec.py
@@ -12,7 +12,6 @@ from typing import Callable, IO
 from bs4.element import Tag
 
 from fetch import Fetcher
-from glowfic import Layout
 from images import ImageStore
 from texify import Texifier
 
@@ -28,7 +27,7 @@ class Spec:
     texifier: Texifier
     texfilter: Callable[[bytes], bytes]
     icon_size: float
-    layout: Layout
+    layout: bytes
     geometry: str | None
     texout: IO[bytes]
     log: Callable[[str], None]