Bring back transparent background to figures

Black arrows are visible only in light theme (unless white background
for dark theme). Two-color arrows are visible in light theme and in
dark theme.

.gitignore

@@ -0,0 +1,6 @@
+bip-0174/coinjoin-workflow.aux
+bip-0174/coinjoin-workflow.log
+bip-0174/coinjoin-workflow.pdf
+bip-0174/multisig-workflow.aux
+bip-0174/multisig-workflow.log
+bip-0174/multisig-workflow.pdf

bip-0174/build.sh

@@ -0,0 +1,9 @@
+#!/bin/bash
+
+pdflatex -output-format=pdf coinjoin-workflow.tex && \
+inkscape --with-gui --export-text-to-path \
+  --export-plain-svg=coinjoin-workflow.svg coinjoin-workflow.pdf && \
+pdflatex -output-format=pdf multisig-workflow.tex && \
+inkscape --with-gui --export-text-to-path \
+  --export-plain-svg=multisig-workflow.svg multisig-workflow.pdf && \
+echo '"success"'

bip-0174/coinjoin-workflow.tex

@@ -7,7 +7,7 @@
 \usepackage{lmodern}
 \renewcommand*\familydefault{\sfdefault}
 \usepackage{tikz}
-\usetikzlibrary{shapes,arrows}
+\usetikzlibrary{shapes,arrows.meta}
 \tikzset{>=latex}
 \begin{document}
 %  \sffamily{}
@@ -22,7 +22,7 @@
       rounded corners]
   \begin{tikzpicture}[auto]
     % outlining the flowchart on a grid
-    \matrix[column sep=3ex,row sep=2ex]{
+    \matrix[column sep=3ex,row sep=3ex]{
       \node [block_center] (0alice1)
       {Alice creates a PSBT with only her inputs
       with UTXOs filled in.\\Sends it to Bob.};
@@ -49,7 +49,13 @@
       \\
     };% end matrix
     % connecting nodes with paths
-    \draw[line width = 1pt, ->]
+    \draw [ultra thick, draw=black, -{Stealth[length=8pt]}]
+      (0alice1) edge (1bob1)
+      (1bob1) edge (2carol1)
+      (2carol1) edge (3bob2)
+      (3bob2) edge (4alice1)
+      (4alice1) edge (5alice2);
+    \draw [thin, white, -{Stealth[color=black, fill=white, length=8pt]}]
       (0alice1) edge (1bob1)
       (1bob1) edge (2carol1)
       (2carol1) edge (3bob2)

bip-0174/multisig-workflow.tex

@@ -7,7 +7,7 @@
 \usepackage{lmodern}
 \renewcommand*\familydefault{\sfdefault}
 \usepackage{tikz}
-\usetikzlibrary{shapes,arrows}
+\usetikzlibrary{shapes,arrows.meta}
 \tikzset{>=latex}
 %\pgfdeclarelayer{bg}    % declare background layer
 %\pgfsetlayers{bg,main}  % set order of layers
@@ -83,7 +83,15 @@
     };% end matrix
     % connecting nodes with paths
 %    \begin{pgfonlayer}{bg}
-    \draw[line width = 1pt, ->]
+    \draw [ultra thick, draw=black, -{Stealth[length=8pt]}]
+      (R1) edge (R2)
+      (R2) edge (R3)
+      (R3) -| (R4C1)
+      (R3) edge (R4C2)
+      (R5) edge (R6)
+      (R6) edge (R7)
+      (R7) edge (stop);
+    \draw [thin, white, -{Stealth[color=black, fill=white, length=8pt]}]
       (R1) edge (R2)
       (R2) edge (R3)
       (R3) -| (R4C1)
@@ -92,7 +100,12 @@
       (R6) edge (R7)
       (R7) edge (stop);
       % circumvent missing arrow
-      \draw[line width = 1pt, ->]
+      \draw [ultra thick, draw=black, -{Stealth[length=8pt]}]
+      (R4C1) |-+(0,-2.2em)-| (R5)
+      (R4C2) edge (R5)
+      (R4C3) |-+(0,-2.2em)-| (R5)
+      (R3) -| (R4C3);
+      \draw [thin, white, -{Stealth[color=black, fill=white, length=8pt]}]
       (R4C1) |-+(0,-2.2em)-| (R5)
       (R4C2) edge (R5)
       (R4C3) |-+(0,-2.2em)-| (R5)