From e27ba726b15e71eca700141c2030ac858bc8025c Mon Sep 17 00:00:00 2001
From: Folke Lemaitre <folke.lemaitre@gmail.com>
Date: Wed, 19 Feb 2025 06:48:02 +0100
Subject: [PATCH] feat(image): make math packages configurable. Closes #1295

---
 lua/snacks/image/doc.lua  |  3 ++-
 lua/snacks/image/init.lua |  5 +++++
 tests/image/test.tex      | 10 ++++++++++
 tests/image/test.typ      |  5 +++--
 4 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/lua/snacks/image/doc.lua b/lua/snacks/image/doc.lua
index ce38c6db..5d9575de 100644
--- a/lua/snacks/image/doc.lua
+++ b/lua/snacks/image/doc.lua
@@ -40,7 +40,8 @@ M.transforms = {
     if not content:find("^\\begin") then
       content = ("\\[%s\\]"):format(content)
     end
-    local packages = { "xcolor", "amsmath", "amssymb" }
+    local packages = { "xcolor" }
+    vim.list_extend(packages, Snacks.image.config.convert.math.packages)
     for _, line in ipairs(vim.api.nvim_buf_get_lines(ctx.buf, 0, -1, false)) do
       if line:find("\\usepackage") then
         for _, p in ipairs(vim.split(line:match("{(.-)}") or "", ",%s*")) do
diff --git a/lua/snacks/image/init.lua b/lua/snacks/image/init.lua
index 3f035479..86b4e791 100644
--- a/lua/snacks/image/init.lua
+++ b/lua/snacks/image/init.lua
@@ -103,6 +103,11 @@ local defaults = {
   ---@class snacks.image.convert.Config
   convert = {
     notify = true, -- show a notification on error
+    math = {
+      -- for latex documents, the doc packages are included automatically,
+      -- but you can add more packages here. Useful for markdown documents.
+      packages = { "amsmath", "amssymb", "amsfonts", "amscd", "mathtools", "physics", "siunitx", "mhchem" },
+    },
     ---@type snacks.image.args
     mermaid = function()
       local theme = vim.o.background == "light" and "neutral" or "dark"
diff --git a/tests/image/test.tex b/tests/image/test.tex
index 54b94977..7f9ca2f3 100644
--- a/tests/image/test.tex
+++ b/tests/image/test.tex
@@ -2,6 +2,7 @@
 \usepackage{graphicx}  % For images
 \usepackage{amsmath}  % For math symbols
 \usepackage{amssymb}  % For extra math symbols
+\usepackage{multirow}  % For extra math symbols
 
 \begin{document}
 
@@ -20,8 +21,17 @@ Inline image:
 
 \newpage
 
+
 \section{Math Tests}
 
+
+$
+  cases(
+  E_x = E_0 e^(j omega t - y z),
+  H_y = gamma / (j omega mu_0) E_x = eta^e E_0 e^(j omega - y z) = H_0 e^(j omega t - y z)
+ )
+$
+
 Inline math: \(E=mc^2$ and $\int_0^1 x^2 \,dx\)
 
 Inline math: $E=mc^2$ and $\int_0^1 x^2 \,dx$
diff --git a/tests/image/test.typ b/tests/image/test.typ
index 9723386c..529193a3 100644
--- a/tests/image/test.typ
+++ b/tests/image/test.typ
@@ -11,7 +11,7 @@
 #set text(size: 12pt, fill: rgb("#FF0000"))
 $ 5 + 5 = 10 $
 
-$ E = m c^2 $
+$ E = g c^2 $
 
 $ A = pi r^2 $
 
@@ -21,7 +21,8 @@ $ cal(A) :=
 
     { x in RR | x "is natural" } $
 #let x = 5
-$ #x < 17 $
+
+$ x < 17 $
 
 $ (3x + y) / 7 &= 9 && "given" \
   3x + y &= 63 & "multiply by 7" \