From ffc719bfc17700fe0af077ea58c99b710d458e92 Mon Sep 17 00:00:00 2001
From: Andrew <andrew@digerati.co.nz>
Date: Wed, 31 May 2023 08:43:07 +1200
Subject: [PATCH] Add warnings about stripping APNGs

---
 src/main.rs    | 2 +-
 src/png/mod.rs | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/main.rs b/src/main.rs
index 71c66fa3..c8cbc604 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -121,7 +121,7 @@ fn main() {
         )
         .arg(
             Arg::new("strip")
-                .help("Strip metadata objects ['safe', 'all', or comma-separated list]")
+                .help("Strip metadata objects ['safe', 'all', or comma-separated list]\nCAUTION: stripping 'all' will convert APNGs to standard PNGs")
                 .long("strip")
                 .takes_value(true)
                 .value_name("mode")
diff --git a/src/png/mod.rs b/src/png/mod.rs
index c2008098..6d41b434 100644
--- a/src/png/mod.rs
+++ b/src/png/mod.rs
@@ -7,6 +7,7 @@ use crate::interlace::{deinterlace_image, interlace_image, Interlacing};
 use crate::Options;
 use bitvec::bitarr;
 use libdeflater::{CompressionLvl, Compressor};
+use log::warn;
 use rgb::ComponentSlice;
 use rustc_hash::FxHashMap;
 use std::fs::File;
@@ -112,6 +113,8 @@ impl PngData {
                             name: chunk.name,
                             data: chunk.data.to_owned(),
                         })
+                    } else if chunk.name == *b"acTL" {
+                        warn!("Stripping animation data from APNG - image will become standard PNG");
                     }
                 }
             }