page rewrite

crates/lib/pixel-transform/src/chain.rs

@@ -38,6 +38,20 @@ impl TransformerChain {
 		return image;
 	}
 
+	pub fn output_mime(&self, input_mime: &MimeType) -> Option<MimeType> {
+		let mime = self
+			.steps
+			.last()
+			.and_then(|x| match x {
+				TransformerEnum::Format { format } => Some(MimeType::from(format.to_mime_type())),
+				_ => None,
+			})
+			.unwrap_or(input_mime.clone());
+
+		let fmt = ImageFormat::from_mime_type(mime.to_string());
+		fmt.map(|_| mime)
+	}
+
 	pub fn transform_bytes(
 		&self,
 		image_bytes: &[u8],