From c771160a05295e3c733ec9bf9dad4025b01ae28c Mon Sep 17 00:00:00 2001
From: Nova Kwok <n0vad3v@riseup.net>
Date: Fri, 1 Dec 2023 20:26:27 +0800
Subject: [PATCH] Ignore GIF when converting to AVIF (#302)

* Ignore GIF when converting to AVIF

* Allow WebP as source
---
 README.md          |  6 ++++--
 config/config.go   |  2 +-
 encoder/encoder.go | 36 ++++++++++++++++++------------------
 3 files changed, 23 insertions(+), 21 deletions(-)

diff --git a/README.md b/README.md
index 5eba22b6b..52f157411 100644
--- a/README.md
+++ b/README.md
@@ -12,9 +12,11 @@
 
 This is a Server based on Golang, which allows you to serve WebP images on the fly.
 
-Currently supported image format: JPEG, PNG, BMP, GIF, SVG, HEIC, NEF
+Currently supported image format: JPEG, PNG, BMP, GIF, SVG, HEIC, NEF, WEBP
 
-> e.g When you visit `https://your.website/pics/tsuki.jpg`，it will serve as `image/webp` format without changing the URL.
+> e.g When you visit `https://your.website/pics/tsuki.jpg`，it will serve as `image/webp`/`image/avif` format without changing the URL.
+>
+> GIF image will not be converted to AVIF format even with `ENABLE_AVIF` to `true`, because the converted AVIF image is not animated.
 
 ## Usage with Docker(recommended)
 
diff --git a/config/config.go b/config/config.go
index 7bf2881af..e501c5159 100644
--- a/config/config.go
+++ b/config/config.go
@@ -80,7 +80,7 @@ func NewWebPConfig() *WebpConfig {
 		Port:              "3333",
 		ImgPath:           "./pics",
 		Quality:           80,
-		AllowedTypes:      []string{"jpg", "png", "jpeg", "bmp", "svg", "nef"},
+		AllowedTypes:      []string{"jpg", "png", "jpeg", "bmp", "svg", "nef", "heic", "webp"},
 		ImageMap:          map[string]string{},
 		ExhaustPath:       "./exhaust",
 		EnableAVIF:        false,
diff --git a/encoder/encoder.go b/encoder/encoder.go
index cf9e15035..d9d03b388 100644
--- a/encoder/encoder.go
+++ b/encoder/encoder.go
@@ -17,6 +17,11 @@ import (
 var (
 	boolFalse   vips.BoolParameter
 	intMinusOne vips.IntParameter
+	// Source image encoder ignore list for WebP and AVIF
+	// We shouldn't convert Unknown and AVIF to WebP
+	webpIgnore = []vips.ImageType{vips.ImageTypeUnknown, vips.ImageTypeAVIF}
+	// We shouldn't convert Unknown,AVIF and GIF to AVIF
+	avifIgnore = append(webpIgnore, vips.ImageTypeGIF)
 )
 
 func init() {
@@ -135,18 +140,6 @@ func convertImage(raw, optimized, imageType string, extraParams config.ExtraPara
 	return err
 }
 
-func imageIgnore(imageFormat vips.ImageType) bool {
-	// Ignore Unknown, WebP, AVIF
-	ignoreList := []vips.ImageType{vips.ImageTypeUnknown, vips.ImageTypeWEBP, vips.ImageTypeAVIF}
-	for _, ignore := range ignoreList {
-		if imageFormat == ignore {
-			// Return err to render original image
-			return true
-		}
-	}
-	return false
-}
-
 func avifEncoder(p1, p2 string, extraParams config.ExtraParams) error {
 	// if convert fails, return error; success nil
 	var (
@@ -160,8 +153,12 @@ func avifEncoder(p1, p2 string, extraParams config.ExtraParams) error {
 		return err
 	}
 
-	if imageIgnore(img.Format()) {
-		return errors.New("encoder: ignore image type")
+	imageFormat := img.Format()
+	for _, ignore := range avifIgnore {
+		if imageFormat == ignore {
+			// Return err to render original image
+			return errors.New("AVIF encoder: ignore image type")
+		}
 	}
 
 	if config.Config.EnableExtraParams {
@@ -225,10 +222,13 @@ func webpEncoder(p1, p2 string, extraParams config.ExtraParams) error {
 		return err
 	}
 
-	if imageIgnore(img.Format()) {
-		return errors.New("encoder: ignore image type")
+	imageFormat := img.Format()
+	for _, ignore := range webpIgnore {
+		if imageFormat == ignore {
+			// Return err to render original image
+			return errors.New("WebP encoder: ignore image type")
+		}
 	}
-
 	if config.Config.EnableExtraParams {
 		err = resizeImage(img, extraParams)
 		if err != nil {
@@ -256,7 +256,7 @@ func webpEncoder(p1, p2 string, extraParams config.ExtraParams) error {
 			StripMetadata: true,
 		})
 	} else {
-		// If some special images cannot encode with default ReductionEffort(0), then try with 4
+		// If some special images cannot encode with default ReductionEffort(0), then retry from 0 to 6
 		// Example: https://github.com/webp-sh/webp_server_go/issues/234
 		ep := vips.WebpExportParams{
 			Quality:       quality,