Merge pull request #245 from gabriel-vasile/apng

Add APNG support. Closes #233

internal/magic/image.go

@@ -4,7 +4,11 @@ import "bytes"
 
 var (
 	// Png matches a Portable Network Graphics file.
+	// https://www.w3.org/TR/PNG/
 	Png = prefix([]byte{0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A})
+	// Apng matches an Animated Portable Network Graphics file.
+	// https://wiki.mozilla.org/APNG_Specification
+	Apng = offset([]byte("acTL"), 37)
 	// Jpg matches a Joint Photographic Experts Group file.
 	Jpg = prefix([]byte{0xFF, 0xD8, 0xFF})
 	// Jp2 matches a JPEG 2000 Image file (ISO 15444-1).

mimetype_test.go

@@ -30,6 +30,7 @@ var files = map[string]string{
 	"amf.amf":            "application/x-amf",
 	"amr.amr":            "audio/amr",
 	"ape.ape":            "audio/ape",
+	"apng.png":           "image/vnd.mozilla.apng",
 	"asf.asf":            "video/x-ms-asf",
 	"atom.atom":          "application/atom+xml",
 	"au.au":              "audio/basic",

supported_mimes.md

@@ -1,4 +1,4 @@
-## 168 Supported MIME types
+## 169 Supported MIME types
 This file is automatically generated when running tests. Do not edit manually.
 
 Extension | MIME type | Aliases
@@ -40,6 +40,7 @@ Extension | MIME type | Aliases
 **.oga** | audio/ogg | -
 **.ogv** | video/ogg | -
 **.png** | image/png | -
+**.png** | image/vnd.mozilla.apng | -
 **.jpg** | image/jpeg | -
 **.jxl** | image/jxl | -
 **.jp2** | image/jp2 | -

tree.go

@@ -113,7 +113,8 @@ var (
 	tcx     = newMIME("application/vnd.garmin.tcx+xml", ".tcx", magic.Tcx)
 	amf     = newMIME("application/x-amf", ".amf", magic.Amf)
 	threemf = newMIME("application/vnd.ms-package.3dmanufacturing-3dmodel+xml", ".3mf", magic.Threemf)
-	png     = newMIME("image/png", ".png", magic.Png)
+	png     = newMIME("image/png", ".png", magic.Png, apng)
+	apng    = newMIME("image/vnd.mozilla.apng", ".png", magic.Apng)
 	jpg     = newMIME("image/jpeg", ".jpg", magic.Jpg)
 	jxl     = newMIME("image/jxl", ".jxl", magic.Jxl)
 	jp2     = newMIME("image/jp2", ".jp2", magic.Jp2)