Add WebP image format support (Bug#51296)

* configure.ac (--with-webp): New option. (HAVE_WEBP): New variable. (emacs_config_features): Add webp. * src/image.c (enum webp_keyword_index) [HAVE_WEBP]: New enum. (webp_format) [HAVE_WEBP]: New variable. (webp_image_p, init_webp_functions, webp_load) [HAVE_WEBP]: New functions for WebP support. (image_types) [HAVE_WEBP]: Define WebP format. (syms_of_image) <Qwebp> [HAVE_WEBP]: New DEFSYM. Add image type Qwebp. * src/Makefile.in (LIBIMAGE): Add WEBP_LIBS. * lisp/files.el (auto-mode-alist): * lisp/image-file.el (image-file-name-extensions): * lisp/image.el (image-type-header-regexps) (image-type-file-name-regexps, image-type-auto-detectable): Add WebP support. * lisp/term/w32-win.el (dynamic-library-alist): Add the libwebp DLL. * INSTALL: * admin/CPP-DEFINES: * doc/lispref/display.texi (Image Formats, Other Image Types): * nt/INSTALL: Document WebP support. * test/lisp/image-tests.el (image-find-image) (image-type-from-file-name): Expand tests. * test/src/image-tests.el (image-tests--files): Add WebP. (image-tests-image-size/webp, image-tests-image-mask-p/webp) (image-tests-image-metadata/webp): New tests. * test/data/image/black.webp: New file.
2021-10-22 10:59:01 +02:00 · 2021-10-22 10:59:01 +02:00 · bc2a5c1127
commit bc2a5c1127
parent 938f10c601
15 changed files with 363 additions and 15 deletions
--- a/2
+++ b/2
@ -187,6 +187,7 @@ X11 is being used.
  X libtiff for TIFF: http://www.simplesystems.org/libtiff/
  X libgif for GIF:   http://giflib.sourceforge.net/
    librsvg2 for SVG: https://wiki.gnome.org/Projects/LibRsvg
+    libwebp for WebP: https://developers.google.com/speed/webp/

 If you supply the appropriate --without-LIB option, 'configure' will
 omit the corresponding library from Emacs, even if that makes for a
@ -313,6 +314,7 @@ or more of these options:
  --without-gif          for GIF image support
  --without-png          for PNG image support
  --without-rsvg         for SVG image support
+  --without-webp         for WebP image support

 Although ImageMagick support is disabled by default due to security
 and stability concerns, you can enable it with --with-imagemagick.
--- a/admin/CPP-DEFINES
+++ b/admin/CPP-DEFINES
@ -287,6 +287,7 @@ HAVE_UTIMENSAT
 HAVE_UTMP_H
 HAVE_VFORK
 HAVE_VFORK_H
+HAVE_WEBP
 HAVE_WCHAR_H
 HAVE_WCHAR_T
 HAVE_WINDOW_SYSTEM
--- a/configure.ac
+++ b/configure.ac
@ -447,6 +447,7 @@ OPTION_DEFAULT_ON([tiff],[don't compile with TIFF image support])
 OPTION_DEFAULT_ON([gif],[don't compile with GIF image support])
 OPTION_DEFAULT_ON([png],[don't compile with PNG image support])
 OPTION_DEFAULT_ON([rsvg],[don't compile with SVG image support])
+OPTION_DEFAULT_ON([webp],[don't compile with WebP image support])
 OPTION_DEFAULT_ON([lcms2],[don't compile with Little CMS support])
 OPTION_DEFAULT_ON([libsystemd],[don't compile with libsystemd support])
 OPTION_DEFAULT_ON([cairo],[don't compile with Cairo drawing])
@ -2588,6 +2589,28 @@ if test "${HAVE_X11}" = "yes" || test "${HAVE_NS}" = "yes" || test "${opsys}" =
  fi
 fi

+### Use -lwebp if available, unless '--with-webp=no'
+### mingw32 doesn't use -lwebp, since it loads the library dynamically.
+HAVE_WEBP=no
+if test "${with_webp}" != "no"; then
+   if test "$opsys" = mingw32; then
+      AC_CHECK_HEADER([webp/decode.h], [HAVE_WEBP=yes])
+   elif test "${HAVE_X11}" = "yes" || test "${HAVE_W32}" = "yes" \
+         || test "${HAVE_NS}" = "yes"; then
+      WEBP_REQUIRED=0.6.0
+      WEBP_MODULE="libwebp >= $WEBP_REQUIRED"
+
+      EMACS_CHECK_MODULES([WEBP], [$WEBP_MODULE])
+      AC_SUBST(WEBP_CFLAGS)
+      AC_SUBST(WEBP_LIBS)
+
+      if test $HAVE_WEBP = yes; then
+        AC_DEFINE(HAVE_WEBP, 1, [Define to 1 if using libwebp.])
+        CFLAGS="$CFLAGS $WEBP_CFLAGS"
+      fi
+   fi
+fi
+
 HAVE_IMAGEMAGICK=no
 if test "${HAVE_X11}" = "yes" || test "${HAVE_NS}" = "yes" || test "${HAVE_W32}" = "yes"; then
  if test "${with_imagemagick}" != "no"; then
@ -5882,8 +5905,8 @@ emacs_config_features=
 for opt in ACL CAIRO DBUS FREETYPE GCONF GIF GLIB GMP GNUTLS GPM GSETTINGS \
 HARFBUZZ IMAGEMAGICK JPEG JSON LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 \
 M17N_FLT MODULES NATIVE_COMP NOTIFY NS OLDXMENU PDUMPER PNG RSVG SECCOMP \
- SOUND THREADS TIFF \
- TOOLKIT_SCROLL_BARS UNEXEC X11 XAW3D XDBE XFT XIM XPM XWIDGETS X_TOOLKIT \
+ SOUND THREADS TIFF TOOLKIT_SCROLL_BARS \
+ UNEXEC WEBP X11 XAW3D XDBE XFT XIM XPM XWIDGETS X_TOOLKIT \
 ZLIB; do

    case $opt in
@ -5928,6 +5951,7 @@ AS_ECHO(["  Does Emacs use -lXaw3d?                                 ${HAVE_XAW3D
  Does Emacs use a gif library?                           ${HAVE_GIF} $LIBGIF
  Does Emacs use a png library?                           ${HAVE_PNG} $LIBPNG
  Does Emacs use -lrsvg-2?                                ${HAVE_RSVG}
+  Does Emacs use -lwebp?                                  ${HAVE_WEBP}
  Does Emacs use cairo?                                   ${HAVE_CAIRO}
  Does Emacs use -llcms2?                                 ${HAVE_LCMS2}
  Does Emacs use imagemagick?                             ${HAVE_IMAGEMAGICK}
--- a/doc/lispref/display.texi
+++ b/doc/lispref/display.texi
@ -5264,13 +5264,13 @@ to modify the set of known names for these dynamic libraries.
  Supported image formats (and the required support libraries) include
 PBM and XBM (which do not depend on support libraries and are always
 available), XPM (@code{libXpm}), GIF (@code{libgif} or
-@code{libungif}), JPEG (@code{libjpeg}), TIFF
-(@code{libtiff}), PNG (@code{libpng}), and SVG (@code{librsvg}).
+@code{libungif}), JPEG (@code{libjpeg}), TIFF (@code{libtiff}), PNG
+(@code{libpng}), SVG (@code{librsvg}), and WebP (@code{libwebp}).

  Each of these image formats is associated with an @dfn{image type
 symbol}.  The symbols for the above formats are, respectively,
-@code{pbm}, @code{xbm}, @code{xpm}, @code{gif},
-@code{jpeg}, @code{tiff}, @code{png}, and @code{svg}.
+@code{pbm}, @code{xbm}, @code{xpm}, @code{gif}, @code{jpeg},
+@code{tiff}, @code{png}, @code{svg}, and @code{webp}.

  Furthermore, if you build Emacs with ImageMagick
 (@code{libMagickWand}) support, Emacs can display any image format
@ -6274,6 +6274,9 @@ Image type @code{png}.
@item TIFF
 Image type @code{tiff}.
 Supports the @code{:index} property.  @xref{Multi-Frame Images}.
+
+@item WebP
+Image type @code{webp}.
@end table

@node Defining Images
--- a/etc/NEWS
+++ b/etc/NEWS
@ -61,6 +61,12 @@ Emacs previously didn't distinguish between the "regular" weight and
 the "medium" weight, but it now also supports the (heavier) "medium"
 weight.

+++
+** Support for the WebP image format.
+This support is built by default when the libwebp library is
+available.  To disable it, use the '--without-webp' configure flag.
+Image specifiers can now use ':type webp'.
+

 * Editing Changes in Emacs 29.1

--- a/lisp/files.el
+++ b/lisp/files.el
@ -2758,6 +2758,7 @@ since only a single case-insensitive search through the alist is made."
     ("\\.gif\\'" . image-mode)
     ("\\.png\\'" . image-mode)
     ("\\.jpe?g\\'" . image-mode)
+     ("\\.webp\\'" . image-mode)
     ("\\.te?xt\\'" . text-mode)
     ("\\.[tT]e[xX]\\'" . tex-mode)
     ("\\.ins\\'" . tex-mode)		;Installation files for TeX packages.
--- a/lisp/image-file.el
+++ b/lisp/image-file.el
@ -37,7 +37,7 @@

 ;;;###autoload
 (defcustom image-file-name-extensions
-  (purecopy '("png" "jpeg" "jpg" "gif" "tiff" "tif" "xbm" "xpm" "pbm" "pgm" "ppm" "pnm" "svg"))
+  (purecopy '("png" "jpeg" "jpg" "gif" "tiff" "tif" "xbm" "xpm" "pbm" "pgm" "ppm" "pnm" "svg" "webp"))
  "A list of image-file filename extensions.
 Filenames having one of these extensions are considered image files,
 in addition to those matching `image-file-name-regexps'.
--- a/lisp/image.el
+++ b/lisp/image.el
@ -48,6 +48,7 @@ static \\(unsigned \\)?char \\1_bits" . xbm)
    ("\\`\\(?:MM\0\\*\\|II\\*\0\\)" . tiff)
    ("\\`[\t\n\r ]*%!PS" . postscript)
    ("\\`\xff\xd8" . jpeg)    ; used to be (image-jpeg-p . jpeg)
+    ("\\`RIFF....WEBPVP8" . webp)
    (,(let* ((incomment-re "\\(?:[^-]\\|-[^-]\\)")
 	     (comment-re (concat "\\(?:!--" incomment-re "*-->[ \t\r\n]*<\\)")))
 	(concat "\\(?:<\\?xml[ \t\r\n]+[^>]*>\\)?[ \t\r\n]*<"
@ -67,6 +68,7 @@ a non-nil value, TYPE is the image's type.")
  '(("\\.png\\'" . png)
    ("\\.gif\\'" . gif)
    ("\\.jpe?g\\'" . jpeg)
+    ("\\.webp\\'" . webp)
    ("\\.bmp\\'" . bmp)
    ("\\.xpm\\'" . xpm)
    ("\\.pbm\\'" . pbm)
@ -92,6 +94,7 @@ be of image type IMAGE-TYPE.")
    (jpeg . maybe)
    (tiff . maybe)
    (svg . maybe)
+    (webp . maybe)
    (postscript . nil))
  "Alist of (IMAGE-TYPE . AUTODETECT) pairs used to auto-detect image files.
 \(See `image-type-auto-detected-p').
--- a/lisp/term/w32-win.el
+++ b/lisp/term/w32-win.el
@ -274,6 +274,7 @@ See the documentation of `create-fontset-from-fontset-spec' for the format.")
 	     '(gif "libgif-6.dll" "giflib5.dll" "gif.dll")
 	 '(gif "libgif-5.dll" "giflib4.dll" "libungif4.dll" "libungif.dll")))
       '(svg "librsvg-2-2.dll")
+       '(libwebp "libwebp-7.dll" "libwebp.dll")
       '(gdk-pixbuf "libgdk_pixbuf-2.0-0.dll")
       '(glib "libglib-2.0-0.dll")
       '(gio "libgio-2.0-0.dll")
--- a/nt/INSTALL
+++ b/nt/INSTALL
@ -488,6 +488,7 @@ build will run on Windows 9X and newer systems).
       Does Emacs use a gif library?                           yes
       Does Emacs use a png library?                           yes
       Does Emacs use -lrsvg-2?                                yes
+       Does Emacs use -lwebp?                                  yes
       Does Emacs use cairo?                                   no
       Does Emacs use -llcms2?                                 yes
       Does Emacs use imagemagick?                             no
@ -597,8 +598,8 @@ build will run on Windows 9X and newer systems).
 * Optional image library support

  In addition to its "native" image formats (pbm and xbm), Emacs can
-  handle other image types: xpm, tiff, gif, png, jpeg and experimental
-  support for svg.
+  handle other image types: xpm, tiff, gif, png, jpeg, webp and
+  experimental support for svg.

  To build Emacs with support for them, the corresponding headers must
  be in the include path and libraries should be where the linker
@ -736,6 +737,10 @@ build will run on Windows 9X and newer systems).
  without it by specifying the --without-rsvg switch to the configure
  script.

+  For WebP images you will need libwebp:
+
+    https://developers.google.com/speed/webp/
+
  Binaries for the other image libraries can be found on the
  ezwinports site or at the GnuWin32 project (the latter are generally
  very old, so not recommended).  Note specifically that, due to some
--- a/src/Makefile.in
+++ b/src/Makefile.in
@ -124,7 +124,7 @@ LIB_MATH=@LIB_MATH@
 ## -lpthread, or empty.
 LIB_PTHREAD=@LIB_PTHREAD@

-LIBIMAGE=@LIBTIFF@ @LIBJPEG@ @LIBPNG@ @LIBGIF@ @LIBXPM@
+LIBIMAGE=@LIBTIFF@ @LIBJPEG@ @LIBPNG@ @LIBGIF@ @LIBXPM@ @WEBP_LIBS@

 XCB_LIBS=@XCB_LIBS@
 XFT_LIBS=@XFT_LIBS@
--- a/src/image.c
+++ b/src/image.c
@ -8739,8 +8739,280 @@ gif_load (struct frame *f, struct image *img)
 #endif /* HAVE_GIF */


+#ifdef HAVE_WEBP
+
+
+/***********************************************************************
+				 WebP
+ ***********************************************************************/
+
+#include "webp/decode.h"
+
+/* Indices of image specification fields in webp_format, below.  */
+
+enum webp_keyword_index
+{
+  WEBP_TYPE,
+  WEBP_DATA,
+  WEBP_FILE,
+  WEBP_ASCENT,
+  WEBP_MARGIN,
+  WEBP_RELIEF,
+  WEBP_ALGORITHM,
+  WEBP_HEURISTIC_MASK,
+  WEBP_MASK,
+  WEBP_BACKGROUND,
+  WEBP_LAST
+};
+
+/* Vector of image_keyword structures describing the format
+   of valid user-defined image specifications.  */
+
+static const struct image_keyword webp_format[WEBP_LAST] =
+{
+  {":type",		IMAGE_SYMBOL_VALUE,			1},
+  {":data",		IMAGE_STRING_VALUE,			0},
+  {":file",		IMAGE_STRING_VALUE,			0},
+  {":ascent",		IMAGE_ASCENT_VALUE,			0},
+  {":margin",		IMAGE_NON_NEGATIVE_INTEGER_VALUE_OR_PAIR, 0},
+  {":relief",		IMAGE_INTEGER_VALUE,			0},
+  {":conversion",	IMAGE_DONT_CHECK_VALUE_TYPE,		0},
+  {":heuristic-mask",	IMAGE_DONT_CHECK_VALUE_TYPE,		0},
+  {":mask",		IMAGE_DONT_CHECK_VALUE_TYPE,		0},
+  {":background",	IMAGE_STRING_OR_NIL_VALUE,		0}
+};
+
+/* Return true if OBJECT is a valid WebP image specification.  */
+
+static bool
+webp_image_p (Lisp_Object object)
+{
+  struct image_keyword fmt[WEBP_LAST];
+  memcpy (fmt, webp_format, sizeof fmt);
+
+  if (!parse_image_spec (object, fmt, WEBP_LAST, Qwebp))
+    return false;
+
+  /* Must specify either the :data or :file keyword.  */
+  return fmt[WEBP_FILE].count + fmt[WEBP_DATA].count == 1;
+}
+
+#ifdef WINDOWSNT
+
+/* WebP library details.  */
+
+DEF_DLL_FN (int, WebPGetInfo, (const uint8_t *, size_t, int *, int *));
+DEF_DLL_FN (VP8StatusCode, WebPGetFeatures, (const uint8_t *, size_t, WebPBitstreamFeatures *));
+DEF_DLL_FN (uint8_t *, WebPDecodeRGB, (const uint8_t *, size_t, int *, int *));
+DEF_DLL_FN (uint8_t *, WebPDecodeBGR, (const uint8_t *, size_t, int *, int *));
+DEF_DLL_FN (void, WebPFreeDecBuffer (WebPDecBuffer *));
+
+static bool
+init_webp_functions (void)
+{
+  HMODULE library;
+
+  if (!(library = w32_delayed_load (Qwebp)))
+    return false;
+
+  LOAD_DLL_FN (library, WebPGetInfo);
+  LOAD_DLL_FN (library, WebPGetFeatures);
+  LOAD_DLL_FN (library, WebPDecodeRGBA);
+  LOAD_DLL_FN (library, WebPDecodeRGB);
+  LOAD_DLL_FN (library, WebPFree);
+  return true;
+}
+
+#undef WebPGetInfo
+#undef WebPGetFeatures
+#undef WebPDecodeRGBA
+#undef WebPDecodeRGB
+#undef WebPFree
+
+#define WebPGetInfo fn_WebPGetInfo
+#define WebPGetFeatures fn_WebPGetFeatures
+#define WebPDecodeRGBA fn_WebPDecodeRGBA
+#define WebPDecodeRGB fn_WebPDecodeRGB
+#define WebPFree fn_WebPFree
+
+#endif /* WINDOWSNT */
+
+/* Load WebP image IMG for use on frame F.  Value is true if
+   successful.  */
+
+static bool
+webp_load (struct frame *f, struct image *img)
+{
+  ptrdiff_t size = 0;
+  uint8_t *contents;
+  Lisp_Object file;
+
+  /* Open the WebP file.  */
+  Lisp_Object specified_file = image_spec_value (img->spec, QCfile, NULL);
+  Lisp_Object specified_data = image_spec_value (img->spec, QCdata, NULL);
+
+  if (NILP (specified_data))
+    {
+      int fd;
+      file = image_find_image_fd (specified_file, &fd);
+      if (!STRINGP (file))
+	{
+	  image_error ("Cannot find image file `%s'", specified_file);
+	  return false;
+	}
+
+      contents = (uint8_t *) slurp_file (fd, &size);
+      if (contents == NULL)
+	{
+	  image_error ("Error loading WebP image `%s'", file);
+	  return false;
+	}
+    }
+  else
+    {
+      if (!STRINGP (specified_data))
+	{
+	  image_error ("Invalid image data `%s'", specified_data);
+	  return false;
+	}
+      contents = SDATA (specified_data);
+      size = SBYTES (specified_data);
+    }
+
+  /* Validate the WebP image header.  */
+  if (!WebPGetInfo (contents, size, NULL, NULL))
+    {
+      if (!NILP (specified_data))
+	image_error ("Not a WebP file: `%s'", file);
+      else
+	image_error ("Invalid header in WebP image data");
+      goto webp_error1;
+    }
+
+  /* Get WebP features.  */
+  WebPBitstreamFeatures features;
+  VP8StatusCode result = WebPGetFeatures (contents, size, &features);
+  switch (result)
+    {
+    case VP8_STATUS_OK:
+      break;
+    case VP8_STATUS_NOT_ENOUGH_DATA:
+    case VP8_STATUS_OUT_OF_MEMORY:
+    case VP8_STATUS_INVALID_PARAM:
+    case VP8_STATUS_BITSTREAM_ERROR:
+    case VP8_STATUS_UNSUPPORTED_FEATURE:
+    case VP8_STATUS_SUSPENDED:
+    case VP8_STATUS_USER_ABORT:
+    default:
+      /* Error out in all other cases.  */
+      if (!NILP (specified_data))
+	image_error ("Error when interpreting WebP image data: `%s'", file);
+      else
+	image_error ("Error when interpreting WebP image data");
+      goto webp_error1;
+    }
+
+  /* Decode WebP data.  */
+  uint8_t *decoded;
+  int width, height;
+  if (features.has_alpha)
+    /* Linear [r0, g0, b0, a0, r1, g1, b1, a1, ...] order.  */
+    decoded = WebPDecodeRGBA (contents, size, &width, &height);
+  else
+    /* Linear [r0, g0, b0, r1, g1, b1, ...] order.  */
+    decoded = WebPDecodeRGB (contents, size, &width, &height);
+
+  if (!(width <= INT_MAX && height <= INT_MAX
+	&& check_image_size (f, width, height)))
+    {
+      image_size_error ();
+      goto webp_error2;
+    }
+
+  /* Create the x image and pixmap.  */
+  Emacs_Pix_Container ximg, mask_img;
+  if (!image_create_x_image_and_pixmap (f, img, width, height, 0, &ximg, false))
+    goto webp_error2;
+
+  /* Create an image and pixmap serving as mask if the WebP image
+     contains an alpha channel.  */
+  if (features.has_alpha
+      && !image_create_x_image_and_pixmap (f, img, width, height, 1, &mask_img, true))
+    {
+      image_destroy_x_image (ximg);
+      image_clear_image_1 (f, img, CLEAR_IMAGE_PIXMAP);
+      goto webp_error2;
+    }
+
+  /* Fill the X image and mask from WebP data.  */
+  init_color_table ();
+
+  uint8_t *p = decoded;
+  for (int y = 0; y < height; ++y)
+    {
+      for (int x = 0; x < width; ++x)
+	{
+	  int r = *p++ << 8;
+	  int g = *p++ << 8;
+	  int b = *p++ << 8;
+	  PUT_PIXEL (ximg, x, y, lookup_rgb_color (f, r, g, b));
+
+	  /* An alpha channel associates variable transparency with an
+	     image.  WebP allows up to 256 levels of partial transparency.
+	     We handle this like with PNG (which see), using the frame's
+	     background color to combine the image with.  */
+	  if (features.has_alpha)
+	    {
+	      if (mask_img)
+		PUT_PIXEL (mask_img, x, y, *p > 0 ? PIX_MASK_DRAW : PIX_MASK_RETAIN);
+	      ++p;
+	    }
+	}
+    }
+
+#ifdef COLOR_TABLE_SUPPORT
+  /* Remember colors allocated for this image.  */
+  img->colors = colors_in_color_table (&img->ncolors);
+  free_color_table ();
+#endif /* COLOR_TABLE_SUPPORT */
+
+  /* Put ximg into the image.  */
+  image_put_x_image (f, img, ximg, 0);
+
+  /* Same for the mask.  */
+  if (mask_img)
+    {
+      /* Fill in the background_transparent field while we have the
+	 mask handy.  Casting avoids a GCC warning.  */
+      image_background_transparent (img, f, (Emacs_Pix_Context)mask_img);
+
+      image_put_x_image (f, img, mask_img, 1);
+    }
+
+  img->width = width;
+  img->height = height;
+
+  /* Clean up.  */
+  WebPFree (decoded);
+  if (NILP (specified_data))
+    xfree (contents);
+  return true;
+
+ webp_error2:
+  WebPFree (decoded);
+
+ webp_error1:
+  if (NILP (specified_data))
+    xfree (contents);
+  return false;
+}
+
+#endif /* HAVE_WEBP */
+
+
 #ifdef HAVE_IMAGEMAGICK

+
 /***********************************************************************
 				 ImageMagick
 ***********************************************************************/
@ -10725,6 +10997,10 @@ static struct image_type const image_types[] =
 #if defined HAVE_XPM || defined HAVE_NS
 { SYMBOL_INDEX (Qxpm), xpm_image_p, xpm_load, image_clear_image,
   IMAGE_TYPE_INIT (init_xpm_functions) },
+#endif
+#if defined HAVE_WEBP
+ { SYMBOL_INDEX (Qwebp), webp_image_p, webp_load, image_clear_image,
+   IMAGE_TYPE_INIT (init_webp_functions) },
 #endif
 { SYMBOL_INDEX (Qxbm), xbm_image_p, xbm_load, image_clear_image },
 { SYMBOL_INDEX (Qpbm), pbm_image_p, pbm_load, image_clear_image },
@ -10891,6 +11167,11 @@ non-numeric, there is no explicit limit on the size of images.  */);
  add_image_type (Qpng);
 #endif

+#if defined (HAVE_WEBP)
+  DEFSYM (Qwebp, "webp");
+  add_image_type (Qwebp);
+#endif
+
 #if defined (HAVE_IMAGEMAGICK)
  DEFSYM (Qimagemagick, "imagemagick");
  add_image_type (Qimagemagick);
--- a/test/data/image/black.webp
+++ b/test/data/image/black.webp
--- a/test/lisp/image-tests.el
+++ b/test/lisp/image-tests.el
@ -49,12 +49,14 @@
    (should (equal image '(image)))))

 (ert-deftest image-find-image ()
-  (find-image '((:type xpm :file "undo.xpm")))
-  (find-image '((:type png :file "newsticker/rss-feed.png" :ascent center))))
+  (should (listp (find-image '((:type xpm :file "undo.xpm")))))
+  (should (listp (find-image '((:type png :file "newsticker/rss-feed.png" :ascent center)))))
+  (should-not (find-image '((:type png :file "does-not-exist-foo-bar.png")))))

 (ert-deftest image-type-from-file-name ()
  (should (eq (image-type-from-file-name "foo.jpg") 'jpeg))
-  (should (eq (image-type-from-file-name "foo.png") 'png)))
+  (should (eq (image-type-from-file-name "foo.png") 'png))
+  (should (eq (image-type-from-file-name "foo.webp") 'webp)))

 (ert-deftest image-type/from-filename ()
  ;; On emba, `image-types' and `image-load-path' do not exist.
--- a/test/src/image-tests.el
+++ b/test/src/image-tests.el
@ -44,6 +44,8 @@
    (tiff . ,(expand-file-name
              "nextstep/GNUstep/Emacs.base/Resources/emacs.tiff"
              source-directory))
+    (webp . ,(expand-file-name "test/data/image/black.webp"
+                               source-directory))
    (xbm . ,(find-image '((:file "gnus/gnus.xbm" :type xbm))))
    (xpm . ,(find-image '((:file "splash.xpm" :type xpm))))
    ;; TODO: gif
@ -86,6 +88,13 @@
     (should (floatp a))
     (should (floatp b)))))

+(ert-deftest image-tests-image-size/webp ()
+  (image-skip-unless 'webp)
+  (pcase (image-size (create-image (cdr (assq 'webp image-tests--files))))
+    (`(,a . ,b)
+     (should (floatp a))
+     (should (floatp b)))))
+
 (ert-deftest image-tests-image-size/xbm ()
  (image-skip-unless 'xbm)
  (pcase (image-size (cdr (assq 'xbm image-tests--files)))
@ -130,7 +139,12 @@
 (ert-deftest image-tests-image-mask-p/tiff ()
  (image-skip-unless 'tiff)
  (should-not (image-mask-p (create-image
-			     (cdr (assq 'tiff image-tests--files))))))
+                             (cdr (assq 'tiff image-tests--files))))))
+
+(ert-deftest image-tests-image-mask-p/webp ()
+  (image-skip-unless 'webp)
+  (should-not (image-mask-p (create-image
+                             (cdr (assq 'webp image-tests--files))))))

 (ert-deftest image-tests-image-mask-p/xbm ()
  (image-skip-unless 'xbm)
@ -173,7 +187,12 @@
 (ert-deftest image-tests-image-metadata/tiff ()
  (image-skip-unless 'tiff)
  (should-not (image-metadata
-	       (create-image (cdr (assq 'tiff image-tests--files))))))
+               (create-image (cdr (assq 'tiff image-tests--files))))))
+
+(ert-deftest image-tests-image-metadata/webp ()
+  (image-skip-unless 'webp)
+  (should-not (image-metadata
+               (create-image (cdr (assq 'webp image-tests--files))))))

 (ert-deftest image-tests-image-metadata/xbm ()
  (image-skip-unless 'xbm)