Subject: 26.1; windows 10 emacs doesn't draw *some* pngs correctly

From: James Nguyen <[email-masked]>
Date: Fri, 17 Aug 2018 18:56:02 -0700

https://github.com/jojojames/emacs-windows-png-repro

Added some screenshots here^

Pngs created using imagemagick from svg files do not display correctly
in Emacs (they do not display transparency correctly). In the linked
repro, the images are surrounded with a yellow/orange instead of transparency.

The images display with transparency in other Windows programs I
tried. (Web browser, File browser, default image viewer in Windows.)
These images also display correctly on OSX (and its various
applications, including Emacs).

After playing around with the imagemagick setting, it seems prefixing
PNG32: to the output file makes the image compatible with Windows Emacs.

In GNU Emacs 27.0.50 (build 1, x86_64-w64-mingw32)
 of 2018-05-03 built on CIRROCUMULUS
Repository revision: cbb9c78de081e37cf0b2ab6f35022abf89507d9c
Windowing system distributor 'Microsoft Corp.', version 10.0.17134
Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Contacting host: www.gnu.org:443
Type C-c C-c or C-c C-x to view the image as text or hex.
Mark set
Quit
Type C-c C-c or C-c C-x to view the image as text or hex. [2 times]
Making completion list... [2 times]
kill-region: Buffer is read-only: #<buffer *GNU Emacs*>
j is undefined

Configured using:
 'configure --without-dbus --host=x86_64-w64-mingw32
 --without-compress-install -C 'CFLAGS=-O2 -static -g3''

Configured features:
XPM JPEG TIFF GIF PNG RSVG SOUND NOTIFY ACL GNUTLS LIBXML2 ZLIB
TOOLKIT_SCROLL_BARS THREADS LCMS2

Important settings:
  value of $LANG: ENU
  locale-coding-system: cp1252

Major mode: Fundamental

Minor modes in effect:
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  global-eldoc-mode: t
  electric-indent-mode: t
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  menu-bar-mode: t
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  global-font-lock-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  buffer-read-only: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
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image-mode dired dired-loaddefs cl-extra help-mode network-stream
starttls url-http tls gnutls mail-parse rfc2231 url-gw nsm rmc url-cache
url-auth eww easymenu mm-url gnus nnheader gnus-util rmail
rmail-loaddefs rfc2047 rfc2045 ietf-drums mail-utils wid-edit mm-util
mail-prsvr url-queue url url-proxy url-privacy url-expand url-methods
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byte-compile cconv dom format-spec cl-loaddefs cl-lib browse-url
time-date elec-pair mule-util tooltip eldoc electric uniquify ediff-hook
vc-hooks lisp-float-type mwheel dos-w32 ls-lisp disp-table term/w32-win
w32-win w32-vars term/common-win tool-bar dnd fontset image regexp-opt
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button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote w32notify w32 lcms2 multi-tty make-network-process emacs)

Memory information:
((conses 16 185420 11623)
 (symbols 56 24180 1)
 (miscs 48 100 162)
 (strings 32 50753 1327)
 (string-bytes 1 1377740)
 (vectors 16 19310)
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