bug#27086: perhaps always use a white background when viewing transparent PNGs etc.

bug#27086: perhaps always use a white background when viewing transparent PNGs etc.

[積丹尼 Dan Jacobson]

With this color,
(add-to-list 'default-frame-alist '(background-color . "DarkSlateGray"))
looking at
http://jidanni.org/location/directions/qingfujie_slope.png
is tough for the words outside the graph.
So perhaps always use a white background when viewing transparent PNGs, etc.

bug#27086: perhaps always use a white background when viewing transparent PNGs etc.

[npostavs]

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積丹尼 Dan Jacobson <jidanni@jidanni.org> writes:

> With this color,
> (add-to-list 'default-frame-alist '(background-color . "DarkSlateGray"))
> looking at
> http://jidanni.org/location/directions/qingfujie_slope.png
> is tough for the words outside the graph.

I don't see any problem.  It looks like that png has a non-transparent
white background?


[-- Attachment #2: screenshot with default background colour --]
[-- Type: image/png, Size: 35769 bytes --]

[-- Attachment #3: screenshot with gray background colour --]
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> So perhaps always use a white background when viewing transparent PNGs, etc.

Seems to me if a PNG needs a certain background colour to be readable,
then it shouldn't be transparent.  What if you had a transparent PNG
with white words?

bug#27086: perhaps always use a white background when viewing transparent PNGs etc.

[積丹尼 Dan Jacobson]

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Here's what I see when I save
http://jidanni.org/location/directions/qingfujie_slope.png
to disk and use C-x C-f on it with my
(add-to-list 'default-frame-alist '(background-color . "DarkSlateGray"))
color.

[-- Attachment #2: d.jpg --]
[-- Type: image/jpeg, Size: 25788 bytes --]

bug#27086: perhaps always use a white background when viewing transparent PNGs etc.

[Stefan Kangas]

積丹尼 Dan Jacobson <jidanni@jidanni.org> writes:

> Here's what I see when I save
> http://jidanni.org/location/directions/qingfujie_slope.png
> to disk and use C-x C-f on it with my
> (add-to-list 'default-frame-alist '(background-color . "DarkSlateGray"))
> color.

I can't reproduce this on current master using:

0. emacs -Q
1. Evaluate:
(add-to-list 'default-frame-alist '(background-color . "DarkSlateGray"))
2. C-x 5 2
3. C-x C-f qingfujie_slope.png RET

Result is a gray background, but the image displays just fine.

Are you still seeing this?

Best regards,
Stefan Kangas

bug#27086: perhaps always use a white background when viewing transparent PNGs etc.

[積丹尼 Dan Jacobson]

>>>>> "SK" == Stefan Kangas <stefan@marxist.se> writes:

SK> Result is a gray background, but the image displays just fine.

Well I got rid of all the transparency on my website. So you will need a
different transparent test file.

bug#27086: perhaps always use a white background when viewing transparent PNGs etc.

[Stefan Kangas]

Dan Jacobson <jidanni@jidanni.org> writes:

> SK> Result is a gray background, but the image displays just fine.
>
> Well I got rid of all the transparency on my website. So you will need a
> different transparent test file.

Could you please provide an image where you can reproduce this issue?

Best regards,
Stefan Kangas

bug#27086: perhaps always use a white background when viewing transparent PNGs etc.

[積丹尼 Dan Jacobson]

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OK. Let's start fresh.
Something I'm doing in https://www.jidanni.org/comp/configuration
makes

[-- Attachment #2: N.png --]
[-- Type: image/png, Size: 16627 bytes --]

[-- Attachment #3: Type: text/plain, Size: 12 bytes --]

render like

[-- Attachment #4: Yuck.jpg --]
[-- Type: image/jpeg, Size: 25961 bytes --]

[-- Attachment #5: Type: text/plain, Size: 178 bytes --]

just as ugly as it does in chromium.

But it looks great in firefox, and emacs -Q.
So there is something in my above configuration causing it to look ugly.

emacs-version "26.3"

bug#27086: perhaps always use a white background when viewing transparent PNGs etc.

[Lars Ingebrigtsen]

積丹尼 Dan Jacobson <jidanni@jidanni.org> writes:

> OK. Let's start fresh.
> Something I'm doing in https://www.jidanni.org/comp/configuration
> makes

I'm guessing it's an image rendered towards white, but with a
transparent background?  And you have a black background in your Emacs?

Then there's nothing we can do here -- the PNG itself is badly made
(instead of using alpha channels it's just marking pixels as either
fully transparent or fully opaque).

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#27086: perhaps always use a white background when viewing transparent PNGs etc.

[積丹尼 Dan Jacobson]

>>>>> "LI" == Lars Ingebrigtsen <larsi@gnus.org> writes:
LI> you have a black background in your Emacs?

Yes.

LI> Then there's nothing we can do here -- the PNG itself is badly made
LI> (instead of using alpha channels it's just marking pixels as either
LI> fully transparent or fully opaque).

Well looks great in Firefox.
Firefox always does the right thing.

bug#27086: perhaps always use a white background when viewing transparent PNGs etc.

[Lars Ingebrigtsen]

積丹尼 Dan Jacobson <jidanni@jidanni.org> writes:

> LI> Then there's nothing we can do here -- the PNG itself is badly made
> LI> (instead of using alpha channels it's just marking pixels as either
> LI> fully transparent or fully opaque).
>
> Well looks great in Firefox.
> Firefox always does the right thing.

Sounds like Firefox defaults to white backgrounds on these images, but
if the PNG had been constructed the other way (towards black), then that
would have looked equally bad.

So it doesn't seem like there's anything we can do here.

Did you forward the original PNG file to the bug tracker?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#27086: perhaps always use a white background when viewing transparent PNGs etc.

[積丹尼 Dan Jacobson]

Well then you are supposed to use a checkerboard pattern I suppose.
https://bugs.chromium.org/p/chromium/issues/detail?id=991197
Not just leave things up to chance so they look good for Mr. X, but not
when sent to Mr. X's boss or later during a conference.

(LI> Did you forward the original PNG file to the bug tracker?
Just use the latest attachment I added.)

bug#27086: perhaps always use a white background when viewing transparent PNGs etc.

[Lars Ingebrigtsen]

積丹尼 Dan Jacobson <jidanni@jidanni.org> writes:

> Well then you are supposed to use a checkerboard pattern I suppose.
> https://bugs.chromium.org/p/chromium/issues/detail?id=991197
> Not just leave things up to chance so they look good for Mr. X, but not
> when sent to Mr. X's boss or later during a conference.

Heh, I don't think so.  Most transparent images look nice.

> (LI> Did you forward the original PNG file to the bug tracker?
> Just use the latest attachment I added.)

Oh, I thought that PNG was to demonstrate how it looked in Emacs.  If
you want to look what it looks like with a checkerboard, open it in
gimp.

(Spoilers: It looks horrible.)

So there's no bug on Emacs' side -- the image is just badly made.
Closing.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no