RSS/Atom feed Twitter
Site is read-only, email is disabled

PNG binary transparency

This discussion is connected to the gimp-user-list.gnome.org mailing list which is provided by the GIMP developers and not related to gimpusers.com.

This is a read-only list on gimpusers.com so this discussion thread is read-only, too.

24 of 24 messages available
Toggle history

Please log in to manage your subscriptions.

PNG binary transparency Diaa Sami 12 Sep 07:37
  PNG binary transparency Brion Vibber 12 Sep 08:35
   PNG binary transparency Diaa Sami 12 Sep 18:12
    PNG binary transparency michael chang 13 Sep 00:04
     PNG binary transparency Jeffrey Brent McBeth 13 Sep 00:18
      PNG binary transparency Diaa Sami 13 Sep 05:06
       PNG binary transparency Jeffrey Brent McBeth 13 Sep 06:06
        PNG binary transparency Diaa Sami 13 Sep 16:30
         PNG binary transparency Jeffrey Brent McBeth 13 Sep 16:54
          PNG binary transparency michael chang 13 Sep 22:26
           PNG binary transparency Jeffrey Brent McBeth 13 Sep 22:54
            PNG binary transparency Chris Kinata [kcom] 13 Sep 23:23
             PNG binary transparency Carol Spears 14 Sep 00:04
              PNG binary transparency Chris Kinata [kcom] 14 Sep 00:41
               PNG binary transparency Carol Spears 14 Sep 01:02
                PNG binary transparency Chris Kinata [kcom] 14 Sep 01:22
                 PNG binary transparency michael chang 14 Sep 02:00
                  PNG binary transparency Carol Spears 14 Sep 02:24
                PNG binary transparency Carol Spears 14 Sep 01:48
              PNG binary transparency Carol Spears 14 Sep 01:10
           PNG binary transparency Patrick Shanahan 13 Sep 23:22
            PNG binary transparency michael chang 13 Sep 23:37
           PNG binary transparency Michael Schumacher 14 Sep 20:00
            PNG binary transparency Jeffrey Brent McBeth 14 Sep 20:42
Diaa Sami
2005-09-12 07:37:52 UTC (over 18 years ago)

PNG binary transparency

hi,

AFAIK, the PNG file format supports two kinds of transparency: variable transparency(alpha channel) and binary transparency. I know how to add an alpha channel to the image and manipulate it, but what I'm asking about is the binary transparency, there should be a method to choose a color that will be the transparent color(like GIF's), I know I can use the alpha channel to simulate this(using Select By Color or something), but I want it to be saved to the PNG file as a transparent color.
Is this supported by the GIMP?

thanks much.

Brion Vibber
2005-09-12 08:35:35 UTC (over 18 years ago)

PNG binary transparency

Diaa Sami wrote:

AFAIK, the PNG file format supports two kinds of transparency: variable transparency(alpha channel) and binary transparency. I know how to add an alpha channel to the image and manipulate it, but what I'm asking about is the binary transparency, there should be a method to choose a color that will be the transparent color(like GIF's), I know I can use the alpha channel to simulate this(using Select By Color or something), but I want it to be saved to the PNG file as a transparent color.
Is this supported by the GIMP?

If you save an indexed-color image as a PNG from Gimp, it will be saved in binary transparency mode just like a GIF.

-- brion vibber (brion @ pobox.com)

Diaa Sami
2005-09-12 18:12:40 UTC (over 18 years ago)

PNG binary transparency

actually I need to do this with 24-bit PNG's, is it possible? it it's not, do u know any other free tool that does this?

michael chang
2005-09-13 00:04:59 UTC (over 18 years ago)

PNG binary transparency

On 9/12/05, Diaa Sami wrote:

actually I need to do this with 24-bit PNG's, is it possible? it it's not, do u know any other free tool that does this?

AFAIK GIMP doesn't support 24-bit colour. Apparently it's a limitation in GIMP's current design, and won't be fixed for a long time.

And Sorry, I don't know of any free tools that do what you want.

Jeffrey Brent McBeth
2005-09-13 00:18:41 UTC (over 18 years ago)

PNG binary transparency

On Mon, Sep 12, 2005 at 06:04:59PM -0400, michael chang wrote:

On 9/12/05, Diaa Sami wrote:

actually I need to do this with 24-bit PNG's, is it possible? it it's not, do u know any other free tool that does this?

AFAIK GIMP doesn't support 24-bit colour. Apparently it's a limitation in GIMP's current design, and won't be fixed for a long time.

Apparently, my e-mail from before didn't go out)

GIMP definitely supports 24-bit color. This is 8-bits per channel (R,G,B). With an Alpha channel (more on that later) that is 32-bit color. GIMP does not support 16-bit per channel (48/64 bit color).

Now that that is cleared up.

Diaa, I have read your e-mail several times, and I don't have a clue what you are trying to do. Perhaps some clarification would be in order? I'm very familiar with the PNG format, having written and ported encoders/decoders for various projects.

You can do binary transparency with 24-bit PNGs by thresholding the alpha channel. This will leave you with just on and off (255 and 0). This is under
Layer -> Transparency -> Threshold Alpha

If you want to convert a color to transparent, you want Layer -> Transparency -> Color to Alpha

If what is really happening, is that your application has the old hack where a certain color represents transparent (usually olive or magenta), then just draw that color in the bits that you want transparent. It is up to your application to then render that color as transparent.

Jeff

Diaa Sami
2005-09-13 05:06:14 UTC (over 18 years ago)

PNG binary transparency

first, I want to thank you for your long and clear response.

well, you're asking about what I'm trying to achieve. what I want is to have somekind of transparent color which is written in the PNG file.
I don't want to have an alpha channel, just that transparent color.

I'm don't know the details of the PNG file format, but I almost sure it is possible, because IrfanView does it. if you want, download that IrfanView, and choose PNG as the saving file format, you'll find a checkbox called 'save transparent color'.

if you are curious why I do want this, well, when I load the image into my program, I check the color of each pixel for equality with the transparent color, and if they're not equal, I modify it, also having a transparent color(as opposed to an alpha channel) speeds up drawing on the library I'm using(which's SDL).

thanks much.

Jeffrey Brent McBeth
2005-09-13 06:06:09 UTC (over 18 years ago)

PNG binary transparency

On Tue, Sep 13, 2005 at 06:06:14AM +0300, Diaa Sami wrote:

first, I want to thank you for your long and clear response.

well, you're asking about what I'm trying to achieve. what I want is to have somekind of transparent color which is written in the PNG file.
I don't want to have an alpha channel, just that transparent color.

I'm don't know the details of the PNG file format, but I almost sure it is possible, because IrfanView does it. if you want, download that IrfanView, and choose PNG as the saving file format, you'll find a checkbox called 'save transparent color'.

Ahhh. "tRNS" I haven't looked at that chunk in a long time. Hmm, I hate to say it, but ImageMagick might be your best bet. I actually wasn't aware of this particular trick of using tRNS without a PLTE chunk in the image. Interesting.

Yeah, create the image in GIMP with whatever the color you want to have be transparent in place, then in ImageMagick, run

convert input.png -transparent color output.png

My initial reaction was that it would be easy to patch the GIMP to mimic ImageMagick's behaviour, but it really is a can of worms having a color pretend to be transparent.

Jeff

Diaa Sami
2005-09-13 16:30:21 UTC (over 18 years ago)

PNG binary transparency

Jeffrey Brent McBeth wrote:

On Tue, Sep 13, 2005 at 06:06:14AM +0300, Diaa Sami wrote:

first, I want to thank you for your long and clear response.

well, you're asking about what I'm trying to achieve. what I want is to have somekind of transparent color which is written in the PNG file.
I don't want to have an alpha channel, just that transparent color.

I'm don't know the details of the PNG file format, but I almost sure it is possible, because IrfanView does it. if you want, download that IrfanView, and choose PNG as the saving file format, you'll find a checkbox called 'save transparent color'.

Ahhh. "tRNS" I haven't looked at that chunk in a long time. Hmm, I hate to say it, but ImageMagick might be your best bet. I actually wasn't aware of this particular trick of using tRNS without a PLTE chunk in the image. Interesting.

Yeah, create the image in GIMP with whatever the color you want to have be transparent in place, then in ImageMagick, run

convert input.png -transparent color output.png

My initial reaction was that it would be easy to patch the GIMP to mimic ImageMagick's behaviour, but it really is a can of worms having a color pretend to be transparent.

Jeff

that's exactly what I wanted, I looked into PNG docs, and I found out that there are two functions responsible for this, which are png_get_tRNS and png_set_tRNS.

ok, I'll use ImageMagick to do it.

Jeffrey Brent McBeth
2005-09-13 16:54:17 UTC (over 18 years ago)

PNG binary transparency

On Tue, Sep 13, 2005 at 05:30:21PM +0300, Diaa Sami wrote:

that's exactly what I wanted, I looked into PNG docs, and I found out that there are two functions responsible for this, which are png_get_tRNS and png_set_tRNS.

Yup. For just about any chunk, there is a get/set pair in the reference implementation. The GIMP could easily figure out when the alpha is binary (to use tRNS rather than RGBA), but picking out an unused color to represent transparent that is acceptible to the user, applications, and further editing is an impossible (or difficult) task.

IE ignores tRNS when you aren't in palette mode, anytime you added some of that color to an image, it would turn transparent seperate from what you expect, etc.

ok, I'll use ImageMagick to do it.

Glad I could help.

michael chang
2005-09-13 22:26:39 UTC (over 18 years ago)

PNG binary transparency

On 9/13/05, Jeffrey Brent McBeth wrote:

On Tue, Sep 13, 2005 at 05:30:21PM +0300, Diaa Sami wrote:

that's exactly what I wanted, I looked into PNG docs, and I found out that there are two functions responsible for this, which are png_get_tRNS and png_set_tRNS.

Yup. For just about any chunk, there is a get/set pair in the reference implementation. The GIMP could easily figure out when the alpha is binary (to use tRNS rather than RGBA), but picking out an unused color to represent transparent that is acceptible to the user, applications, and further editing is an impossible (or difficult) task.

This sounds like something that should be only created if it's set by the user -- e.g. a save option. Although then it'd have to be specified every time, which might be annoying. In that case, you'd still see the colour that acts transparent in GIMP - just not when it's actually edited. That said, that might be inconvienent for those who use GIMP as an image viewer, and confuddle users of GAP.

IE ignores tRNS when you aren't in palette mode, anytime you added some of that color to an image, it would turn transparent seperate from what you expect, etc.

So logically, should we even be using tRNS in PNG anyway? IE is one of the most commonly used browsers, AFAIK...

Jeffrey Brent McBeth
2005-09-13 22:54:57 UTC (over 18 years ago)

PNG binary transparency

On Tue, Sep 13, 2005 at 04:26:39PM -0400, michael chang wrote:

IE ignores tRNS when you aren't in palette mode, anytime you added some of that color to an image, it would turn transparent seperate from what you expect, etc.

So logically, should we even be using tRNS in PNG anyway? IE is one of the most commonly used browsers, AFAIK...

Absolutely. IE's PNG transparency support is broken. Has been, and will be for a long time. People can't ignore standards just because MS does. Plus, the question was for a file that will never see the light of day in IE.

Jeff

Patrick Shanahan
2005-09-13 23:22:51 UTC (over 18 years ago)

PNG binary transparency

* michael chang [09-13-05 15:33]:

So logically, should we even be using tRNS in PNG anyway? IE is one of the most commonly used browsers, AFAIK...

Why would you cripple a *good* program because a *bad* program, IE, is broken?

Chris Kinata [kcom]
2005-09-13 23:23:14 UTC (over 18 years ago)

PNG binary transparency

Hi all...

I was frustrated about IE PNG support (still am), but did some research, and found several ways to fix this in IE, depending on what you want. Here are some links:

http://homepage.ntlworld.com/bobosola/ http://www.webcolors.freeserve.co.uk/png/png-alpha-transparency.htm http://blogs.msdn.com/dmassy/archive/2004/08/05/209428.aspx http://youngpup.net/2001/sleight

Regards, Chris

||||| www.kinata.net web design and hosting

| -----Original Message----- | From: gimp-user-bounces@lists.xcf.berkeley.edu | [mailto:gimp-user-bounces@lists.xcf.berkeley.edu] On | Behalf Of Jeffrey Brent McBeth
| Sent: 20050913 Sep Tue 13:55
| To: michael chang
| Cc: gimp-user@lists.xcf.berkeley.edu | Subject: Re: [Gimp-user] Re: PNG binary transparency |
|
| On Tue, Sep 13, 2005 at 04:26:39PM -0400, michael chang wrote: | > > IE ignores tRNS when you aren't in palette mode, | anytime you added some of
| > > that color to an image, it would turn transparent | seperate from what you
| > > expect, etc.
| >
| > So logically, should we even be using tRNS in PNG | anyway? IE is one
| > of the most commonly used browsers, AFAIK... |
| Absolutely. IE's PNG transparency support is broken. | Has been, and will be
| for a long time. People can't ignore standards just | because MS does. Plus,
| the question was for a file that will never see the | light of day in IE.
|
| Jeff
|

michael chang
2005-09-13 23:37:58 UTC (over 18 years ago)

PNG binary transparency

On 9/13/05, Patrick Shanahan wrote:

* michael chang [09-13-05 15:33]:

So logically, should we even be using tRNS in PNG anyway? IE is one of the most commonly used browsers, AFAIK...

Why would you cripple a *good* program because a *bad* program, IE, is broken?

Hm. Good point. My apologies if anyone interpreted my poorly-researched remarks (above) as trolling, BTW.

Carol Spears
2005-09-14 00:04:52 UTC (over 18 years ago)

PNG binary transparency

On Tue, Sep 13, 2005 at 02:23:14PM -0700, Chris Kinata [kcom] wrote:

Hi all...

I was frustrated about IE PNG support (still am), but did some research, and found several ways to fix this in IE, depending on what you want.

we were discussing this on the irc some. it is all very confusing to me as i refuse to use wine to see what my pages look like in ie and ie refuses to work with my operating system without something like this.

we were talking about how to make this page: http://carol.gimp.org/blog.html show the pattern in IE. my idea was to get a screen shot of it being rendered correctly and use image mapping for the links.

and, i think this is quicker and more predictible than any of the silly hoops the other browser asks the web designer to jump through and also would give the instant satisfaction of having made the software do the jumping instead. "here IE! jump! jump!" /me whistles encouragingly.

personally, i thank everyone who has been involved in giving me a lifestyle in which i do not need to worry about broken propietary software when i make pages. the mess you see on my web site is all my own making for my own purposes. and frankly, i don't really care if msie users can see the gimp pattern of the day or not. a better question is, can you install other software and perhaps go without government aid?

everyone, practice with me "Here IE, Jump, Jump!". software should work for you and not against you.

carol

Chris Kinata [kcom]
2005-09-14 00:41:58 UTC (over 18 years ago)

PNG binary transparency

Hi Carol,

With respect, could you clarify what the issue is on the page you've referenced? I'm looking at

http://carol.gimp.org/blog.html

in both IE6 and Firefox, and the major differences I see are some spacing variations and the absent img in the "Pattern" box.

By the way, I agree that jumping through browser-specific hoops to design webpages is a major pain, and often resent having to take on the pain. But it seems there's sort of a spectrum from lowest-common-denominator-and-works-everywhere design to maximum-bells-and-whistles-and-must-be-tweaked-for- every-browser design. I absolutely do not know where the line should be drawn, but really want to achieve certain effects anyway. Hence the pain 8).

Regards, Chris

||||| www.kinata.net web design and hosting

| -----Original Message----- | From: Carol Spears [mailto:carol@gimp.org] | Sent: 20050913 Sep Tue 15:05
| To: Chris Kinata [kcom]
| Cc: GIMPUser
| Subject: Re: [Gimp-user] Re: PNG binary transparency |
|
| On Tue, Sep 13, 2005 at 02:23:14PM -0700, Chris Kinata | [kcom] wrote:
| >
| > Hi all...
| >
| > I was frustrated about IE PNG support (still am), but | did some research,
| > and found several ways to fix this in IE, depending | on what you want.
| >
| we were discussing this on the irc some. it is all | very confusing to me
| as i refuse to use wine to see what my pages look like | in ie and ie
| refuses to work with my operating system without | something like this.
|
| we were talking about how to make this page: | http://carol.gimp.org/blog.html show the pattern in IE. | my idea was to
| get a screen shot of it being rendered correctly and | use image mapping
| for the links.
|
| and, i think this is quicker and more predictible than | any of the silly
| hoops the other browser asks the web designer to jump | through and also
| would give the instant satisfaction of having made the | software do the
| jumping instead. "here IE! jump! jump!" /me whistles | encouragingly.
|
| personally, i thank everyone who has been involved in | giving me a
| lifestyle in which i do not need to worry about broken | propietary
| software when i make pages. the mess you see on my web | site is all my
| own making for my own purposes. and frankly, i don't | really care if
| msie users can see the gimp pattern of the day or not. a better | question is, can you install other software and perhaps | go without
| government aid?
|
| everyone, practice with me "Here IE, Jump, Jump!". | software should work
| for you and not against you.
|
| carol
|

Carol Spears
2005-09-14 01:02:13 UTC (over 18 years ago)

PNG binary transparency

On Tue, Sep 13, 2005 at 03:41:58PM -0700, Chris Kinata [kcom] wrote:

With respect, could you clarify what the issue is on the page you've referenced? I'm looking at

http://carol.gimp.org/blog.html

in both IE6 and Firefox, and the major differences I see are some spacing variations and the absent img in the "Pattern" box.

yes. that was my prediction. every time i use a transparent png i am able to predict that IE will not display it correctly. i actually used this fact when designing my index page, btw. there is a message that is much clearer if you read it from IE than if you read it in any mozilla product. IE users need to understand the message somewhat more than users of hmm, should i call it gecko instead of mozilla products?

the first thing i did was review css2 things to see if there were some elliptical clipping there i had not seen yet. the next thing was to decide that i did not care about what IE displayed and went for this sappy portrait style with the transparent png instead.

By the way, I agree that jumping through browser-specific hoops to design webpages is a major pain, and often resent having to take on the pain. But it seems there's sort of a spectrum from lowest-common-denominator-and-works-everywhere design to maximum-bells-and-whistles-and-must-be-tweaked-for- every-browser design. I absolutely do not know where the line should be drawn, but really want to achieve certain effects anyway. Hence the pain 8).

there will not be a good style for broken software.

i fully admit that i am unable to use the gimp image map plug-in to its fullest, however even with my limited skills, it would be easy to get a screenshot of the page being rendered correctly and send all IE viewers to this demonstration. this is a web server configuration, last time i looked. if i were not designing this script to run silently without a display from a web server, i would be so tempted to make the image map page just to show how simple it is to make your pages work properly and look correctly in IE. perhaps this would also work in Netscape3 as well as IE5?

that would be such a larger sample for your least common denominator!

perhaps you could use your experience and predict if my solution would work in IE for me?

carol

Carol Spears
2005-09-14 01:10:05 UTC (over 18 years ago)

PNG binary transparency

On Tue, Sep 13, 2005 at 03:04:52PM -0700, Carol Spears wrote:

personally, i thank everyone who has been involved in giving me a lifestyle in which i do not need to worry about broken propietary software when i make pages. the mess you see on my web site is all my own making for my own purposes. and frankly, i don't really care if msie users can see the gimp pattern of the day or not. a better question is, can you install other software and perhaps go without government aid?

i probably should append this with an appeal to consider that in spite of the fact i am a female, i might actually need an income that allows me to recoupe my stuff and pay back the additional debt i have gained while enjoying this freedom.

oh yes, and some "getting your facts straight" would be very nice as well.

being that several of the people who have loaned the funds to me have good jobs in the industry, a few moments of looking at what you are doing and how you could be affective in making the world better might be a good start.

having facts that match from before my problems and after my problems would also be a very very good starting place.

carol

Chris Kinata [kcom]
2005-09-14 01:22:07 UTC (over 18 years ago)

PNG binary transparency

Hi Carol,

By "absent image" are we talking about the img frame.png in the passages

:
:
.pattern
{background-image:url(/gimp2/resources/default/2.3.0-patterns-Stripes.png); border:thick ridge #bdbdbd; height:156px;
width:128px;}
:
:



:
:

In Firefox, I can get to

http://carol.gimp.org/gimp2/resources/default/2.3.0-patterns-Stripes.png

but can't find a correct path for frame.png.

Regards, Chris

||||| www.kinata.net web design and hosting

| -----Original Message----- | From: Carol Spears [mailto:carol@gimp.org] | Sent: 20050913 Sep Tue 16:02
| To: Chris Kinata [kcom]
| Cc: GIMPUser
| Subject: Re: [Gimp-user] Re: PNG binary transparency |
|
| On Tue, Sep 13, 2005 at 03:41:58PM -0700, Chris Kinata | [kcom] wrote:
| >
| > With respect, could you clarify what the issue is on | > the page you've referenced? I'm looking at | >
| > http://carol.gimp.org/blog.html
| >
| > in both IE6 and Firefox, and the major differences | > I see are some spacing variations and the absent img | > in the "Pattern" box.
| >
|
| yes. that was my prediction. every time i use a | transparent png i am
| able to predict that IE will not display it correctly. | i actually used
| this fact when designing my index page, btw. there is | a message that is
| much clearer if you read it from IE than if you read it | in any mozilla
| product. IE users need to understand the message | somewhat more than
| users of hmm, should i call it gecko instead of mozilla | products?
|
| the first thing i did was review css2 things to see if | there were some
| elliptical clipping there i had not seen yet. the next | thing was to
| decide that i did not care about what IE displayed and | went for this
| sappy portrait style with the transparent png instead. |
| > By the way, I agree that jumping through browser-specific | > hoops to design webpages is a major pain, and often resent | > having to take on the pain. But it seems there's sort of | > a spectrum from lowest-common-denominator-and-works-everywhere | > design to maximum-bells-and-whistles-and-must-be-tweaked-for- | > every-browser design. I absolutely do not know where the | > line should be drawn, but really want to achieve certain | > effects anyway. Hence the pain 8). | >
| there will not be a good style for broken software. |
| i fully admit that i am unable to use the gimp image | map plug-in to its
| fullest, however even with my limited skills, it would | be easy to get a
| screenshot of the page being rendered correctly and | send all IE viewers
| to this demonstration. this is a web server | configuration, last time i
| looked. if i were not designing this script to run | silently without a
| display from a web server, i would be so tempted to | make the image map
| page just to show how simple it is to make your pages | work properly and
| look correctly in IE. perhaps this would also work in | Netscape3 as well
| as IE5?
|
| that would be such a larger sample for your least | common denominator!
|
| perhaps you could use your experience and predict if my | solution would
| work in IE for me?
|
| carol
|

Carol Spears
2005-09-14 01:48:57 UTC (over 18 years ago)

PNG binary transparency

one more time:
On Tue, Sep 13, 2005 at 04:02:13PM -0700, Carol Spears wrote:

i fully admit that i am unable to use the gimp image map plug-in to its fullest, however even with my limited skills, it would be easy to get a screenshot of the page being rendered correctly and send all IE viewers to this demonstration. this is a web server configuration, last time i looked. if i were not designing this script to run silently without a display from a web server, i would be so tempted to make the image map page just to show how simple it is to make your pages work properly and look correctly in IE. perhaps this would also work in Netscape3 as well as IE5?

that would be such a larger sample for your least common denominator!

perhaps you could use your experience and predict if my solution would work in IE for me?

i have asked nicely twice and now this is a third time. you perform for browsers but not for humans?

carol

michael chang
2005-09-14 02:00:48 UTC (over 18 years ago)

PNG binary transparency

On 9/13/05, Chris Kinata [kcom] wrote:

By "absent image" are we talking about the img frame.png in the passages



but can't find a correct path for frame.png.

I think we call this generative loss or something... frame.png was there before. I swear, it was, honest. I don't know where it is now -- Carol, I don't suppose you have a backup? Or maybe when you changed the script somewhere, you forgot to prepend something in the path (or did it in a seperate version). *shrugs*

Carol Spears
2005-09-14 02:24:57 UTC (over 18 years ago)

PNG binary transparency

On Tue, Sep 13, 2005 at 08:00:48PM -0400, michael chang wrote:

On 9/13/05, Chris Kinata [kcom] wrote:

By "absent image" are we talking about the img frame.png in the passages



but can't find a correct path for frame.png.

I think we call this generative loss or something... frame.png was there before. I swear, it was, honest. I don't know where it is now -- Carol, I don't suppose you have a backup? Or maybe when you changed the script somewhere, you forgot to prepend something in the path (or did it in a seperate version). *shrugs*

yeah, i figured out what Chris was speaking about and cp'ed it over.

here is a broken mozilla problem for you. in my history there is a http://carol.gimp.org/blog.html/ with that slash at the end.

it is free and it does display transparent png. it does not mean that its design is all that great either. in fact, i loathe the way it seems to insist that i only go to the web sites i have already been to. for whatever reason, its designers seem to think they know better than me where i am going and what i would like to see.

the best thing possible at this moment is to not allow this crap to happen to gimp.

thanks and sorry. a browser is not a wysiwyg, even though it should be.

carol

Michael Schumacher
2005-09-14 20:00:01 UTC (over 18 years ago)

PNG binary transparency

michael chang wrote:

This sounds like something that should be only created if it's set by the user -- e.g. a save option. Although then it'd have to be specified every time, which might be annoying. In that case, you'd still see the colour that acts transparent in GIMP - just not when it's actually edited. That said, that might be inconvienent for those who use GIMP as an image viewer, and confuddle users of GAP.

IMO it could be a reasonable default to set tRNS to the currently selected background color when saving with "keep tranparent pixels' color" unset. This would copy the behaviour for the bKGD chunk.

HTH, Michael

Jeffrey Brent McBeth
2005-09-14 20:42:51 UTC (over 18 years ago)

PNG binary transparency

On Wed, Sep 14, 2005 at 08:00:01PM +0200, Michael Schumacher wrote:

IMO it could be a reasonable default to set tRNS to the currently selected background color when saving with "keep tranparent pixels' color" unset. This would copy the behaviour for the bKGD chunk.

Except that would make any pixels with the background color transparent in any app that correctly parses tRNS. I seriously doubt there is a good automatic solution.

Jeff