Hi!
A while ago I've grabbed up https://bugs.php.net/32803 and submitted
PR #2024[1]. This lay dormant until recently when Joe had a look at so
many PRs (thanks!), so I'm bringing this issue to your attention.
I presume nobody is opposed that ext/gd should support the creation of
animated GIFs (they appear to be still in fashion again), but I'm not
sure about the API. My first shot (as implemented in the PR) was to
offer a rather minimal layer over gdImageGifAnimBeginCtx(),
gdImageGifAnimAddCtx() and gdImageGifAnimEndCtx()[2] (you can see an
usage example in the submitted PHPT[3]).
Kalle raised some objections regarding the direct use of streams in the
API, namely that imagegifanimbegin() expects an open stream to be passed
as parameter, so perhaps it would be better to accept a stream URL
instead and manage the stream behind the scenes. That appears to be
much more solid (as the developer couldn't fiddle with the stream), but
would require some encapsulation mechanism, either a resource, what
would be in line with the other GD resource types[4], or an (opaque)
object, what appears more suitable for PHP 7.
Currently, I'd prefer an opaque object which would be created by
imagegifanimbegin() (creating the respective stream internally), passed
to imageanimadd() and be destroyed by imagegifanimend().
Before proceeding to the implementation, I'd like to hear your thoughts
about that!
[1] https://github.com/php/php-src/pull/2024
[2] https://libgd.github.io/manuals/2.2.3/files/gd_gif_out-c.html
[3]
https://github.com/php/php-src/pull/2024/files#diff-bbb4c7a8497032f98d062ac418d9fbbe
[4] http://php.net/manual/en/image.resources.php
--
Christoph M. Becker
Morning Christoph,
We have to face facts: Resources are still a thing.
While there is talk of switching resources to use opaque objects, I'm
worried about introducing a mixture of objects and resources in random
places throughout core exts, and having exts with both seems very strange
to me.
I know that this has already started to happen, but before it goes any
further I would implore you to stick to resources for now.
There needs to be an organised effort for some future version of PHP to
remove the resource type and replace it with opaque (or not) objects.
Cheers
Joe
On Sun, Jan 8, 2017 at 11:53 PM, Christoph M. Becker cmbecker69@gmx.de
wrote:
Hi!
A while ago I've grabbed up https://bugs.php.net/32803 and submitted
PR #2024[1]. This lay dormant until recently when Joe had a look at so
many PRs (thanks!), so I'm bringing this issue to your attention.I presume nobody is opposed that ext/gd should support the creation of
animated GIFs (they appear to be still in fashion again), but I'm not
sure about the API. My first shot (as implemented in the PR) was to
offer a rather minimal layer over gdImageGifAnimBeginCtx(),
gdImageGifAnimAddCtx() and gdImageGifAnimEndCtx()[2] (you can see an
usage example in the submitted PHPT[3]).Kalle raised some objections regarding the direct use of streams in the
API, namely that imagegifanimbegin() expects an open stream to be passed
as parameter, so perhaps it would be better to accept a stream URL
instead and manage the stream behind the scenes. That appears to be
much more solid (as the developer couldn't fiddle with the stream), but
would require some encapsulation mechanism, either a resource, what
would be in line with the other GD resource types[4], or an (opaque)
object, what appears more suitable for PHP 7.Currently, I'd prefer an opaque object which would be created by
imagegifanimbegin() (creating the respective stream internally), passed
to imageanimadd() and be destroyed by imagegifanimend().Before proceeding to the implementation, I'd like to hear your thoughts
about that![1] https://github.com/php/php-src/pull/2024
[2] https://libgd.github.io/manuals/2.2.3/files/gd_gif_out-c.html
[3]
<https://github.com/php/php-src/pull/2024/files#diff-
bbb4c7a8497032f98d062ac418d9fbbe>
[4] http://php.net/manual/en/image.resources.php--
Christoph M. Becker
Hi Joe,
Joe Watkins wrote:
We have to face facts: Resources are still a thing.
While there is talk of switching resources to use opaque objects, I'm
worried about introducing a mixture of objects and resources in random
places throughout core exts, and having exts with both seems very strange
to me.I know that this has already started to happen, but before it goes any
further I would implore you to stick to resources for now.
The more things are made objects now, the less things need to be
converted to be objects later.
It might be “strange” to mix them, but would it actually cause
confusion? So far as the user cares, resources and objects returned by
Gd could just be integers. They're just opaque handles.
Thanks.
--
Andrea Faulds
https://ajf.me/
Joe Watkins wrote:
We have to face facts: Resources are still a thing.
While there is talk of switching resources to use opaque objects, I'm
worried about introducing a mixture of objects and resources in random
places throughout core exts, and having exts with both seems very strange
to me.
ACK.
I know that this has already started to happen, but before it goes any
further I would implore you to stick to resources for now.The more things are made objects now, the less things need to be
converted to be objects later.
ACK.
It might be “strange” to mix them, but would it actually cause
confusion? So far as the user cares, resources and objects returned by
Gd could just be integers. They're just opaque handles.
I think that they should be opaque handles, but you never know how
one's going to treat them. Presumably the most crucial point nowadays
are type declarations; changing a resource to be an object could cause
massive BC break (think of streams) – changing all resources to objects
appears to be even impracticable for a major version. Therefore I think
this has to be done in small steps ("eating the elephpant one bite at a
time"), and so introducing new opaque handles as objects appears
somewhat sensible even if that causes a mix of resources and objects in
a single extension.
Anyhow, I understand that the animated GIF support will need an RFC, and
there should be a secondary voting option whether the API should use a
resource or an opaque object.
--
Christoph M. Becker
Hi,
Christoph M. Becker wrote:
Kalle raised some objections regarding the direct use of streams in the
API, namely that imagegifanimbegin() expects an open stream to be passed
as parameter, so perhaps it would be better to accept a stream URL
instead and manage the stream behind the scenes. That appears to be
much more solid (as the developer couldn't fiddle with the stream), but
would require some encapsulation mechanism, either a resource, what
would be in line with the other GD resource types[4], or an (opaque)
object, what appears more suitable for PHP 7.Currently, I'd prefer an opaque object which would be created by
imagegifanimbegin() (creating the respective stream internally), passed
to imageanimadd() and be destroyed by imagegifanimend().
Would this opaque object still allow you to use an arbitrary stream of
your choice?
Also, like with imagepng() etc., could you stream the output to uh…
PHP's default output stream? (I'm not sure what it's called. The thing
that echo goes to.)
If it does both, I don't have much objection.
Mind you… is it really necessary to hide the stream from the user?
fopen() is not particularly hard to use, and there are (admittedly
niche) cases where you might want to handle the stream yourself.
Thanks.
--
Andrea Faulds
https://ajf.me/
Christoph M. Becker wrote:
Kalle raised some objections regarding the direct use of streams in the
API, namely that imagegifanimbegin() expects an open stream to be passed
as parameter, so perhaps it would be better to accept a stream URL
instead and manage the stream behind the scenes. That appears to be
much more solid (as the developer couldn't fiddle with the stream), but
would require some encapsulation mechanism, either a resource, what
would be in line with the other GD resource types[4], or an (opaque)
object, what appears more suitable for PHP 7.Currently, I'd prefer an opaque object which would be created by
imagegifanimbegin() (creating the respective stream internally), passed
to imageanimadd() and be destroyed by imagegifanimend().Would this opaque object still allow you to use an arbitrary stream of
your choice?Also, like with
imagepng()etc., could you stream the output to uh…
PHP's default output stream? (I'm not sure what it's called. The thing
thatechogoes to.)
It would be possible to allow either a stream URL or a stream to given,
what would fit to image(png|jpeg|…)(). However, these are "stand-alone"
functions which close the stream when they're finished, while the
animated GIF writing functions would allow the stream to be
manipulated by the userland developer, even though I can't see practical
reason to do so.
And, of course, we could also let the functions accept NULL to directly
write to stdout. Passing in 'php://stdout' should have the same effect.
If it does both, I don't have much objection.
Mind you… is it really necessary to hide the stream from the user?
fopen()is not particularly hard to use, and there are (admittedly
niche) cases where you might want to handle the stream yourself.
Are there really such cases? Should we sacrifice the safety of internal
stream handling to support some (hypothetical?) use cases?
--
Christoph M. Becker
Hi,
Christoph M. Becker wrote:
Would this opaque object still allow you to use an arbitrary stream of
your choice?Also, like with
imagepng()etc., could you stream the output to uh…
PHP's default output stream? (I'm not sure what it's called. The thing
thatechogoes to.)It would be possible to allow either a stream URL or a stream to given,
what would fit to image(png|jpeg|…)(). However, these are "stand-alone"
functions which close the stream when they're finished, while the
animated GIF writing functions would allow the stream to be
manipulated by the userland developer, even though I can't see practical
reason to do so.And, of course, we could also let the functions accept
NULLto directly
write to stdout. Passing in 'php://stdout' should have the same effect.
Alright.
If it does both, I don't have much objection.
Mind you… is it really necessary to hide the stream from the user?
fopen()is not particularly hard to use, and there are (admittedly
niche) cases where you might want to handle the stream yourself.Are there really such cases? Should we sacrifice the safety of internal
stream handling to support some (hypothetical?) use cases?
In fairness, I'm not sure. I know animated GIF streaming has been tried
before, though I doubt if it's actually used at all these days. A more
reasonable case might be embedding an animated GIF in other binary data.
But that's a hypothetical.
What is the actual “safety” gain of not using streams? That you don't
need to use fopen() yourself? (PHP will close files for you.) I'm just
not super convinced there's a need for adding this extra layer.
Thanks for your response.
--
Andrea Faulds
https://ajf.me/
Hi!
Christoph M. Becker wrote:
Would this opaque object still allow you to use an arbitrary stream of
your choice?Also, like with
imagepng()etc., could you stream the output to uh…
PHP's default output stream? (I'm not sure what it's called. The thing
thatechogoes to.)It would be possible to allow either a stream URL or a stream to given,
what would fit to image(png|jpeg|…)(). However, these are "stand-alone"
functions which close the stream when they're finished, while the
animated GIF writing functions would allow the stream to be
manipulated by the userland developer, even though I can't see practical
reason to do so.And, of course, we could also let the functions accept
NULLto directly
write to stdout. Passing in 'php://stdout' should have the same effect.Alright.
If it does both, I don't have much objection.
Mind you… is it really necessary to hide the stream from the user?
fopen()is not particularly hard to use, and there are (admittedly
niche) cases where you might want to handle the stream yourself.Are there really such cases? Should we sacrifice the safety of internal
stream handling to support some (hypothetical?) use cases?In fairness, I'm not sure. I know animated GIF streaming has been tried
before, though I doubt if it's actually used at all these days. A more
reasonable case might be embedding an animated GIF in other binary data.
But that's a hypothetical.
Okay.
What is the actual “safety” gain of not using streams? That you don't
need to usefopen()yourself? (PHP will close files for you.) I'm just
not super convinced there's a need for adding this extra layer.
It's not about having to fopen() the stream – in my opinion at least
that's a non-brainer. What is a minor issue though, is that either
imagegifanimend() closes the stream automatically (what imagepng() and
friends are doing), or not (in my opinion the proper solution, but
inconsistent). The major issue for me would be the possibility that the
user fiddles with the stream between imagegifanimbegin() and
imagegifanimend() – in the worst case closing the stream, so
imagegifanimend() would fail or had to catch that. Of course, that
would be a programmer error, but nonetheless it would have to be
documented, and I'm pretty sure that at least some devs would walk into
this trap.
Anyhow, thanks for the feedback. I'll see how to unify this in a single
RFC (probably with secondary voting options).
--
Christoph M. Becker