9 Sep
2010
9 Sep
'10
12:42 p.m.
On 09/09/2010 12:18 PM, Caleb James DeLisle wrote:
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Marius Dumitru Florea wrote:
'IMO wiki syntax is independent from HTML. When you write [...]
"width" is a parameter of the image. This wiki syntax could be
rendered in many formats.'
Hi Caleb,
On 09/09/2010 02:22 AM, Caleb James DeLisle wrote:
I can see the logic in this.
+1
Marius Dumitru Florea wrote:
> Hi devs,
>
> Currently the image plugin [1] allows us to create image thumbnails by
> specifying the image width and/or height in the query string of the
> image attachment download URL:
>
> /xwiki/bin/download/Spage/Page/image.jpg?width=100
>
> I propose that we:
>
> (A) Use the image width and/or height (when they are specified in the
> image syntax using pixel unit) to resize the image on the server side.
> For instance:
>
> [[image:logo.jpg||width="100px"]]
>
> will be linked to
>
> /xwiki/bin/download/Spage/Page/logo.jpg?width=100
This seems to be fuzzing the line between url
parameters and html
tag attributes. why not just use [[image:logo.jpg?width=100px]]
First of all, you make the assumption that users know what a URL query
string is. I don't fully agree with this. Then some users might get
confused if there are two ways of specifying image width/height: should
we put the width/height in the image reference or in the image
parameters? Finally, writing:
[[image:logo.jpg?width=100||width=50px]]
makes no sense. Why would you want to download a 100px image when you
display it at 50px only.
Also, IMO wiki syntax is independent from HTML. When you write:
[[image:logo.jpg||width="100px"]]
"width" is a parameter of the image. This wiki syntax could be rendered
in many formats. One of these formats is HTML, but it's not the only
one. When rendered in HTML the width parameter is mapped to the width
HTML image attribute but that doesn't mean we can't use the width
parameter for other things, like adjusting the image URL.
IMO what's really important is to honor user expectations. When a user
writes:
[[image:logo.jpg||width="100px"]]
he expects to see the logo.jpg image displayed and its width to be
100px. My proposal doesn't change this. Resizing the image on the server
is an optimization and I think most of the users will be happy with it
(the page will load faster). > and
>
> [[image:logo.jpg||style="height: 50px; width: 70px"]]
>
> will be linked to
>
> /xwiki/bin/download/Spage/Page/logo.jpg?width=70&height=50
Parsing CSS and extracting widths and heights for
server side scaling?
Yes, using http://cssparser.sourceforge.net/ . After thinking it over I agree but now aren't we
risking an too much
dependence on CSS? It seems a bit odd to have a CSS parser for only
one job and specifying style in an html attribute is WCAG invalid.
Is there a common use case?
Right now the common use case is when a user resizes an image from the
WYSIWYG editor using the image resize handlers. The browser puts the
width and height information in the style attribute. I can move the
width and height to the corresponding attributes afterwards but:
* The style attribute is still required when width and height are not
expressed in pixel or percent. This won't happen often but the user can
explicitly set the width/height to other units like em in the edit image
WYSIWYG wizard.
* The user can still write:
[[image:logo.jpg||style="height: 50px; width: 70px"]]
in the wiki editor and the image will be displayed as expected.
I admit that the style parameter for image syntax (and not only) is HTML
oriented but I think it's ok to parse it in order to optimize page
loading speed.
Thanks,
Marius
The image
plugin also accepts a quality parameter that controls the
compression quality when encoding jpeg images. The default value of this
parameter (i.e. when not specified in the URL) is configurable. I
propose we use 0.3 by default, 1 representing the best quality.
(B) Add the ability to limit the image dimensions (preserving aspect
ratio) when the image width and/or height are not specified in the image
syntax (or when they are not using pixel unit). The width and height
limit will be configurable and -1 by default (i.e. no limitation). For
instance:
image:logo.jpg
will be linked to
/xwiki/bin/download/Spage/Page/logo.jpg?width=1024
when width limit is 1024, and to
/xwiki/bin/download/Spage/Page/logo.jpg?width=1024&height=768&keepAspectRatio=true
when width limit is 1024 and height limit is 768. Note that in this case
the image aspect ratio is preserved. The image is resized to best fit
the limits. If the user want to bypass the limit he has to specify the
image width/height in the image syntax.
I'm +1 for both (A) and (B). WDYT?
+1 B A I need to hear more about how it will be
implemented, from what i
read it doesn't look right.
As Thomas said, it will be implemented in a XWiki specific
implementation of WikiModel (
http://svn.xwiki.org/svnroot/xwiki/platform/core/trunk/xwiki-rendering/xwik…
). We're going to add a method to get the image URL based on: document
reference, attachment file name and image parameters. The implementation
looks for the width, height and style parameters and tries to extract
image width/height from them. If it succeeds then it adds this
information to the query string of the attachment download URL. When the
image is requested by the browser the image plugin is called and it uses
the width and height request parameters (if specified) to scale the
image attachment. The image size is never increased. The image plugin
uses a component for image processing (decode, scale, encode). The
default implementation of this component uses javax.imageio and java.awt
classes for image processing.
Thanks for your feedback,
Marius
Caleb
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Thanks,
Marius
[1]
http://svn.xwiki.org/svnroot/xwiki/platform/core/trunk/xwiki-core/src/main/…
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