Re: [xwiki-users] [Vote] Resize images on the server side to reduce page loading time

Hi Caleb, On 09/09/2010 02:22 AM, Caleb James DeLisle wrote: > 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/ .

>> 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 > > >> Thanks, >> Marius >> >> [1] >> http://svn.xwiki.org/svnroot/xwiki/platform/core/trunk/xwiki-core/src/main/… >> _______________________________________________ >> users mailing list >> users(a)xwiki.org >> http://lists.xwiki.org/mailman/listinfo/users >> >> > _______________________________________________ > users mailing list > users(a)xwiki.org > http://lists.xwiki.org/mailman/listinfo/users > _______________________________________________ users mailing list users(a)xwiki.org http://lists.xwiki.org/mailman/listinfo/users