ditto!

On Fri, Oct 3, 2014 at 11:30 AM, Dominic McDevitt-Parks <[email protected]>
wrote:

> Since no one else has done so yet, I just want to give a big thanks to
> Brian for working on this. This is a problem that has especially plagued
> big GLAM content contributions with high-resolution scans, and it's great
> to see those finally rendered. Your work is appreciated!
>
> Dominic
>
> On 2 October 2014 21:08, Brian Wolff <[email protected]> wrote:
>
>> On 10/2/14, Brian Wolff <[email protected]> wrote:
>> > Hi everyone.
>> >
>> > tl;dr: Can we do https://gerrit.wikimedia.org/r/164476
>> >
>> > Now that the pre-requisite patches for using VIPS with tiff has been
>> > merged (Woo!), lets umm use it.
>> >
>> > So for those who don't know what vips is, vips is an alternative to
>> > image magick which can scale certain file formats in essentially
>> > constant memory (Or probably to be pedantic, linear in the number of
>> > pixels in the resulting file, instead of linear in the number of
>> > pixels in the source). This means we would be able to make thumbnails
>> > no matter how big the source file is. Which is good because we have
>> > lots of very high resolution tiff files, such as [[File:Zoomit2.tif]]
>> > and [[File:Zentralbibliothek Zürich - Mittelalterliche Stadt -
>> > 000005203.tif]]. We already use VIPS to scale png files larger than 20
>> > megapixels, and non-progressive jpeg files can be scaled efficiently
>> > with image magick, so tiff is the current pain point in terms of
>> > scaling limits (although GIF is also painful).
>> >
>> > I would like to propose the following:
>> >
>> > First we experiment with turning it on for files > 50 megapixels.
>> > Currently we do not even try to render such files, so I doubt this
>> > will cause any community angst. To that end I proposed a patch (
>> > https://gerrit.wikimedia.org/r/164476 ) that uses the following
>> > settings:
>> >
>> >                array(
>> >                        'conditions' => array(
>> >                                'mimeType' => 'image/tiff',
>> >                                'minShrinkFactor' => 1.2,
>> >                                'minArea' => 5e7,
>> >                        ),
>> >                        'sharpen' => array( 'sigma' => 0.8 ),
>> >                )
>> >
>> > This will turn the feature on for big files (which currently do not
>> > render), and also enable sharpening (Most tiff images benefit from it
>> > and the community has asked for it repeatedly, I think its less
>> > disruptive to enable sharpening at the same time as VIPS, instead of
>> > two separate changes to tiff rendering).
>> >
>> > I would propose we let that sit for a little bit. We should than have
>> > a community discussion (With the commons community, since its hard to
>> > have a discussion with every community, and commons (+esp. Glams) are
>> > the people who care the most about this) to see if the community likes
>> > that. Hopefully if all is well we could move to stage 2, which would
>> > be something like:
>> >
>> >                array(
>> >                        'conditions' => array(
>> >                                'mimeType' => 'image/tiff',
>> >                                'minShrinkFactor' => 1.2,
>> >                        ),
>> >                        'sharpen' => array( 'sigma' => 0.8 ),
>> >                ),
>> >                array(
>> >                        'conditions' => array(
>> >                                'mimeType' => 'image/tiff',
>> >                        ),
>> >                ),
>> >
>> >
>> > Anyways, thoughts. Does this sound like a good plan? Someone want to
>> > be bold and deploy my change ;)
>> >
>> > --bawolff
>> >
>>
>>
>> This is live now. First results look promising, however some images
>> don't seem to be working
>>
>> *Really big images (>350 megapixels) seem to run into a timeout
>> (especially lzw compressed images, but that could be a coincidence,
>> very small sample size)
>> *https://commons.wikimedia.org/wiki/File:Carr_wilbur_j_honorable.tif
>> and
>> https://commons.wikimedia.org/wiki/File:Amelia_earhart_received_by_president_coolidge.tif
>> are broken. Not sure what the deal with those two are yet. They do not
>> appear broken (locally anyways) if converting directly instead of
>> using intermediary step. Random theory is something to do with colour
>> profiles as they're both greyscale images, but needs further
>> investigation.
>>
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-- 
Greg Grossmeier
Release Team Manager
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