Created
September 3, 2012 09:22
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Retina image swap-out for Google-hosted images
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| if (window.devicePixelRatio > 1) { | |
| img_re = new RegExp(/=(s|w)(\d*)(\-c)?$/) | |
| $("img").each(function(id, el){ | |
| img_src = $(el).attr("src") | |
| if (img_re.test(img_src)) { | |
| img_size = parseInt(img_src.match(img_re)[2]) | |
| dimension = img_src.match(img_re)[1] | |
| new_img_size = img_size*2 | |
| new_src = img_src.replace(img_re,"=" + dimension + new_img_size) | |
| $(el).attr("src",new_src) | |
| } | |
| }) | |
| } |
Worth noting that we don't use this technique anymore - it's all picture element and http://scottjehl.github.io/picturefill/ now
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Google App Engine uses get_serving_url [1] to produce an image URL [2] that can be resized by changing the last digits. This javascript detects is its running on a device capable of displaying 'retina' images and swaps out the img src to one double the size. You can see this running on the Potato website [3].
[1] https://developers.google.com/appengine/docs/python/images/functions
[2] E.g. http://lh5.ggpht.com/IFPH6YSiPKtCp1HZtIFr3R21i_Cgjmqfq-9sBsY03QvQZEcnvu-xYPvi8rINATms6Rdlrt3Jjn1az4R8EkbsdQ=s220
[3] http://p.ota.to/work/google-art-project/