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| -rw-r--r-- | doc/bugs/img_tag_should_support_relative_size.mdwn | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/doc/bugs/img_tag_should_support_relative_size.mdwn b/doc/bugs/img_tag_should_support_relative_size.mdwn index a625487c4..b6966e056 100644 --- a/doc/bugs/img_tag_should_support_relative_size.mdwn +++ b/doc/bugs/img_tag_should_support_relative_size.mdwn @@ -1 +1,29 @@ The size parameter should accept relative values, like "100%". When including large images, I would like it to be scaled relative to the available space. + +> 100% of what? +> +> The purpose of `[[!img]]` is to scale large images, for example photos, down +> to a more web-suitable size. When ikiwiki rebuilds the website, it cannot +> know how large visitors' web browser windows are going to be, so it cannot +> scale the image relative to the size of a visitor's web browser window. +> +> The closest thing it could do would be to not scale the image at all +> (potentially a very large download if it's a high-resolution photo), +> and use CSS or `<img sizes=...>` to ask the visitor's web browser to scale +> the image relative to something the web browser knows, such as the viewport +> size. +> +> With HTML5 `<img sizes="..." srcset="...">`, it would be possible to extend +> `[[!img]]` to produce more than one resized image and let the visitor's +> browser choose which one to download, but I'm not sure what a good syntax +> for that would look like... +> +> "The available space" is not something we can use, because current HTML +> standards do not offer that. In HTML5 it is possible to base sizes on the +> viewport (window) size, but the available space (excluding sidebars etc.) +> is not something the browser can know in advance, because it needs to know +> how large images are before it carries out layout calculations, and it +> needs to carry out layout calculations before it can know the available +> space. +> +> --[[smcv]] |