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Comment by romwell | Hacker News Reader

>JPEG can't do transparency

JPEG "can't" do depth maps either, and yet it manages to do them just fine.

"Portrait mode" on Android is simply JPEG + greyscale JPEG embedded in metadata.

If anyone really wanted transparency, it is very easy to add it to JPEG.

That said, in practice, transparency is not needed in non-vector / non-generated graphics formats. The nature doesn't really have an alpha channel, photographs certainly do not.

Transparency is extra information, and can be passed along as such.

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The problem is always standards. I want transparency to work correctly everywhere, not just in one application and broken everywhere else.

Even if transparency was add to JPEG right now, it would take sometime to become available everywhere, and you would have tons of legacy devices showing broken transparency.

The advantage of a new format that supports transparency from is interception is that every device that is compatible with it will display it correctly. So there is no issue with some devices supporting the format partially.

The larger picture is that you can use PNG or SVG anywhere you need transparency, which are also better suited for the content that has transparency.

JPEG is optimized for photos, which don't have transparent parts.

SVG and PNG are optimized for graphics.

So, if you need transparency, WEBP is probably not the format you'd choose anyway.

> The larger picture is that you can use PNG or SVG anywhere you need transparency, which are also better suited for the content that has transparency.

It is pretty common to have anime characters where you remove the background to use as reactions, and while you can use PNG in those cases it makes the images huge. WebP makes it ideal for those cases, this is even the case that I saw this being used in some image boards (specially also including animation, another thing that is popular).

Just because you can't think in a use case there isn't mean that there isn't a use case.

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