Problems imbedding images without format suffix

I'm trying to do math in a document by imbedding an image generated by a remote service, such as

image:https://render.githubusercontent.com/render/math?math=\displaystyle \text{b} = V D[]

In the HTML5 renderer, this works. In asciidoctor-pdf (using -a allow-uri-read, of course), I get a message like this:

> asciidoctor: WARNING: could not embed image: /tmp/image-20201112-19102-165jx60; image file is an unrecognised format

Capturing the returned image, it's just normal SVG. If I take that returned image and name it e.g. 'foo.svg' and feed that into asciidoctor as an image (HTML5 or PDF), it works fine. But if I name it in the same fashion as the WARNING, e.g. 'image-20201112-19102-165jx60', and feed that into asciidoctor as an image, I get the exact same WARNING from asciidoctor-pdf - and, although there is no warning or error message, the HTML5 renderer generates a broken-image link.

I infer that asciidoctor usually, though not always, requires an image format suffix on the source argument of image: to determine how to process it. There do not appear to be any options for the image: directive that allow specifying the format explicitly. There's no apparent reason the asciidoctor component (or external ruby gem?) fetching the image couldn't name it properly or otherwise recognize the format; the HTTP headers returned from the render server label it 'Content-Type: image/svg+xml' so that information is available, just apparently not being used.

Any thoughts on how to proceed?

Jon

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NAML

Jon,

If the target does not end in a file extension, then the processor cannot infer the format. In that case, you can define the format explicitly using the format attribute:

image::https://render.githubusercontent.com/render/math?math=\displaystyle \text{b} = V D[format=svg]

Specifying the format is only necessary if the converter needs to know it. SVG is one of those cases.

Best Regards,

-Dan

p.s. I did not realize that GitHub had an API to render LaTeX math. We could make use of that to render LaTeX math on GitHub.

On Thu, Nov 12, 2020 at 6:28 AM oddhack [via Asciidoctor :: Discussion] <[hidden email]> wrote:

I'm trying to do math in a document by imbedding an image generated by a remote service, such as

image:https://render.githubusercontent.com/render/math?math=\displaystyle \text{b} = V D[]

In the HTML5 renderer, this works. In asciidoctor-pdf (using -a allow-uri-read, of course), I get a message like this:

> asciidoctor: WARNING: could not embed image: /tmp/image-20201112-19102-165jx60; image file is an unrecognised format

Capturing the returned image, it's just normal SVG. If I take that returned image and name it e.g. 'foo.svg' and feed that into asciidoctor as an image (HTML5 or PDF), it works fine. But if I name it in the same fashion as the WARNING, e.g. 'image-20201112-19102-165jx60', and feed that into asciidoctor as an image, I get the exact same WARNING from asciidoctor-pdf - and, although there is no warning or error message, the HTML5 renderer generates a broken-image link.

I infer that asciidoctor usually, though not always, requires an image format suffix on the source argument of image: to determine how to process it. There do not appear to be any options for the image: directive that allow specifying the format explicitly. There's no apparent reason the asciidoctor component (or external ruby gem?) fetching the image couldn't name it properly or otherwise recognize the format; the HTTP headers returned from the render server label it 'Content-Type: image/svg+xml' so that information is available, just apparently not being used.

Any thoughts on how to proceed?

Jon

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NAML

--

Dan Allen (he, him, his) | @mojavelinux | https://twitter.com/mojavelinux

Thanks! The image: format attribute is not defined in the User Guide (section 29.5), AFAICT, but I was hoping one existed.

Regarding render.githubusercontent.com site, I think it was more or less an accidental discovery by someone that this functionality exists for other purposes - https://gist.github.com/a-rodin/fef3f543412d6e1ec5b6cf55bf197d7b . It seems to be undocumented and probably not a robust site to rely on (they might easily decide to block access from outside their intended userbase, for example), though it is useful.

Jon

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NAML