Ability to identify image type without URL filetype (long term)

[jywarren]

I tried running Image Sequencer (in bookmarklet mode) on a Google map page on MapKnitter.org --

https://khms1.googleapis.com/kh?v=798&hl=en-US&x=38213&y=49619&z=17

This is a jpg (i think , but maybe png) -- but i get:

Uncaught Error: Unsupported file type: com
    at savePixels (VM144 image-sequencer.js:54401)
    at VM144 image-sequencer.js:58087
    at Image.img.onload (VM144 image-sequencer.js:7408)

Can we identify images using mime-type or something? Or at least fallback to jpg if you don't detect anything?

[jywarren]

GitMate.io thinks the contributor most likely able to help you is @ccpandhare.

Possibly related issues are #19 (Filetype extraction), #5 (image cropping module), and #116 (Image overlay module).

[jywarren]

This could be implemented within this new function:

image-sequencer/src/util/GetFormat.js

Line 5 in 58a4798

module.exports = function GetFormat(src) {

Which needs some documentation too!

[tech4GT]

@jywarren the link is now broken, I am working on this can you please elaborate on this?

[jywarren]

So, I think the issue was that the file URL didn't end in .jpg or .png -- but simply resolved to a file with such an ending. So the URL couldn't be used to fetch the format. I think we could try to determine it with mime type, or maybe the fallback you linked to in #296 would be a good start? But if there's an efficient way to do it, we could refactor GetFormat to be able to detect file type without needing the URL to include it.

[tech4GT]

@jywarren I was thinking we start off with this and build it up

[jywarren]

+1!

…

On Wed, Jun 27, 2018 at 5:16 PM Varun Gupta ***@***.***> wrote: @jywarren <https://github.com/jywarren> I was thinking we start off with this and build it up — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#234 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AABfJ4711daQCCcuoJyN5nJX-C4NwlzKks5uA_YigaJpZM4TwD49> .

[tech4GT]

@jywarren I have been reading up on this and it seems to me even if we are able to do this, it will be async and we would have to refactor our calling code to use callbacks instead of returning the value

[tech4GT]

Can you give me a permalink to where we use this getformat?

[jywarren]

Right now only in ImportImage -- https://github.com/publiclab/image-sequencer/search?q=getformat&unscoped_q=getformat

But i'd like to see it more widely adopted if it's efficient!

Hmm, yeah, if it's async maybe not worth it... can you link to what you've been reading? Maybe we get inspired later with an idea.

[tech4GT]

Actually @jywarren what i figured out was we can use any way but we would have to convert the image into its dataURI which will take a callback.

[tech4GT]

@jywarren should we close this coz this will call for a major refactor using async?

[jywarren]

sure, or you can leave it open with "wontfix" or just clearly note that it's a long-term project, not high priority... maybe someday!

…

On Wed, Jul 11, 2018 at 10:44 AM Varun Gupta ***@***.***> wrote: @jywarren <https://github.com/jywarren> should we close this coz this will call for a major refactor using async? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#234 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AABfJyQC5f_jH2otj6JJ1VnewxfSVf-Lks5uFg9bgaJpZM4TwD49> .

[tech4GT]

sure