Export snapshot - is it usable on LiveCode web apps?

[William de Smet]

And in addition to this I have another question:
How do we download this created snapshot in a web browser?



greetings,

William




Op do 8 aug 2024 om 16:48 schreef Jimmieson, Phil via use-livecode <
use-livecode at lists.runrev.com>:

> Hi folks,
> Thanks to everyone who responded to my question. Where else would you get
> such support? And in particular, with what other development system would
> you get one of the actual architects of the system, responding to your
> question? LIveCode is something else.
>
> OK, I have updated my screenshot code. I’m still getting a javascript
> exception, but it looks like it’s now caused by something else that web
> doesn’t like. Something that works ok on iPad. More investigation is
> required...
>
>
> On 8 Aug 2024, at 13:39, Mark Waddingham via use-livecode <
> use-livecode at lists.runrev.com> wrote:
>
> Caution: This email originated from outside of the University. Do not
> click links or open attachments unless you recognise the source of this
> email and know the content is safe. Check sender address, hover over URLs
> and don't open suspicious email attachments.
>
> On 2024-08-08 10:22, Jimmieson, Phil via use-livecode wrote:
> Hi folks,
> I’m experimenting with converting one of my LiveCode iPad Apps into a web
> version, to see how well it works, but there’s an issue that seems to be a
> deal-breaker. My iPad app takes a screenshot of the LiveCode stack when the
> user navigates away from the main card, so that the image can be used
> elsewhere in the app. This works fine on iPad, but I noticed that the web
> version of the app generates a javascript exception when I try to leave the
> main card. On checking the dictionary, I noticed that the export snapshot
> command is not listed as being supported on web. Is this correct? If so, is
> there an alternative that will work for web?
>
> So 'export snapshot from screen' is not supported - this is the form which
> takes the pixel data from the actual (composited) screen buffer.
>
> However, there is an alternate form which is entirely internal to the
> engine:
>
>   export snapshot from [ rect <rect> of ] <object>
>
> To use the internal form for a card you can do:
>
>   export snapshot from this card
>
> Or if you want a portion of the card:
>
>   export snapshot from rect 0,0,100,100 of this card
>
> Further there is an `at size <width>,<height>` clause which allows you to
> specify the size you want the resulting image.
>
> The difference here is that the internal form replicates the same process
> that the engine uses to render objects to a window - it renders the given
> rectangle of the object into a rect of the specified size (or the size of
> the rect/object if 'at size' is not specified).
>
> In contrast, the 'external' form has to ask the OS for the given rectangle
> of the actual screen's framebuffer.
>
> Hope this helps,
>
> Mark.
>
> --
> Mark Waddingham ~ mark at livecode.com ~ http://www.livecode.com/
> LiveCode: Build Amazing Things
>
> _______________________________________________
> use-livecode mailing list
> use-livecode at lists.runrev.com
> Please visit this url to subscribe, unsubscribe and manage your
> subscription preferences:
> http://lists.runrev.com/mailman/listinfo/use-livecode
>
> --
> Phil Jimmieson (He/Him)
> University of Liverpool, Computer Science Department
> Ashton Bldg, Ashton Street, Liverpool. L69 3BX
> 0151 795 4236
>
> _______________________________________________
> use-livecode mailing list
> use-livecode at lists.runrev.com
> Please visit this url to subscribe, unsubscribe and manage your
> subscription preferences:
> http://lists.runrev.com/mailman/listinfo/use-livecode
>