Creating an auto-updating button icon thumbnail image from card snapshot

[Bob Sneidar]

That's worth saving in my Livecode Keepers! Someday I am going to make a stack of this stuff!

Bob


On Apr 1, 2011, at 10:09 AM, J. Landman Gay wrote:

> On 4/1/11 11:14 AM, J. Landman Gay wrote:
>> 
>> Since you are taking snapshots of other cards and the "preopen" is for
>> the control, I'm not sure you need to wait for the control to load. I
>> think the issue is the ID of the icon.
>> 
> 
> I just tried the handler you posted and there's more wrong than just the icon ID.
> 
> on preOpenControl
>   import snapshot from the rect of card "Example"
>   set the icon of me to it
> end preOpenControl
> 
> It might be a typo, but the first line will error without the "rect" keyword:  import snapshot from rect (the rect of cd "example"). Also, snapshots use the 0,0 point of the monitor (not the stack) for coordinates when dealing with cards, so the rect of a card will result in the snapshot containing the top left portion of whatever's on the monitor at that position. You'll need to translate the coordinates from global to local coords. You can either do that using the globalloc function or you can just use the rect of the stack instead of the rect of the card. The second method won't always work if you have a menubar on a Mac (which makes the stack shorter than the card.)
> 
> After either an import or an export, the "it" variable is not given a value, so it becomes the string literal "it". You can't set an icon to a string literal, you need an ID number.
> 
> While you can take snapshots of objects that aren't open, you can't take them of cards that aren't open. Cards are not objects. I was unable to get a snapshot of another card unless I went there first. This did work:
> 
> on test
>  get the rect of this cd
>  put globalloc(item 1 to 2 of it) into tRect
>  put globalLoc(item 3 to 4 of it) into item 3 to 4 of tRect
>  go cd 2
>  import snapshot from rect tRect
>  go back
>  set the icon of me to the short id of last img of cd 2
> end test
> 
> The "export snapshot" offers more options. You can export a snapshot to a variable and then put that variable into an image object. However, I was still unable to get a snapshot without going to the card. This works:
> 
> on test2
>  lock screen
>  go cd 2
>  export snapshot from cd 2 to tVar as JPEG
>  go back
>  unlock screen
>  create img "iconImg"
>  set the text of img "iconImg" to tVar
>  set the icon of me to the short id of img "iconImg"
> end test2
> 
> -- 
> Jacqueline Landman Gay         |     jacque at hyperactivesw.com
> HyperActive Software           |     http://www.hyperactivesw.com
> 
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