On 2016-03-01 22:57, Terence Heaford wrote:
On 1 Mar 2016, at 21:32, J. Landman Gay <jac...@hyperactivesw.com>
wrote:
"To export a snapshot for a portion of a stack you use the form:
export snapshot from rect[angle] of window windowID to ...
Where windowId is the windowId property of the required stack."
This does not work correctly on a Mac for the reason given previously.
The top and bottom of the image exported has shifted down by the depth
of the menubar.
put the rect widget "Chart" into tRect
export snapshot from rectangle tRect of window (the windowId of window
"Test") to tVar as PNG
The corrected version would be:
put the rect widget "Chart" into tRect
subtract 22 from item 2 of tRect
subtract 22 from item 4 of tRect
export snapshot from rectangle tRect of window (the windowId of window
“Test") to tVar as PNG
There are three types of export/import snapshot.
The first uses the screen buffer - the co-ordinates have to be in screen
co-ordinate space:
export snapshot from rectangle tRect
The second uses the window buffer (if the OS has such things, otherwise
it is equivalent to using the screen buffer after a translation of
co-ordinates) - the co-ordinates have to be in window co-ordinate space
(NOT card co-ordinate space):
export snapshot from rectangle tRect of window tWindowId
The third uses no buffer at all, it asks the target object (and
children) to render the specified rect of itself into an offscreen
buffer (the same mechanism which the engine uses to update a window when
the OS requests it, or a portion gets changed) - the co-ordinates have
to be in card co-ordinate space:
export snapshot from rectangle tRect of <object>
Now, the final form here will work for any object which is drawn by the
LiveCode engine - it will not necessarily work for objects which use
'native' layers to display things (such as the browser). Whether or not
one can get a native layer to render itself entirely depends on the
native layer. For example, we've not had any success at all in
persuading the CEF browser to give us a snapshot as it uses various
'native' things which do not want to give up their backing store of
pixels.
Therefore, if you want to take a snapshot of a stack containing native
layers your best bet to make this work generally is to use the screen or
window form. When you do this you do have to take into account the fact
that cards might have a vertical scroll due to menus (that mysterious 22
px) - you can get the current scroll amount by using 'the vscroll of
stack ...'.
Warmest Regards,
Mark.
--
Mark Waddingham ~ m...@livecode.com ~ http://www.livecode.com/
LiveCode: Everyone can create apps
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