[GEM-dev] Someone sent a bogus pointer to copy2Image (was Re: GEM-dev Digest, Vol 141, Issue 1)

[IOhannes m zmölnig]

On 3/25/20 12:41 PM, Michael Beil wrote:
> after more testing yesterday I can describe more precisely:
> 
> I send an image from pix_video to a rectangle and I use a gemwin with the same resolution.
> pix_video = 1280*720
> gemwin = 1280*720
> I use facetime (builtin), external webcam (logitech) and blackmagic intensity interface (USB3/HDMI)
> I get a proper image and I can switch the cams. THAT’S GREAT !!!! :)
> 
> but
> - when I change the resolution of pix_video I have to recreate gemwin to see the effect

oops. that should not be necessary.

> - when I send create, 1 to gemwin I get the bogus errors and I have to wait for them popping up (more for facetime, less for external cams)

only when re-creating the gemwin, or also when creating it for the first
time?

do those errors stop eventually?
(might be, that the camera takes some time to start streaming images;
and Gem complains that it doesn't get any images).


> - real issue: the border 0 message to gemwin creates a black gap where the border was and changes the image frame (part of the image at the left side vanishes by an x-zoom, the window-size remains the same)

not sure i understand what you are saying.
could you post a screenshot?
also, does the problem persist if you send the [border 0( *before* you
create the Gem-windows (for the first time)? or are you doing that anyhow.


> - the rectangle object needs weird numbers like 7.5 and 4 to get the image fitting to a gemwin, the original image is very small in the gemwin without scaling and adapting

this is expected behaviour.
a [rectangle] is not some space on the screen to be occupied by whatever
incoming video you have; but instead it is a representation of a
3d-dimensional object (without depth :-)) in a 3d-world, and you just
happen to look at it. the closer you (or the camera) is to the object,
the larger it gets. it's the same as with your TV, really :-)

in the default camera position, the upper window border is Y=+4 and the
lower window border is Y=-4; since [square] (and [rectangle]) really
expand from -size to +size, a [square] of size=4 will cover the entire
height of the screen.
depending on the aspect ration of your video (or your gemwindow/screen,
if you want to show the video fullscreen, even if you are distorting
it), you have to adjust the width of your [rectangle].
if the aspect ratio is 1:1, then an object that covers X=-4 thru X=+4
will cover the entire width of the window (as in [square 4]).
if the aspect ratio is 2:1, then you need a [rectangle 8 4].

if your aspect ratio is 1280/720 (which, after doing some maths is the
same as 1.777777/1 or (if we multiply by 4) 7.1111111/4), then you need
to use a [rectangle 7.111111111 4].

you can automate this with

|
[pix_info]
|  | | |||
|  [/]
|  |
|  [* 4]
|  |
[rectangle 0 4]
|

> 
> I found the help-file for pix_video in the Max folder. But when I open it in the patch it is blank.

Max-folder?
do you get some Tcl/Tk error in the Pd-console?


gfmdsar
IOhannes

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