}
Let us look at these lines in more details.
yocto_api and yocto_display import
These two import provide access to functions allowing you to manage Yoctopuce modules.
yocto_api
is always needed,
yocto_display
is necessary to manage modules containing a
display, such as Yocto-Display. Other imports can be useful in other cases, such as
YModule
which
can let you enumerate any type of Yoctopuce device.
YAPI.RegisterHub
The
RegisterHub
method allows you to indicate on which machine the Yoctopuce modules are
located, more precisely on which machine the VirtualHub software is running. In our case, the
127.0.0.1:4444
address indicates the local machine, port
4444
(the standard port used by
Yoctopuce). You can very well modify this address, and enter the address of another machine on
which the VirtualHub software is running, or of a YoctoHub. If the host cannot be reached, this
function will trigger an exception.
YDisplay.FindDisplay
The
FindDisplay
method allows you to find a display from the serial number of the module on
which it resides and from its function name. You can also use logical names, as long as you have
initialized them. Let us imagine a Yocto-Display module with serial number
YD128X32-123456
which
you have named "
MyModule
", and for which you have given the
display
function the name
"
MyFunction
". The following five calls are strictly equivalent, as long as "
MyFunction
" is defined only
once.
display
=
YDisplay
.
FindDisplay
(
"YD128X32-123456.display"
)
display
=
YDisplay
.
FindDisplay
(
"YD128X32-123456.MaFonction"
)
display
=
YDisplay
.
FindDisplay
(
"MonModule.display"
)
display
=
YDisplay
.
FindDisplay
(
"MonModule.MaFonction"
)
display
=
YDisplay
.
FindDisplay
(
"MaFonction"
)
YDisplay.FindDisplay
returns an object which you can then use at will to control the display.
isOnline
The
isOnline()
method of the object returned by
FindDisplay
allows you to know if the
corresponding module is present and in working order.
get_displayLayer
The
get_displayLayer()
method of the object returned by
YDisplay.FindDisplay
allows
you to retrieve the object corresponding to one of the screen layers. This object implements all the
graphical routines.
A real example, for Node.js
Open a command window (a terminal, a shell...) and go into the directory
example_nodejs/Doc-
GettingStarted-Yocto-Display
within Yoctopuce library for JavaScript / EcmaScript 2017. In there,
you will find a file named
demo.js
with the sample code below, which uses the functions explained
above, but this time used with all side materials needed to make it work nicely as a small demo.
If your Yocto-Display is not connected on the host running the browser, replace in the example the
address
127.0.0.1
by the IP address of the host on which the Yocto-Display is connected and
where you run the VirtualHub.
"use strict"
;
require
(
'yoctolib-es2017/yocto_api.js'
);
require
(
'yoctolib-es2017/yocto_display.js'
);
let
disp
,
l1
;
let
h
,
w
,
y
,
x
,
vx
,
vy
;
9. Using Yocto-Display with JavaScript / EcmaScript
www.yoctopuce.com
39
Содержание Yocto-Display
Страница 1: ...Yocto Display User Manual...
Страница 2: ......
Страница 40: ...34 www yoctopuce com...
Страница 52: ...46 www yoctopuce com...
Страница 84: ...78 www yoctopuce com...
Страница 92: ...86 www yoctopuce com...
Страница 130: ...124 www yoctopuce com...
Страница 158: ...22 High level API Reference 152 www yoctopuce com On failure throws an exception or returns a negative error code...
Страница 422: ...416 www yoctopuce com...
Страница 424: ...24 Characteristics 418 www yoctopuce com...