handle object
This feature is available with version 0.1.6 and more:
A handle is a reference to an internal object (equivalent to C++ pointer). Nelson allows to manipulate a generic type: handle and support overloading on this type.
Currently, Nelson allows to use QML objects (GUI & graphics) as handles. Other pointers can be added easily in the future (COM, java, …)
Example:
In this example, we load a basic qml file and modify text of the button:
hello.qml:
import QtQuick 2.0
import QtQuick.Window 2.0
import QtQuick.Controls 1.4
Window {
id: mainWindow
visible: true
width: 360
height: 360
title: "Qml Window"
objectName: "Fenetre"
Text {
id: text
text: "Hello world!"
objectName: "text1"
}
Button {
text: "Button"
anchors.centerIn: parent
onClicked: nelson.evaluate("A = 3")
objectName: "myBut1"
}
}
>> a = qml_loadfile('hello.qml')
a =
1×1 handle [QObject]
active: bool true
activeFocusItem: QQuickItem* handle
children: handle 1x3
className: QQuickWindow
color: QColor r:255 g:255 b:255 a:255
contentItem: QQuickItem* handle
contentOrientation: int 0
data: QQmlListProperty<QObject> handle
flags: int 1
height: int 360
maximumHeight: int 16777215
maximumWidth: int 16777215
minimumHeight: int 0
minimumWidth: int 0
modality: int 0
objectName: QString basic_window
opacity: double 1
parent: handle
title: QString Qml Window
transientParent: QWindow* handle
visibility: int 2
visible: bool true
width: int 360
x: int 780
y: int 335
With overloading, many basic functions come available for handles:
examples: disp, size, fieldnames, …
>> disp(a)
1×1 handle [QObject]
active: bool false
activeFocusItem: QQuickItem* handle
children: handle 1x3
className: QQuickWindow
color: QColor r:255 g:255 b:255 a:255
contentItem: QQuickItem* handle
contentOrientation: int 0
data: QQmlListProperty<QObject> handle
flags: int 1
height: int 360
maximumHeight: int 16777215
maximumWidth: int 16777215
minimumHeight: int 0
minimumWidth: int 0
modality: int 0
objectName: QString basic_window
opacity: double 1
parent: handle
title: QString Qml Window
transientParent: QWindow* handle
visibility: int 2
visible: bool true
width: int 360
x: int 780
y: int 335
>> fieldnames(a)
ans =
25×1 cell array
{'active'}
{'activeFocusItem'}
{'children'}
{'className'}
{'color'}
{'contentItem'}
{'contentOrientat…'}
{'data'}
{'flags'}
{'height'}
{'maximumHeight'}
{'maximumWidth'}
{'minimumHeight'}
{'minimumWidth'}
{'modality'}
{'objectName'}
{'opacity'}
{'parent'}
{'title'}
{'transientParent'}
{'visibility'}
{'visible'}
{'width'}
{'x'}
{'y'}
Example how to modify title of the button “Button”:
Get children of the figure created by ‘hello.qml’
% or children = get(a, 'children')
>> children = a.children
children =
1×3 handle
Two children, previously created:
one for text field with “hello world” content,
>> text_child = children(1)
text_child =
1×1 handle [QObject]
activeFocus: bool false
activeFocusOnTab: bool false
anchors: QQuickAnchors* handle
antialiasing: bool false
baselineOffset: double 0
childrenRect: QRectF x:0 y:0 w:226 h:194
className: QQuickRootItem
clip: bool false
containmentMask: QObject* handle
data: QQmlListProperty<QObject> handle
enabled: bool true
focus: bool false
height: double 360
implicitHeight: double 0
implicitWidth: double 0
layer: QQuickItemLayer* handle
objectName: QString
opacity: double 1
parent: handle
rotation: double 0
scale: double 1
smooth: bool true
state: QString
transformOrigin: int 4
transformOriginPoint: QRectF x:180 y:180
visible: bool true
visibleChildren: QQmlListProperty<QQuickItem> handle
width: double 360
x: double 0
y: double 0
z: double 0
one for the button with “Button” content:
>> button_child = children(2)
button_child =
1×1 handle [QObject]
activeFocus: bool false
activeFocusOnTab: bool false
advance: QSizeF handle
anchors: QQuickAnchors* handle
antialiasing: bool true
baseUrl: QUrl file:///D:/Developpements/Github/nelson/modules/qml_engine/examples/basic_window/hello.qml
baselineOffset: double 13
bottomPadding: double 0
childrenRect: QRectF x:0 y:0 w:0 h:0
className: QQuickText
clip: bool false
color: QColor r:0 g:0 b:0 a:255
containmentMask: QObject* handle
contentHeight: double 16
contentWidth: double 69
effectiveHorizontalAlignment: int 1
elide: int 3
enabled: bool true
focus: bool false
font: QFont MS Shell Dlg 2,7.8,-1,5,50,0,0,0,0,0
fontInfo: QJSValue handle
fontSizeMode: int 0
height: double 16
horizontalAlignment: int 1
hoveredLink: QString
implicitHeight: double 16
implicitWidth: double 69
layer: QQuickItemLayer* handle
leftPadding: double 0
lineCount: int 1
lineHeight: double 1
lineHeightMode: int 0
linkColor: QColor r:0 g:0 b:255 a:255
maximumLineCount: int 2147483647
minimumPixelSize: int 12
minimumPointSize: int 12
objectName: QString text1
opacity: double 1
padding: double 0
paintedHeight: double 16
paintedWidth: double 69
parent: handle
renderType: int 0
rightPadding: double 0
rotation: double 0
scale: double 1
smooth: bool true
state: QString
style: int 0
styleColor: QColor r:0 g:0 b:0 a:255
text: QString Hello world!
textFormat: int 2
topPadding: double 0
transformOrigin: int 4
transformOriginPoint: QRectF x:34.500000 y:8.000000
truncated: bool false
verticalAlignment: int 32
visible: bool true
width: double 69
wrapMode: int 0
x: double 0
y: double 0
z: double 0
To get the text of the button:
% text_button = get(button_child, 'text')
>> text_button = button_child.text
text_button =
'Hello world!'
To set the text of the button:
% or set(button_child, 'text', 'new button text'); button_child
>> button_child.text = 'new button text'; button_child
button_child =
1×1 handle [QObject]
activeFocus: bool false
activeFocusOnTab: bool false
advance: QSizeF handle
anchors: QQuickAnchors* handle
antialiasing: bool true
baseUrl: QUrl file:///D:/Developpements/Github/nelson/modules/qml_engine/examples/basic_window/hello.qml
baselineOffset: double 13
bottomPadding: double 0
childrenRect: QRectF x:0 y:0 w:0 h:0
className: QQuickText
clip: bool false
color: QColor r:0 g:0 b:0 a:255
containmentMask: QObject* handle
contentHeight: double 16
contentWidth: double 89
effectiveHorizontalAlignment: int 1
elide: int 3
enabled: bool true
focus: bool false
font: QFont MS Shell Dlg 2,7.8,-1,5,50,0,0,0,0,0
fontInfo: QJSValue handle
fontSizeMode: int 0
height: double 16
horizontalAlignment: int 1
hoveredLink: QString
implicitHeight: double 16
implicitWidth: double 89
layer: QQuickItemLayer* handle
leftPadding: double 0
lineCount: int 1
lineHeight: double 1
lineHeightMode: int 0
linkColor: QColor r:0 g:0 b:255 a:255
maximumLineCount: int 2147483647
minimumPixelSize: int 12
minimumPointSize: int 12
objectName: QString text1
opacity: double 1
padding: double 0
paintedHeight: double 16
paintedWidth: double 89
parent: handle
renderType: int 0
rightPadding: double 0
rotation: double 0
scale: double 1
smooth: bool true
state: QString
style: int 0
styleColor: QColor r:0 g:0 b:0 a:255
text: QString new button text
textFormat: int 2
topPadding: double 0
transformOrigin: int 4
transformOriginPoint: QRectF x:44.500000 y:8.000000
truncated: bool false
verticalAlignment: int 32
visible: bool true
width: double 89
wrapMode: int 0
x: double 0
y: double 0
z: double 0
The result:
Others examples about QML capabilities:
Advanced example with QML:
Nelson interaction with QML and D3.js:
Nelson interaction with QML and QCharts.js:
