qml

package module
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 Go to latest Published: Sep 22, 2013 License: LGPL-3.0 Imports: 17 Imported by: 0

README

QML support for the Go language

This is an ALPHA release

This package is in an alpha stage, and still in heavy development. APIs may change, and things may break.

At this time contributors and developers that are interested in tracking the development closely are encouraged to use it. If you'd prefer a more stable release, please hold on a bit and subscribe to the mailing list for news. It's in a pretty good state, so it shall not take too long.

Demo

See this video for a quick introduction.

Community

Please join the mailing list for following relevant development news and discussing project details.

API documentation

The API documentation is available in the usual location.

Requirements

To try the alpha release, you'll need:

  • Go 1.2 (release candidate), for the C++ support of go build
  • The current Ubuntu SDK, or equivalent Qt libraries
  • Packages qtbase5-private-dev and qtdeclarative5-private-dev or equivalent header files, for the dynamic meta object support

In practice, if you are in Ubuntu, this should work for the Qt dependencies:

$ sudo add-apt-repository ppa:ubuntu-sdk-team/ppa
$ sudo apt-get update
$ sudo apt-get install ubuntu-sdk qtbase5-private-dev qtdeclarative5-private-dev

and Go 1.2 may be installed using godeb:

$ # Pick the right one for your system: 386 or amd64
$ ARCH=amd64
$ wget -q https://godeb.s3.amazonaws.com/godeb-$ARCH.tar.gz
$ tar xzvf godeb-$ARCH.tar.gz
godeb
$ sudo mv godeb /usr/local/bin
$ godeb list | head -1
1.2rc1
$ godeb install 1.2rc1

If you're not in Ubuntu and your operating system does not offer these dependencies, you may have success installing Go 1.2rc1 and Qt 5.0.2 directly from the upstreams.

Installation

Once the requirements above are satisfied, go get should work as usual:

go get github.com/niemeyer/qml

Documentation

Overview

Package qml offers graphical QML application support for the Go language.

Warning

This package is in an alpha stage, and still in heavy development. APIs may change, and things may break.

At this time contributors and developers that are interested in tracking the development closely are encouraged to use it. If you'd prefer a more stable release, please hold on a bit and subscribe to the mailing list for news. It's in a pretty good state, so it shall not take too long.

See http://github.com/niemeyer/qml for details.

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func Changed 

func Changed(value, fieldAddr interface{})

Changed notifies all QML bindings that the given field value has changed.

For example: 

qml.Changed(&value, &value.Field)

func CollectStats 

func CollectStats(enabled bool)

func Flush 

func Flush()

Flush synchronously flushes all pending QML activities.

func Init 

func Init(options *InitOptions)

Init initializes the qml package with the provided parameters. If the options parameter is nil, default options suitable for a normal graphic application will be used.

Init must be called only once, and before any other functionality from the qml package is used.

func Lock 

func Lock()

Lock freezes all QML activity by blocking the main event loop. Locking is necessary before updating shared data structures without race conditions.

It's safe to use qml functionality while holding a lock, as long as the requests made do not depend on follow up QML events to be processed before returning. If that happens, the problem will be observed as the application freezing.

The Lock function is reentrant. That means it may be called multiple times, and QML activities will only be resumed after Unlock is called a matching number of times.

func RegisterSingleton 

func RegisterSingleton(spec *TypeSpec) error

func RegisterType 

func RegisterType(spec *TypeSpec) error

func ResetStats 

func ResetStats()

func SetLogger 

func SetLogger(logger interface{})

SetLogger sets the target for messages logged by the qml package, including console.log and related calls from within qml code.

The logger value must implement either the StdLogger interface, which is satisfied by the standard *log.Logger type, or the QmlLogger interface, which offers more control over the logged message.

If no logger is provided, the qml package will send messages to the default log package logger. This behavior may also be restored by providing a nil logger to this function.

func Unlock 

func Unlock()

Unlock releases the QML event loop. See Lock for details.

Types

type Context 

type Context struct {
	// contains filtered or unexported fields
}

Context represents a QML context that can hold variables visible to logic running within it.

func (*Context) SetVar 

func (ctx *Context) SetVar(name string, value interface{})

SetVar makes the provided value available as a variable with the given name for QML code executed within the c context.

If value is a struct, its exported fields are also made accessible to QML code as attributes of the named object. The attribute name in the object has the same name of the Go field name, except for the first letter which is lowercased. This is conventional and enforced by the QML implementation.

The engine will hold a reference to the provided value, so it will not be garbage collected until the engine is destroyed, even if the value is unused or changed.

func (*Context) SetVars 

func (ctx *Context) SetVars(value interface{})

SetVars makes the exported fields of the provided value available as variables for QML code executed within the c context. The variable names will have the same name of the Go field names, except for the first letter which is lowercased. This is conventional and enforced by the QML implementation.

The engine will hold a reference to the provided value, so it will not be garbage collected until the engine is destroyed, even if the value is unused or changed.

func (*Context) Var 

func (ctx *Context) Var(name string) interface{}

Var returns the context variable with the given name.

type Engine 

type Engine struct {
	// contains filtered or unexported fields
}

Engine provides an environment for instantiating QML components.

func NewEngine 

func NewEngine() *Engine

NewEngine returns a new QML engine.

The Destory method must be called to finalize the engine and release any resources used.

func (*Engine) Context 

func (e *Engine) Context() *Context

Context returns the engine's root context.

func (*Engine) Destroy 

func (e *Engine) Destroy()

Destroy finalizes the engine and releases any resources used. The engine must not be used after calling this method.

It is safe to call Destroy more than once.

func (*Engine) Load 

func (e *Engine) Load(location string, r io.Reader) (*Object, error)

Load loads a new component with the provided location and with the content read from r. The location informs the resource name for logged messages, and its path is used to locate any other resources referenced by the QML content.

Once a component is loaded, component instances may be created from the resulting object via its Create and CreateWindow methods.

func (*Engine) LoadFile 

func (e *Engine) LoadFile(path string) (*Object, error)

LoadFile loads a component from the provided QML file. Resources referenced by the QML content will be resolved relative to its path.

Once a component is loaded, component instances may be created from the resulting object via its Create and CreateWindow methods.

func (*Engine) LoadString 

func (e *Engine) LoadString(location, qml string) (*Object, error)

LoadString loads a component from the provided QML string. The location informs the resource name for logged messages, and its path is used to locate any other resources referenced by the QML content.

Once a component is loaded, component instances may be created from the resulting object via its Create and CreateWindow methods.

type InitOptions 

type InitOptions struct {
}

InitOptions holds options to initialize the qml package.

type LogMessage 

type LogMessage interface {
	Severity() LogSeverity
	Text() string
	File() string
	Line() int

	String() string // returns "file:line: text"
	// contains filtered or unexported methods
}

LogMessage is implemented by values provided to QmlLogger.QmlOutput.

type LogSeverity 

type LogSeverity int
const (
	LogDebug LogSeverity = iota
	LogWarning
	LogCritical
	LogFatal
)

type Object 

type Object struct {
	// contains filtered or unexported fields
}

Object represents a QML object.

func (*Object) Bool 

func (obj *Object) Bool(property string) bool

Bool returns the bool value of the given property. Bool panics if the property value is not a bool.

func (*Object) Call 

func (obj *Object) Call(method string, params ...interface{}) interface{}

Call calls the given object method with the provided parameters. Call panics if the method does not exist.

func (*Object) Create 

func (obj *Object) Create(ctx *Context) *Object

Create creates a new instance of the component held by obj. The component instance runs under the ctx context. If ctx is nil, it runs under the same context as obj.

The Create method panics if called on an object that does not represent a QML component.

func (*Object) CreateWindow 

func (obj *Object) CreateWindow(ctx *Context) *Window

CreateWindow creates a new instance of the component held by obj, and creates a new window holding the instance as its root object. The component instance runs under the ctx context. If ctx is nil, it runs under the same context as obj.

The CreateWindow method panics if called on an object that does not represent a QML component.

func (*Object) Destroy 

func (obj *Object) Destroy()

Destroy finalizes the value and releases any resources used. The value must not be used after calling this method.

func (*Object) Float64 

func (obj *Object) Float64(property string) float64

Float64 returns the float64 value of the given property. Float64 panics if the property value cannot be represented as float64.

func (*Object) Int 

func (obj *Object) Int(property string) int

Int returns the int value of the given property. Int panics if the property value cannot be represented as an int.

func (*Object) Int64 

func (obj *Object) Int64(property string) int64

Int64 returns the int64 value of the given property. Int64 panics if the property value cannot be represented as an int64.

func (*Object) Object 

func (obj *Object) Object(property string) *Object

Object returns the *qml.Object value of the given property. Object panics if the property value is not a *qml.Object.

func (*Object) ObjectByName 

func (obj *Object) ObjectByName(objectName string) *Object

ObjectByName returns the *qml.Object value of the descendant object that was defined with the objectName property set to the provided value. ObjectByName panics if the object is not found.

func (*Object) Property 

func (obj *Object) Property(name string) interface{}

Property returns the current value for a property of the object. If the property type is known, type-specific methods such as Int and String are more convenient to use. Property panics if the property does not exist.

func (*Object) Set 

func (obj *Object) Set(property string, value interface{}) error

Set changes the named object property to the given value.

func (*Object) String 

func (obj *Object) String(property string) string

String returns the string value of the given property. String panics if the property value is not a string.

type QmlLogger 

type QmlLogger interface {
	// QmlOutput is called whenever a new message is available for logging.
	// The message value must not be used after the method returns.
	QmlOutput(message LogMessage) error
}

The QmlLogger interface may be implemented to better control how log messages from the qml package are handled. Values that implement either StdLogger or QmlLogger may be provided to the SetLogger function.

type Statistics 

type Statistics struct {
	EnginesAlive int
	ValuesAlive  int
}

func Stats 

func Stats() (snapshot Statistics)

type StdLogger 

type StdLogger interface {
	// Output is called whenever a new message is available for logging.
	// See the standard log.Logger type for more details.
	Output(calldepth int, s string) error
}

The StdLogger interface is implemented by standard *log.Logger values. Values that implement either StdLogger or QmlLogger may be provided to the SetLogger function.

type TypeSpec 

type TypeSpec struct {
	Location     string
	Major, Minor int
	// TODO Consider refactoring this type into ModuleSpec for the above + []TypeSpec for the below
	Name string
	New  func() interface{}
}

type Window 

type Window struct {
	// contains filtered or unexported fields
}

Window represents a QML window where components are rendered.

func (*Window) Destroy 

func (win *Window) Destroy()

Destroy destroys the window. The window should not be used after this method is called.

func (*Window) Hide 

func (win *Window) Hide()

Hide hides the window.

func (*Window) Root 

func (win *Window) Root() *Object

Root returns the root object being rendered in the window.

func (*Window) Show 

func (win *Window) Show()

Show exposes the window.

func (*Window) Wait 

func (win *Window) Wait()

Wait blocks the current goroutine until the window is closed.

Source Files

View all Source files

Directories

Path Synopsis
examples
particle
qmlscene

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