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[polarby]

Render

With the Render widget you can render and convert wigets into a wide range of exportable file formats. Main features include:

• Render static or animated widgets to png, jpg, gif, mov and mp4 (including sound)
• Rendering wigets that are not in your widget tree (not displayed/build)
• Render multiple variations of your widget at the same time with layered rendering (including mixed building visualisation)

Important: Note that rendering front-end elements is not considered the most efficient and native approach to editing images and videos. Use with own responsabilty.

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Examples

Video

Usage

final _controller   = RenderController();

Render(
    controller: _controller,
    duration: Duration(seconds: 5),
    builder: (context, RenderSnapshot snapshot){
       return Container();
    } 
) 

await  _controller.render(overwriteFrames: 269, frame: 5);

Tip: full interactive example for usage in ./example folder.

Layered rendering

You might encounter situations where you want to have variations of your widget rendering (eg. one version with round corners & and one without). Instead of rendering your widget multiple times you can use layered rendering, which renderes the widget only ones instead of multiple times and consequently reduces your rendering time and significantly.

Simply wrap a widget within your Render build with RenderLayer:

RenderLayer(
    visualize: false,
    child: ... 
) 

Properties of Render

Name	Type	Default Behavior	Description
controller	PageController?	PageController()	The controller to manipulate the state of your list. The behavior of list and controller equals the default PageView widget
required itemBuilder	Widget Function(BuildContext, int)
required itemCount	int
scrollDirection	Axis	Axis.horizontal
physics	ScrollPhysics?	AlwaysScrollable()
itemExtent	double?
minCacheExtent	double?
itemSnapping	bool	false
addSemanticIndexes	bool	true
addAutomaticKeepAlives	bool	true
addRepaintBoundaries	bool	true
reverse	bool	false
itemPositionsListener	ItemPositionsListener?
onPageChanged	void Function(int index, double size)?
onPageChange	void Function(double page, double size)?
overscrollPhysics	PageOverscrollPhysics?	normal PageView scrolling
scrollBehavoir	ScrollBehavoir?
visualisation	ListVisualisation?	ListVisualisation.normal()
allowItemSizes	bool	false
snapAlignment	SnapAlignment	SnapAlignment.static(0.5)
snapOnItemAlignment	SnapAlignment	SnapAlignment.static(0.5)

Properties of RenderLayer

Properties of RenderController

Additional information

Contributions are very welcome and can be merged within hours if testing is successful.