Wt
3.2.1
|
A video-playing widget. More...
#include <Wt/WVideo>
Public Member Functions | |
WVideo (WContainerWidget *parent=0) | |
Creates a video widget. | |
void | setPoster (const std::string &url) |
Set the poster image. | |
std::string | jsVideoRef () const |
Returns the JavaScript reference to the video object, or null. | |
virtual void | resize (const WLength &width, const WLength &height) |
Resizes the widget. |
A video-playing widget.
This is a low-level widget, mapping directly onto a <video>
element available in HTML5 compliant browsers.
In almost every situation you should use the WMediaPlayer widget instead, which has fallback and flexible user-interface options.
Usage of the video element consists of adding one or more video sources and setting some options. Since not every browser supports HTML5 video, the class provides a mechanism to display alternative content in browsers that cannot play the video.
Usage example:
WVideo *v = new WVideo(parent); v->setOptions(WVideo::Autoplay | WVideo::Controls); // Addsources may be called multiple times for different formats: // Firefox only plays ogg v->addSource("wt.ogv"); // many others play mp4 v->addSource("wt.mp4", "video/mp4"); // Image to be displayed before playback starts v->setPoster("wt.jpg"); // You may display a simple text to explain that you need html5 support... // v->setAlternativeContent(new WText("You have no HTML5 Video!")); // ... or provide an alternative player, e.g. Flash-based WFlashObject *f = new WFlashObject("player.swf", root()); f->setFlashVariable("startimage", "wt.jpg"); f->setFlashVariable("flv", "wt.mp4"); f->resize(640, 384); v->setAlternativeContent(f);
There are two reasons why the a browser may use the alternative content: either because the browser does not support the HTML5 video tag (alternative content is displayed even when JavaScript is not available), or because none of the specified sources contain a video format that is understood by the browser (requires JavaScript to display the alternative content).
The addSource() and setAlternativeContent() may not be called after the widget is rendered.
WVideo::WVideo | ( | WContainerWidget * | parent = 0 | ) |
Creates a video widget.
The constructor sets the 'controls' option, which causes the browser to display a bar with play/pauze/volume/... controls.
A freshly constructed video widget has no poster image, no media sources, has preload mode set to PreloadAuto, and only the Controls flag is set.
std::string WVideo::jsVideoRef | ( | ) | const |
Returns the JavaScript reference to the video object, or null.
It is possible, for compatibility reasons, that jsRef() is not the video element. jsVideoRef() is guaranteed to be an expression that evaluates to the video object. This expression may yield null, if the video object is not rendered at all (e.g. on older versions of Internet Explorer).
Resizes the widget.
Specify a new size for this widget, by specifying width and height. By default a widget has automatic width and height, see WLength::isAuto().
This applies to CSS-based layout, and only block widgets can be given a size reliably.
When inserted in a layout manager, the widget may be informed about its current size using setLayoutSizeAware(). If you have defined a "wtResize()"
JavaScript method for the widget, then this method will also be called. operation.
Reimplemented from Wt::WWebWidget.
void WVideo::setPoster | ( | const std::string & | url | ) |
Set the poster image.
On browsers that support it, the poster image is displayed before the video is playing. Some browsers display the first frame of the video stream once the video stream is loaded; it is therefore a good idea to include the poster image as first frame in the video feed too.