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C++ TextTrackCue::updateDisplay方法代码示例

本文整理汇总了C++中TextTrackCue::updateDisplay方法的典型用法代码示例。如果您正苦于以下问题:C++ TextTrackCue::updateDisplay方法的具体用法?C++ TextTrackCue::updateDisplay怎么用?C++ TextTrackCue::updateDisplay使用的例子?那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在TextTrackCue的用法示例。


在下文中一共展示了TextTrackCue::updateDisplay方法的1个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于系统推荐出更棒的C++代码示例。

示例1: updateDisplay

void MediaControlTextTrackContainerElement::updateDisplay()
{
    if (!mediaElement().closedCaptionsVisible()) {
        removeChildren();
        return;
    }

    // 1. If the media element is an audio element, or is another playback
    // mechanism with no rendering area, abort these steps. There is nothing to
    // render.
    if (isHTMLAudioElement(mediaElement()))
        return;

    // 2. Let video be the media element or other playback mechanism.
    HTMLVideoElement& video = toHTMLVideoElement(mediaElement());

    // 3. Let output be an empty list of absolutely positioned CSS block boxes.
    Vector<RefPtr<HTMLDivElement> > output;

    // 4. If the user agent is exposing a user interface for video, add to
    // output one or more completely transparent positioned CSS block boxes that
    // cover the same region as the user interface.

    // 5. If the last time these rules were run, the user agent was not exposing
    // a user interface for video, but now it is, let reset be true. Otherwise,
    // let reset be false.

    // There is nothing to be done explicitly for 4th and 5th steps, as
    // everything is handled through CSS. The caption box is on top of the
    // controls box, in a container set with the -webkit-box display property.

    // 6. Let tracks be the subset of video's list of text tracks that have as
    // their rules for updating the text track rendering these rules for
    // updating the display of WebVTT text tracks, and whose text track mode is
    // showing or showing by default.
    // 7. Let cues be an empty list of text track cues.
    // 8. For each track track in tracks, append to cues all the cues from
    // track's list of cues that have their text track cue active flag set.
    CueList activeCues = video.currentlyActiveCues();

    // 9. If reset is false, then, for each text track cue cue in cues: if cue's
    // text track cue display state has a set of CSS boxes, then add those boxes
    // to output, and remove cue from cues.

    // There is nothing explicitly to be done here, as all the caching occurs
    // within the TextTrackCue instance itself. If parameters of the cue change,
    // the display tree is cleared.

    // 10. For each text track cue cue in cues that has not yet had
    // corresponding CSS boxes added to output, in text track cue order, run the
    // following substeps:
    for (size_t i = 0; i < activeCues.size(); ++i) {
        TextTrackCue* cue = activeCues[i].data();

        ASSERT(cue->isActive());
        if (!cue->track() || !cue->track()->isRendered() || !cue->isActive())
            continue;

        cue->updateDisplay(m_videoDisplaySize.size(), *this);
    }

    // 11. Return output.
    if (hasChildren())
        show();
    else
        hide();
}
开发者ID:junmin-zhu,项目名称:blink,代码行数:67,代码来源:MediaControlElements.cpp


注:本文中的TextTrackCue::updateDisplay方法示例由纯净天空整理自Github/MSDocs等开源代码及文档管理平台,相关代码片段筛选自各路编程大神贡献的开源项目,源码版权归原作者所有,传播和使用请参考对应项目的License;未经允许,请勿转载。