bool ScrollbarActivity::UpdateOpacity(TimeStamp aTime) { double progress = (aTime - mFadeBeginTime) / FadeDuration(); double opacity = 1.0 - std::max(0.0, std::min(1.0, progress)); // 'this' may be getting destroyed during SetOpacityOnElement calls. nsWeakFrame weakFrame((do_QueryFrame(mScrollableFrame))); SetOpacityOnElement(GetHorizontalScrollbar(), opacity); if (!weakFrame.IsAlive()) { return false; } SetOpacityOnElement(GetVerticalScrollbar(), opacity); if (!weakFrame.IsAlive()) { return false; } return true; }
bool ScrollbarActivity::UpdateOpacity(TimeStamp aTime) { // Avoid division by zero if mScrollbarFadeDuration is zero, just jump // to the end of the fade animation double progress = mScrollbarFadeDuration ? ((aTime - mFadeBeginTime) / FadeDuration()) : 1.0; double opacity = 1.0 - std::max(0.0, std::min(1.0, progress)); // 'this' may be getting destroyed during SetOpacityOnElement calls. nsWeakFrame weakFrame((do_QueryFrame(mScrollableFrame))); SetOpacityOnElement(GetHorizontalScrollbar(), opacity); if (!weakFrame.IsAlive()) { return false; } SetOpacityOnElement(GetVerticalScrollbar(), opacity); if (!weakFrame.IsAlive()) { return false; } return true; }