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diff --git a/doc/dw-stacking-context.doc b/doc/dw-stacking-context.doc deleted file mode 100644 index 6138ca5d..00000000 --- a/doc/dw-stacking-context.doc +++ /dev/null @@ -1,114 +0,0 @@ -/** \page dw-stacking-context Handling stacking contexts - -Stacking Context and dw::core::StackingContextMgr -================================================= - -For the definition of stacking contexts, see CSS 2.1 specification, - -- <a href="http://www.w3.org/TR/CSS2/visuren.html#z-index">section - 9.9.1: Specifying the stack level: the 'z-index' property</a> and -- <a href="http://www.w3.org/TR/CSS2/zindex.html">appendix E</a>. - -A widget establishes a stacking context when it is positioned and its -style value of *z-index* is different from *auto* (see -dw::core::StackingContextMgr::isEstablishingStackingContext). In this -case, it is assigned an instance of dw::core::StackingContextMgr, -which has also access to the widgets establishing the child contexts. - - -Stacking Order -============== - -The stacking order influences - -1. the order in which child widgets are drawn (dw::core::Widget::draw), - and -2. the order in which mouse events are dispatched to child widgets - (dw::core::Widget::getWidgetAtPoint). - -The first is done from bottom to top, the latter from top to bottom. - -I'm here referring to the simplified description in -<a href="http://www.w3.org/TR/CSS2/visuren.html#z-index">section -9.9.1</a>. The table shows a recommended order for the implementations -of dw::core::Widget::draw and dw::core::Widget::getWidgetAtPoint -(for the latter, read from bottom to top): - -<table> -<tr> -<th> CSS specification <th> Drawing <th> Mouse events -<tr> -<td> *1. the background and borders of the element forming the - stacking context.* -<td> dw::core::Widget::drawBox -<td> Nothing necessary. -<tr> -<td> *2. the child stacking contexts with negative stack levels (most - negative first).* -<td> dw::core::StackingContextMgr::drawBottom (when defined) -<td> dw::core::StackingContextMgr::getBottomWidgetAtPoint (when defined) -<tr> -<td> *3. the in-flow, non-inline-level, non-positioned descendants.* - -<td rowspan="4"> When (i) widget specific content is drawn, then (ii) - dw::oof::OOFAwareWidget::drawOOF is called, this will - have this effect: - - 1. all in-flow elements are drawn, - 2. floats are drawn and - 3. positioned elements with *z-index: auto* are drawn - (latter two done by - dw::oof::OOFAwareWidget::drawOOF, in this order). - - This order differs from the specified order, but - since floats and in-flow elements do not overlap, - this difference has no effect. - - Drawing in-line elements, floats and positioned - elements with *z-index: auto* and should avoid - duplicate calls: Widgets drawn by - dw::core::StackingContextMgr::drawBottom and by - dw::core::StackingContextMgr::drawTop should be - excluded here. This can be tested with - dw::core::StackingContextMgr::handledByStackingContextMgr. - -<td rowspan="4"> Likewise, the implementation should (i) test - dw::oof::OOFAwareWidget::getWidgetOOFAtPoint, and - (ii) search through the chilren. Also, duplicate - calls should be avoided using - dw::core::StackingContextMgr::handledByStackingContextMgr. - - There are already the implementations - dw::core::Widget::getWidgetAtPoint (ignoring - dw::oof::OutOfFlowMgr) and - dw::oof::OOFAwareWidget::getWidgetAtPoint (including - dw::oof::OutOfFlowMgr). - -<tr> -<td> *4. the non-positioned floats.* -<tr> -<td> *5. the in-flow, inline-level, non-positioned descendants, - including inline tables and inline blocks.* -<tr> -<td> (What about positioned elements with *z-index: auto*? Seems to be - missing in - <a href="http://www.w3.org/TR/CSS2/visuren.html#z-index">section - 9.9.1</a>, but mentioned in - <a href="http://www.w3.org/TR/CSS2/zindex.html">appendix E</a>, - item 8. -<tr> -<td> *6. the child stacking contexts with stack level 0 and the - positioned descendants with stack level 0.* -<td rowspan="2"> dw::core::StackingContextMgr::drawTop (when defined) -<td rowspan="2"> dw::core::StackingContextMgr::getTopWidgetAtPoint - (when defined) -<tr> -<td> *7. the child stacking contexts with positive stack levels (least - positive first).* -</table> - -Note: This is not quite in conformance with the specification: this -description refers to any widget, not only widgets establishing a -stacking context. Does this make a difference? - -*/
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