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Diffstat (limited to 'doc/dw-out-of-flow.doc')
| -rw-r--r-- | doc/dw-out-of-flow.doc | 33 |
1 files changed, 31 insertions, 2 deletions
diff --git a/doc/dw-out-of-flow.doc b/doc/dw-out-of-flow.doc index 9a43a178..9febee55 100644 --- a/doc/dw-out-of-flow.doc +++ b/doc/dw-out-of-flow.doc @@ -209,7 +209,36 @@ Integration of line breaking and floats Absolute and fixed positiones ============================= -... - +If you look at dw::OutOfFlowMgr in detail, you will find that some +work on absolute positions has already be done, but is +deactivated. Absolutely positioned elements will also be handled by +dw::OutOfFlowMgr, in a way transparent to dw::Textblock. Positioning +is much simpler than for floats: the complicated relation between +dw::Textblock and dw::OutOfFlowMgr (calculation of the vertical +position of floats on one hand, limiting line widths by floats on the +other hand) does not occur here. + +Since handling sizes becomes an important part for absolute positions, +the full implementation will be realized after finishing the planned +redesign of widget sizes (see \ref dw-grows). + +(One note already about the *z-index* attribute: different blocks, +represented by widgets, may overlap; *z-index* has an influence the +order in which + +1. widgets are drawn (in *ascending* order of *z-index*), and +2. mouse events are deligated to the widgets (in *descending* oder of + *z-index*). + +Something similar is already done for floats: effectively, floats have +a larger *z-index* than the textblocks in flow. (See *end* of +dw::Textblock::draw and *beginning* of +dw::Textblock::getWidgetAtPoint.) + +For a complete implementation, handling *z-index* becomes a bit more +complicated. An idea is to keep track of the minimum and maximum value +of *z-index*, and then iterating over all possible values (ascending +for drawing, descending for event handling), handling only widgets +with a specific *z-index* in one iteration.) */
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