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Diffstat (limited to 'doc/dw-grows.doc')
| -rw-r--r-- | doc/dw-grows.doc | 43 |
1 files changed, 41 insertions, 2 deletions
diff --git a/doc/dw-grows.doc b/doc/dw-grows.doc index 32800c19..7ed938e5 100644 --- a/doc/dw-grows.doc +++ b/doc/dw-grows.doc @@ -14,6 +14,45 @@ calculating widget sizes. Goals are: - *display: inline-block*; - <button>. -(...) +A short sketch: -*/
\ No newline at end of file +**dw::core::Widget::sizeRequest and dw::core::Widget::getExtremes will +return final results.** The caller does not have to correct the size, +e. g. when percentages are defined. As an example, +dw::Textblock::calcWidgetSize has already become much simpler. + +**A new hierarchy, *container*:** Aside from dw::core::Widget::parent +and dw::core::Widget::generator, there is a third hierarchy +dw::core::Widget::container, which is (unlike *generator*) always a +direct ancestor, and represents what in CSS is called *containing +block*. Containers are important to define the "context size", which +is (not solely) used for percentage sizes. + +(There is another "containing block", dw::Textblock::containingBlock; +these may be consolidated some day.) + +**The process of size calculation is split between the widget itself +and its container:** + +- The container provides some abstract methods: + dw::core::Widget::getAvailWidthOfChild, + dw::core::Widget::getAvailHeightOfChild, + dw::core::Widget::correctRequisitionOfChild, and + dw::core::Widget::correctExtremesOfChild, which can be used in the + actual implementation of dw::core::Widget::sizeRequestImpl; + different containers with different ways how to arrange their + children will implement these methods in a different way. (Simple + example: the *available width* for children within a textblock is + the *available width* for the textblock itself, minus + margin/border/padding; on the other hand, it is completely different + for children of tables, for which a complex column width calculation + is used.) + +- The actual size calculation is, however, controlled by the widget + itself, which only *uses* these methods above. + +**Size hints are removed.** Instead, the container methods in the +previous paragraph are used. Changes of container sizes (especially +viewport the size) are handled in a different way. + +*/ |