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Diffstat (limited to 'xml/Component.xml')
-rw-r--r-- | xml/Component.xml | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/xml/Component.xml b/xml/Component.xml index 4260a828..8505c861 100644 --- a/xml/Component.xml +++ b/xml/Component.xml @@ -110,6 +110,45 @@ <arg direction="out" name="height" type="i"/> </method> + <!-- + GetLayer: + + Queries the UI layer at which a component is rendered, which can help in + determining when components occlude one another. + + The layer of a component indicates its relative stacking order with respect to the + onscreen visual representation of the UI. The layer index, in combination + with the component's extents, can be used to compute the visibility of + all or part of a component. This is important in programmatic determination of + region-of-interest for magnification, and in flat screen review models of the + screen, as well as for other uses. Objects residing in two of the + Layer categories support further z-ordering information, with + respect to their peers in the same layer: namely, WINDOW and + MDI. Relative stacking order for other objects within the same layer + is not available; the recommended heuristic is first child paints first. In other + words, assume that the first siblings in the child list are subject to being + overpainted by later siblings if their bounds intersect. The order of layers, from + bottom to top, is as follows: + + 0 - INVALID: Error condition. + + 1 - BACKGROUND: Reserved for the desktop background; this is the bottom-most + layer, over which everything else is painted. + + 2 - CANVAS: The 'background' layer for most content renderers and UI component containers. + + 3 - WIDGET: The layer in which the majority of ordintary 'foreground' widgets reside. + + 4 - MDI: A special layer between CANVAS and WIDGET, in which the 'pseudo-windows' + (e.g. the Multiple-Document Interface frames) reside. See the GetMDIZOrder + method. + + 5 - POPUP: Layer for popup window content, above WIDGET. + + 6 - OVERLAY: The topmost layer. + + 7 - WINDOW: The layer in which a toplevel window background usually resides. + --> <method name="GetLayer"> <arg direction="out" type="u"/> </method> |