This document covers the following topics:
A wallpaper control is defines a background that can be displayed by dialogs or certain dialog elements (e.g. control box and dialog bar). A wallpaper control specifies an image together with associated attributes that determine how the wallpaper is to be rendered. For example, it is possible to specify that the wallpaper is to be rendered as a repeated pattern (tiling) rather than as a single image. Or, in the latter case, the horizontal and vertical justification of the image relative to the host dialog or dialog element can be set.
A wallpaper image is drawn transparently if the wallpaper control's "transparent" style is set, implying that all pixels in the wallpaper control's background color (if any) are not drawn. If no explicit background color is set, the transparent color is assumed to be the color of the top-left pixel in the image.
To use a wallpaper to paint the background of a dialog or dialog element, the WALLPAPER attribute of that dialog or dialog element must be set to the handle of the desired wallpaper control. Natural keeps track of the objects using a particular wallpaper control, and updates each of these objects automatically if any changes are made to the wallpaper control, or if the wallpaper control is deleted. In the latter case, the WALLPAPER attribute of each object is automatically reset to NULL-HANDLE.
| Attribute Name | Query | Set/Modify | In Attr. Window |
|---|---|---|---|
| BACKGROUND-COLOUR-NAME | X | X/X | X |
| BACKGROUND-COLOUR-VALUE | X | X/X | X |
| BITMAP-FILE-NAME | X | X/X | X |
| BLEND | X | X/- | X |
| CLIENT-HANDLE | X | X/X | |
| CLIENT-KEY | X | X/X | |
| CLIENT-VALUE | X | X/X | |
| FIRST-CHILD | X | -/- | |
| LAST-CHILD | X | -/- | |
| PARENT | X | X/- | |
| PREDECESSOR | X | -/- | |
| STYLE | X | X/- | X |
| SUCCESSOR | X | X/- | |
| TYPE | X | X/- | |
| VISIBLE | X | X/X | X |
This dialog element does not create events.