Screen Overlay

Draws an image overlay fixed to the screen. Sample use for screen overlays are compasses, logos, and heads-up displays. Screen overlay sizing is determined by the Size X, Y. Positioning of the overlay is handled by mapping a point in the image specified by Overlay X, Y to a point on the screen specified by Screen X, Y. Then the image is rotated by Rotation degrees about a point relative to the screen specified by Rotation X, Y.

The Screen Overlay does not offer Edit capabilities in the Preview window, you must change the values manually.

Href: The image associated with the Overlay. This location can be either on a local file or on the Internet. If this element is omitted or contains no path, a rectangle is drawn using the color and size defined by the ground or screen overlay.

Refresh:
Specifies to use a time-based refresh mode.

View Refresh:
Specifies how the link is refreshed when the viewport changes.

Bounding Scale: Scales the Bounding Box parameters before sending them to the server. A value less than 1 specifies to use less than the full view (screen). A value greater than 1 specifies to fetch an area that extends beyond the edges of the current view.

Format:
Specifies the format of the query string that is appended to the Link's Href before the file is fetched. (If the Href specifies a local file, this element is ignored)

Color:
Opens a Color dialog. The color white is equivalent to removing the color, that is, the icon will not have its color altered.

Opacity:
A ratio indicating how opaque the icon is. The ratio is between 0 for transparent and 100 for fully opaque.

Draw order:
This element defines the stacking order for the images in overlapping overlays. Overlays with higher draw order values are drawn on top of overlays with lower draw order values.

Screen X, Y

Specifies a point relative to the screen origin that the overlay image is mapped to. The x and y values can be specified in three different ways: as pixels, as fractions of the screen, or, as Inset Pixels, which is an offset in pixels from the upper right corner of the screen. The x and y positions can be specified in different ways—for example, x can be in pixels and y can be a fraction. The origin of the coordinate system is in the lower left corner of the screen.

x » Either the number of pixels, a fractional component of the screen, or a pixel inset indicating the x component of a point on the screen.
y » Either the number of pixels, a fractional component of the screen, or a pixel inset indicating the y component of a point on the screen.
x unit » Unit in which the x value is specified. A value of fraction indicates the x value is a fraction of the screen. A value of pixels indicates the x value in pixels. A value of Inset Pixels indicates the indent from the right edge of the screen.
y unit » Unit in which the y value is specified. A value of fraction indicates the y value is a fraction of the screen. A value of pixels indicates the y value in pixels. A value of Inset Pixels indicates the indent from the top edge of the screen.

For example, Screen X =. 5, y = .5, x unit = fraction, y unit = fraction indicates a point in the middle of the screen.

Overlay X, Y

Specifies a point on (or outside of) the overlay image that is mapped to the screen coordinate Screen X, Y. It requires x and y values, and the units for those values.

The x and y values can be specified in three different ways: as pixels, as fractions of the image fraction, or as inset pixels Inset Pixels, which is an offset in pixels from the upper right corner of the image. The x and y positions can be specified in different ways—for example, x can be in pixels and y can be a fraction. The origin of the coordinate system is in the lower left corner of the image.

x » Either the number of pixels, a fractional component of the image, or a pixel inset indicating the x component of a point on the overlay image.
y » Either the number of pixels, a fractional component of the image, or a pixel inset indicating the y component of a point on the overlay image.
x unit » Unit in which the x value is specified. A value of fraction indicates the x value is a fraction of the image. A value of pixels indicates the x value in pixels. A value of Inset Pixels indicates the indent from the right edge of the image.
y unit » Units in which the y value is specified. A value of fraction indicates the y value is a fraction of the image. A value of pixels indicates the y value in pixels. A value of Inset Pixels indicates the indent from the top edge of the image.

Size X, Y

Specifies the size of the image for the screen overlay, as follows:

A value of -1 indicates to use the native dimension
A value of 0 indicates to maintain the aspect ratio
A value of n sets the value of the dimension

Rotation

Adjusts how the image is placed inside the field of view. This element is useful if your image has been rotated and deviates slightly from a desired horizontal view.

Href:	The image associated with the Overlay. This location can be either on a local file or on the Internet. If this element is omitted or contains no path, a rectangle is drawn using the color and size defined by the ground or screen overlay.
Refresh:	Specifies to use a time-based refresh mode.
View Refresh:	Specifies how the link is refreshed when the viewport changes.
Bounding Scale:	Scales the Bounding Box parameters before sending them to the server. A value less than 1 specifies to use less than the full view (screen). A value greater than 1 specifies to fetch an area that extends beyond the edges of the current view.
Format:	Specifies the format of the query string that is appended to the Link's Href before the file is fetched. (If the Href specifies a local file, this element is ignored)
Color:	Opens a Color dialog. The color white is equivalent to removing the color, that is, the icon will not have its color altered.
Opacity:	A ratio indicating how opaque the icon is. The ratio is between 0 for transparent and 100 for fully opaque.
Draw order:	This element defines the stacking order for the images in overlapping overlays. Overlays with higher draw order values are drawn on top of overlays with lower draw order values.