A class that defines display properties for images.
|
Property |
Type |
Description |
|
ImageDPI |
double |
The number of pixels per inch. Used to calculate scale on the server. |
|
ImageHeight |
int |
The height of the image in pixels. |
|
ImageWidth |
int |
The width of the image in pixels. |
|
TransparentColor |
A color to render transparent in the image. |
Remarks
The Image Display object contains the display characteristics of the image to be generated. These characteristics include the height and width of the image in pixels (ImageHeight and ImageWidth), the device resolution, in dots per inch of the image (ImageDPI) and the transparent color (TransparentColor).
Use TransparentColor
to make a specified color transparent. This is most commonly done to make
the background transparent. This can be performed on any MapServer function
that takes an ImageDisplay as a parameter. Setting
a transparent color is valid only for formats that support transparency.
These include: png, png24 and gif. When using ExportMapImage if different colors
are set as transparent in the TransparentColor
property of the MapDescription and
in the ImageDisplay, the color set in the ImageDisplay takes precedence
over the one set in the MapDescription.
To make background of the image transparent
set the ImageDisplay TransparentColor
equal to the BackgroundColor
property specified in MapServerInfo.