HostRast option—Perform raster image processing at the System/370 host

Purpose

Use the HostRast option to perform raster image processing at the System/370 host.

Use the HostRast option when:

Multiplane character symbol sets are required by the application.
GDDM® color mixing is important to the application.

The default device model for GDDMXD/MVS is an IBM® 3179G with a mouse and the raster image processing is performed at the workstation.

Format


                      .-N-.   
>>-gddmx*HOSTRAST--:--+---+------------------------------------><
                      +-Y-+   
                      '-X-'

Parameters

N: Directs GDDMXD/MVS to use the IBM 3179G as a device model. This is the default.
Y: Directs GDDMXD/MVS to use the IBM 3279 as a device model.
X: Directs GDDMXD/MVS to use the IBM 3279 as a device model and expand the pixel mapping to reduce aspect ratio distortion.

Usage

The APL2® character set is not supported when the HostRast option is active.
When the HostRast option is specified as Y, the GDDM application performs the raster image processing and transmits the picture as a series of characters whose pixel definitions have been transmitted to Programmed Symbol Sets. The picture is mapped exactly as an IBM 3279.
If the ratio of horizontal to vertical pixel spacing is not the same as that of an IBM 3279, the aspect ratio can be distorted.