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TGA2CEG

Convert a Targa image to a CEG image


Syntax

TGA2CEG <cINFILE.TGA> <cOUTFILE.CEG> [<nScreenWidth>] [<nScreenHeight>]


Arguments

<cINFILE.TGA>
The 16- or 24-bit Targa image to be converted.

<cOUTFILE.CEG>
The file to save the Edsun CEG - DPL to after conversion.

<nScreenWidth>
Optional new screen width.

<nScreenHeight>
Optional new screen height.


Remarks

CEG images must be created from 16- or 24-bit Targa images. CEG requires 
all of the image information contained in these large files in order to 
calculate the 8-bit CEG image. There are two methods of creating Advanced 
8 Edsun CEG files.

CEG DPL - conversion requires that the current SVGA card have an Edsun 
CEG/DAC chip installed for the conversion from Targa and for display, as it 
uses the CEG/DAC services and video memory to create the best CEG quality. 
It creates an optimum CEG palette from the 24-bit image data, using an 
array of Dynamic Palette Locations (DPL) and mix codes for a combination of 
additional colors and anti-aliasing according to seven processing rules. 
Conversion is slow due to the extensive calculations and is best done in a 
batch mode, at a non-critical time. This is the method to use for DOS 
presentation quality. Upon display, CEG - DPL images produces harmless 
flashing in conflict with a graphic mouse. This is distracting, and should 
not be used within Microsoft Windows. It happens when a graphic mouse cursor 
passes over active DPLs or mix code locations. The palette of the mouse 
cursor is not the correct palette for that location in the image. Since 
DPLS and mix codes are dynamic and active, they process the mouse colors as 
if a part of the image, causing the "psychedelic" display.

CEG Flash - conversion from 16- or 24-bit Targa uses a fixed, predetermined, 
default CEG Palette that does not require DPLs  for processing to CEG. It 
does create an array of mix codes. It is a file-to-file conversion method 
that does not require the services of an Edsun CEG/DAC to be installed for 
conversion. The CEG/DAC is only required for display. This conversion method 
is very fast and produces very good quality but not quite as good as 
CEG - DPL. This is the recommended method for display under Microsoft 
Windows. Unusual effects caused by a graphic mouse cursor are minimal.

Note: Since the CEG image is an array of active image information that is 
coordinate specific, you may not scale, clip, or otherwise modify a CEG 
image. You must process the image while as a Targa image prior to conversion 
or use CEG2TGA to convert CEGs back to Targa for modification.

When the CEG portion of the RAMDAC is turned on by the Sunshow Pro 
application, the additional CEG logic contained between the RAM and the DAC 
blocks is activated. This extra logic decodes the special video opcodes 
which were placed directly in the image by TGA2CEG or CEGFlash, and performs 
a special blending in the palette RAM to produce new display colors at 
specific coodinates.

The best quality images (because they contain full image data) are 24-bit 
true color files having 16.8 million colors displayed on video cards that 
are capable of 24-bit display. 24-bit files are very large, slow to load, 
and use system resources to the maximum. Mapping the 24-bit files to 8-bit 
SVGA compatible file produces strongly degraded images.


Example

To convert a 16- or 24-bit Targa file, teacup.tga to Edsun CEG with the 
CEG - DPL method:

TGA2CEG TEACUP.TGA TEACUP.CEG 640 480