Thermo 42i, Instruction Manual

Page: 275 / 314

C-Link Protocol Commands
Keys/Display
Thermo Electron Corporation Model 42
i
Low Source Instruction Manual B-27
isc
iscreen
This command retrieves the framebuffer data used for the display on the
iSeries instrument. It is 19200 bytes in size, 2-bits per pixel, 4 pixels per
byte arranged as 320 by 240 characters. The data is sent in RLE encoded
form to save time in transmission. It is sent as a type '5' binary c_link
response with no checksum.
The RLE encoding consists of a 0 followed by an 8-bit count of consecutive
0xFF bytes. The following 'c' code will expand the incoming data.
To convert this data into a BMP for use with windows, it needs to be turned
into a 4BPP as that is the smallest windows can display. Also note that BMP
files are upside down relative to this data, i.e. the top display line is the last
line in the BMP.
Void unpackDisplay ( void far* tdib, unsigned char far* rlescreen )
{
int i,j,k;
unsigned char far *sc4bpp, *sc2bpp, *screen, *ptr;
ptr = screen = (unsigned char far *)malloc(19200);
//RLE decode the screen
for (i=0; i<19200 && (ptr - screen) < 19200; i++)
{
*(ptr++) = *(rle i);
if (*(rle i) == 0)
{
unsigned char rlecount = *(unsigned char *)(rle ++i);
while (rlecount)
{
*(ptr++) = 0;
rlecount--;
}
}
else if (*(rle i) == 0xff)
{
unsigned char rlecount = *(unsigned char *)(rle ++i);
while (rlecount)
{
*(ptr++) = 0xff;
rlecount--;
}
}
}