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Epson Research and Development Page 57
Vancouver Design Center
Programming Notes and Examples S1D13705
Issue Date: 02/01/22 X27A-G-002-03
int seVirtInit(DWORD VirtX, DWORD * VirtY)
Description: This function prepares the system for virtual screen operation. The programmer
passes the desired virtual width in pixels. When the routine returns VirtY will contain
the maximum number of line that can be displayed at the requested virtual width.
Parameter: VirtX - horizontal size of virtual display in pixels.
(Must be greater or equal to physical size of display)
VirtY - pointer to an integer to receive the maximum number of displayable
lines of 'VirtX' width.
Return Value: ERR_OK - operation completed with no problems
ERR_HAL_BAD_ARG - returned in three situations:
1) the virtual width (VirtX) is greater than the largest possible width
(VirtX varies with color depth and ranges from 4096 pixels wider
than the panel at 1 bit-per-pixel down to 512 pixels wider than the
panel at 8 bit-per-pixel)
2) the virtual width is less than the physical width or
3) the maximum number of lines becomes less than the physical
number of lines
Note
The system must have been initialized prior to calling seVirtInit()
int seVirtMove(int Screen, int x, int y)
Description: This routine pans and scrolls the display. In the case where split screen operation is
being used, the Screen argument specifies which screen to move. The x and y param-
eters specify, in pixels, the starting location in the virtual image for the top left
corner of the applicable display.
Parameter: Screen - must be set to 1 or 2, or use the constants SCREEN1 or SCREEN2,
to identify which screen to base calculations on
x - new starting X position in pixels
y - new starting Y position in pixels
Return Value: ERR_OK - operation completed with no problems
ERR_HAL_BAD_ARG- there are several reasons for this return value:
1) WhichScreen is not SCREEN1 or SCREEN2.
2) the y argument is greater than the last available line less the screen height.
Note
seVirtInit() must be been called before calling seVirtMove().