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The DEVMODE structure is used for the environment and the initialization
data (which are the same). By convention, all drivers place the device name
in the first 32 bytes of DEVMODE as a null-terminated string. All the other
data is device dependent.
 
For Windows 3.x, a new convention has been adopted that defines an
additional number of members. These members enable the application to
perform device-independent manipulations of the device environment.
 
When Enable is called, the device driver should first check the lpInitData
parameter to see if the application has supplied valid initialization data.
If it is valid, then the driver should use that environment to initialize
the GDIINFO and PDEVICE structures and not use or modify the default
environment information.
 
If the environment cannot be found or if the data obtained is invalid or
intended for another device, the device driver should extract user settings
from the WIN.INI file, by using the profile string functions, such as
GetProfileInt.
 
However, the driver should contain useful defaults for all strings, so that
it can create a valid environment even if the WIN.INI file is empty.
 
The driver should use the device name string at the beginning of the
DEVMODE structure to determine whether or not the environment obtained from
GetEnvironment is correct.
 
A driver may also maintain additional information in its DEVMODE structure
to determine validity if the device name matches one the driver supports.
 
The printer driver can set or delete the environment by using the
SetEnvironment function (GDI.132). It can retrieve the current environment
using the GetEnvironment function (GDI.133).
 
The driver should always set up the default environment if it is not
present, except when the driver is initialized with a non-default
environment (that is, the lpInitData parameter to Enable points to
application-supplied data).
 
New Members in the DEVMODE Structure
 
The dmYResolution and dmTTOption members in the DEVMODE structure are new
for Windows 3.1. The DEVMODE structure returned by the ExtDeviceMode
function contains one or both of these members if the dmField member
includes the following values:
 
DM_YRESOLUTION  0x0002000L
DM_TTOPTION     0x0004000L
 
The dmYResolution member specifies the vertical resolution of the printer in
dots per inch. In this case, the dmPrintQuality member specifies the
horizontal resolution in dots per inch. If the DM_YRESOLUTION bit is not set
in dmFields, dmYResolution is not used and dmPrintQuality retains the
original meaning.
 
The dmTTOption member specifies how TrueType fonts should be printed. The
member can be set to one of the following values.
 
Value              Meaning
────────────────────────────────────────────────────────────────────────────
DMTT_BITMAP (1)    Prints TrueType fonts as graphics.
 
DMTT_DOWNLOAD (2)  Downloads TrueType fonts as soft fonts.
 
DMTT_SUBDEV (3)    Substitutes device fonts for TrueType.
 
Note:  Before calling the the CreateDC or CreateIC functions, an application
       should call the DeviceCapabilities function with the DC_TRUETYPE
       index to retrieve the driver's TrueType capabilities. The application
       can use the value returned by the driver to set the dmTTOption member
       to the appropriate value.
 
       The default action is to download TrueType as soft fonts for
       Hewlett-Packard printers that use PCL; substitute device fonts for
       TrueType for PostScript printers; and to print TrueType fonts as
       graphics for dot-matrix printers.
 
 
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