short Escape(hdc, GETSETSCREENPARAMS, sizeof(SCREENPARAMS),lpInData,lpOutData)
The GETSETSCREENPARAMS printer escape retrieves or sets the current screen information for rendering halftones.
hdc
HDC Identifies the device context.
lpInData
SCREENPARAMS FAR * Points to a SCREENPARAMS structure that contains the new screen information. For more information about this structure, see the following Comments section. This parameter may be NULL.
lpOutData
SCREENPARAMS FAR * Points to a SCREENPARAMS structure that retrieves the previous screen information. For more information about this structure, see the following Comments section. This parameter may be NULL.
The return value specifies the outcome of the escape. This value is positive if the escape is successful. Otherwise, it is negative.
This escape affects how device-independent bitmaps (DIBs) are rendered and how color objects are filled.
The SCREENPARAMS structure has the following form:
typedef struct tagSCREENPARAMS {
int angle;
int frequency;
} SCREENPARAMS;
Following are the members of the SCREENPARAMS structure:
angle
Specifies, in degrees, the angle of the halftone screen.
frequency
Specifies, in dots per inch, the screen frequency.