The Digitizer Information Structure(IM: QC)

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Chapter 8 - Video Digitizer Components / Video Digitizer Components Reference

The Digitizer Information Structure
Your application can retrieve information about the capabilities and current status of a video digitizer component. You call the VDGetDigitizerInfo function, described on page 8-24, to retrieve all this information from a video digitizer component. In response, the component formats a digitizer information structure. The contents of this structure fully define the capabilities and current status of the video digitizer component.

Note
If you are interested only in the current status information, you can call the VDGetCurrentFlags function, which is described on page 8-25. This function returns the input and output current flags of the video digitizer component.
The DigitizerInfo data type defines the layout of the digitizer information structure.
struct DigitizerInfo {
   short    vdigType;               /* type of digitizer component */
   long     inputCapabilityFlags;   /* input video signal features */
   long     outputCapabilityFlags;  /* output digitized video data
                                       features of digitizer component */
   long     inputCurrentFlags;      /* status of input video signal */
   long     outputCurrentFlags;     /* status of output digitized 
                                       video information */
   short    slot;                   /* for connection purposes */
   GDHandle gdh;                    /* for digitizers with preferred 
                                       screen */
   GDHandle maskgdh;                /* for digitizers with mask planes */
   short    minDestHeight;          /* smallest resizable height */
   short    minDestWidth;           /* smallest resizable width */
   short    maxDestHeight;          /* largest resizable height */
   short    maxDestWidth;           /* largest resizable width */
   short    blendLevels;            /* number of blend levels supported 
                                       (2 if 1-bit mask) */
   long     private;                   /* reserved--set to 0 */
};
typedef struct DigitizerInfo DigitizerInfo;
Field descriptions

vdigType
Specifies the type of video digitizer component. Valid values are
vdTypeBasic
Basic video digitizer--does not support any clipping
vdTypeAlpha
Supports clipping by means of an alpha channel
vdTypeMask
Supports clipping by means of a mask plane
vdTypeKey

Supports clipping by means of key colors
inputCapabilityFlags
Specifies the capabilities of the video digitizer component with respect to the input video signal. These flags are discussed in "Capability Flags" beginning on page 8-14.
outputCapabilityFlags
Specifies the capabilities of the video digitizer component with respect to the output digitized video information. These flags are discussed in "Capability Flags" beginning on page 8-14.
inputCurrentFlags
Specifies the current status of the video digitizer with respect to the input video signal. These flags are discussed in "Current Flags" on page 8-19.
outputCurrentFlags
Specifies the current status of the video digitizer with respect to the output digitized video information. These flags are discussed in "Current Flags" on page 8-19.
slot
Identifies the slot that contains the video digitizer interface card.
gdh
Contains a handle to the graphics device that defines the screen to which the digitized data is to be written. Set this field to nil if your application is not constrained to a particular graphics device.
maskgdh
Contains a handle to the graphics device that contains the mask plane. This field is used only by digitizers that clip by means of mask planes.
minDestHeight
Indicates the smallest height value the digitizer component can accommodate in its destination.
minDestWidth
Indicates the smallest width value the digitizer component can accommodate in its destination.
maxDestHeight
Indicates the largest height value the digitizer component can accommodate in its destination.
maxDestWidth
Indicates the largest width value the digitizer component can accommodate in its destination.
blendLevels
Specifies the number of blend levels the video digitizer component supports.
private
Reserved. Set this field to 0.