MIL-STD-2301 Computer Graphics Metafile Cgm Implementation Standard For The National Imagery Transmission Format StandardThis standard establishes the requirements necessary to implement Computer Graphics Metafiles CGM used for the representation of symbol graphics in the National Imagery Transmission Format Standard NITFS.

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MIL-STD-2301A

vector components are those which produce vectors of non-zero length.  If the start ray and end ray are coincident, it is ambiguous whether the defined arc is null (zero arc length) or the entire ellipse.  The last parameter, Close Type, specifies how the arc is closed (0=pie or 1=chord).  If the close type is chord, a line is drawn between the endpoints of the arc.  If the close type is pie, a line is drawn from the beginning of the arc to the centerpoint of the ellipse and then to the end of the arc.  The interior of the arc will be specified by the Interior Style command, and the edge width, type and color will be specified in the Edge Width, Edge Type, and Edge Color commands, respectively.

TABLE LIII.  Elliptical Arc Close input.

MSB                                                                                                                                                               LSB

15        14      13       12       11       10        9         8         7         6          5         4         3          2       1         0

4                                                           19                                                               22                                = 0x4276

CenterX CenterY End1X End1Y End2X End2Y StartVectorX StartVectorY End VectorX EndVectorY Close Type

5.1.1.5.7  Rectangle element input.  The CGM implementation for NITFS shall provide the capability to input and interpret the Rectangle element using the following format.  The rectangle is defined by two distinct points that are diagonal opposite corners of the rectangle where the rectangle is oriented parallel to the VDC axes. The interior of the rectangle will be as specified by the Interior Style command, and the edge width, type and color will be as specified in the Edge Width, Edge Type, and Edge Color commands, respectively.

TABLE LIV.  Rectangle input.

MSB                                                                                                                                                               LSB

15        14      13       12       11       10        9         8         7         6          5         4         3          2       1         0

4                                                           11                                                                 8                                 = 0x4168

Corner1X Corner1Y Corner2X Corner2Y

5.1.1.5.8  Circle element input.  The CGM implementation for NITFS shall provide the capability to input and interpret the Circle element using the following format.  The first two parameters, CenterX and CenterY, give the location of the center of the circle.  The next parameter, Radius, specifies the radius of the circle.  Only non- negative values are valid for the radius.  The interior of the circle will be specified by the Interior Style command, and the edge width, type and color will be as specified in the Edge Width, Edge Type, and Edge Color commands, respectively.

TABLE LV.  Circle input.

MSB                                                                                                                                                               LSB

15        14      13       12       11       10        9         8         7         6          5         4         3          2       1         0

= 0x4186

22