fmmatrix(3W)

NAME
     fminitpagematrix,  fmsetpagematrix, fmgetpagematrix, fmscalepagematrix,
     fmrotatepagematrix, fmconcatpagematrix - font manager page matrix
     operations

SYNOPSIS
     #include <fmclient.h>

     void fminitpagematrix()

     void fmsetpagematrix(m)
     double m[3][2];

     void fmgetpagematrix(m)
     double m[3][2];

     void fmscalepagematrix(x)
     double x;

     void fmrotatepagematrix(angle)
     double angle;

     void fmconcatpagematrix(m)
     double m[3][2];

DESCRIPTION
     The argument m points to a 3x2 matrix of doubles, of which you need fill
     in only the first two rows when loading values. (The third row is
     reserved for future development and is currently ignored.)  This matrix
     is a two dimensional transformation matrix that you can multiply against
     the page matrix.  (The page matrix is independent of the hardware matrix
     stack.)  You can use this multiplication of the page matrix to scale and
     rotate text.  For more information on two-dimensional transformation
     matrices, see Chapter 7, "Geometrical Transformations" in Fundamentals of
     Interactive Computer Graphics by J.D. Foley and A. Van Dam, (Addison-
     Wesley, 1982).

     Changing the page matrix changes the page, which you can visualize as a
     transparent sheet that lies on top of the window.  Distorting this sheet
     changes the appearance of text rendered on it.  If you rotate the page,
     you rotate the text in the window.  If you stretch or compress the page
     (scale the page) you stretch or compress the text on the page.

     If you are not familiar with using transformation matrices, you should
     avoid the routines that require the m matrix.  Fortunately, you can still
     perform scales or rotations on the page matrix.  Use the
     fmscalepagematrix and fmrotatepagematrix routines. Currently, the only
     way to render rotated text is to alter the page matrix. However, you do
     not always need to scale the page matrix (call fmscalepagematrix) to
     render text of a different size.  In fact, the preferred method for
     scaling text often is to call fmscalefont. This associates a scaling
     factor to a given font, which, as in PostScript, begins as a 1-point-high
     set of characters.

     But, getting back to the page matrix, use:  fminitpagematrix to
     initialize the page matrix to an identity matrix.

     fmsetpagematrix to load the page matrix with the floating point values
     supplied in matrix m.

     fmgetpagematrix to return the current page matrix in the matrix supplied
     by the client.

     fmscalepagematrix to uniformly scale the page matrix by x.

     fmrotatepagematrix to rotate the page matrix by the specified angle,
     where the angle (measured in degrees) increases up from the x axis.

     fmconcatpagematrix to post concatenate the m matrix (supplied by the
     client) with the current page matrix.

SEE ALSO
     fminit(3W), fmgetfontinfo(3W), fmprstr(3W), fmscalefont(3W),
     fmsetfont(3W).

NOTE
     This routine is available only in immediate mode.