NAME
    TextFit - count characters that will fit in a given extent (V36)

SYNOPSIS
    chars = TextFit(rastport, string, strLen, textExtent,
    D0              A1        A0      D0      A2
            constrainingExtent, strDirection,
            A3                  D1
            constrainingBitWidth, constrainingBitHeight)
            D2                    D3

    ULONG TextFit(struct RastPort *, STRPTR, UWORD,
        struct TextExtent *, struct TextExtent *, WORD, UWORD, UWORD);

FUNCTION
    This function determines how many of the characters of the
    provided string will fit into the space described by the
    constraining parameters.  It also returns the extent of
    that number of characters.

INPUTS
    rp     - a pointer to the RastPort which describes where the
             text attributes reside.
    string - the address of string to determine the constraint of
    strLen - The number of characters in the string.
             If zero, there are no characters in the string.
    textExtent - a structure to hold the extent result.
    constrainingExtent - the extent that the text must fit in.
        This can be NULL, indicating only the constrainingBit
        dimensions will describe the constraint.
    strDirection - the offset to add to the string pointer to
        get to the next character in the string.  Usually 1.
        Set to -1 and the string to the end of the string to
        perform a TextFit() anchored at the end.  No other value
        is valid.
    constrainingBitWidth - an alternative way to specify the
        rendering box constraint width that is independent of
        the rendering origin.  Range 0..32767.
    constrainingBitHeight - an alternative way to specify the
        rendering box constraint height that is independent of
        the rendering origin.  Range 0..32767.

RESULTS
    chars - the number of characters from the origin of the
            given string that will fit in both the constraining
            extent (which specifies a CP bound and a rendering
            box relative to the origin) and in the rendering width
            and height specified.

NOTES
    The result is zero chars and an empty textExtent when the fit
    cannot be performed.  This occurs not only when no text will
    fit in the provided constraints, but also when:
    -   the RastPort rp's rp_TxSpacing sign and magnitude is so
        great it reverses the path of the text.
    -   the constrainingExtent does not include x = 0.

SEE ALSO
    TextExtent()  TextLength()  Text()
    graphics/text.h  graphics/rastport.h