.TH RTGRPBLIB_DRAW_CIRCULAR_ARC 3 LIBRIFUNKTIONSTECKENSNITTSGLYFRASTERISERINGSPROGRAMBIBLIOTEKET
.SH NAME
rtgrpblib_draw_circular_arc - Draw a circular arc
.SH DESCRIPTION
.LP
.nf
#include <librifunktionsteckensnittsglyfrasteriseringsprogrambiblioteket.h>
void rtgrpblib_draw_circular_arc(RTGRPBLIB_RASTER *\fIraster\fP,
double \fIx0\fP, double \fIy0\fP,
double \fIsemiwidth\fP, double \fIsemiheight\fP,
double \fIstart\fP, double \fIend\fP);
.fi
.PP
Link with
.IR "-lrifunktionsteckensnittsglyfrasteriseringsprogrambiblioteket -lm" .
.SH DESCRIPTION
The
.BR rtgrpblib_draw_circular_arc ()
function draws onto
.I raster
a circular arch, as part of a contour. The arc's circle
is defined as the circle with the midpoint
.RI ( x0 ,
.IR y0 )
and the radius that is
.I semiwidth
cells horizontally and
.I semiheight
cells vertically. The arc itself is drawn from the angle
.I start
to the
.IR end ,
both are specified in radians.
.SH RETURN VALUES
None.
.SH ERRORS
None.
.SH NOTES
The
.BR rtgrpblib_draw_circular_arc ()
function is intended to draw the arc of a circle, not the
arc of an ellipse, which is why it doesn't have a way to
rotate the ellipse despite the function providing a way
to specify the semimajor and the semiminor, not just a
radius. The function provides this two parameters, rather
than a single radius parameter because the image may, and
indeed probably will, have a different horizontal cell
density than vertical cell density, this is because the
pixels on a monitor are not perfect squares (and might
not even approximate square), and because the image may
be created (for example) for a horizontal cell density
three times greater than the monitor's horizontal pixel
density, but the same vertical density, in order to
render an image that will use subpixel antialiasing.
.SH SEE ALSO
.BR librifunktionsteckensnittsglyfrasteriseringsprogrambiblioteket (7),
.BR rtgrpblib_create_raster (3),
.BR rtgrpblib_fill_shapes (3),
.BR rtgrpblib_draw_linear_bezier (3),
.BR rtgrpblib_draw_quadratic_bezier (3),
.BR rtgrpblib_draw_cubic_bezier (3)
