MirBSD manpage: XArc(3), XDrawArc(3), XDrawArcs(3)

XDrawArc(3X11)           XLIB FUNCTIONS            XDrawArc(3X11)


     XDrawArc, XDrawArcs, XArc - draw arcs and arc structure


     int XDrawArc(Display *display, Drawable d, GC gc, int x, int
          y, unsigned int width, unsigned int height, int angle1,
          int angle2);

     int XDrawArcs(Display *display, Drawable d, GC gc, XArc
          *arcs, int narcs);


     angle1    Specifies the start of the arc relative to the
               three-o'clock position from the center, in units
               of degrees * 64.

     angle2    Specifies the path and extent of the arc relative
               to the start of the arc, in units of degrees * 64.

     arcs      Specifies an array of arcs.

     d         Specifies the drawable.

     display   Specifies the connection to the X server.

     gc        Specifies the GC.

     narcs     Specifies the number of arcs in the array.

     height    Specify the width and height, which are the major
               and minor axes of the arc. and specify the upper-
               left corner of the bounding rectangle

     y         Specify the x and y coordinates, which are rela-
               tive to the origin of the drawable.


     XDrawArc draws a single circular or elliptical arc, and
     XDrawArcs draws multiple circular or elliptical arcs. Each
     arc is specified by a rectangle and two angles. The center
     of the circle or ellipse is the center of the rectangle, and
     the major and minor axes are specified by the width and
     height. Positive angles indicate counterclockwise motion,
     and negative angles indicate clockwise motion. If the magni-
     tude of angle2 is greater than 360 degrees, XDrawArc or
     XDrawArcs truncates it to 360 degrees.

     For an arc specified as                _e__g__t_], and the
     [ x, y, width, height, angle1,_a_d_t_h_,2y+ t2e origin of the
     major and minor axes is at [x+  2

XFree86                   Version 4.5.0                         1

XDrawArc(3X11)           XLIB FUNCTIONS            XDrawArc(3X11)

                         _i__t__, y+height]. These coordinates can
     [nxa+tweisd.thT,hey+pathhshouldtbe defined by,the ideal mathematical
     path. For a wide line with line-width lw, the bounding out-
     lines for filling are given by the two infinitely thin paths
     consisting of all points whose perpendicular distance from
     the path of the circle/ellipse is equal to lw/2 (which may
     be a fractional value). The cap-style and join-style are
     applied the same as for a line corresponding to the tangent
     of the circle/ellipse at the endpoint.

     For an arc specified as
     [ x, y, width, height, angle1, angle2], the angles must be
     specified in the effectively skewed coordinate system of the
     ellipse (for a circle, the angles and coordinate systems are
     identical).  The relationship between these angles and
     angles expressed in the normal coordinate system of the
     screen (as measured with a protractor) is as follows:

     skewed-angle = atan|                  __i__t__|

     The skewed-angle and normal-angle are expressed in_̅i]dands
     adjustris:an in degrees scaled by 64) in 3_ii3_i̅i̅2i̅i̅,i̅]2[0, 2i̅i̅]
     2i̅i̅ where fornnormal-angleainethe rangea[ii̅2,ii2
     iFo̅r any gifvoern naorrcm,alX-DarnagwlAercinantdheXDrraanwgAerc[s2do2not draw a
     pixel more than once. If two arcs join correctly and if the
     line-width is greater than zero and the arcs intersect,
     XDrawArc and XDrawArcs do not draw a pixel more than once.
     Otherwise, the intersecting pixels of intersecting arcs are
     drawn multiple times. Specifying an arc with one endpoint
     and a clockwise extent draws the same pixels as specifying
     the other endpoint and an equivalent counterclockwise
     extent, except as it affects joins.

     If the last point in one arc coincides with the first point
     in the following arc, the two arcs will join correctly. If
     the first point in the first arc coincides with the last
     point in the last arc, the two arcs will join correctly. By
     specifying one axis to be zero, a horizontal or vertical
     line can be drawn. Angles are computed based solely on the
     coordinate system and ignore the aspect ratio.

XFree86                   Version 4.5.0                         2

XDrawArc(3X11)           XLIB FUNCTIONS            XDrawArc(3X11)

     Both functions use these GC components: function, plane-
     mask, line-width, line-style, cap-style, join-style, fill-
     style, subwindow-mode, clip-x-origin, clip-y-origin, and
     clip-mask. They also use these GC mode-dependent components:
     foreground, background, tile, stipple, tile-stipple-x-
     origin, tile-stipple-y-origin, dash-offset, and dash-list.

     XDrawArc and XDrawArcs can generate BadDrawable, BadGC, and
     BadMatch errors.


     The XArc structure contains:

     typedef struct {
          short x, y;
          unsigned short width, height;
          short angle1, angle2;             /* Degrees * 64 */
     } XArc;

     All x and y members are signed integers. The width and
     height members are 16-bit unsigned integers. You should be
     careful not to generate coordinates and sizes out of the
     16-bit ranges, because the protocol only has 16-bit fields
     for these values.


               A value for a Drawable argument does not name a
               defined Window or Pixmap.

     BadGC     A value for a GContext argument does not name a
               defined GContext.

     BadMatch  An InputOnly window is used as a Drawable.

     BadMatch  Some argument or pair of arguments has the correct
               type and range but fails to match in some other
               way required by the request.


     XDrawLine(3X11), XDrawPoint(3X11), XDrawRectangle(3X11)
     Xlib - C Language X Interface

XFree86                   Version 4.5.0                         3

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