BUTTON(9.2)                                           BUTTON(9.2)

          button123, mouse, cursallow, cursinhibit, cursset,
          cursswitch, getrect123 - mouse control

          #include <jerq.h>

          extern struct Mouse {
              Point xy;
              short buttons;
          } mouse;

          int button(n) int n;
          int button1(), button2(), button3();
          int button12(), button23(), button123();

          void cursinhibit();
          void cursallow();

          void cursset(p); Point p;

          Texture *cursswitch(t); Texture *t;

          Rectangle getrect(n) int n;
          Rectangle getrect1(), getrect2(), getrect3();
          Rectangle getrect12(), getrect23(), getrect123();

          For processes that request the mouse (see request(9.2)), the
          mouse state is updated asynchronously in the per-process
          structure mouse. The coordinates of the mouse are held in
          mouse.xy, and the state of the buttons in mouse.buttons.
          Each process's mouse structure is independent of the others,
          so that (except for cursset) actions such as changing the
          tracking cursor do not affect other process's use of the
          mouse.  Mouse is not updated if the process does not `own'
          the mouse; see request(9.2).

          The macro button and its counterparts return the state of
          the associated mouse button: non-zero if the button is
          depressed, 0 otherwise.  The buttons are numbered 1 to 3
          from left to right.  Button12 and the other multi-button
          functions return the OR of their states: true if either but-
          ton 1 or button 2 is depressed (as opposed to button 1 and
          button 2).

          Cursinhibit turns off interrupt-time cursor tracking (the
          drawing of the cursor on the screen), although the mouse
          coordinates are still kept current and available.  Cursallow
          enables interrupt-time cursor tracking.  Cursallow and

     BUTTON(9.2)                                           BUTTON(9.2)

          cursinhibit stack: to enable cursor tracking after two calls
          to cursinhibit, two calls to cursallow are required.

          Cursset moves the mouse cursor to the Point p.

          Cursswitch changes the mouse cursor (a 16×16 pixel image) to
          that specified by the Texture *t. If the argument is (Tex-
          ture *)0, the cursor is restored to the default arrow.
          Cursswitch returns the previous value of the cursor: the
          argument of the previous call to cursswitch.

          Getrect prompts the user with a box cursor and waits for a
          rectangle to be swept out named button, identified as with
          the button primitives.  It returns the screen coordinates of
          the box swept.  The box may be partly or wholly outside the
          process's layer.