The World of Computer Software/World_Of_Computer_Software-02-387-Vol-3of3.iso/x/xvisrc.zoo/mouse.c

C/C++ Source or Header | 1992-07-28 | 5KB | 248 lines

/* Copyright (c) 1990,1991,1992 Chris and John Downey */
#ifndef lint
static char *sccsid = "@(#)mouse.c    2.1 (Chris & John Downey) 7/29/92";
#endif

/***

* program name:
    xvi
* function:
    PD version of UNIX "vi" editor, with extensions.
* module name:
    mouse.c
* module function:
    Machine-independent mouse interface routines.
* history:
    STEVIE - ST Editor for VI Enthusiasts, Version 3.10
    Originally by Tim Thompson (twitch!tjt)
    Extensive modifications by Tony Andrews (onecom!wldrdg!tony)
    Heavily modified by Chris & John Downey
***/

#include "xvi.h"

/*
 * Find the Line corresponding to a given physical screen row.
 *
 * Also return (in *pstartrow) the physical screen row on which that
 * Line starts.
 */
static Line *
findline(wp, row, pstartrow)
Xviwin        *wp;
register int    row;
int        *pstartrow;
{
    register int    lposn;
    int            maxrow;
    register Line    *lp;
    Line        *lastline;

    lp = wp->w_topline;
    lastline = wp->w_buffer->b_lastline;
    lposn = wp->w_winpos;
    maxrow = wp->w_cmdline;

    for (;;) {
    register int    newposn;

    newposn = lposn + LONG2INT(plines(wp, lp));
    if (
        (
        /*
         * If we've found the right line ...
         */
        row >= lposn
        &&
        row < newposn
        )
        ||
        (
        /*
         * ... or we've got to the end of the buffer ...
         */
        lp->l_next == wp->w_buffer->b_lastline
        )
        ||
        (
        /*
         * ... or we're at the bottom of the window ...
         */
        newposn >= maxrow
        )
    ) {
        /*
         * ... we return this line.
         */
        *pstartrow = lposn;
        return lp;
    }
    lposn = newposn;
    lp = lp->l_next;
    }
}

/*
 * Move the text cursor as near as possible to the given physical
 * screen co-ordinates.
 */
static void
setcursor(wp, row, col)
Xviwin    *wp;
int    row;        /* row where mouse was clicked */
int    col;        /* column where mouse was clicked */
{
    int        startrow;    /* row at which line starts */
    int        vcol;        /* virtual column */
    Line    *lp;        /* logical line corresponding to row */

    lp = findline(wp, row, &startrow);
    vcol = col + ((row - startrow) * wp->w_ncols);
    move_cursor(wp, lp, 0);
    coladvance(wp, (wp->w_curswant = vcol));
}

/*
 * Find the window a given physical screen row is in.
 */
static Xviwin *
findwin(row)
register int    row;
{
    register Xviwin    *wp;

    wp = curwin;
    for (;;) {
    if (wp->w_winpos <= row && row <= wp->w_cmdline) {
        /*
         * We've found the right window.
         */
        return wp;
    }
    if ((wp = next_window(wp)) == curwin) {
        /*
         * This can't happen: the mouse isn't in any
         * window.
         */
        return NULL;
    }
    }
}

/*
 * Handle mouse drag event.
 */
void
mousedrag(row1, row2, col1, col2)
int row1, row2, col1, col2;
{
    if (State == NORMAL && row1 != row2 && row1 < Rows - 1) {
    Xviwin *wp;

    if ((wp = findwin(row1)) == NULL) {
        /*
         * This can't happen.
         */
        return;
    }

    if (wp->w_cmdline == row1) {
        unsigned savecho;

        savecho = echo;
        echo &= ~e_CHARUPDATE;

        (void) move_sline(wp, row2 - row1);

        echo = savecho;

        move_cursor_to_window(curwin);
        update_all();
        cursupdate(curwin);
        wind_goto(curwin);
    }
    }
}

/*
 * This function is called by the (obviously machine-dependent) mouse
 * event handling code when a mouse button is pressed & released.
 *
 * The algorithm we use here is semantically complicated, but seems to
 * be fairly intuitive in actual use.
 */
void
mouseclick(row, col)
register int    row;    /* row the mouse cursor is in */
int        col;    /* column the mouse cursor is in */
{
    register Xviwin    *wp;

    if (State != NORMAL) {
    return;
    }

    /*
     * First find which window the mouse is in.
     */
    if ((wp = findwin(row)) == NULL) {
    /*
     * This can't happen.
     */
    return;
    }

    if (wp != curwin) {
    /*
     * The window the mouse is in isn't the current window.
     * Make it the current window.
     */
    curwin = wp;
    curbuf = wp->w_buffer;
    }

    if (row == wp->w_cmdline) {
    /*
     * If the mouse is on the status line of any window,
     * we update the information on the status line. This
     * applies whether or not it was already the current
     * window.
     */
    show_file_info(wp);
    } else {
    /*
     * Move the cursor as near as possible to where the
     * mouse was clicked.
     */
    setcursor(wp, row, col);

    /*
     * If the window has at least 2 text rows, and ...
     */
    if (wp->w_nrows > 2) {
        if (row == wp->w_winpos) {
        /*
         * ... we're on the top line of the
         * window - scroll down ...
         */
        scrolldown(wp, (unsigned) 1);
        update_window(wp);
        } else if (row == wp->w_cmdline - 1) {
        /*
         * ... or we're on the bottom line of
         * the window - scroll up ...
         */
        scrollup(wp, (unsigned) 1);
        update_window(wp);
        }
    }
    }

    /*
     * Make sure physical screen and cursor position are updated.
     */
    cursupdate(wp);
    wind_goto(wp);
}