Size on split-window is -l not -s. Doh.

[tmux-openbsd.git] / layout.c

/* $OpenBSD$ */

/*
 * Copyright (c) 2009 Nicholas Marriott <nicm@users.sourceforge.net>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
 * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>

#include <stdlib.h>

#include "tmux.h"

/*
 * The window layout is a tree of cells each of which can be one of: a
 * left-right container for a list of cells, a top-bottom container for a list
 * of cells, or a container for a window pane.
 *
 * Each window has a pointer to the root of its layout tree (containing its
 * panes), every pane has a pointer back to the cell containing it, and each
 * cell a pointer to its parent cell.
 */

int     layout_resize_pane_grow(struct layout_cell *, enum layout_type, int);
int     layout_resize_pane_shrink(struct layout_cell *, enum layout_type, int);

struct layout_cell *
layout_create_cell(struct layout_cell *lcparent)
{
        struct layout_cell      *lc;

        lc = xmalloc(sizeof *lc);
        lc->type = LAYOUT_WINDOWPANE;
        lc->parent = lcparent;

        TAILQ_INIT(&lc->cells);

        lc->sx = UINT_MAX;
        lc->sy = UINT_MAX;

        lc->xoff = UINT_MAX;
        lc->yoff = UINT_MAX;

        lc->wp = NULL;

        return (lc);
}

void
layout_free_cell(struct layout_cell *lc)
{
        struct layout_cell      *lcchild;

        switch (lc->type) {
        case LAYOUT_LEFTRIGHT:
        case LAYOUT_TOPBOTTOM:
                while (!TAILQ_EMPTY(&lc->cells)) {
                        lcchild = TAILQ_FIRST(&lc->cells);
                        TAILQ_REMOVE(&lc->cells, lcchild, entry);
                        layout_free_cell(lcchild);
                }
                break;
        case LAYOUT_WINDOWPANE:
                if (lc->wp != NULL)
                        lc->wp->layout_cell = NULL;
                break;
        }

        xfree(lc);
}

void
layout_print_cell(struct layout_cell *lc, const char *hdr, u_int n)
{
        struct layout_cell      *lcchild;

        log_debug(
            "%s:%*s%p type %u [parent %p] wp=%p [%u,%u %ux%u]", hdr, n, " ", lc,
            lc->type, lc->parent, lc->wp, lc->xoff, lc->yoff, lc->sx, lc->sy);
        switch (lc->type) {
        case LAYOUT_LEFTRIGHT:
        case LAYOUT_TOPBOTTOM:
                TAILQ_FOREACH(lcchild, &lc->cells, entry)
                        layout_print_cell(lcchild, hdr, n + 1);
                break;
        case LAYOUT_WINDOWPANE:
                break;
        }
}

void
layout_set_size(
    struct layout_cell *lc, u_int sx, u_int sy, u_int xoff, u_int yoff)
{
        lc->sx = sx;
        lc->sy = sy;

        lc->xoff = xoff;
        lc->yoff = yoff;
}

void
layout_make_leaf(struct layout_cell *lc, struct window_pane *wp)
{
        lc->type = LAYOUT_WINDOWPANE;

        TAILQ_INIT(&lc->cells);

        wp->layout_cell = lc;
        lc->wp = wp;
}

void
layout_make_node(struct layout_cell *lc, enum layout_type type)
{
        if (type == LAYOUT_WINDOWPANE)
                fatalx("bad layout type");
        lc->type = type;

        TAILQ_INIT(&lc->cells);

        if (lc->wp != NULL)
                lc->wp->layout_cell = NULL;
        lc->wp = NULL;
}

/* Fix cell offsets based on their sizes. */
void
layout_fix_offsets(struct layout_cell *lc)
{
        struct layout_cell      *lcchild;
        u_int                    xoff, yoff;

        if (lc->type == LAYOUT_LEFTRIGHT) {
                xoff = lc->xoff;
                TAILQ_FOREACH(lcchild, &lc->cells, entry) {
                        lcchild->xoff = xoff;
                        lcchild->yoff = lc->yoff;
                        if (lcchild->type != LAYOUT_WINDOWPANE)
                                layout_fix_offsets(lcchild);
                        xoff += lcchild->sx + 1;
                }
        } else {
                yoff = lc->yoff;
                TAILQ_FOREACH(lcchild, &lc->cells, entry) {
                        lcchild->xoff = lc->xoff;
                        lcchild->yoff = yoff;
                        if (lcchild->type != LAYOUT_WINDOWPANE)
                                layout_fix_offsets(lcchild);
                        yoff += lcchild->sy + 1;
                }
        }
}

/* Update pane offsets and sizes based on their cells. */
void
layout_fix_panes(struct window *w, u_int wsx, u_int wsy)
{
        struct window_pane      *wp;
        struct layout_cell      *lc;
        u_int                    sx, sy;

        TAILQ_FOREACH(wp, &w->panes, entry) {
                if ((lc = wp->layout_cell) == NULL)
                        continue;
                wp->xoff = lc->xoff;
                wp->yoff = lc->yoff;

                /*
                 * Layout cells are limited by the smallest size of other cells
                 * within the same row or column; if this isn't the case
                 * resizing becomes difficult.
                 *
                 * However, panes do not have to take up their entire cell, so
                 * they can be cropped to the window edge if the layout
                 * overflows and they are partly visible.
                 *
                 * This stops cells being hidden unnecessarily.
                 */

                /*
                 * Work out the horizontal size. If the pane is actually
                 * outside the window or the entire pane is already visible,
                 * don't crop.
                 */
                if (lc->xoff >= wsx || lc->xoff + lc->sx < wsx)
                        sx = lc->sx;
                else {
                        sx = wsx - lc->xoff;
                        if (sx < 1)
                                sx = lc->sx;
                }

                /*
                 * Similarly for the vertical size; the minimum vertical size
                 * is two because scroll regions cannot be one line.
                 */
                if (lc->yoff >= wsy || lc->yoff + lc->sy < wsy)
                        sy = lc->sy;
                else {
                        sy = wsy - lc->yoff;
                        if (sy < 2)
                                sy = lc->sy;
                }

                window_pane_resize(wp, sx, sy);
        }
}

/* Count the number of available cells in a layout. */
u_int
layout_count_cells(struct layout_cell *lc)
{
        struct layout_cell      *lcchild;
        u_int                    n;

        switch (lc->type) {
        case LAYOUT_WINDOWPANE:
                return (1);
        case LAYOUT_LEFTRIGHT:
        case LAYOUT_TOPBOTTOM:
                n = 0;
                TAILQ_FOREACH(lcchild, &lc->cells, entry)
                        n += layout_count_cells(lcchild);
                return (n);
        default:
                fatalx("bad layout type");
        }
}

/* Calculate how much size is available to be removed from a cell. */
u_int
layout_resize_check(struct layout_cell *lc, enum layout_type type)
{
        struct layout_cell      *lcchild;
        u_int                    available, minimum;

        if (lc->type == LAYOUT_WINDOWPANE) {
                /* Space available in this cell only. */
                if (type == LAYOUT_LEFTRIGHT)
                        available = lc->sx;
                else
                        available = lc->sy;

                if (available > PANE_MINIMUM)
                        available -= PANE_MINIMUM;
                else
                        available = 0;
        } else if (lc->type == type) {
                /* Same type: total of available space in all child cells. */
                available = 0;
                TAILQ_FOREACH(lcchild, &lc->cells, entry)
                        available += layout_resize_check(lcchild, type);
        } else {
                /* Different type: minimum of available space in child cells. */
                minimum = UINT_MAX;
                TAILQ_FOREACH(lcchild, &lc->cells, entry) {
                        available = layout_resize_check(lcchild, type);
                        if (available < minimum)
                                minimum = available;
                }
                available = minimum;
        }

        return (available);
}

/*
 * Adjust cell size evenly, including altering its children. This function
 * expects the change to have already been bounded to the space available.
 */
void
layout_resize_adjust(struct layout_cell *lc, enum layout_type type, int change)
{
        struct layout_cell      *lcchild;

        /* Adjust the cell size. */
        if (type == LAYOUT_LEFTRIGHT)
                lc->sx += change;
        else
                lc->sy += change;

        /* If this is a leaf cell, that is all that is necessary. */
        if (type == LAYOUT_WINDOWPANE)
                return;

        /* Child cell runs in a different direction. */
        if (lc->type != type) {
                TAILQ_FOREACH(lcchild, &lc->cells, entry)
                        layout_resize_adjust(lcchild, type, change);
                return;
        }

        /*
         * Child cell runs in the same direction. Adjust each child equally
         * until no further change is possible.
         */
        while (change != 0) {
                TAILQ_FOREACH(lcchild, &lc->cells, entry) {
                        if (change == 0)
                                break;
                        if (change > 0) {
                                layout_resize_adjust(lcchild, type, 1);
                                change--;
                                continue;
                        }
                        if (layout_resize_check(lcchild, type) > 0) {
                                layout_resize_adjust(lcchild, type, -1);
                                change++;
                        }
                }
        }
}

/* Destroy a cell and redistribute the space. */
void
layout_destroy_cell(struct layout_cell *lc, struct layout_cell **lcroot)
{
        struct layout_cell     *lcother, *lcparent;

        /*
         * If no parent, this is the last pane so window close is imminent and
         * there is no need to resize anything.
         */
        lcparent = lc->parent;
        if (lcparent == NULL) {
                layout_free_cell(lc);
                *lcroot = NULL;
                return;
        }

        /* Merge the space into the previous or next cell. */
        if (lc == TAILQ_FIRST(&lcparent->cells))
                lcother = TAILQ_NEXT(lc, entry);
        else
                lcother = TAILQ_PREV(lc, layout_cells, entry);
        if (lcparent->type == LAYOUT_LEFTRIGHT)
                layout_resize_adjust(lcother, lcparent->type, lc->sx + 1);
        else
                layout_resize_adjust(lcother, lcparent->type, lc->sy + 1);

        /* Remove this from the parent's list. */
        TAILQ_REMOVE(&lcparent->cells, lc, entry);
        layout_free_cell(lc);

        /*
         * If the parent now has one cell, remove the parent from the tree and
         * replace it by that cell.
         */
        lc = TAILQ_FIRST(&lcparent->cells);
        if (TAILQ_NEXT(lc, entry) == NULL) {
                TAILQ_REMOVE(&lcparent->cells, lc, entry);

                lc->parent = lcparent->parent;
                if (lc->parent == NULL) {
                        lc->xoff = 0; lc->yoff = 0;
                        *lcroot = lc;
                } else
                        TAILQ_REPLACE(&lc->parent->cells, lcparent, lc, entry);

                layout_free_cell(lcparent);
        }
}

void
layout_init(struct window *w)
{
        struct layout_cell      *lc;

        lc = w->layout_root = layout_create_cell(NULL);
        layout_set_size(lc, w->sx, w->sy, 0, 0);
        layout_make_leaf(lc, TAILQ_FIRST(&w->panes));

        layout_fix_panes(w, w->sx, w->sy);
}

void
layout_free(struct window *w)
{
        layout_free_cell(w->layout_root);
}

/* Resize the entire layout after window resize. */
void
layout_resize(struct window *w, u_int sx, u_int sy)
{
        struct layout_cell      *lc = w->layout_root;
        int                      xlimit, ylimit, xchange, ychange;

        /*
         * Adjust horizontally. Do not attempt to reduce the layout lower than
         * the minimum (more than the amount returned by layout_resize_check).
         *
         * This can mean that the window size is smaller than the total layout
         * size: redrawing this is handled at a higher level, but it does leave
         * a problem with growing the window size here: if the current size is
         * < the minimum, growing proportionately by adding to each pane is
         * wrong as it would keep the layout size larger than the window size.
         * Instead, spread the difference between the minimum and the new size
         * out proportionately - this should leave the layout fitting the new
         * window size.
         */
        xchange = sx - w->sx;
        xlimit = layout_resize_check(lc, LAYOUT_LEFTRIGHT);
        if (xchange < 0 && xchange < -xlimit)
                xchange = -xlimit;
        if (xlimit == 0) {
                if (sx <= lc->sx)       /* lc->sx is minimum possible */
                        xchange = 0;
                else
                        xchange = sx - lc->sx;
        }
        if (xchange != 0)
                layout_resize_adjust(lc, LAYOUT_LEFTRIGHT, xchange);

        /* Adjust vertically in a similar fashion. */
        ychange = sy - w->sy;
        ylimit = layout_resize_check(lc, LAYOUT_TOPBOTTOM);
        if (ychange < 0 && ychange < -ylimit)
                ychange = -ylimit;
        if (ylimit == 0) {
                if (sy <= lc->sy)       /* lc->sy is minimum possible */
                        ychange = 0;
                else
                        ychange = sy - lc->sy;
        }
        if (ychange != 0)
                layout_resize_adjust(lc, LAYOUT_TOPBOTTOM, ychange);

        /* Fix cell offsets. */
        layout_fix_offsets(lc);
        layout_fix_panes(w, sx, sy);
}

/* Resize a single pane within the layout. */
void
layout_resize_pane(struct window_pane *wp, enum layout_type type, int change)
{
        struct layout_cell     *lc, *lcparent;
        int                     needed, size;

        lc = wp->layout_cell;

        /* Find next parent of the same type. */
        lcparent = lc->parent;
        while (lcparent != NULL && lcparent->type != type) {
                lc = lcparent;
                lcparent = lc->parent;
        }
        if (lcparent == NULL)
                return;

        /* If this is the last cell, move back one. */
        if (lc == TAILQ_LAST(&lcparent->cells, layout_cells))
                lc = TAILQ_PREV(lc, layout_cells, entry);

        /* Grow or shrink the cell. */
        needed = change;
        while (needed != 0) {
                if (change > 0) {
                        size = layout_resize_pane_grow(lc, type, needed);
                        needed -= size;
                } else {
                        size = layout_resize_pane_shrink(lc, type, needed);
                        needed += size;
                }

                if (size == 0)  /* no more change possible */
                        break;
        }

        /* Fix cell offsets. */
        layout_fix_offsets(wp->window->layout_root);
        layout_fix_panes(wp->window, wp->window->sx, wp->window->sy);
}

int
layout_resize_pane_grow(
    struct layout_cell *lc, enum layout_type type, int needed)
{
        struct layout_cell      *lcadd, *lcremove;
        u_int                    size;

        /* Growing. Always add to the current cell. */
        lcadd = lc;

        /* Look towards the tail for a suitable cell for reduction. */
        lcremove = TAILQ_NEXT(lc, entry);
        while (lcremove != NULL) {
                size = layout_resize_check(lcremove, type);
                if (size > 0)
                        break;
                lcremove = TAILQ_NEXT(lcremove, entry);
        }

        /* If none found, look towards the head. */
        if (lcremove == NULL) {
                lcremove = TAILQ_PREV(lc, layout_cells, entry);
                while (lcremove != NULL) {
                        size = layout_resize_check(lcremove, type);
                        if (size > 0)
                                break;
                        lcremove = TAILQ_PREV(lcremove, layout_cells, entry);
                }
                if (lcremove == NULL)
                        return (0);
        }

        /* Change the cells. */
        if (size > (u_int) needed)
                size = needed;
        layout_resize_adjust(lcadd, type, size);
        layout_resize_adjust(lcremove, type, -size);
        return (size);
}

int
layout_resize_pane_shrink(
    struct layout_cell *lc, enum layout_type type, int needed)
{
        struct layout_cell      *lcadd, *lcremove;
        u_int                    size;

        /* Shrinking. Find cell to remove from by walking towards head. */
        lcremove = lc;
        do {
                size = layout_resize_check(lcremove, type);
                if (size != 0)
                        break;
                lcremove = TAILQ_PREV(lcremove, layout_cells, entry);
        } while (lcremove != NULL);
        if (lcremove == NULL)
                return (0);

        /* And add onto the next cell (from the original cell). */
        lcadd = TAILQ_NEXT(lc, entry);
        if (lcadd == NULL)
                return (0);

        /* Change the cells. */
        if (size > (u_int) -needed)
                size = -needed;
        layout_resize_adjust(lcadd, type, size);
        layout_resize_adjust(lcremove, type, -size);
        return (size);
}

/* Assign window pane to newly split cell. */
void
layout_assign_pane(struct layout_cell *lc, struct window_pane *wp)
{
        layout_make_leaf(lc, wp);
        layout_fix_panes(wp->window, wp->window->sx, wp->window->sy);
}

/*
 * Split a pane into two. size is a hint, or -1 for default half/half
 * split. This must be followed by layout_assign_pane before much else happens!
 **/
struct layout_cell *
layout_split_pane(struct window_pane *wp, enum layout_type type, int size)
{
        struct layout_cell     *lc, *lcparent, *lcnew;
        u_int                   sx, sy, xoff, yoff, size1, size2;

        lc = wp->layout_cell;

        /* Copy the old cell size. */
        sx = lc->sx;
        sy = lc->sy;
        xoff = lc->xoff;
        yoff = lc->yoff;

        /* Check there is enough space for the two new panes. */
        switch (type) {
        case LAYOUT_LEFTRIGHT:
                if (sx < PANE_MINIMUM * 2 + 1)
                        return (NULL);
                break;
        case LAYOUT_TOPBOTTOM:
                if (sy < PANE_MINIMUM * 2 + 1)
                        return (NULL);
                break;
        default:
                fatalx("bad layout type");
        }

        if (lc->parent != NULL && lc->parent->type == type) {
                /*
                 * If the parent exists and is of the same type as the split,
                 * create a new cell and insert it after this one.
                 */

                /* Create the new child cell. */
                lcnew = layout_create_cell(lc->parent);
                TAILQ_INSERT_AFTER(&lc->parent->cells, lc, lcnew, entry);
        } else {
                /*
                 * Otherwise create a new parent and insert it.
                 */

                /* Create and insert the replacement parent. */
                lcparent = layout_create_cell(lc->parent);
                layout_make_node(lcparent, type);
                layout_set_size(lcparent, sx, sy, xoff, yoff);
                if (lc->parent == NULL)
                        wp->window->layout_root = lcparent;
                else
                        TAILQ_REPLACE(&lc->parent->cells, lc, lcparent, entry);

                /* Insert the old cell. */
                lc->parent = lcparent;
                TAILQ_INSERT_HEAD(&lcparent->cells, lc, entry);

                /* Create the new child cell. */
                lcnew = layout_create_cell(lcparent);
                TAILQ_INSERT_TAIL(&lcparent->cells, lcnew, entry);
        }

        /* Set new cell sizes.  size is the target size or -1 for middle split,
         * size1 is the size of the top/left and size2 the bottom/right.
         */
        switch (type) {
        case LAYOUT_LEFTRIGHT:
                if (size < 0)
                        size2 = ((sx + 1) / 2) - 1;
                else
                        size2 = size;
                if (size2 < PANE_MINIMUM)
                        size2 = PANE_MINIMUM;
                else if (size2 > sx - 2)
                        size2 = sx - 2;
                size1 = sx - 1 - size2;
                layout_set_size(lc, size1, sy, xoff, yoff);
                layout_set_size(lcnew, size2, sy, xoff + lc->sx + 1, yoff);
                break;
        case LAYOUT_TOPBOTTOM:
                if (size < 0)
                        size2 = ((sy + 1) / 2) - 1;
                else
                        size2 = size;
                if (size2 < PANE_MINIMUM)
                        size2 = PANE_MINIMUM;
                else if (size2 > sy - 2)
                        size2 = sy - 2;
                size1 = sy - 1 - size2;
                layout_set_size(lc, sx, size1, xoff, yoff);
                layout_set_size(lcnew, sx, size2, xoff, yoff + lc->sy + 1);
                break;
        default:
                fatalx("bad layout type");
        }

        /* Assign the panes. */
        layout_make_leaf(lc, wp);

        return (lcnew);
}

/* Destroy the cell associated with a pane. */
void
layout_close_pane(struct window_pane *wp)
{
        /* Remove the cell. */
        layout_destroy_cell(wp->layout_cell, &wp->window->layout_root);

        /* Fix pane offsets and sizes. */
        if (wp->window->layout_root != NULL) {
                layout_fix_offsets(wp->window->layout_root);
                layout_fix_panes(wp->window, wp->window->sx, wp->window->sy);
        }
}