path: root/calendar/gui/e-week-view-layout.c

/*
 * Lays out events for the Week & Month views of the calendar. It is also
 * used for printing.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) version 3.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with the program; if not, see <http://www.gnu.org/licenses/>
 *
 * Authors:
 *      Damon Chaplin <damon@ximian.com>
 *
 * Copyright (C) 1999-2008 Novell, Inc. (www.novell.com)
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "e-week-view-layout.h"
#include "calendar-config.h"

static void e_week_view_layout_event    (EWeekViewEvent *event,
                     guint8     *grid,
                     GArray     *spans,
                     GArray     *old_spans,
                     gboolean    multi_week_view,
                     gint        weeks_shown,
                     gboolean    compress_weekend,
                     gint        start_weekday,
                     time_t     *day_starts,
                     gint       *rows_per_day);
static gint e_week_view_find_day    (time_t      time_to_find,
                     gboolean    include_midnight_in_prev_day,
                     gint        days_shown,
                     time_t     *day_starts);
static gint e_week_view_find_span_end   (gboolean    multi_week_view,
                     gboolean    compress_weekend,
                     gint        display_start_day,
                     gint        day);

GArray *
e_week_view_layout_events (GArray *events,
                           GArray *old_spans,
                           gboolean multi_week_view,
                           gint weeks_shown,
                           gboolean compress_weekend,
                           gint start_weekday,
                           time_t *day_starts,
                           gint *rows_per_day)
{
    EWeekViewEvent *event;
    EWeekViewEventSpan *span;
    gint num_days, day, event_num, span_num;
    guint8 *grid;
    GArray *spans;

    /* This is a temporary 2-d grid which is used to place events.
     * Each element is 0 if the position is empty, or 1 if occupied.
     * We allocate the maximum size possible here, assuming that each
     * event will need its own row. */
    grid = g_new0 (guint8, E_WEEK_VIEW_MAX_ROWS_PER_CELL * 7
               * E_WEEK_VIEW_MAX_WEEKS);

    /* We create a new array of spans, which will replace the old one. */
    spans = g_array_new (FALSE, FALSE, sizeof (EWeekViewEventSpan));

    /* Clear the number of rows used per day. */
    num_days = multi_week_view ? weeks_shown * 7 : 7;
    for (day = 0; day < num_days; day++) {
        rows_per_day[day] = 0;
    }

    /* Iterate over the events, finding which weeks they cover, and putting
     * them in the first free row available. */
    for (event_num = 0; event_num < events->len; event_num++) {
        event = &g_array_index (events, EWeekViewEvent, event_num);
        e_week_view_layout_event (event, grid, spans, old_spans,
                      multi_week_view,
                      weeks_shown, compress_weekend,
                      start_weekday, day_starts,
                      rows_per_day);
    }

    /* Free the grid. */
    g_free (grid);

    /* Destroy the old spans array, destroying any unused canvas items. */
    if (old_spans) {
        for (span_num = 0; span_num < old_spans->len; span_num++) {
            span = &g_array_index (old_spans, EWeekViewEventSpan,
                           span_num);
            if (span->background_item)
                g_object_run_dispose (G_OBJECT (span->background_item));
            if (span->text_item)
                g_object_run_dispose (G_OBJECT (span->text_item));
        }
        g_array_free (old_spans, TRUE);
    }

    return spans;
}

static void
e_week_view_layout_event (EWeekViewEvent *event,
                                 guint8 *grid,
                                 GArray *spans,
                                 GArray *old_spans,
                                 gboolean multi_week_view,
                                 gint weeks_shown,
                                 gboolean compress_weekend,
                                 gint start_weekday,
                                 time_t *day_starts,
                                 gint *rows_per_day)
{
    gint start_day, end_day, span_start_day, span_end_day, rows_per_cell;
    gint free_row, row, day, span_num, spans_index, num_spans, days_shown;
    EWeekViewEventSpan span, *old_span;

    days_shown = multi_week_view ? weeks_shown * 7 : 7;
    start_day = e_week_view_find_day (event->start, FALSE, days_shown,
                      day_starts);
    end_day = e_week_view_find_day (event->end, TRUE, days_shown,
                    day_starts);
    start_day = CLAMP (start_day, 0, days_shown - 1);
    end_day = CLAMP (end_day, 0, days_shown - 1);

#if 0
    g_print ("In e_week_view_layout_event Start:%i End: %i\n",
         start_day, end_day);
#endif

    /* Iterate through each of the spans of the event, where each span
     * is a sequence of 1 or more days displayed next to each other. */
    span_start_day = start_day;
    rows_per_cell = E_WEEK_VIEW_MAX_ROWS_PER_CELL;
    span_num = 0;
    spans_index = spans->len;
    num_spans = 0;
    while (span_start_day <= end_day) {
        span_end_day = e_week_view_find_span_end (multi_week_view,
                              compress_weekend,
                              start_weekday,
                              span_start_day);
        span_end_day = MIN (span_end_day, end_day);
#if 0
        g_print ("  Span start:%i end:%i\n", span_start_day,
             span_end_day);
#endif
        /* Try each row until we find a free one or we fall off the
         * bottom of the available rows. */
        row = 0;
        free_row = -1;
        while (free_row == -1 && row < rows_per_cell) {
            free_row = row;
            for (day = span_start_day; day <= span_end_day;
                 day++) {
                if (grid[day * rows_per_cell + row]) {
                    free_row = -1;
                    break;
                }
            }
            row++;
        };

        if (free_row != -1) {
            /* Mark the cells as full. */
            for (day = span_start_day; day <= span_end_day;
                 day++) {
                grid[day * rows_per_cell + free_row] = 1;
                rows_per_day[day] = MAX (rows_per_day[day],
                             free_row + 1);
            }
#if 0
            g_print ("  Span start:%i end:%i row:%i\n",
                 span_start_day, span_end_day, free_row);
#endif
            /* Add the span to the array, and try to reuse any
             * canvas items from the old spans. */
            span.start_day = span_start_day;
            span.num_days = span_end_day - span_start_day + 1;
            span.row = free_row;
            span.background_item = NULL;
            span.text_item = NULL;
            if (event->num_spans > span_num) {
                old_span = &g_array_index (
                    old_spans, EWeekViewEventSpan,
                    event->spans_index + span_num);
                span.background_item = old_span->background_item;
                span.text_item = old_span->text_item;
                old_span->background_item = NULL;
                old_span->text_item = NULL;
            }

            g_array_append_val (spans, span);
            num_spans++;
        }

        span_start_day = span_end_day + 1;
        span_num++;
    }

    /* Set the event's spans. */
    event->spans_index = spans_index;
    event->num_spans = num_spans;
}

/* Finds the day containing the given time.
 * If include_midnight_in_prev_day is TRUE then if the time exactly
 * matches the start of a day the previous day is returned. This is useful
 * when calculating the end day of an event. */
static gint
e_week_view_find_day (time_t time_to_find,
                      gboolean include_midnight_in_prev_day,
                      gint days_shown,
                      time_t *day_starts)
{
    gint day;

    if (time_to_find < day_starts[0])
        return -1;
    if (time_to_find > day_starts[days_shown])
        return days_shown;

    for (day = 1; day <= days_shown; day++) {
        if (time_to_find <= day_starts[day]) {
            if (time_to_find == day_starts[day]
                && !include_midnight_in_prev_day)
                return day;
            return day - 1;
        }
    }

    g_return_val_if_reached (days_shown);
}

/* This returns the last possible day in the same span as the given day.
 * A span is all the days which are displayed next to each other from left to
 * right. In the week view all spans are only 1 day, since Tuesday is below
 * Monday rather than beside it etc. In the month view, if the weekends are not
 * compressed then each week is a span, otherwise we have to break a span up
 * on Saturday, use a separate span for Sunday, and start again on Monday. */
static gint
e_week_view_find_span_end (gboolean multi_week_view,
                           gboolean compress_weekend,
                           gint display_start_day,
                           gint day)
{
    gint week, col, sat_col, end_col;

    if (multi_week_view) {
        week = day / 7;
        col = day % 7;

        /* We default to the last column in the row. */
        end_col = 6;

        /* If the weekend is compressed we must end any spans on
         * Saturday and Sunday. */
        if (compress_weekend) {
            sat_col = (5 + 7 - display_start_day) % 7;
            if (col <= sat_col)
                end_col = sat_col;
            else if (col == sat_col + 1)
                end_col = sat_col + 1;
        }

        return week * 7 + end_col;
    } else {
        return day;
    }
}

void
e_week_view_layout_get_day_position (gint day,
                                     gboolean multi_week_view,
                                     gint weeks_shown,
                                     gint display_start_day,
                                     gboolean compress_weekend,
                                     gint *day_x,
                                     gint *day_y,
                                     gint *rows)
{
    gint week, day_of_week, col, weekend_col;

    *day_x = *day_y = *rows = 0;
    g_return_if_fail (day >= 0);

    if (multi_week_view) {
        g_return_if_fail (day < weeks_shown * 7);

        week = day / 7;
        col = day % 7;
        day_of_week = (display_start_day + day) % 7;
        if (compress_weekend && day_of_week >= 5) {
            /* In the compressed view Saturday is above Sunday and
             * both have just one row as opposed to 2 for all the
             * other days. */
            if (day_of_week == 5) {
                *day_y = week * 2;
                *rows = 1;
            } else {
                *day_y = week * 2 + 1;
                *rows = 1;
                col--;
            }
            /* Both Saturday and Sunday are in the same column. */
            *day_x = col;
        } else {
            /* If the weekend is compressed and the day is after
             * the weekend we have to move back a column. */
            if (compress_weekend) {
                /* Calculate where the weekend column is.
                 * Note that 5 is Saturday. */
                weekend_col = (5 + 7 - display_start_day) % 7;
                if (col > weekend_col)
                    col--;
            }

            *day_y = week * 2;
            *rows = 2;
            *day_x = col;
        }
    } else {
        #define wk(x) \
            ((working_days & \
            (days[((x) + display_start_day) % 7])) ? 1 : 0)
        CalWeekdays days[] = {
            CAL_MONDAY,
            CAL_TUESDAY,
            CAL_WEDNESDAY,
            CAL_THURSDAY,
            CAL_FRIDAY,
            CAL_SATURDAY,
            CAL_SUNDAY };
        CalWeekdays working_days;
        gint arr[4] = {1, 1, 1, 1};
        gint edge, i, wd, m, M;
        gboolean any = TRUE;

        g_return_if_fail (day < 7);

        working_days = calendar_config_get_working_days ();
        edge = 3;

        if (wk (0) + wk (1) + wk (2) < wk (3) + wk (4) + wk (5) + wk (6))
            edge++;

        if (day < edge) {
            *day_x = 0;
            m = 0;
            M = edge;
        } else {
            *day_x = 1;
            m = edge;
            M = 7;
        }

        wd = 0; /* number of used rows in column */
        for (i = m; i < M; i++) {
            arr[i - m] += wk (i);
            wd += arr[i - m];
        }

        while (wd != 6 && any) {
            any = FALSE;

            for (i = M - 1; i >= m; i--) {
                if (arr[i - m] > 1) {
                    any = TRUE;

                    if (wd > 6) { /* too many rows, make last shorter */
                        arr[i - m] --;
                        wd--;
                    } else if (wd < 6) { /* free rows left, enlarge those bigger */
                        arr[i - m] ++;
                        wd++;
                    }

                    if (wd == 6)
                        break;
                }
            }

            if (!any && wd != 6) {
                any = TRUE;

                for (i = m; i < M; i++) {
                    arr[i - m] += 3;
                    wd += 3;
                }
            }
        }

        *rows = arr [day - m];

        *day_y = 0;
        for (i = m; i < day; i++) {
            *day_y += arr [i - m];
        }

        #undef wk
    }
}

/* Returns TRUE if the event span is visible or FALSE if it isn't.
 * It also returns the number of days of the span that are visible.
 * Usually this can easily be determined by the start & end days and row of
 * the span, which are set in e_week_view_layout_event (). Though we need a
 * special case for the weekends when they are compressed, since the span may
 * not fit. */
gboolean
e_week_view_layout_get_span_position (EWeekViewEvent *event,
                                      EWeekViewEventSpan *span,
                                      gint rows_per_cell,
                                      gint rows_per_compressed_cell,
                                      gint display_start_day,
                                      gboolean multi_week_view,
                                      gboolean compress_weekend,
                                      gint *span_num_days)
{
    gint end_day_of_week;

    if (multi_week_view && span->row >= rows_per_cell)
        return FALSE;

    end_day_of_week = (display_start_day + span->start_day
               + span->num_days - 1) % 7;
    *span_num_days = span->num_days;
    /* Check if the row will not be visible in compressed cells. */
    if (span->row >= rows_per_compressed_cell) {
        if (multi_week_view) {
            if (compress_weekend) {
                /* If it ends on a Saturday and is 1 day glong
                 * we skip it, else we shorten it. If it ends
                 * on a Sunday it must be 1 day long and we
                 * skip it. */
                if (end_day_of_week == 5) {    /* Sat */
                    if (*span_num_days == 1) {
                        return FALSE;
                    } else {
                        (*span_num_days)--;
                    }
                } else if (end_day_of_week == 6) { /* Sun */
                    return FALSE;
                }
            }
        } else {
            gint day_x, day_y, rows = 0;
            e_week_view_layout_get_day_position (
                end_day_of_week, multi_week_view, 1,
                display_start_day, compress_weekend,
                &day_x, &day_y, &rows);

            if (((rows / 2) * rows_per_cell) + ((rows % 2) *
                rows_per_compressed_cell) <= span->row)
                return FALSE;
        }
    }

    return TRUE;
}