evolution/e-util/e-table-header.c

/*
 * 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:
 *		Chris Lahey <clahey@ximian.com>
 *		Miguel de Icaza <miguel@ximian.com>
 *
 * Copyright (C) 1999-2008 Novell, Inc. (www.novell.com)
 *
 */

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

#include <string.h>

#include <gtk/gtk.h>

#include "e-marshal.h"
#include "e-table-defines.h"
#include "e-table-header.h"

enum {
	PROP_0,
	PROP_SORT_INFO,
	PROP_WIDTH,
	PROP_WIDTH_EXTRAS
};

enum {
	STRUCTURE_CHANGE,
	DIMENSION_CHANGE,
	EXPANSION_CHANGE,
	REQUEST_WIDTH,
	LAST_SIGNAL
};

static void eth_set_size (ETableHeader *eth, gint idx, gint size);
static void eth_calc_widths (ETableHeader *eth);

static guint eth_signals[LAST_SIGNAL] = { 0, };

G_DEFINE_TYPE (ETableHeader, e_table_header, G_TYPE_OBJECT)

struct two_ints {
	gint column;
	gint width;
};

static void
eth_set_width (ETableHeader *eth,
               gint width)
{
	eth->width = width;
}

static void
dequeue (ETableHeader *eth,
         gint *column,
         gint *width)
{
	GSList *head;
	struct two_ints *store;
	head = eth->change_queue;
	eth->change_queue = eth->change_queue->next;
	if (!eth->change_queue)
		eth->change_tail = NULL;
	store = head->data;
	g_slist_free_1 (head);
	if (column)
		*column = store->column;
	if (width)
		*width = store->width;
	g_free (store);
}

static gboolean
dequeue_idle (ETableHeader *eth)
{
	gint column, width;

	dequeue (eth, &column, &width);
	while (eth->change_queue && ((struct two_ints *)
		eth->change_queue->data)->column == column)
		dequeue (eth, &column, &width);

	if (column == -1)
		eth_set_width (eth, width);
	else if (column < eth->col_count)
		eth_set_size (eth, column, width);
	if (eth->change_queue)
		return TRUE;
	else {
		eth_calc_widths (eth);
		eth->idle = 0;
		return FALSE;
	}
}

static void
enqueue (ETableHeader *eth,
         gint column,
         gint width)
{
	struct two_ints *store;
	store = g_new (struct two_ints, 1);
	store->column = column;
	store->width = width;

	eth->change_tail = g_slist_last (g_slist_append (eth->change_tail, store));
	if (!eth->change_queue)
		eth->change_queue = eth->change_tail;

	if (!eth->idle) {
		eth->idle = g_idle_add_full (
			G_PRIORITY_LOW, (GSourceFunc)
			dequeue_idle, eth, NULL);
	}
}

void
e_table_header_set_size (ETableHeader *eth,
                         gint idx,
                         gint size)
{
	g_return_if_fail (eth != NULL);
	g_return_if_fail (E_IS_TABLE_HEADER (eth));

	enqueue (eth, idx, size);
}

static void
eth_do_remove (ETableHeader *eth,
               gint idx,
               gboolean do_unref)
{
	if (do_unref)
		g_object_unref (eth->columns[idx]);

	memmove (
		&eth->columns[idx], &eth->columns[idx + 1],
		sizeof (ETableCol *) * (eth->col_count - idx - 1));
	eth->col_count--;
}

static void
eth_finalize (GObject *object)
{
	ETableHeader *eth = E_TABLE_HEADER (object);
	const gint cols = eth->col_count;
	gint i;

	if (eth->sort_info) {
		if (eth->sort_info_group_change_id)
			g_signal_handler_disconnect (
				eth->sort_info,
				eth->sort_info_group_change_id);
		g_object_unref (eth->sort_info);
		eth->sort_info = NULL;
	}

	if (eth->idle)
		g_source_remove (eth->idle);
	eth->idle = 0;

	if (eth->change_queue) {
		g_slist_foreach (eth->change_queue, (GFunc) g_free, NULL);
		g_slist_free (eth->change_queue);
		eth->change_queue = NULL;
	}

	/*
	 * Destroy columns
	 */
	for (i = cols - 1; i >= 0; i--) {
		eth_do_remove (eth, i, TRUE);
	}
	g_free (eth->columns);

	eth->col_count = 0;
	eth->columns = NULL;

	/* Chain up to parent's finalize() method. */
	G_OBJECT_CLASS (e_table_header_parent_class)->finalize (object);
}

static void
eth_group_info_changed (ETableSortInfo *info,
                        ETableHeader *eth)
{
	enqueue (eth, -1, eth->nominal_width);
}

static void
eth_set_property (GObject *object,
                  guint property_id,
                  const GValue *val,
                  GParamSpec *pspec)
{
	ETableHeader *eth = E_TABLE_HEADER (object);

	switch (property_id) {
	case PROP_WIDTH:
		eth->nominal_width = g_value_get_double (val);
		enqueue (eth, -1, eth->nominal_width);
		break;
	case PROP_WIDTH_EXTRAS:
		eth->width_extras = g_value_get_double (val);
		enqueue (eth, -1, eth->nominal_width);
		break;
	case PROP_SORT_INFO:
		if (eth->sort_info) {
			if (eth->sort_info_group_change_id)
				g_signal_handler_disconnect (
					eth->sort_info,
					eth->sort_info_group_change_id);
			g_object_unref (eth->sort_info);
		}
		eth->sort_info = E_TABLE_SORT_INFO (g_value_get_object (val));
		if (eth->sort_info) {
			g_object_ref (eth->sort_info);
			eth->sort_info_group_change_id = g_signal_connect (
				eth->sort_info, "group_info_changed",
				G_CALLBACK (eth_group_info_changed), eth);
		}
		enqueue (eth, -1, eth->nominal_width);
		break;
	default:
		break;
	}
}

static void
eth_get_property (GObject *object,
                  guint property_id,
                  GValue *val,
                  GParamSpec *pspec)
{
	ETableHeader *eth = E_TABLE_HEADER (object);

	switch (property_id) {
	case PROP_SORT_INFO:
		g_value_set_object (val, eth->sort_info);
		break;
	case PROP_WIDTH:
		g_value_set_double (val, eth->nominal_width);
		break;
	case PROP_WIDTH_EXTRAS:
		g_value_set_double (val, eth->width_extras);
		break;
	default:
		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
		break;
	}
}

static void
e_table_header_class_init (ETableHeaderClass *class)
{
	GObjectClass *object_class = G_OBJECT_CLASS (class);

	object_class->finalize = eth_finalize;
	object_class->set_property = eth_set_property;
	object_class->get_property = eth_get_property;

	g_object_class_install_property (
		object_class,
		PROP_WIDTH,
		g_param_spec_double (
			"width", "Width", "Width",
			0.0, G_MAXDOUBLE, 0.0,
			G_PARAM_READWRITE));

	g_object_class_install_property (
		object_class,
		PROP_WIDTH_EXTRAS,
		g_param_spec_double (
			"width_extras",
			"Width of Extras",
			"Width of Extras",
			0.0, G_MAXDOUBLE, 0.0,
			G_PARAM_READWRITE));

	g_object_class_install_property (
		object_class,
		PROP_SORT_INFO,
		g_param_spec_object (
			"sort_info",
			"Sort Info",
			"Sort Info",
			E_TYPE_TABLE_SORT_INFO,
			G_PARAM_READWRITE));

	eth_signals[STRUCTURE_CHANGE] = g_signal_new (
		"structure_change",
		G_TYPE_FROM_CLASS (object_class),
		G_SIGNAL_RUN_LAST,
		G_STRUCT_OFFSET (ETableHeaderClass, structure_change),
		(GSignalAccumulator) NULL, NULL,
		g_cclosure_marshal_VOID__VOID,
		G_TYPE_NONE, 0);

	eth_signals[DIMENSION_CHANGE] = g_signal_new (
		"dimension_change",
		G_TYPE_FROM_CLASS (object_class),
		G_SIGNAL_RUN_LAST,
		G_STRUCT_OFFSET (ETableHeaderClass, dimension_change),
		(GSignalAccumulator) NULL, NULL,
		g_cclosure_marshal_VOID__INT,
		G_TYPE_NONE, 1,
		G_TYPE_INT);

	eth_signals[EXPANSION_CHANGE] = g_signal_new (
		"expansion_change",
		G_TYPE_FROM_CLASS (object_class),
		G_SIGNAL_RUN_LAST,
		G_STRUCT_OFFSET (ETableHeaderClass, expansion_change),
		(GSignalAccumulator) NULL, NULL,
		g_cclosure_marshal_VOID__VOID,
		G_TYPE_NONE, 0);

	eth_signals[REQUEST_WIDTH] = g_signal_new (
		"request_width",
		G_TYPE_FROM_CLASS (object_class),
		G_SIGNAL_RUN_LAST,
		G_STRUCT_OFFSET (ETableHeaderClass, request_width),
		(GSignalAccumulator) NULL, NULL,
		e_marshal_INT__INT,
		G_TYPE_INT, 1,
		G_TYPE_INT);

	class->structure_change = NULL;
	class->dimension_change = NULL;
	class->expansion_change = NULL;
	class->request_width = NULL;
}

static void
e_table_header_init (ETableHeader *eth)
{
	eth->col_count                 = 0;
	eth->width                     = 0;

	eth->sort_info                 = NULL;
	eth->sort_info_group_change_id = 0;

	eth->columns                   = NULL;

	eth->change_queue              = NULL;
	eth->change_tail               = NULL;

	eth->width_extras              = 0;
}

/**
 * e_table_header_new:
 *
 * Returns: A new @ETableHeader object.
 */
ETableHeader *
e_table_header_new (void)
{

	return g_object_new (E_TYPE_TABLE_HEADER, NULL);
}

static void
eth_update_offsets (ETableHeader *eth)
{
	gint i;
	gint x = 0;

	for (i = 0; i < eth->col_count; i++) {
		ETableCol *etc = eth->columns[i];

		etc->x = x;
		x += etc->width;
	}
}

static void
eth_do_insert (ETableHeader *eth,
               gint pos,
               ETableCol *val)
{
	memmove (
		&eth->columns[pos + 1], &eth->columns[pos],
		sizeof (ETableCol *) * (eth->col_count - pos));
	eth->columns[pos] = val;
	eth->col_count++;
}

/**
 * e_table_header_add_column:
 * @eth: the table header to add the column to.
 * @tc: the ETableCol definition
 * @pos: position where the ETableCol will go.
 *
 * This function adds the @tc ETableCol definition into the @eth ETableHeader
 * at position @pos.  This is the way you add new ETableCols to the
 * ETableHeader.  The header will assume ownership of the @tc; you should not
 * unref it after you add it.
 *
 * This function will emit the "structure_change" signal on the @eth object.
 * The ETableCol is assumed
 */
void
e_table_header_add_column (ETableHeader *eth,
                           ETableCol *tc,
                           gint pos)
{
	g_return_if_fail (eth != NULL);
	g_return_if_fail (E_IS_TABLE_HEADER (eth));
	g_return_if_fail (tc != NULL);
	g_return_if_fail (E_IS_TABLE_COL (tc));
	g_return_if_fail (pos >= -1 && pos <= eth->col_count);

	if (pos == -1)
		pos = eth->col_count;
	eth->columns = g_realloc (
		eth->columns, sizeof (ETableCol *) * (eth->col_count + 1));

	/*
	 * We are the primary owners of the column
	 */
	g_object_ref (tc);

	eth_do_insert (eth, pos, tc);

	enqueue (eth, -1, eth->nominal_width);
	g_signal_emit (eth, eth_signals[STRUCTURE_CHANGE], 0);
}

/**
 * e_table_header_get_column:
 * @eth: the ETableHeader to query
 * @column: the column inside the @eth.
 *
 * Returns: The ETableCol at @column in the @eth object
 */
ETableCol *
e_table_header_get_column (ETableHeader *eth,
                           gint column)
{
	g_return_val_if_fail (eth != NULL, NULL);
	g_return_val_if_fail (E_IS_TABLE_HEADER (eth), NULL);

	if (column < 0)
		return NULL;

	if (column >= eth->col_count)
		return NULL;

	return eth->columns[column];
}

/**
 * e_table_header_get_column_by_spec:
 * @eth: the ETableHeader to query
 * @spec: an #ETableColumnSpecification
 *
 * Returns the #ETableCol having @spec as the column specification, or
 * %NULL if there is no matching #ETableCol.
 *
 * Returns: an #ETableCol, or %NULL
 **/
ETableCol *
e_table_header_get_column_by_spec (ETableHeader *eth,
                                   ETableColumnSpecification *spec)
{
	gint ii;

	g_return_val_if_fail (E_IS_TABLE_HEADER (eth), NULL);
	g_return_val_if_fail (E_IS_TABLE_COLUMN_SPECIFICATION (spec), NULL);

	for (ii = 0; ii < eth->col_count; ii++) {
		gboolean column_specs_equal;

		column_specs_equal = e_table_column_specification_equal (
			spec, eth->columns[ii]->spec);

		if (column_specs_equal)
			return eth->columns[ii];
	}

	return NULL;
}

/**
 * e_table_header_get_column_by_col_id:
 * @eth: the ETableHeader to query
 * @col_id: the col_id to search for.
 *
 * Returns: The ETableCol with col_idx = @col_idx in the @eth object
 */
ETableCol *
e_table_header_get_column_by_col_idx (ETableHeader *eth,
                                      gint col_idx)
{
	gint i;
	g_return_val_if_fail (eth != NULL, NULL);
	g_return_val_if_fail (E_IS_TABLE_HEADER (eth), NULL);

	for (i = 0; i < eth->col_count; i++) {
		if (eth->columns[i]->spec->model_col == col_idx) {
			return eth->columns[i];
		}
	}

	return NULL;
}

/**
 * e_table_header_count:
 * @eth: the ETableHeader to query
 *
 * Returns: the number of columns in this ETableHeader.
 */
gint
e_table_header_count (ETableHeader *eth)
{
	g_return_val_if_fail (eth != NULL, 0);
	g_return_val_if_fail (E_IS_TABLE_HEADER (eth), 0);

	return eth->col_count;
}

/**
 * e_table_header_index:
 * @eth: the ETableHeader to query
 * @col: the column to fetch.
 *
 * ETableHeaders contain the visual list of columns that the user will
 * view.  The visible columns will typically map to different columns
 * in the ETableModel (because the user reordered the data for
 * example).
 *
 * Returns: the column in the model that the @col column
 * in the ETableHeader points to.  */
gint
e_table_header_index (ETableHeader *eth,
                      gint col)
{
	g_return_val_if_fail (eth != NULL, -1);
	g_return_val_if_fail (E_IS_TABLE_HEADER (eth), -1);
	g_return_val_if_fail (col >= 0 && col < eth->col_count, -1);

	return eth->columns[col]->spec->model_col;
}

/**
 * e_table_header_get_index_at:
 * @eth: the ETableHeader to query
 * @x_offset: a pixel count from the beginning of the ETableHeader
 *
 * This will return the ETableHeader column that would contain
 * the @x_offset pixel.
 *
 * Returns: the column that contains pixel @x_offset, or -1
 * if no column inside this ETableHeader contains that pixel.
 */
gint
e_table_header_get_index_at (ETableHeader *eth,
                             gint x_offset)
{
	gint i, total;

	g_return_val_if_fail (eth != NULL, 0);
	g_return_val_if_fail (E_IS_TABLE_HEADER (eth), 0);

	total = 0;
	for (i = 0; i < eth->col_count; i++) {
		total += eth->columns[i]->width;

		if (x_offset < total)
			return i;
	}

	return -1;
}

/**
 * e_table_header_get_columns:
 * @eth: The ETableHeader to query
 *
 * Returns: A NULL terminated array of the ETableCols
 * contained in the ETableHeader @eth.  Note that every
 * returned ETableCol in the array has been referenced, to release
 * this information you need to g_free the buffer returned
 * and you need to g_object_unref every element returned
 */
ETableCol **
e_table_header_get_columns (ETableHeader *eth)
{
	ETableCol **ret;
	gint i;

	g_return_val_if_fail (eth != NULL, NULL);
	g_return_val_if_fail (E_IS_TABLE_HEADER (eth), NULL);

	ret = g_new (ETableCol *, eth->col_count + 1);
	memcpy (ret, eth->columns, sizeof (ETableCol *) * eth->col_count);
	ret[eth->col_count] = NULL;

	for (i = 0; i < eth->col_count; i++) {
		g_object_ref (ret[i]);
	}

	return ret;
}

/**
 * e_table_header_get_selected:
 * @eth: The ETableHeader to query
 *
 * Returns: The number of selected columns in the @eth object.
 */
gint
e_table_header_get_selected (ETableHeader *eth)
{
	gint i;
	gint selected = 0;

	g_return_val_if_fail (eth != NULL, 0);
	g_return_val_if_fail (E_IS_TABLE_HEADER (eth), 0);

	for (i = 0; i < eth->col_count; i++) {
		if (eth->columns[i]->selected)
			selected++;
	}

	return selected;
}

/**
 * e_table_header_total_width:
 * @eth: The ETableHeader to query
 *
 * Returns: the number of pixels used by the @eth object
 * when rendered on screen
 */
gint
e_table_header_total_width (ETableHeader *eth)
{
	gint total, i;

	g_return_val_if_fail (eth != NULL, 0);
	g_return_val_if_fail (E_IS_TABLE_HEADER (eth), 0);

	total = 0;
	for (i = 0; i < eth->col_count; i++)
		total += eth->columns[i]->width;

	return total;
}

/**
 * e_table_header_min_width:
 * @eth: The ETableHeader to query
 *
 * Returns: the minimum number of pixels required by the @eth object.
 **/
gint
e_table_header_min_width (ETableHeader *eth)
{
	gint total, i;

	g_return_val_if_fail (eth != NULL, 0);
	g_return_val_if_fail (E_IS_TABLE_HEADER (eth), 0);

	total = 0;
	for (i = 0; i < eth->col_count; i++)
		total += eth->columns[i]->min_width;

	return total;
}

/**
 * e_table_header_move:
 * @eth: The ETableHeader to operate on.
 * @source_index: the source column to move.
 * @target_index: the target location for the column
 *
 * This function moves the column @source_index to @target_index
 * inside the @eth ETableHeader.  The signals "dimension_change"
 * and "structure_change" will be emmited
 */
void
e_table_header_move (ETableHeader *eth,
                     gint source_index,
                     gint target_index)
{
	ETableCol *old;

	g_return_if_fail (eth != NULL);
	g_return_if_fail (E_IS_TABLE_HEADER (eth));
	g_return_if_fail (source_index >= 0);
	g_return_if_fail (target_index >= 0);
	g_return_if_fail (source_index < eth->col_count);

	/* Can be moved beyond the last item. */
	g_return_if_fail (target_index < eth->col_count + 1);

	if (source_index < target_index)
		target_index--;

	old = eth->columns[source_index];
	eth_do_remove (eth, source_index, FALSE);
	eth_do_insert (eth, target_index, old);
	eth_update_offsets (eth);

	g_signal_emit (eth, eth_signals[DIMENSION_CHANGE], 0, eth->width);
	g_signal_emit (eth, eth_signals[STRUCTURE_CHANGE], 0);
}

/**
 * e_table_header_remove:
 * @eth: The ETableHeader to operate on.
 * @idx: the index to the column to be removed.
 *
 * Removes the column at @idx position in the ETableHeader @eth.
 * This emmits the "structure_change" signal on the @eth object.
 */
void
e_table_header_remove (ETableHeader *eth,
                       gint idx)
{
	g_return_if_fail (eth != NULL);
	g_return_if_fail (E_IS_TABLE_HEADER (eth));
	g_return_if_fail (idx >= 0);
	g_return_if_fail (idx < eth->col_count);

	eth_do_remove (eth, idx, TRUE);
	enqueue (eth, -1, eth->nominal_width);
	g_signal_emit (eth, eth_signals[STRUCTURE_CHANGE], 0);
}

/*
 * FIXME: deprecated?
 */
void
e_table_header_set_selection (ETableHeader *eth,
                              gboolean allow_selection)
{
	g_return_if_fail (eth != NULL);
	g_return_if_fail (E_IS_TABLE_HEADER (eth));
}

static void
eth_set_size (ETableHeader *eth,
              gint idx,
              gint size)
{
	gdouble expansion;
	gdouble old_expansion;
	gint min_width;
	gint left_width;
	gint total_extra;
	gint expandable_count;
	gint usable_width;
	gint i;
	g_return_if_fail (eth != NULL);
	g_return_if_fail (E_IS_TABLE_HEADER (eth));
	g_return_if_fail (idx >= 0);
	g_return_if_fail (idx < eth->col_count);

	/* If this column is not resizable, don't do anything. */
	if (!eth->columns[idx]->spec->resizable)
		return;

	expansion = 0;
	min_width = 0;
	left_width = 0;
	expandable_count = -1;

	/* Calculate usable area. */
	for (i = 0; i < idx; i++) {
		left_width += eth->columns[i]->width;
	}
	/* - 1 to account for the last pixel border. */
	usable_width = eth->width - left_width - 1;

	if (eth->sort_info)
		usable_width -= e_table_sort_info_grouping_get_count (
			eth->sort_info) * GROUP_INDENT;

	/* Calculate minimum_width of stuff on the right as well as
	 * total usable expansion on the right.
	 */
	for (; i < eth->col_count; i++) {
		min_width += eth->columns[i]->min_width + eth->width_extras;
		if (eth->columns[i]->spec->resizable) {
			expansion += eth->columns[i]->expansion;
			expandable_count++;
		}
	}
	/* If there's no room for anything, don't change. */
	if (expansion == 0)
		return;

	/* (1) If none of the columns to the right are expandable, use
	 * all the expansion space in this column.
	 */
	if (expandable_count == 0) {
		eth->columns[idx]->expansion = expansion;
		for (i = idx + 1; i < eth->col_count; i++) {
			eth->columns[i]->expansion = 0;
		}

		g_signal_emit (eth, eth_signals[EXPANSION_CHANGE], 0);
		return;
	}

	total_extra = usable_width - min_width;
	/* If there's no extra space, set all expansions to 0. */
	if (total_extra <= 0) {
		for (i = idx; i < eth->col_count; i++) {
			eth->columns[i]->expansion = 0;
		}
		g_signal_emit (eth, eth_signals[EXPANSION_CHANGE], 0);
		return;
	}

	/* If you try to resize smaller than the minimum width, it
	 * uses the minimum. */
	if (size < eth->columns[idx]->min_width + eth->width_extras)
		size = eth->columns[idx]->min_width + eth->width_extras;

	/* If all the extra space will be used up in this column, use
	 * all the expansion and set all others to 0.
	 */
	if (size >= total_extra + eth->columns[idx]->min_width + eth->width_extras) {
		eth->columns[idx]->expansion = expansion;
		for (i = idx + 1; i < eth->col_count; i++) {
			eth->columns[i]->expansion = 0;
		}
		g_signal_emit (eth, eth_signals[EXPANSION_CHANGE], 0);
		return;
	}

	/* The old_expansion used by columns to the right. */
	old_expansion = expansion;
	old_expansion -= eth->columns[idx]->expansion;
	/* Set the new expansion so that it will generate the desired size. */
	eth->columns[idx]->expansion =
		expansion * (((gdouble)(size - (eth->columns[idx]->min_width +
		eth->width_extras))) / ((gdouble) total_extra));
	/* The expansion left for the columns on the right. */
	expansion -= eth->columns[idx]->expansion;

	/* (2) If the old columns to the right didn't have any
	 * expansion before, expand them evenly.  old_expansion > 0 by
	 * expansion = SUM(i=idx to col_count -1,
	 * columns[i]->min_width) - columns[idx]->min_width) =
	 * SUM(non-negatives).
	 */
	if (old_expansion == 0) {
		for (i = idx + 1; i < eth->col_count; i++) {
			if (eth->columns[idx]->spec->resizable) {
				/* expandable_count != 0 by (1) */
				eth->columns[i]->expansion = expansion / expandable_count;
			}
		}
		g_signal_emit (eth, eth_signals[EXPANSION_CHANGE], 0);
		return;
	}

	for (i = idx + 1; i < eth->col_count; i++) {
		if (eth->columns[idx]->spec->resizable) {
			/* old_expansion != 0 by (2) */
			eth->columns[i]->expansion *= expansion / old_expansion;
		}
	}
	g_signal_emit (eth, eth_signals[EXPANSION_CHANGE], 0);
}

/**
 * e_table_header_col_diff:
 * @eth: the ETableHeader to query.
 * @start_col: the starting column
 * @end_col: the ending column.
 *
 * Computes the number of pixels between the columns @start_col and
 * @end_col.
 *
 * Returns: the number of pixels between @start_col and @end_col on the
 * @eth ETableHeader object
 */
gint
e_table_header_col_diff (ETableHeader *eth,
                         gint start_col,
                         gint end_col)
{
	gint total, col;

	g_return_val_if_fail (eth != NULL, 0);
	g_return_val_if_fail (E_IS_TABLE_HEADER (eth), 0);

	if (start_col < 0)
		start_col = 0;
	if (end_col > eth->col_count)
		end_col = eth->col_count;

	total = 0;
	for (col = start_col; col < end_col; col++) {

		total += eth->columns[col]->width;
	}

	return total;
}

static void
eth_calc_widths (ETableHeader *eth)
{
	gint i;
	gint extra;
	gdouble expansion;
	gint last_position = 0;
	gdouble next_position = 0;
	gint last_resizable = -1;
	gint *widths;
	gboolean changed;

	widths = g_new (int, eth->col_count);

	/* - 1 to account for the last pixel border. */
	extra = eth->width - 1;
	expansion = 0;
	for (i = 0; i < eth->col_count; i++) {
		extra -= eth->columns[i]->min_width + eth->width_extras;
		if (eth->columns[i]->spec->resizable && eth->columns[i]->expansion > 0)
			last_resizable = i;
		expansion += eth->columns[i]->spec->resizable ? eth->columns[i]->expansion : 0;
		widths[i] = eth->columns[i]->min_width + eth->width_extras;
	}
	if (eth->sort_info)
		extra -= e_table_sort_info_grouping_get_count (eth->sort_info)
			* GROUP_INDENT;
	if (expansion != 0 && extra > 0) {
		for (i = 0; i < last_resizable; i++) {
			next_position +=
				extra * (eth->columns[i]->spec->resizable ?
				eth->columns[i]->expansion : 0) / expansion;
			widths[i] += next_position - last_position;
			last_position = next_position;
		}
		widths[i] += extra - last_position;
	}

	changed = FALSE;

	for (i = 0; i < eth->col_count; i++) {
		if (eth->columns[i]->width != widths[i]) {
			changed = TRUE;
			eth->columns[i]->width = widths[i];
		}
	}
	g_free (widths);
	if (changed)
		g_signal_emit (eth, eth_signals[DIMENSION_CHANGE], 0, eth->width);
	eth_update_offsets (eth);
}

void
e_table_header_update_horizontal (ETableHeader *eth)
{
	gint i;
	gint cols;

	cols = eth->col_count;

	for (i = 0; i < cols; i++) {
		gint width = 0;

		g_signal_emit_by_name (
			eth, "request_width", i, &width);
		eth->columns[i]->min_width = width + 10;
		eth->columns[i]->expansion = 1;
	}
	enqueue (eth, -1, eth->nominal_width);
	g_signal_emit (eth, eth_signals[EXPANSION_CHANGE], 0);
}

gint
e_table_header_prioritized_column (ETableHeader *eth)
{
	gint best_model_col = 0;
	gint best_priority;
	gint i;
	gint count;

	count = e_table_header_count (eth);
	if (count == 0)
		return -1;
	best_priority = e_table_header_get_column (eth, 0)->spec->priority;
	best_model_col = e_table_header_get_column (eth, 0)->spec->model_col;
	for (i = 1; i < count; i++) {
		gint priority = e_table_header_get_column (eth, i)->spec->priority;
		if (priority > best_priority) {
			best_priority = priority;
			best_model_col = e_table_header_get_column (eth, i)->spec->model_col;
		}
	}
	return best_model_col;
}

ETableCol *
e_table_header_prioritized_column_selected (ETableHeader *eth,
                                            ETableColCheckFunc check_func,
                                            gpointer user_data)
{
	ETableCol *best_col = NULL;
	gint best_priority = G_MININT;
	gint i;
	gint count;

	count = e_table_header_count (eth);
	if (count == 0)
		return NULL;
	for (i = 1; i < count; i++) {
		ETableCol *col = e_table_header_get_column (eth, i);
		if (col) {
			if ((best_col == NULL || col->spec->priority > best_priority)
			   && check_func (col, user_data)) {
				best_priority = col->spec->priority;
				best_col = col;
			}
		}
	}
	return best_col;
}