path: root/widgets/misc/e-reflow.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* 
 * e-reflow.c
 * Copyright (C) 2000, 2001  Ximian, Inc.
 * Author: Chris Lahey <clahey@helixcode.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * 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
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include <config.h>

#include "e-reflow.h"

#include <math.h>
#include <gdk/gdkkeysyms.h>
#include "e-canvas-utils.h"
#include "e-canvas.h"
#include "gal/e-text/e-text.h"
#include "gal/util/e-util.h"
#include <gtk/gtksignal.h>
#include "e-selection-model-simple.h"

#include <string.h>

static gboolean e_reflow_event (GnomeCanvasItem *item, GdkEvent *event);
static void e_reflow_realize (GnomeCanvasItem *item);
static void e_reflow_unrealize (GnomeCanvasItem *item);
static void e_reflow_draw (GnomeCanvasItem *item, GdkDrawable *drawable,
                    int x, int y, int width, int height);
static void e_reflow_update (GnomeCanvasItem *item, double affine[6], ArtSVP *clip_path, gint flags);
static double e_reflow_point (GnomeCanvasItem *item, double x, double y, int cx, int cy, GnomeCanvasItem **actual_item);
static void e_reflow_reflow (GnomeCanvasItem *item, int flags);
static void set_empty(EReflow *reflow);

static void e_reflow_resize_children (GnomeCanvasItem *item);

#define E_REFLOW_DIVIDER_WIDTH 2
#define E_REFLOW_BORDER_WIDTH 7
#define E_REFLOW_FULL_GUTTER (E_REFLOW_DIVIDER_WIDTH + E_REFLOW_BORDER_WIDTH * 2)

static GnomeCanvasGroupClass *parent_class = NULL;

/* The arguments we take */
enum {
    ARG_0,
    ARG_MINIMUM_WIDTH,
    ARG_WIDTH,
    ARG_HEIGHT,
    ARG_EMPTY_MESSAGE,
    ARG_MODEL,
};

enum {
    SELECTION_EVENT,
    LAST_SIGNAL
};

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

static gint
er_compare (int i1, int i2, gpointer user_data)
{
    EReflow *reflow = user_data;
    return e_reflow_model_compare (reflow->model, i1, i2);
}

static gint
e_reflow_pick_line (EReflow *reflow, double x)
{
    x += E_REFLOW_BORDER_WIDTH + E_REFLOW_DIVIDER_WIDTH;
    x /= reflow->column_width + E_REFLOW_FULL_GUTTER;
    return x;
}

static int
er_find_item (EReflow *reflow, GnomeCanvasItem *item)
{
    int i;
    for (i = 0; i < reflow->count; i++) {
        if (reflow->items[i] == item)
            return i;
    }
    return -1;
}

static void
e_reflow_resize_children (GnomeCanvasItem *item)
{
    EReflow *reflow;
    int i;
    int count;

    reflow = E_REFLOW (item);

    count = reflow->count;
    for (i = 0; i < count; i++) {
        if (reflow->items[i])
            gnome_canvas_item_set(reflow->items[i],
                          "width", (double) reflow->column_width,
                          NULL);
    }
}

static void
e_reflow_update_selection (EReflow *reflow)
{
    int i;
    int count;

    count = reflow->count;
    for (i = 0; i < count; i++) {
        if (reflow->items[i]) {
            gtk_object_set(GTK_OBJECT(reflow->items[i]),
                           "selected", e_selection_model_is_row_selected(E_SELECTION_MODEL(reflow->selection), i),
                       NULL);
        } else if (e_selection_model_is_row_selected (E_SELECTION_MODEL (reflow->selection), i)) {
            reflow->items[i] = e_reflow_model_incarnate (reflow->model, i, GNOME_CANVAS_GROUP (reflow));
            gtk_object_set (GTK_OBJECT (reflow->items[i]),
                    "selected", e_selection_model_is_row_selected(E_SELECTION_MODEL(reflow->selection), i),
                    "width", (double) reflow->column_width,
                    NULL);
        }
    }
}

static void
selection_changed (ESelectionModel *selection, EReflow *reflow)
{
    e_reflow_update_selection (reflow);
}

static void
incarnate (EReflow *reflow)
{
    int column_width;
    int first_column;
    int last_column;
    int first_cell;
    int last_cell;
    int i;
    GtkAdjustment *adjustment = gtk_layout_get_hadjustment (GTK_LAYOUT (GNOME_CANVAS_ITEM (reflow)->canvas));

    column_width = reflow->column_width;

    first_column = adjustment->value - 1 + E_REFLOW_BORDER_WIDTH;
    first_column /= column_width + E_REFLOW_FULL_GUTTER;

    last_column = adjustment->value + adjustment->page_size + 1 - E_REFLOW_BORDER_WIDTH - E_REFLOW_DIVIDER_WIDTH;
    last_column /= column_width + E_REFLOW_FULL_GUTTER;
    last_column ++;

    if (first_column >= 0 && first_column < reflow->column_count)
        first_cell = reflow->columns[first_column];
    else
        first_cell = 0;

    if (last_column >= 0 && last_column < reflow->column_count)
        last_cell = reflow->columns[last_column];
    else
        last_cell = reflow->count;

    for (i = first_cell; i < last_cell; i++) {
        int unsorted = e_sorter_sorted_to_model (E_SORTER (reflow->sorter), i);
        if (reflow->items[unsorted] == NULL) {
            if (reflow->model) {
                reflow->items[unsorted] = e_reflow_model_incarnate (reflow->model, unsorted, GNOME_CANVAS_GROUP (reflow));
                gtk_object_set (GTK_OBJECT (reflow->items[unsorted]),
                        "selected", e_selection_model_is_row_selected(E_SELECTION_MODEL(reflow->selection), unsorted),
                        "width", (double) reflow->column_width,
                        NULL);
            }
        }
    }
    reflow->incarnate_idle_id = 0;
}

static gboolean
invoke_incarnate (gpointer user_data)
{
    EReflow *reflow = user_data;
    incarnate (reflow);
    return FALSE;
}

static void
queue_incarnate (EReflow *reflow)
{
    if (reflow->incarnate_idle_id == 0)
        reflow->incarnate_idle_id =
            g_idle_add_full (25, invoke_incarnate, reflow, NULL);
}

static void
reflow_columns (EReflow *reflow)
{
    GSList *list;
    int count;
    int i;
    int column_count;
    double running_height;

    g_free (reflow->columns);
    reflow->column_count = 0;
    reflow->columns      = NULL;

    list = NULL;

    running_height = E_REFLOW_BORDER_WIDTH;
    column_count = 1;

    count = reflow->count;
    for (i = 0; i < count; i++) {
        int unsorted = e_sorter_sorted_to_model (E_SORTER (reflow->sorter), i);
        if (reflow->heights[unsorted] == -1) {
            if (reflow->model)
                reflow->heights[unsorted] = e_reflow_model_height (reflow->model, unsorted, GNOME_CANVAS_GROUP (reflow));
            else
                reflow->heights[unsorted] = 0;
        }
        if (i != 0 && running_height + reflow->heights[unsorted] + E_REFLOW_BORDER_WIDTH > reflow->height) {
            list = g_slist_prepend (list, GINT_TO_POINTER(i));
            column_count ++;
            running_height = E_REFLOW_BORDER_WIDTH * 2 + reflow->heights[2];
        } else
            running_height += reflow->heights[unsorted] + E_REFLOW_BORDER_WIDTH;
    }

    reflow->column_count = column_count;
    reflow->columns = g_new (int, column_count);
    column_count --;
    for (; column_count > 0; column_count--) {
        GSList *to_free;
        reflow->columns[column_count] = GPOINTER_TO_INT(list->data);
        to_free = list;
        list = list->next;
        g_slist_free_1 (to_free);
    }
    reflow->columns[0] = 0;

    queue_incarnate (reflow);

    reflow->need_reflow_columns = FALSE;
}

static void
item_changed (EReflowModel *model, int i, EReflow *reflow)
{
    if (i < 0 || i >= reflow->count)
        return;

    reflow->heights[i] = -1;
    if (reflow->items[i] != NULL)
        e_reflow_model_reincarnate (model, i, reflow->items[i]);
    e_sorter_array_clean (reflow->sorter);
    reflow->need_reflow_columns = TRUE;
    e_canvas_item_request_reflow(GNOME_CANVAS_ITEM (reflow));
}

static void
items_inserted (EReflowModel *model, int position, int count, EReflow *reflow)
{
    int i;
    int oldcount;
    if (position < 0 || position > reflow->count)
        return;

    oldcount = reflow->count;

    reflow->count += count;

    if (reflow->count > reflow->allocated_count) {
        while (reflow->count > reflow->allocated_count)
            reflow->allocated_count += 256;
        reflow->heights = g_renew (int, reflow->heights, reflow->allocated_count);
        reflow->items = g_renew (GnomeCanvasItem *, reflow->items, reflow->allocated_count);
    }
    memmove (reflow->heights + position + count, reflow->heights + position, (reflow->count - position - count) * sizeof (int));
    memmove (reflow->items + position + count, reflow->items + position, (reflow->count - position - count) * sizeof (GnomeCanvasItem *));
    for (i = position; i < position + count; i++) {
        reflow->items[i] = 0;
        reflow->heights[i] = -1;
    }

    e_selection_model_simple_set_row_count (E_SELECTION_MODEL_SIMPLE (reflow->selection), reflow->count);
    if (position == oldcount)
        e_sorter_array_append (reflow->sorter, count);
    else
        e_sorter_array_set_count (reflow->sorter, reflow->count);
    reflow->need_reflow_columns = TRUE;
    set_empty (reflow);
    e_canvas_item_request_reflow(GNOME_CANVAS_ITEM (reflow));
}

static void
model_changed (EReflowModel *model, EReflow *reflow)
{
    int i;
    int count;
    int oldcount;

    count = reflow->count;
    oldcount = count;

    for (i = 0; i < count; i++) {
        if (reflow->items[i])
            gtk_object_destroy (GTK_OBJECT (reflow->items[i]));
    }
    g_free (reflow->items);
    g_free (reflow->heights);
    reflow->count = e_reflow_model_count (model);
    reflow->allocated_count = reflow->count;
    reflow->items = g_new (GnomeCanvasItem *, reflow->count);
    reflow->heights = g_new (int, reflow->count);

    count = reflow->count;
    for (i = 0; i < count; i++) {
        reflow->items[i] = 0;
        reflow->heights[i] = -1;
    }

    e_selection_model_simple_set_row_count (E_SELECTION_MODEL_SIMPLE (reflow->selection), count);
    e_sorter_array_set_count (reflow->sorter, reflow->count);

    reflow->need_reflow_columns = TRUE;
    if (oldcount > reflow->count)
        reflow_columns (reflow);
    set_empty (reflow);
    e_canvas_item_request_reflow(GNOME_CANVAS_ITEM (reflow));
}

static void
set_empty(EReflow *reflow)
{
    if (reflow->count == 0) {
        if (reflow->empty_text) {
            if (reflow->empty_message) {
                gnome_canvas_item_set(reflow->empty_text,
                              "width", reflow->minimum_width,
                              "text", reflow->empty_message,
                              NULL);
                e_canvas_item_move_absolute(reflow->empty_text,
                                reflow->minimum_width / 2,
                                0);
            } else {
                gtk_object_destroy(GTK_OBJECT(reflow->empty_text));
                reflow->empty_text = NULL;
            }
        } else {
            if (reflow->empty_message)
                reflow->empty_text =
                    gnome_canvas_item_new(GNOME_CANVAS_GROUP(reflow),
                                  e_text_get_type(),
                                  "anchor", GTK_ANCHOR_N,
                                  "width", reflow->minimum_width,
                                  "clip", TRUE,
                                  "use_ellipsis", TRUE,
                                  "font_gdk", GTK_WIDGET(GNOME_CANVAS_ITEM(reflow)->canvas)->style->font,
                                  "fill_color", "black",
                                  "justification", GTK_JUSTIFY_CENTER,
                                  "text", reflow->empty_message,
                                  "draw_background", FALSE,
                                  NULL);
            e_canvas_item_move_absolute(reflow->empty_text,
                            reflow->minimum_width / 2,
                            0);
        }
    } else {
        if (reflow->empty_text) {
            gtk_object_destroy(GTK_OBJECT(reflow->empty_text));
            reflow->empty_text = NULL;
        }
    }
}

static void
disconnect_model (EReflow *reflow)
{
    if (reflow->model == NULL)
        return;

    gtk_signal_disconnect (GTK_OBJECT (reflow->model),
                   reflow->model_changed_id);
    gtk_signal_disconnect (GTK_OBJECT (reflow->model),
                   reflow->model_items_inserted_id);
    gtk_signal_disconnect (GTK_OBJECT (reflow->model),
                   reflow->model_item_changed_id);
    gtk_object_unref (GTK_OBJECT (reflow->model));

    reflow->model_changed_id        = 0;
    reflow->model_items_inserted_id = 0;
    reflow->model_item_changed_id   = 0;
    reflow->model                   = NULL;
}

static void
disconnect_selection (EReflow *reflow)
{
    if (reflow->selection == NULL)
        return;

    gtk_signal_disconnect (GTK_OBJECT (reflow->selection),
                   reflow->selection_changed_id);
    gtk_object_unref (GTK_OBJECT (reflow->selection));

    reflow->selection_changed_id = 0;
    reflow->selection            = NULL;
}

static void
connect_model (EReflow *reflow, EReflowModel *model)
{
    if (reflow->model != NULL)
        disconnect_model (reflow);

    if (model == NULL)
        return;

    reflow->model = model;
    gtk_object_ref (GTK_OBJECT (reflow->model));
    reflow->model_changed_id =
        gtk_signal_connect (GTK_OBJECT (reflow->model), "model_changed",
                    GTK_SIGNAL_FUNC (model_changed), reflow);
    reflow->model_items_inserted_id =
        gtk_signal_connect (GTK_OBJECT (reflow->model), "model_items_inserted",
                    GTK_SIGNAL_FUNC (items_inserted), reflow);
    reflow->model_item_changed_id =
        gtk_signal_connect (GTK_OBJECT (reflow->model), "model_item_changed",
                    GTK_SIGNAL_FUNC (item_changed), reflow);
}

static void
adjustment_changed (GtkAdjustment *adjustment, EReflow *reflow)
{
    incarnate (reflow);
}

static void
disconnect_adjustment (EReflow *reflow)
{
    if (reflow->adjustment == NULL)
        return;

    gtk_signal_disconnect (GTK_OBJECT (reflow->adjustment),
                   reflow->adjustment_changed_id);
    gtk_signal_disconnect (GTK_OBJECT (reflow->adjustment),
                   reflow->adjustment_value_changed_id);

    gtk_object_unref (GTK_OBJECT (reflow->adjustment));

    reflow->adjustment_changed_id = 0;
    reflow->adjustment_value_changed_id = 0;
    reflow->adjustment = NULL;
}

static void
connect_adjustment (EReflow *reflow, GtkAdjustment *adjustment)
{
    if (reflow->adjustment != NULL)
        disconnect_adjustment (reflow);

    if (adjustment == NULL)
        return;

    reflow->adjustment = adjustment;
    reflow->adjustment_changed_id =
        gtk_signal_connect (GTK_OBJECT (adjustment), "changed",
                    adjustment_changed, reflow);
    reflow->adjustment_value_changed_id =
        gtk_signal_connect (GTK_OBJECT (adjustment), "value_changed",
                    adjustment_changed, reflow);
    gtk_object_ref (GTK_OBJECT (adjustment));
}

static void
set_scroll_adjustments (GtkLayout *layout, GtkAdjustment *hadj, GtkAdjustment *vadj, EReflow *reflow)
{
    connect_adjustment (reflow, hadj);
}

static void
disconnect_set_adjustment (EReflow *reflow)
{
    gtk_signal_disconnect (GTK_OBJECT (GNOME_CANVAS_ITEM (reflow)->canvas),
                   reflow->set_scroll_adjustments_id);
    reflow->set_scroll_adjustments_id = 0;
}

static void
connect_set_adjustment (EReflow *reflow)
{
    reflow->set_scroll_adjustments_id =
        gtk_signal_connect (GTK_OBJECT (GNOME_CANVAS_ITEM (reflow)->canvas),
                    "set_scroll_adjustments",
                    GTK_SIGNAL_FUNC (set_scroll_adjustments), reflow);
}




/* Virtual functions */
static void
e_reflow_set_arg (GtkObject *o, GtkArg *arg, guint arg_id)
{
    GnomeCanvasItem *item;
    EReflow *reflow;

    item = GNOME_CANVAS_ITEM (o);
    reflow = E_REFLOW (o);
    
    switch (arg_id){
    case ARG_HEIGHT:
        reflow->height = GTK_VALUE_DOUBLE (*arg);
        reflow->need_reflow_columns = TRUE;
        e_canvas_item_request_reflow(item);
        break;
    case ARG_MINIMUM_WIDTH:
        reflow->minimum_width = GTK_VALUE_DOUBLE (*arg);
        if (GNOME_CANVAS_ITEM_REALIZED & GTK_OBJECT_FLAGS(o))
            set_empty(reflow);
        e_canvas_item_request_reflow(item);
        break;
    case ARG_EMPTY_MESSAGE:
        g_free(reflow->empty_message);
        reflow->empty_message = g_strdup(GTK_VALUE_STRING (*arg));
        if (GNOME_CANVAS_ITEM_REALIZED & GTK_OBJECT_FLAGS(o))
            set_empty(reflow);
        break;
    case ARG_MODEL:
        connect_model (reflow, (EReflowModel *) GTK_VALUE_OBJECT (*arg));
        break;
    }
}

static void
e_reflow_get_arg (GtkObject *object, GtkArg *arg, guint arg_id)
{
    EReflow *reflow;

    reflow = E_REFLOW (object);

    switch (arg_id) {
    case ARG_MINIMUM_WIDTH:
        GTK_VALUE_DOUBLE (*arg) = reflow->minimum_width;
        break;
    case ARG_WIDTH:
        GTK_VALUE_DOUBLE (*arg) = reflow->width;
        break;
    case ARG_HEIGHT:
        GTK_VALUE_DOUBLE (*arg) = reflow->height;
        break;
    case ARG_EMPTY_MESSAGE:
        GTK_VALUE_STRING (*arg) = g_strdup(reflow->empty_message);
        break;
    case ARG_MODEL:
        GTK_VALUE_OBJECT (*arg) = (GtkObject *) reflow->model;
        break;
    default:
        arg->type = GTK_TYPE_INVALID;
        break;
    }
}

static void
e_reflow_destroy (GtkObject *object)
{
    EReflow *reflow = E_REFLOW(object);

    g_free (reflow->items);
    g_free (reflow->heights);
    g_free (reflow->columns);

    reflow->items          = NULL;
    reflow->heights        = NULL;
    reflow->columns        = NULL;
    reflow->count          = 0;
    reflow->allocated_count = 0;

    if (reflow->incarnate_idle_id != 0)
        g_source_remove (reflow->incarnate_idle_id);

    disconnect_model (reflow);
    disconnect_selection (reflow);
    
    g_free(reflow->empty_message);
  
    GTK_OBJECT_CLASS(parent_class)->destroy (object);
}

static void
e_reflow_realize (GnomeCanvasItem *item)
{
    EReflow *reflow;
    GnomeCanvasGroup *group;
    GtkAdjustment *adjustment;
    int count;
    int i;

    reflow = E_REFLOW (item);
    group = GNOME_CANVAS_GROUP (item);

    if (GNOME_CANVAS_ITEM_CLASS(parent_class)->realize)
        (* GNOME_CANVAS_ITEM_CLASS(parent_class)->realize) (item);
    
    reflow->arrow_cursor = gdk_cursor_new (GDK_SB_H_DOUBLE_ARROW);
    reflow->default_cursor = gdk_cursor_new (GDK_LEFT_PTR);

    count = reflow->count;
    for(i = 0; i < count; i++) {
        if (reflow->items[i])
            gnome_canvas_item_set(reflow->items[i],
                          "width", (double) reflow->column_width,
                          NULL);
    }

    set_empty(reflow);

    reflow->need_reflow_columns = TRUE;
    e_canvas_item_request_reflow(item);

    adjustment = gtk_layout_get_hadjustment(GTK_LAYOUT(item->canvas));

    connect_set_adjustment (reflow);
    connect_adjustment (reflow, adjustment);

    adjustment->step_increment = (reflow->column_width + E_REFLOW_FULL_GUTTER) / 2;
    adjustment->page_increment = adjustment->page_size - adjustment->step_increment;
    gtk_adjustment_changed(adjustment);
    
    if (!item->canvas->aa) {
    }
}

static void
e_reflow_unrealize (GnomeCanvasItem *item)
{
    EReflow *reflow;

    reflow = E_REFLOW (item);

    if (!item->canvas->aa) {
    }
  
    gdk_cursor_destroy (reflow->arrow_cursor);
    gdk_cursor_destroy (reflow->default_cursor);
    reflow->arrow_cursor = NULL;
    reflow->default_cursor = NULL;

    g_free (reflow->columns);
    reflow->columns = NULL;

    disconnect_set_adjustment (reflow);
    disconnect_adjustment (reflow);

    if (GNOME_CANVAS_ITEM_CLASS(parent_class)->unrealize)
        (* GNOME_CANVAS_ITEM_CLASS(parent_class)->unrealize) (item);
}

static gboolean
e_reflow_event (GnomeCanvasItem *item, GdkEvent *event)
{
    EReflow *reflow;
    int return_val = FALSE;
 
    reflow = E_REFLOW (item);

    switch( event->type )
        {
        case GDK_KEY_PRESS:
            return_val = e_selection_model_key_press(reflow->selection, (GdkEventKey *) event);
            break;
#if 0
            if (event->key.keyval == GDK_Tab || 
                event->key.keyval == GDK_KP_Tab || 
                event->key.keyval == GDK_ISO_Left_Tab) {
                int i;
                int count;
                count = reflow->count;
                for (i = 0; i < count; i++) {
                    int unsorted = e_sorter_sorted_to_model (E_SORTER (reflow->sorter), i);
                    GnomeCanvasItem *item = reflow->items[unsorted];
                    EFocus has_focus;
                    if (item) {
                        gtk_object_get(GTK_OBJECT(item),
                                   "has_focus", &has_focus,
                                   NULL);
                        if (has_focus) {
                            if (event->key.state & GDK_SHIFT_MASK) {
                                if (i == 0)
                                    return 0;
                                i--;
                            } else {
                                if (i == count - 1)
                                    return 0;
                                i++;
                            }
                            
                            unsorted = e_sorter_sorted_to_model (E_SORTER (reflow->sorter), i);
                            if (reflow->items[unsorted] == NULL) {
                                reflow->items[unsorted] = e_reflow_model_incarnate (reflow->model, unsorted, GNOME_CANVAS_GROUP (reflow));
                            }

                            item = reflow->items[unsorted];
                            gnome_canvas_item_set(item,
                                          "has_focus", (event->key.state & GDK_SHIFT_MASK) ? E_FOCUS_END : E_FOCUS_START,
                                          NULL);
                            return 1;
                        }
                    }
                }
            }
#endif
            break;
        case GDK_BUTTON_PRESS:
            switch(event->button.button) 
                {
                case 1:
                    {
                        GdkEventButton *button = (GdkEventButton *) event;
                        double n_x, max_x;
                        n_x = button->x;
                        n_x += E_REFLOW_BORDER_WIDTH + E_REFLOW_DIVIDER_WIDTH;
                        n_x = fmod(n_x,(reflow->column_width + E_REFLOW_FULL_GUTTER));

                        max_x = E_REFLOW_BORDER_WIDTH;
                        max_x += (reflow->column_width + E_REFLOW_FULL_GUTTER) * reflow->column_count;
                        if ( button->y >= E_REFLOW_BORDER_WIDTH && button->y <= reflow->height - E_REFLOW_BORDER_WIDTH && n_x < E_REFLOW_FULL_GUTTER && max_x > button->x ) {
                            reflow->which_column_dragged = e_reflow_pick_line(reflow, button->x);
                            reflow->start_x = reflow->which_column_dragged * (reflow->column_width + E_REFLOW_FULL_GUTTER) - E_REFLOW_DIVIDER_WIDTH / 2;
                            reflow->temp_column_width = reflow->column_width;
                            reflow->column_drag = TRUE;
                          
                            gnome_canvas_item_grab (item, 
                                        GDK_BUTTON_RELEASE_MASK | GDK_POINTER_MOTION_MASK,
                                        reflow->arrow_cursor,
                                        button->time);
                          
                            reflow->previous_temp_column_width = -1;
                            reflow->need_column_resize = TRUE;
                            gnome_canvas_item_request_update(item);
                            return TRUE;
                        }
                    }
                    break;
                case 4:
                    {
                        GtkAdjustment *adjustment = gtk_layout_get_hadjustment(GTK_LAYOUT(item->canvas));
                        gdouble new_value = adjustment->value;
                        new_value -= adjustment->step_increment;
                        gtk_adjustment_set_value(adjustment, new_value);
                    }
                    break;
                case 5: 
                    {
                        GtkAdjustment *adjustment = gtk_layout_get_hadjustment(GTK_LAYOUT(item->canvas));
                        gdouble new_value = adjustment->value;
                        new_value += adjustment->step_increment;
                        if ( new_value > adjustment->upper - adjustment->page_size )
                            new_value = adjustment->upper - adjustment->page_size;
                        gtk_adjustment_set_value(adjustment, new_value);
                    }
                    break;
                }
            break;
        case GDK_BUTTON_RELEASE:
            if (reflow->column_drag) {
                gdouble old_width = reflow->column_width;
                GdkEventButton *button = (GdkEventButton *) event;
                GtkAdjustment *adjustment = gtk_layout_get_hadjustment(GTK_LAYOUT(item->canvas));
                reflow->temp_column_width = reflow->column_width +
                    (button->x - reflow->start_x)/(reflow->which_column_dragged - e_reflow_pick_line(reflow, adjustment->value));
                if ( reflow->temp_column_width < 50 )
                    reflow->temp_column_width = 50;
                reflow->column_drag = FALSE;
                if ( old_width != reflow->temp_column_width ) {
                    gtk_adjustment_set_value(adjustment, adjustment->value + e_reflow_pick_line(reflow, adjustment->value) * (reflow->temp_column_width - reflow->column_width));
                    reflow->column_width = reflow->temp_column_width;
                    adjustment->step_increment = (reflow->column_width + E_REFLOW_FULL_GUTTER) / 2;
                    adjustment->page_increment = adjustment->page_size - adjustment->step_increment;
                    gtk_adjustment_changed(adjustment);
                    e_reflow_resize_children(item);
                    e_canvas_item_request_reflow(item);
                }
                reflow->need_column_resize = TRUE;
                gnome_canvas_item_request_update(item);
                gnome_canvas_item_ungrab (item, button->time);
                return TRUE;
            }
            break;
        case GDK_MOTION_NOTIFY:
            if (reflow->column_drag) {
                double old_width = reflow->temp_column_width;
                GdkEventMotion *motion = (GdkEventMotion *) event;
                GtkAdjustment *adjustment = gtk_layout_get_hadjustment(GTK_LAYOUT(item->canvas));
                reflow->temp_column_width = reflow->column_width +
                    (motion->x - reflow->start_x)/(reflow->which_column_dragged - e_reflow_pick_line(reflow, adjustment->value));
                if (reflow->temp_column_width < 50)
                    reflow->temp_column_width = 50;
                if (old_width != reflow->temp_column_width) {
                    reflow->need_column_resize = TRUE;
                    gnome_canvas_item_request_update(item);
                }
                return TRUE;
            } else {
                GdkEventMotion *motion = (GdkEventMotion *) event;
                double n_x, max_x;

                n_x = motion->x;
                n_x += E_REFLOW_BORDER_WIDTH + E_REFLOW_DIVIDER_WIDTH;
                n_x = fmod(n_x,(reflow->column_width + E_REFLOW_FULL_GUTTER));

                max_x = E_REFLOW_BORDER_WIDTH;
                max_x += (reflow->column_width + E_REFLOW_FULL_GUTTER) * reflow->column_count;

                if ( motion->y >= E_REFLOW_BORDER_WIDTH && motion->y <= reflow->height - E_REFLOW_BORDER_WIDTH && n_x < E_REFLOW_FULL_GUTTER && max_x > motion->x) {
                    if ( reflow->default_cursor_shown ) {
                        gdk_window_set_cursor(GTK_WIDGET(item->canvas)->window, reflow->arrow_cursor);
                        reflow->default_cursor_shown = FALSE;
                    }
                } else 
                    if ( ! reflow->default_cursor_shown ) {
                        gdk_window_set_cursor(GTK_WIDGET(item->canvas)->window, reflow->default_cursor);
                        reflow->default_cursor_shown = TRUE;
                    }
                
            }
            break;
        case GDK_ENTER_NOTIFY:
            if (!reflow->column_drag) {
                GdkEventCrossing *crossing = (GdkEventCrossing *) event;
                double n_x, max_x;
                n_x = crossing->x;
                n_x += E_REFLOW_BORDER_WIDTH + E_REFLOW_DIVIDER_WIDTH;
                n_x = fmod(n_x,(reflow->column_width + E_REFLOW_FULL_GUTTER));

                max_x = E_REFLOW_BORDER_WIDTH;
                max_x += (reflow->column_width + E_REFLOW_FULL_GUTTER) * reflow->column_count;
                if ( crossing->y >= E_REFLOW_BORDER_WIDTH && crossing->y <= reflow->height - E_REFLOW_BORDER_WIDTH && n_x < E_REFLOW_FULL_GUTTER && max_x > crossing->x) {
                    if ( reflow->default_cursor_shown ) {
                        gdk_window_set_cursor(GTK_WIDGET(item->canvas)->window, reflow->arrow_cursor);
                        reflow->default_cursor_shown = FALSE;
                    }
                }
            }
            break;
        case GDK_LEAVE_NOTIFY:
            if (!reflow->column_drag) {
                GdkEventCrossing *crossing = (GdkEventCrossing *) event;
                double n_x;
                n_x = crossing->x;
                n_x += E_REFLOW_BORDER_WIDTH + E_REFLOW_DIVIDER_WIDTH;
                n_x = fmod(n_x,(reflow->column_width + E_REFLOW_FULL_GUTTER));
                if ( !( crossing->y >= E_REFLOW_BORDER_WIDTH && crossing->y <= reflow->height - E_REFLOW_BORDER_WIDTH && n_x < E_REFLOW_FULL_GUTTER ) ) {
                    if ( ! reflow->default_cursor_shown ) {
                        gdk_window_set_cursor(GTK_WIDGET(item->canvas)->window, reflow->default_cursor);
                        reflow->default_cursor_shown = TRUE;
                    }
                }
            }
            break;
        default:
            break;
        }
    if (return_val)
        return return_val;
    else if (GNOME_CANVAS_ITEM_CLASS( parent_class )->event)
        return (* GNOME_CANVAS_ITEM_CLASS( parent_class )->event) (item, event);
    else
        return FALSE;
}

static void e_reflow_draw (GnomeCanvasItem *item, GdkDrawable *drawable,
                    int x, int y, int width, int height)
{
    int x_rect, y_rect, width_rect, height_rect;
    gdouble running_width;
    EReflow *reflow = E_REFLOW(item);
    int i;
    double column_width;

    if (GNOME_CANVAS_ITEM_CLASS(parent_class)->draw)
        GNOME_CANVAS_ITEM_CLASS(parent_class)->draw (item, drawable, x, y, width, height);
    column_width = reflow->column_width;
    running_width = E_REFLOW_BORDER_WIDTH + column_width + E_REFLOW_BORDER_WIDTH;
    x_rect = running_width;
    y_rect = E_REFLOW_BORDER_WIDTH;
    width_rect = E_REFLOW_DIVIDER_WIDTH;
    height_rect = reflow->height - (E_REFLOW_BORDER_WIDTH * 2);

    /* Compute first column to draw. */
    i = x;
    i /= column_width + E_REFLOW_FULL_GUTTER;
    running_width += i * (column_width + E_REFLOW_FULL_GUTTER);

    for ( ; i < reflow->column_count; i++) {
        if ( running_width > x + width )
            break;
        x_rect = running_width;
        gtk_paint_flat_box(GTK_WIDGET(item->canvas)->style,
                   drawable,
                   GTK_STATE_ACTIVE,
                   GTK_SHADOW_NONE,
                   NULL,
                   GTK_WIDGET(item->canvas),
                   "reflow",
                   x_rect - x,
                   y_rect - y,
                   width_rect,
                   height_rect);
        running_width += E_REFLOW_DIVIDER_WIDTH + E_REFLOW_BORDER_WIDTH + column_width + E_REFLOW_BORDER_WIDTH;
    }
    if (reflow->column_drag) {
        int start_line = e_reflow_pick_line(reflow,
                            gtk_layout_get_hadjustment(GTK_LAYOUT(item->canvas))->value); 
        i = x - start_line * (column_width + E_REFLOW_FULL_GUTTER);
        running_width = start_line * (column_width + E_REFLOW_FULL_GUTTER);
        column_width = reflow->temp_column_width;
        running_width -= start_line * (column_width + E_REFLOW_FULL_GUTTER);
        i += start_line * (column_width + E_REFLOW_FULL_GUTTER);
        running_width += E_REFLOW_BORDER_WIDTH + column_width + E_REFLOW_BORDER_WIDTH;
        x_rect = running_width;
        y_rect = E_REFLOW_BORDER_WIDTH;
        width_rect = E_REFLOW_DIVIDER_WIDTH;
        height_rect = reflow->height - (E_REFLOW_BORDER_WIDTH * 2);

        /* Compute first column to draw. */
        i /= column_width + E_REFLOW_FULL_GUTTER;
        running_width += i * (column_width + E_REFLOW_FULL_GUTTER);
        
        for ( ; i < reflow->column_count; i++) {
            if ( running_width > x + width )
                break;
            x_rect = running_width;
            gdk_draw_rectangle(drawable,
                       GTK_WIDGET(item->canvas)->style->fg_gc[GTK_STATE_NORMAL],
                       TRUE,
                       x_rect - x,
                       y_rect - y,
                       width_rect - 1,
                       height_rect - 1);                       
            running_width += E_REFLOW_DIVIDER_WIDTH + E_REFLOW_BORDER_WIDTH + column_width + E_REFLOW_BORDER_WIDTH;
        }
    }
}

static void
e_reflow_update (GnomeCanvasItem *item, double affine[6], ArtSVP *clip_path, gint flags)
{
    EReflow *reflow;
    double x0, x1, y0, y1;

    reflow = E_REFLOW (item);

    if (GNOME_CANVAS_ITEM_CLASS(parent_class)->update)
        GNOME_CANVAS_ITEM_CLASS(parent_class)->update (item, affine, clip_path, flags);
    
    x0 = item->x1;
    y0 = item->y1;
    x1 = item->x2;
    y1 = item->y2;
    if ( x1 < x0 + reflow->width )
        x1 = x0 + reflow->width;
    if ( y1 < y0 + reflow->height )
        y1 = y0 + reflow->height;
    item->x2 = x1;
    item->y2 = y1;

    if (reflow->need_height_update) {
        x0 = item->x1;
        y0 = item->y1;
        x1 = item->x2;
        y1 = item->y2;
        if ( x0 > 0 )
            x0 = 0;
        if ( y0 > 0 )
            y0 = 0;
        if ( x1 < E_REFLOW(item)->width )
            x1 = E_REFLOW(item)->width;
        if ( x1 < E_REFLOW(item)->height )
            x1 = E_REFLOW(item)->height;

        gnome_canvas_request_redraw(item->canvas, x0, y0, x1, y1);
        reflow->need_height_update = FALSE;
    } else if (reflow->need_column_resize) {
        int x_rect, y_rect, width_rect, height_rect;
        int start_line = e_reflow_pick_line(reflow,
                            gtk_layout_get_hadjustment(GTK_LAYOUT(item->canvas))->value); 
        gdouble running_width;
        int i;
        double column_width;
        
        if ( reflow->previous_temp_column_width != -1 ) {
            running_width = start_line * (reflow->column_width + E_REFLOW_FULL_GUTTER);
            column_width = reflow->previous_temp_column_width;
            running_width -= start_line * (column_width + E_REFLOW_FULL_GUTTER);
            running_width += E_REFLOW_BORDER_WIDTH + column_width + E_REFLOW_BORDER_WIDTH;
            y_rect = E_REFLOW_BORDER_WIDTH;
            width_rect = E_REFLOW_DIVIDER_WIDTH;
            height_rect = reflow->height - (E_REFLOW_BORDER_WIDTH * 2);
            
            for ( i = 0; i < reflow->column_count; i++) {
                x_rect = running_width;
                gnome_canvas_request_redraw(item->canvas, x_rect, y_rect, x_rect + width_rect, y_rect + height_rect);
                running_width += E_REFLOW_DIVIDER_WIDTH + E_REFLOW_BORDER_WIDTH + column_width + E_REFLOW_BORDER_WIDTH;
            }
        }
        
        if ( reflow->temp_column_width != -1 ) {
            running_width = start_line * (reflow->column_width + E_REFLOW_FULL_GUTTER);
            column_width = reflow->temp_column_width;
            running_width -= start_line * (column_width + E_REFLOW_FULL_GUTTER);
            running_width += E_REFLOW_BORDER_WIDTH + column_width + E_REFLOW_BORDER_WIDTH;
            y_rect = E_REFLOW_BORDER_WIDTH;
            width_rect = E_REFLOW_DIVIDER_WIDTH;
            height_rect = reflow->height - (E_REFLOW_BORDER_WIDTH * 2);
            
            for ( i = 0; i < reflow->column_count; i++) {
                x_rect = running_width;
                gnome_canvas_request_redraw(item->canvas, x_rect, y_rect, x_rect + width_rect, y_rect + height_rect);
                running_width += E_REFLOW_DIVIDER_WIDTH + E_REFLOW_BORDER_WIDTH + column_width + E_REFLOW_BORDER_WIDTH;
            }
        }
        
        reflow->previous_temp_column_width = reflow->temp_column_width;
        reflow->need_column_resize = FALSE;
    }
}

static double
e_reflow_point (GnomeCanvasItem *item,
        double x, double y, int cx, int cy,
        GnomeCanvasItem **actual_item)
{
    double distance = 1;

    *actual_item = NULL;

    if (GNOME_CANVAS_ITEM_CLASS(parent_class)->point)
        distance = GNOME_CANVAS_ITEM_CLASS(parent_class)->point (item, x, y, cx, cy, actual_item);
    if ((int) (distance * item->canvas->pixels_per_unit + 0.5) <= item->canvas->close_enough && *actual_item)
        return distance;
    
    *actual_item = item;
    return 0;
#if 0
    if (y >= E_REFLOW_BORDER_WIDTH && y <= reflow->height - E_REFLOW_BORDER_WIDTH) {
            float n_x;
        n_x = x;
        n_x += E_REFLOW_BORDER_WIDTH + E_REFLOW_DIVIDER_WIDTH;
        n_x = fmod(n_x, (reflow->column_width + E_REFLOW_FULL_GUTTER));
        if (n_x < E_REFLOW_FULL_GUTTER) {
            *actual_item = item;
            return 0;
        }
    }
    return distance;
#endif
}

static void
e_reflow_reflow( GnomeCanvasItem *item, int flags )
{
    EReflow *reflow = E_REFLOW(item);
    gdouble old_width;
    gdouble running_width;
    gdouble running_height;
    int next_column;
    int i;

    if (! (GTK_OBJECT_FLAGS (reflow) & GNOME_CANVAS_ITEM_REALIZED))
        return;

    if (reflow->need_reflow_columns) {
        reflow_columns (reflow);
    }
        
    old_width = reflow->width;

    running_width = E_REFLOW_BORDER_WIDTH;
    running_height = E_REFLOW_BORDER_WIDTH;

    next_column = 1;

    for (i = 0; i < reflow->count; i++) {
        int unsorted = e_sorter_sorted_to_model (E_SORTER (reflow->sorter), i);
        if (next_column < reflow->column_count && i == reflow->columns[next_column]) {
            running_height = E_REFLOW_BORDER_WIDTH;
            running_width += reflow->column_width + E_REFLOW_FULL_GUTTER;
            next_column ++;
        }

        if (reflow->items[unsorted])
            e_canvas_item_move_absolute(GNOME_CANVAS_ITEM(reflow->items[unsorted]),
                            (double) running_width,
                            (double) running_height);
        running_height += reflow->heights[unsorted] + E_REFLOW_BORDER_WIDTH;
    }
    reflow->width = running_width + reflow->column_width + E_REFLOW_BORDER_WIDTH;
    if ( reflow->width < reflow->minimum_width )
        reflow->width = reflow->minimum_width;
    if (old_width != reflow->width)
        e_canvas_item_request_parent_reflow(item);
}

static int
e_reflow_selection_event_real (EReflow *reflow, GnomeCanvasItem *item, GdkEvent *event)
{
    int row;
    int return_val = TRUE;
    switch (event->type) {
    case GDK_BUTTON_PRESS:
        switch (event->button.button) {
        case 1: /* Fall through. */
        case 2:
            row = er_find_item (reflow, item);
            e_selection_model_do_something(reflow->selection, row, 0, event->button.state);
            break;
        case 3:
            row = er_find_item (reflow, item);
            e_selection_model_maybe_do_something(reflow->selection, row, 0, event->button.state);
            break;
        default:
            return_val = FALSE;
            break;
        }
        break;
    case GDK_KEY_PRESS:
        return_val = e_selection_model_key_press(reflow->selection, (GdkEventKey *) event);
        break;
    default:
        return_val = FALSE;
        break;
    }

    return return_val;
}

static void
e_reflow_class_init (EReflowClass *klass)
{
    GtkObjectClass *object_class;
    GnomeCanvasItemClass *item_class;

    object_class = (GtkObjectClass*) klass;
    item_class = (GnomeCanvasItemClass *) klass;

    parent_class = gtk_type_class (gnome_canvas_group_get_type ());
  
    gtk_object_add_arg_type ("EReflow::minimum_width", GTK_TYPE_DOUBLE,
                 GTK_ARG_READWRITE, ARG_MINIMUM_WIDTH);
    gtk_object_add_arg_type ("EReflow::width", GTK_TYPE_DOUBLE,
                 GTK_ARG_READABLE, ARG_WIDTH);
    gtk_object_add_arg_type ("EReflow::height", GTK_TYPE_DOUBLE,
                 GTK_ARG_READWRITE, ARG_HEIGHT);
    gtk_object_add_arg_type ("EReflow::empty_message", GTK_TYPE_STRING,
                 GTK_ARG_READWRITE, ARG_EMPTY_MESSAGE);
    gtk_object_add_arg_type ("EReflow::model", E_REFLOW_MODEL_TYPE,
                 GTK_ARG_READWRITE, ARG_MODEL);

    signals [SELECTION_EVENT] =
        gtk_signal_new ("selection_event",
                GTK_RUN_LAST,
                object_class->type,
                GTK_SIGNAL_OFFSET (EReflowClass, selection_event),
                e_marshal_INT__OBJECT_POINTER,
                GTK_TYPE_INT, 2, GTK_TYPE_OBJECT, GTK_TYPE_GDK_EVENT);

    gtk_object_class_add_signals (object_class, signals, LAST_SIGNAL);

    object_class->set_arg  = e_reflow_set_arg;
    object_class->get_arg  = e_reflow_get_arg;
    object_class->destroy  = e_reflow_destroy;
  
    /* GnomeCanvasItem method overrides */
    item_class->event      = e_reflow_event;
    item_class->realize    = e_reflow_realize;
    item_class->unrealize  = e_reflow_unrealize;
    item_class->draw       = e_reflow_draw;
    item_class->update     = e_reflow_update;
    item_class->point      = e_reflow_point;

    klass->selection_event = e_reflow_selection_event_real;
}

static void
e_reflow_init (EReflow *reflow)
{
    reflow->model                = NULL;
    reflow->items                = NULL;
    reflow->heights              = NULL;
    reflow->count                = 0;

    reflow->columns              = NULL;
    reflow->column_count         = 0;

    reflow->empty_text           = NULL;
    reflow->empty_message        = NULL;

    reflow->minimum_width        = 10;
    reflow->width                = 10;
    reflow->height               = 10;

    reflow->column_width         = 150;

    reflow->column_drag          = FALSE;

    reflow->need_height_update   = FALSE;
    reflow->need_column_resize   = FALSE;

    reflow->default_cursor_shown = TRUE;
    reflow->arrow_cursor         = NULL;
    reflow->default_cursor       = NULL;

    reflow->incarnate_idle_id    = 0;

    reflow->selection            = E_SELECTION_MODEL (e_selection_model_simple_new());
    reflow->sorter               = e_sorter_array_new (er_compare, reflow);

    gtk_object_set (GTK_OBJECT (reflow->selection),
            "sorter", reflow->sorter,
            NULL);

    reflow->selection_changed_id = 
        gtk_signal_connect(GTK_OBJECT(reflow->selection), "selection_changed",
                   GTK_SIGNAL_FUNC(selection_changed), reflow);

    e_canvas_item_set_reflow_callback(GNOME_CANVAS_ITEM(reflow), e_reflow_reflow);
}

GtkType
e_reflow_get_type (void)
{
    static GtkType type = 0;

    if (!type) {
        static const GtkTypeInfo info = {
            "EReflow",
            sizeof (EReflow),
            sizeof (EReflowClass),
            (GtkClassInitFunc) e_reflow_class_init,
            (GtkObjectInitFunc) e_reflow_init,
            /* reserved_1 */ NULL,
            /* reserved_2 */ NULL,
            (GtkClassInitFunc) NULL,
        };

        type = gtk_type_unique (gnome_canvas_group_get_type (), &info);
    }

    return type;
}