inkscape/src/sp-marker.cpp

	sp-marker.cpp revision f65d8b8e49fa8aadec915cd195bb9d077299b258
#define __SP_MARKER_C__

/*
 * SVG <marker> implementation
 *
 * Authors:
 *   Lauris Kaplinski <lauris@kaplinski.com>
 *
 * Copyright (C) 1999-2003 Lauris Kaplinski
 *
 * Released under GNU GPL, read the file 'COPYING' for more information
 */

#include "config.h"


#include "libnr/nr-matrix-fns.h"
#include "libnr/nr-matrix-ops.h"
#include "libnr/nr-scale-matrix-ops.h"
#include "libnr/nr-rotate-fns.h"
#include "svg/svg.h"
#include "display/nr-arena-group.h"
#include "xml/repr.h"
#include "attributes.h"
#include "marker.h"

struct SPMarkerView {
    SPMarkerView *next;
    unsigned int key;
    unsigned int size;
    NRArenaItem *items[1];
};

static void sp_marker_class_init (SPMarkerClass *klass);
static void sp_marker_init (SPMarker *marker);

static void sp_marker_build (SPObject *object, SPDocument *document, Inkscape::XML::Node *repr);
static void sp_marker_release (SPObject *object);
static void sp_marker_set (SPObject *object, unsigned int key, const gchar *value);
static void sp_marker_update (SPObject *object, SPCtx *ctx, guint flags);
static Inkscape::XML::Node *sp_marker_write (SPObject *object, Inkscape::XML::Node *repr, guint flags);

static NRArenaItem *sp_marker_private_show (SPItem *item, NRArena *arena, unsigned int key, unsigned int flags);
static void sp_marker_private_hide (SPItem *item, unsigned int key);
static void sp_marker_bbox(SPItem const *item, NRRect *bbox, NR::Matrix const &transform, unsigned const flags);
static void sp_marker_print (SPItem *item, SPPrintContext *ctx);

static void sp_marker_view_remove (SPMarker *marker, SPMarkerView *view, unsigned int destroyitems);

static SPGroupClass *parent_class;

/**
 * Registers the SPMarker class with Gdk and returns its type number.
 */
GType
sp_marker_get_type (void)
{
    static GType type = 0;
    if (!type) {
        GTypeInfo info = {
            sizeof (SPMarkerClass),
            NULL, NULL,
            (GClassInitFunc) sp_marker_class_init,
            NULL, NULL,
            sizeof (SPMarker),
            16,
            (GInstanceInitFunc) sp_marker_init,
            NULL,   /* value_table */
        };
        type = g_type_register_static (SP_TYPE_GROUP, "SPMarker", &info, (GTypeFlags)0);
    }
    return type;
}

/**
 * Initializes a SPMarkerClass object.  Establishes the function pointers to the class'
 * member routines in the class vtable, and sets pointers to parent classes.
 */
static void
sp_marker_class_init (SPMarkerClass *klass)
{
    GObjectClass *object_class;
    SPObjectClass *sp_object_class;
    SPItemClass *sp_item_class;

    object_class = G_OBJECT_CLASS (klass);
    sp_object_class = (SPObjectClass *) klass;
    sp_item_class = (SPItemClass *) klass;

    parent_class = (SPGroupClass *)g_type_class_ref (SP_TYPE_GROUP);

    sp_object_class->build = sp_marker_build;
    sp_object_class->release = sp_marker_release;
    sp_object_class->set = sp_marker_set;
    sp_object_class->update = sp_marker_update;
    sp_object_class->write = sp_marker_write;

    sp_item_class->show = sp_marker_private_show;
    sp_item_class->hide = sp_marker_private_hide;
    sp_item_class->bbox = sp_marker_bbox;
    sp_item_class->print = sp_marker_print;
}

/**
 * Initializes an SPMarker object.  This notes the marker's viewBox is
 * not set and initializes the marker's c2p identity matrix.
 */
static void
sp_marker_init (SPMarker *marker)
{
    marker->viewBox_set = FALSE;

    nr_matrix_set_identity (&marker->c2p);
}

/**
 * Virtual build callback for SPMarker.
 *
 * This is to be invoked immediately after creation of an SPMarker.  This
 * method fills an SPMarker object with its SVG attributes, and calls the
 * parent class' build routine to attach the object to its document and
 * repr.  The result will be creation of the whole document tree.
 *
 * \see sp_object_build()
 */
static void
sp_marker_build (SPObject *object, SPDocument *document, Inkscape::XML::Node *repr)
{
    SPGroup *group;
    SPMarker *marker;

    group = (SPGroup *) object;
    marker = (SPMarker *) object;

    sp_object_read_attr (object, "markerUnits");
    sp_object_read_attr (object, "refX");
    sp_object_read_attr (object, "refY");
    sp_object_read_attr (object, "markerWidth");
    sp_object_read_attr (object, "markerHeight");
    sp_object_read_attr (object, "orient");
    sp_object_read_attr (object, "viewBox");
    sp_object_read_attr (object, "preserveAspectRatio");

    if (((SPObjectClass *) parent_class)->build)
        ((SPObjectClass *) parent_class)->build (object, document, repr);
}

/**
 * Removes, releases and unrefs all children of object
 *
 * This is the inverse of sp_marker_build().  It must be invoked as soon
 * as the marker is removed from the tree, even if it is still referenced
 * by other objects.  It hides and removes any views of the marker, then
 * calls the parent classes' release function to deregister the object
 * and release its SPRepr bindings.  The result will be the destruction
 * of the entire document tree.
 *
 * \see sp_object_release()
 */
static void
sp_marker_release (SPObject *object)
{
    SPMarker *marker;

    marker = (SPMarker *) object;

    while (marker->views) {
        /* Destroy all NRArenaitems etc. */
        /* Parent class ::hide method */
        ((SPItemClass *) parent_class)->hide ((SPItem *) marker, marker->views->key);
        sp_marker_view_remove (marker, marker->views, TRUE);
    }

    if (((SPObjectClass *) parent_class)->release)
        ((SPObjectClass *) parent_class)->release (object);
}

/**
 * Sets an attribute, 'key', of a marker object to 'value'.  Supported
 * attributes that can be set with this routine include:
 *
 *     SP_ATTR_MARKERUNITS
 *     SP_ATTR_REFX
 *     SP_ATTR_REFY
 *     SP_ATTR_MARKERWIDTH
 *     SP_ATTR_MARKERHEIGHT
 *     SP_ATTR_ORIENT
 *     SP_ATTR_VIEWBOX
 *     SP_ATTR_PRESERVEASPECTRATIO
 */
static void
sp_marker_set (SPObject *object, unsigned int key, const gchar *value)
{
    SPItem *item;
    SPMarker *marker;

    item = SP_ITEM (object);
    marker = SP_MARKER (object);

    switch (key) {
    case SP_ATTR_MARKERUNITS:
        marker->markerUnits_set = FALSE;
        marker->markerUnits = SP_MARKER_UNITS_STROKEWIDTH;
        if (value) {
            if (!strcmp (value, "strokeWidth")) {
                marker->markerUnits_set = TRUE;
            } else if (!strcmp (value, "userSpaceOnUse")) {
                marker->markerUnits = SP_MARKER_UNITS_USERSPACEONUSE;
                marker->markerUnits_set = TRUE;
            }
        }
        object->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG | SP_OBJECT_VIEWPORT_MODIFIED_FLAG);
        break;
    case SP_ATTR_REFX:
            marker->refX.readOrUnset(value);
        object->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
        break;
    case SP_ATTR_REFY:
            marker->refY.readOrUnset(value);
        object->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
        break;
    case SP_ATTR_MARKERWIDTH:
            marker->markerWidth.readOrUnset(value, SVGLength::NONE, 3.0, 3.0);
        object->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
        break;
    case SP_ATTR_MARKERHEIGHT:
            marker->markerHeight.readOrUnset(value, SVGLength::NONE, 3.0, 3.0);
        object->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
        break;
    case SP_ATTR_ORIENT:
        marker->orient_set = FALSE;
        marker->orient_auto = FALSE;
        marker->orient = 0.0;
        if (value) {
            if (!strcmp (value, "auto")) {
                marker->orient_auto = TRUE;
                marker->orient_set = TRUE;
            } else if (sp_svg_number_read_f (value, &marker->orient)) {
                marker->orient_set = TRUE;
            }
        }
        object->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
        break;
    case SP_ATTR_VIEWBOX:
        marker->viewBox_set = FALSE;
        if (value) {
            double x, y, width, height;
            char *eptr;
            /* fixme: We have to take original item affine into account */
            /* fixme: Think (Lauris) */
            eptr = (gchar *) value;
            x = g_ascii_strtod (eptr, &eptr);
            while (*eptr && ((*eptr == ',') || (*eptr == ' '))) eptr++;
            y = g_ascii_strtod (eptr, &eptr);
            while (*eptr && ((*eptr == ',') || (*eptr == ' '))) eptr++;
            width = g_ascii_strtod (eptr, &eptr);
            while (*eptr && ((*eptr == ',') || (*eptr == ' '))) eptr++;
            height = g_ascii_strtod (eptr, &eptr);
            while (*eptr && ((*eptr == ',') || (*eptr == ' '))) eptr++;
            if ((width > 0) && (height > 0)) {
                /* Set viewbox */
                marker->viewBox.x0 = x;
                marker->viewBox.y0 = y;
                marker->viewBox.x1 = x + width;
                marker->viewBox.y1 = y + height;
                marker->viewBox_set = TRUE;
            }
        }
        object->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG | SP_OBJECT_VIEWPORT_MODIFIED_FLAG);
        break;
    case SP_ATTR_PRESERVEASPECTRATIO:
        /* Do setup before, so we can use break to escape */
        marker->aspect_set = FALSE;
        marker->aspect_align = SP_ASPECT_NONE;
        marker->aspect_clip = SP_ASPECT_MEET;
        object->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG | SP_OBJECT_VIEWPORT_MODIFIED_FLAG);
        if (value) {
            int len;
            gchar c[256];
            const gchar *p, *e;
            unsigned int align, clip;
            p = value;
            while (*p && *p == 32) p += 1;
            if (!*p) break;
            e = p;
            while (*e && *e != 32) e += 1;
            len = e - p;
            if (len > 8) break;
            memcpy (c, value, len);
            c[len] = 0;
            /* Now the actual part */
            if (!strcmp (c, "none")) {
                align = SP_ASPECT_NONE;
            } else if (!strcmp (c, "xMinYMin")) {
                align = SP_ASPECT_XMIN_YMIN;
            } else if (!strcmp (c, "xMidYMin")) {
                align = SP_ASPECT_XMID_YMIN;
            } else if (!strcmp (c, "xMaxYMin")) {
                align = SP_ASPECT_XMAX_YMIN;
            } else if (!strcmp (c, "xMinYMid")) {
                align = SP_ASPECT_XMIN_YMID;
            } else if (!strcmp (c, "xMidYMid")) {
                align = SP_ASPECT_XMID_YMID;
            } else if (!strcmp (c, "xMaxYMin")) {
                align = SP_ASPECT_XMAX_YMID;
            } else if (!strcmp (c, "xMinYMax")) {
                align = SP_ASPECT_XMIN_YMAX;
            } else if (!strcmp (c, "xMidYMax")) {
                align = SP_ASPECT_XMID_YMAX;
            } else if (!strcmp (c, "xMaxYMax")) {
                align = SP_ASPECT_XMAX_YMAX;
            } else {
                break;
            }
            clip = SP_ASPECT_MEET;
            while (*e && *e == 32) e += 1;
            if (e) {
                if (!strcmp (e, "meet")) {
                    clip = SP_ASPECT_MEET;
                } else if (!strcmp (e, "slice")) {
                    clip = SP_ASPECT_SLICE;
                } else {
                    break;
                }
            }
            marker->aspect_set = TRUE;
            marker->aspect_align = align;
            marker->aspect_clip = clip;
        }
        break;
    default:
        if (((SPObjectClass *) parent_class)->set)
            ((SPObjectClass *) parent_class)->set (object, key, value);
        break;
    }
}

/**
 * Updates <marker> when its attributes have changed.  Takes care of setting up
 * transformations and viewBoxes.
 */
static void
sp_marker_update (SPObject *object, SPCtx *ctx, guint flags)
{
    SPItem *item;
    SPMarker *marker;
    SPItemCtx rctx;
    NRRect *vb;
    double x, y, width, height;
    NRMatrix q;
    SPMarkerView *v;

    item = SP_ITEM (object);
    marker = SP_MARKER (object);

    /* fixme: We have to set up clip here too */

    /* Copy parent context */
    rctx.ctx = *ctx;
    /* Initialize tranformations */
    rctx.i2doc = NR::identity();
    rctx.i2vp = NR::identity();
    /* Set up viewport */
    rctx.vp.x0 = 0.0;
    rctx.vp.y0 = 0.0;
    rctx.vp.x1 = marker->markerWidth.computed;
    rctx.vp.y1 = marker->markerHeight.computed;

    /* Start with identity transform */
    nr_matrix_set_identity (&marker->c2p);

    /* Viewbox is always present, either implicitly or explicitly */
    if (marker->viewBox_set) {
        vb = &marker->viewBox;
    } else {
        vb = &rctx.vp;
    }
    /* Now set up viewbox transformation */
    /* Determine actual viewbox in viewport coordinates */
    if (marker->aspect_align == SP_ASPECT_NONE) {
        x = 0.0;
        y = 0.0;
        width = rctx.vp.x1 - rctx.vp.x0;
        height = rctx.vp.y1 - rctx.vp.y0;
    } else {
        double scalex, scaley, scale;
        /* Things are getting interesting */
        scalex = (rctx.vp.x1 - rctx.vp.x0) / (vb->x1 - vb->x0);
        scaley = (rctx.vp.y1 - rctx.vp.y0) / (vb->y1 - vb->y0);
        scale = (marker->aspect_clip == SP_ASPECT_MEET) ? MIN (scalex, scaley) : MAX (scalex, scaley);
        width = (vb->x1 - vb->x0) * scale;
        height = (vb->y1 - vb->y0) * scale;
        /* Now place viewbox to requested position */
        switch (marker->aspect_align) {
        case SP_ASPECT_XMIN_YMIN:
            x = 0.0;
            y = 0.0;
            break;
        case SP_ASPECT_XMID_YMIN:
            x = 0.5 * ((rctx.vp.x1 - rctx.vp.x0) - width);
            y = 0.0;
            break;
        case SP_ASPECT_XMAX_YMIN:
            x = 1.0 * ((rctx.vp.x1 - rctx.vp.x0) - width);
            y = 0.0;
            break;
        case SP_ASPECT_XMIN_YMID:
            x = 0.0;
            y = 0.5 * ((rctx.vp.y1 - rctx.vp.y0) - height);
            break;
        case SP_ASPECT_XMID_YMID:
            x = 0.5 * ((rctx.vp.x1 - rctx.vp.x0) - width);
            y = 0.5 * ((rctx.vp.y1 - rctx.vp.y0) - height);
            break;
        case SP_ASPECT_XMAX_YMID:
            x = 1.0 * ((rctx.vp.x1 - rctx.vp.x0) - width);
            y = 0.5 * ((rctx.vp.y1 - rctx.vp.y0) - height);
            break;
        case SP_ASPECT_XMIN_YMAX:
            x = 0.0;
            y = 1.0 * ((rctx.vp.y1 - rctx.vp.y0) - height);
            break;
        case SP_ASPECT_XMID_YMAX:
            x = 0.5 * ((rctx.vp.x1 - rctx.vp.x0) - width);
            y = 1.0 * ((rctx.vp.y1 - rctx.vp.y0) - height);
            break;
        case SP_ASPECT_XMAX_YMAX:
            x = 1.0 * ((rctx.vp.x1 - rctx.vp.x0) - width);
            y = 1.0 * ((rctx.vp.y1 - rctx.vp.y0) - height);
            break;
        default:
            x = 0.0;
            y = 0.0;
            break;
        }
    }
    /* Compose additional transformation from scale and position */
    q.c[0] = width / (vb->x1 - vb->x0);
    q.c[1] = 0.0;
    q.c[2] = 0.0;
    q.c[3] = height / (vb->y1 - vb->y0);
    q.c[4] = -vb->x0 * q.c[0] + x;
    q.c[5] = -vb->y0 * q.c[3] + y;
    /* Append viewbox transformation */
    nr_matrix_multiply (&marker->c2p, &q, &marker->c2p);


    /* Append reference translation */
    /* fixme: lala (Lauris) */
    nr_matrix_set_translate (&q, -marker->refX.computed, -marker->refY.computed);
    nr_matrix_multiply (&marker->c2p, &q, &marker->c2p);

    rctx.i2doc = marker->c2p * rctx.i2doc;

    /* If viewBox is set reinitialize child viewport */
    /* Otherwise it already correct */
    if (marker->viewBox_set) {
        rctx.vp.x0 = marker->viewBox.x0;
        rctx.vp.y0 = marker->viewBox.y0;
        rctx.vp.x1 = marker->viewBox.x1;
        rctx.vp.y1 = marker->viewBox.y1;
        rctx.i2vp = NR::identity();
    }

    /* And invoke parent method */
    if (((SPObjectClass *) (parent_class))->update)
        ((SPObjectClass *) (parent_class))->update (object, (SPCtx *) &rctx, flags);

    /* As last step set additional transform of arena group */
    for (v = marker->views; v != NULL; v = v->next) {
        for (unsigned i = 0 ; i < v->size ; i++) {
            if (v->items[i]) {
                nr_arena_group_set_child_transform(NR_ARENA_GROUP(v->items[i]), &marker->c2p);
            }
        }
    }
}

/**
 * Writes the object's properties into its repr object.
 */
static Inkscape::XML::Node *
sp_marker_write (SPObject *object, Inkscape::XML::Node *repr, guint flags)
{
    SPMarker *marker;

    marker = SP_MARKER (object);

    if ((flags & SP_OBJECT_WRITE_BUILD) && !repr) {
        repr = sp_repr_new ("svg:marker");
    }

    if (marker->markerUnits_set) {
        if (marker->markerUnits == SP_MARKER_UNITS_STROKEWIDTH) {
            repr->setAttribute("markerUnits", "strokeWidth");
        } else {
            repr->setAttribute("markerUnits", "userSpaceOnUse");
        }
    } else {
        repr->setAttribute("markerUnits", NULL);
    }
    if (marker->refX._set) {
        sp_repr_set_svg_double(repr, "refX", marker->refX.computed);
    } else {
        repr->setAttribute("refX", NULL);
    }
    if (marker->refY._set) {
        sp_repr_set_svg_double (repr, "refY", marker->refY.computed);
    } else {
        repr->setAttribute("refY", NULL);
    }
    if (marker->markerWidth._set) {
        sp_repr_set_svg_double (repr, "markerWidth", marker->markerWidth.computed);
    } else {
        repr->setAttribute("markerWidth", NULL);
    }
    if (marker->markerHeight._set) {
        sp_repr_set_svg_double (repr, "markerHeight", marker->markerHeight.computed);
    } else {
        repr->setAttribute("markerHeight", NULL);
    }
    if (marker->orient_set) {
        if (marker->orient_auto) {
            repr->setAttribute("orient", "auto");
        } else {
            sp_repr_set_css_double(repr, "orient", marker->orient);
        }
    } else {
        repr->setAttribute("orient", NULL);
    }
    /* fixme: */
    repr->setAttribute("viewBox", object->repr->attribute("viewBox"));
    repr->setAttribute("preserveAspectRatio", object->repr->attribute("preserveAspectRatio"));

    if (((SPObjectClass *) (parent_class))->write)
        ((SPObjectClass *) (parent_class))->write (object, repr, flags);

    return repr;
}

/**
 * This routine is disabled to break propagation.
 */
static NRArenaItem *
sp_marker_private_show (SPItem *item, NRArena *arena, unsigned int key, unsigned int flags)
{
    /* Break propagation */
    return NULL;
}

/**
 * This routine is disabled to break propagation.
 */
static void
sp_marker_private_hide (SPItem *item, unsigned int key)
{
    /* Break propagation */
}

/**
 * This routine is disabled to break propagation.
 */
static void
sp_marker_bbox(SPItem const *, NRRect *, NR::Matrix const &, unsigned const)
{
    /* Break propagation */
}

/**
 * This routine is disabled to break propagation.
 */
static void
sp_marker_print (SPItem *item, SPPrintContext *ctx)
{
    /* Break propagation */
}

/* fixme: Remove link if zero-sized (Lauris) */

/**
 * Removes any SPMarkerViews that a marker has with a specific key.
 * Set up the NRArenaItem array's size in the specified SPMarker's SPMarkerView.
 * This is called from sp_shape_update() for shapes that have markers.  It
 * removes the old view of the marker and establishes a new one, registering
 * it with the marker's list of views for future updates.
 *
 * \param marker Marker to create views in.
 * \param key Key to give each SPMarkerView.
 * \param size Number of NRArenaItems to put in the SPMarkerView.
 */
void
sp_marker_show_dimension (SPMarker *marker, unsigned int key, unsigned int size)
{
    SPMarkerView *view;
    unsigned int i;

    for (view = marker->views; view != NULL; view = view->next) {
        if (view->key == key) break;
    }
    if (view && (view->size != size)) {
        /* Free old view and allocate new */
        /* Parent class ::hide method */
        ((SPItemClass *) parent_class)->hide ((SPItem *) marker, key);
        sp_marker_view_remove (marker, view, TRUE);
        view = NULL;
    }
    if (!view) {
        view = (SPMarkerView *)g_malloc (sizeof (SPMarkerView) + (size) * sizeof (NRArenaItem *));
        for (i = 0; i < size; i++) view->items[i] = NULL;
        view->next = marker->views;
        marker->views = view;
        view->key = key;
        view->size = size;
    }
}

/**
 * Shows an instance of a marker.  This is called during sp_shape_update_marker_view()
 * show and transform a child item in the arena for all views with the given key.
 */
NRArenaItem *
sp_marker_show_instance (SPMarker *marker, NRArenaItem *parent,
             unsigned int key, unsigned int pos,
             NR::Matrix const &base, float linewidth)
{
    for (SPMarkerView *v = marker->views; v != NULL; v = v->next) {
        if (v->key == key) {
            if (pos >= v->size) {
              return NULL;
            }
            if (!v->items[pos]) {
                /* Parent class ::show method */
                v->items[pos] = ((SPItemClass *) parent_class)->show ((SPItem *) marker,
                                              parent->arena, key,
                                              SP_ITEM_REFERENCE_FLAGS);
                if (v->items[pos]) {
                    /* fixme: Position (Lauris) */
                    nr_arena_item_add_child (parent, v->items[pos], NULL);
                    /* nr_arena_item_unref (v->items[pos]); */
                    nr_arena_group_set_child_transform((NRArenaGroup *) v->items[pos], &marker->c2p);
                }
            }
            if (v->items[pos]) {
                NR::Matrix m;
                if (marker->orient_auto) {
                    m = base;
                } else {
                    /* fixme: Orient units (Lauris) */
                    m = NR::Matrix(rotate_degrees(marker->orient));
                    m *= get_translation(base);
                }
                if (marker->markerUnits == SP_MARKER_UNITS_STROKEWIDTH) {
                    m = NR::scale(linewidth) * m;
                }

                nr_arena_item_set_transform(v->items[pos], m);
            }
            return v->items[pos];
        }
    }

    return NULL;
}

/**
 * Hides/removes all views of the given marker that have key 'key'.
 * This replaces SPItem implementation because we have our own views
 * \param key SPMarkerView key to hide.
 */
void
sp_marker_hide (SPMarker *marker, unsigned int key)
{
    SPMarkerView *v;

    v = marker->views;
    while (v != NULL) {
        SPMarkerView *next;
        next = v->next;
        if (v->key == key) {
            /* Parent class ::hide method */
            ((SPItemClass *) parent_class)->hide ((SPItem *) marker, key);
            sp_marker_view_remove (marker, v, TRUE);
            return;
        }
        v = next;
    }
}

/**
 * Removes a given view.  Also will destroy sub-items in the view if destroyitems
 * is set to a non-zero value.
 */
static void
sp_marker_view_remove (SPMarker *marker, SPMarkerView *view, unsigned int destroyitems)
{
    unsigned int i;
    if (view == marker->views) {
        marker->views = view->next;
    } else {
        SPMarkerView *v;
        for (v = marker->views; v->next != view; v = v->next) if (!v->next) return;
        v->next = view->next;
    }
    if (destroyitems) {
        for (i = 0; i < view->size; i++) {
            /* We have to walk through the whole array because there may be hidden items */
            if (view->items[i]) nr_arena_item_unref (view->items[i]);
        }
    }
    g_free (view);
}