Fix computation of drawbox for filtered, rotated items

(bzr r9508.1.60)

4 files changed, 34 insertions, 50 deletions

diff --git a/src/display/nr-arena-item.cpp b/src/display/nr-arena-item.cpp
index adbf772bc..ea162ca3d 100644
--- a/src/display/nr-arena-item.cpp
+++ b/src/display/nr-arena-item.cpp
@@ -265,12 +265,15 @@ nr_arena_item_invoke_update (NRArenaItem *item, NRRectL *area, NRGC *gc,
     if (item->state & NR_ARENA_ITEM_STATE_INVALID)
         return item->state;
 
-    // get a copy of bbox
-    memcpy(&item->drawbox, &item->bbox, sizeof(item->bbox));
-
     /* Enlarge the drawbox to contain filter effects */
-    if (item->filter && filter) {
-        item->filter->bbox_enlarge (item->drawbox);
+    if (item->filter && filter && item->item_bbox) {
+        item->drawbox.x0 = item->item_bbox->min()[Geom::X];
+        item->drawbox.y0 = item->item_bbox->min()[Geom::Y];
+        item->drawbox.x1 = item->item_bbox->max()[Geom::X];
+        item->drawbox.y1 = item->item_bbox->max()[Geom::Y];
+        item->filter->compute_drawbox (item, item->drawbox);
+    } else {
+        memcpy(&item->drawbox, &item->bbox, sizeof(item->bbox));
     }
     // fixme: to fix the display glitches, in outline mode bbox must be a combination of 
     // full item bbox and its clip and mask (after we have the API to get these)
@@ -568,7 +571,8 @@ nr_arena_item_invoke_pick (NRArenaItem *item, Geom::Point p, double delta,
 
     if (((x + delta) >= item->bbox.x0) &&
         ((x - delta) < item->bbox.x1) &&
-        ((y + delta) >= item->bbox.y0) && ((y - delta) < item->bbox.y1)) {
+        ((y + delta) >= item->bbox.y0) && ((y - delta) < item->bbox.y1))
+    {
         if (((NRArenaItemClass *) NR_OBJECT_GET_CLASS (item))->pick)
             return ((NRArenaItemClass *) NR_OBJECT_GET_CLASS (item))->
                 pick (item, p, delta, sticky);
diff --git a/src/display/nr-filter-gaussian.cpp b/src/display/nr-filter-gaussian.cpp
index f8a483acb..ba6f0bbe7 100644
--- a/src/display/nr-filter-gaussian.cpp
+++ b/src/display/nr-filter-gaussian.cpp
@@ -648,14 +648,13 @@ void FilterGaussian::area_enlarge(NRRectL &area, Geom::Matrix const &trans)
     area.y1 += area_max;
 }
 
-bool FilterGaussian::can_handle_affine(Geom::Matrix const &m)
+bool FilterGaussian::can_handle_affine(Geom::Matrix const &)
 {
-    if (Geom::are_near(_deviation_x, _deviation_y)) {
-        // TODO after 2Geom sync, change this to m.preservesAngles()
-        return Geom::are_near(m[0], m[3]) && Geom::are_near(m[1], -m[2]);
-    } else {
-        return false;
-    }
+    // Previously we tried to be smart and return true for rotations.
+    // However, the transform passed here is NOT the total transform
+    // from filter user space to screen.
+    // TODO: fix this, or replace can_handle_affine() with isotropic().
+    return false;
 }
 
 void FilterGaussian::set_deviation(double deviation)
diff --git a/src/display/nr-filter.cpp b/src/display/nr-filter.cpp
index e163b6346..148b14f53 100644
--- a/src/display/nr-filter.cpp
+++ b/src/display/nr-filter.cpp
@@ -59,24 +59,6 @@ namespace Filters {
 using Geom::X;
 using Geom::Y;
 
-static Geom::OptRect get_item_bbox(NRArenaItem const *item) {
-    Geom::Rect item_bbox;
-    if (item->item_bbox) {
-        item_bbox = *(item->item_bbox);
-    } else {
-        // Bounding box might not exist, so create a dummy one.
-        Geom::Point zero(0, 0);
-        item_bbox = Geom::Rect(zero, zero);
-    }
-    if (item_bbox.min()[X] > item_bbox.max()[X]
-        || item_bbox.min()[Y] > item_bbox.max()[Y])
-    {
-        // In case of negative-size bbox, return an empty OptRect
-        return Geom::OptRect();
-    }
-    return Geom::OptRect(item_bbox);
-}
-
 Filter::Filter()
 {
     _common_init();
@@ -134,19 +116,18 @@ int Filter::render(NRArenaItem const *item, cairo_t *bgct, NRRectL const *bgarea
 
     Geom::Rect item_bbox;
     {
-        Geom::OptRect maybe_bbox = get_item_bbox(item);
+        Geom::OptRect maybe_bbox = item->item_bbox;
         if (maybe_bbox.isEmpty()) {
             // Code below needs a bounding box
             return 1;
         }
         item_bbox = *maybe_bbox;
     }
-
-    Geom::Rect filter_area = filter_effect_area(item_bbox);
     if (item_bbox.hasZeroArea()) {
         // It's no use to try and filter an empty object.
         return 1;
     }
+    Geom::Rect filter_area = filter_effect_area(item_bbox);
 
     FilterUnits units(_filter_units, _primitive_units);
     units.set_ctm(trans);
@@ -225,7 +206,7 @@ void Filter::area_enlarge(NRRectL &bbox, NRArenaItem const *item) const {
     }
 
     Geom::Rect item_bbox;
-    Geom::OptRect maybe_bbox = get_item_bbox(item);
+    Geom::OptRect maybe_bbox = item->item_bbox;
     if (maybe_bbox.isEmpty()) {
         // Code below needs a bounding box
         return;
@@ -245,30 +226,29 @@ void Filter::area_enlarge(NRRectL &bbox, NRArenaItem const *item) const {
 */
 }
 
-void Filter::bbox_enlarge(NRRectL &bbox) {
+void Filter::compute_drawbox(NRArenaItem const *item, NRRectL &item_bbox) {
     // Modifying empty bounding boxes confuses rest of the renderer, so
     // let's not do that.
-    if (bbox.x0 > bbox.x1 || bbox.y0 > bbox.y1) return;
+    if (item_bbox.x0 > item_bbox.x1 || item_bbox.y0 > item_bbox.y1) return;
 
-    /* TODO: this is wrong. Should use bounding box in user coordinates
-     * and find its extents in display coordinates. */
-    Geom::Point min(bbox.x0, bbox.y0);
-    Geom::Point max(bbox.x1, bbox.y1);
+    Geom::Point min(item_bbox.x0, item_bbox.y0);
+    Geom::Point max(item_bbox.x1, item_bbox.y1);
     Geom::Rect tmp_bbox(min, max);
 
     Geom::Rect enlarged = filter_effect_area(tmp_bbox);
+    enlarged = enlarged * item->ctm;
 
-    bbox.x0 = (NR::ICoord) floor(enlarged.min()[X]);
-    bbox.y0 = (NR::ICoord) floor(enlarged.min()[Y]);
-    bbox.x1 = (NR::ICoord) ceil(enlarged.max()[X]);
-    bbox.y1 = (NR::ICoord) ceil(enlarged.max()[Y]);
+    item_bbox.x0 = (NR::ICoord) floor(enlarged.min()[X]);
+    item_bbox.y0 = (NR::ICoord) floor(enlarged.min()[Y]);
+    item_bbox.x1 = (NR::ICoord) ceil(enlarged.max()[X]);
+    item_bbox.y1 = (NR::ICoord) ceil(enlarged.max()[Y]);
 }
 
 Geom::Rect Filter::filter_effect_area(Geom::Rect const &bbox)
 {
     Geom::Point minp, maxp;
-    double len_x = bbox.max()[X] - bbox.min()[X];
-    double len_y = bbox.max()[Y] - bbox.min()[Y];
+    double len_x = bbox.width();
+    double len_y = bbox.height();
     /* TODO: fetch somehow the object ex and em lengths */
     _region_x.update(12, 6, len_x);
     _region_y.update(12, 6, len_y);
diff --git a/src/display/nr-filter.h b/src/display/nr-filter.h
index 9349ba9c6..b266ba053 100644
--- a/src/display/nr-filter.h
+++ b/src/display/nr-filter.h
@@ -151,10 +151,11 @@ public:
      */
     void area_enlarge(NRRectL &area, NRArenaItem const *item) const;
     /**
-     * Given an object bounding box, this function enlarges it so that
-     * it contains the filter effect area.
+     * Given an item bounding box (in user coords), this function enlarges it
+     * to contain the filter effects region and transforms it to screen
+     * coordinates
      */
-    void bbox_enlarge(NRRectL &bbox);
+    void compute_drawbox(NRArenaItem const *item, NRRectL &item_bbox);
     /**
      * Returns the filter effects area in user coordinate system.
      * The given bounding box should be a bounding box as specified in