Per-item render cache.

Cache some offscreen data to facilitate smoother navigation.

(bzr r10347.1.20)

1 files changed, 10 insertions, 115 deletions

diff --git a/src/display/canvas-arena.cpp b/src/display/canvas-arena.cpp
index 1d5cfe826..0f653a258 100644
--- a/src/display/canvas-arena.cpp
+++ b/src/display/canvas-arena.cpp
@@ -33,10 +33,8 @@ static void sp_canvas_arena_destroy(GtkObject *object);
 
 static void sp_canvas_arena_update (SPCanvasItem *item, Geom::Affine const &affine, unsigned int flags);
 static void sp_canvas_arena_render (SPCanvasItem *item, SPCanvasBuf *buf);
-static void sp_canvas_arena_render_cache (SPCanvasItem *item, Geom::IntRect const &area);
-static void sp_canvas_arena_dirty_cache (SPCanvasArena *arena, NRRectL *area);
 static double sp_canvas_arena_point (SPCanvasItem *item, Geom::Point p, SPCanvasItem **actual_item);
-static void sp_canvas_arena_visible_area_changed (SPCanvasItem *item, Geom::IntRect const &old_area, Geom::IntRect const &new_area);
+static void sp_canvas_arena_viewbox_changed (SPCanvasItem *item, Geom::IntRect const &new_area);
 static gint sp_canvas_arena_event (SPCanvasItem *item, GdkEvent *event);
 
 static gint sp_canvas_arena_send_event (SPCanvasArena *arena, GdkEvent *event);
@@ -98,7 +96,7 @@ sp_canvas_arena_class_init (SPCanvasArenaClass *klass)
     item_class->render = sp_canvas_arena_render;
     item_class->point = sp_canvas_arena_point;
     item_class->event = sp_canvas_arena_event;
-    item_class->visible_area_changed = sp_canvas_arena_visible_area_changed;
+    item_class->viewbox_changed = sp_canvas_arena_viewbox_changed;
 }
 
 static void
@@ -110,11 +108,9 @@ sp_canvas_arena_init (SPCanvasArena *arena)
     arena->arena->canvasarena = arena;
     arena->root = NRArenaGroup::create(arena->arena);
     nr_arena_group_set_transparent (NR_ARENA_GROUP (arena->root), TRUE);
+    nr_arena_item_set_cache(arena->root, true);
 
     arena->active = NULL;
-    arena->cache = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, 1, 1);
-    arena->cache_area = Geom::IntRect::from_xywh(0,0,1,1);
-    arena->dirty = cairo_region_create();
 
     nr_active_object_add_listener ((NRActiveObject *) arena->arena, (NRObjectEventVector *) &carenaev, sizeof (carenaev), arena);
 }
@@ -140,11 +136,6 @@ sp_canvas_arena_destroy (GtkObject *object)
         nr_object_unref ((NRObject *) arena->arena);
         arena->arena = NULL;
     }
-    if (arena->cache) {
-        cairo_surface_destroy(arena->cache);
-        arena->cache = NULL;
-    }
-    cairo_region_destroy(arena->dirty);
 
     if (GTK_OBJECT_CLASS (parent_class)->destroy)
         (* GTK_OBJECT_CLASS (parent_class)->destroy) (object);
@@ -209,42 +200,8 @@ sp_canvas_arena_render (SPCanvasItem *item, SPCanvasBuf *buf)
 
     Geom::OptIntRect r = buf->rect;
     if (!r || r->hasZeroArea()) return;
-    
-    cairo_rectangle_int_t crect;
-    crect.x = r->left();
-    crect.y = r->top();
-    crect.width = r->width();
-    crect.height = r->height();
-    if (cairo_region_contains_rectangle(arena->dirty, &crect) != CAIRO_REGION_OVERLAP_OUT) {
-        sp_canvas_arena_render_cache(item, *r);
-        cairo_region_subtract_rectangle(arena->dirty, &crect);
-    }
-
-    cairo_save(buf->ct);
-    cairo_translate(buf->ct, -r->left(), -r->top());
-    cairo_set_source_surface(buf->ct, arena->cache, arena->cache_area.left(), arena->cache_area.top());
-    cairo_paint(buf->ct);
-    cairo_restore(buf->ct);
-}
-
-static void sp_canvas_arena_render_cache (SPCanvasItem *item, Geom::IntRect const &area)
-{
-    SPCanvasArena *arena = SP_CANVAS_ARENA (item);
-    
-    Geom::OptIntRect r = Geom::intersect(arena->cache_area, area);
-    if (!r || r->hasZeroArea()) return; // nothing to do
-
-    Inkscape::DrawingSurface cache(arena->cache, arena->cache_area.min());
-    Inkscape::DrawingContext ct(cache);
 
-    ct.rectangle(area);
-    ct.clip();
-
-    {   Inkscape::DrawingContext::Save save(ct);
-        ct.setSource(0,0,0,0);
-        ct.setOperator(CAIRO_OPERATOR_SOURCE);
-        ct.paint();
-    }
+    Inkscape::DrawingContext ct(buf->ct, r->min());
 
     nr_arena_item_invoke_update (arena->root, Geom::IntRect::infinite(), &arena->gc,
                                  NR_ARENA_ITEM_STATE_BBOX | NR_ARENA_ITEM_STATE_RENDER,
@@ -252,17 +209,6 @@ static void sp_canvas_arena_render_cache (SPCanvasItem *item, Geom::IntRect cons
     nr_arena_item_invoke_render (ct, arena->root, *r, 0);
 }
 
-static void
-sp_canvas_arena_dirty_cache (SPCanvasArena *arena, NRRectL *area)
-{
-    cairo_rectangle_int_t rect;
-    rect.x = area->x0;
-    rect.y = area->y0;
-    rect.width = area->x1 - area->x0;
-    rect.height = area->y1 - area->y0;
-    cairo_region_union_rectangle(arena->dirty, &rect);
-}
-
 static double
 sp_canvas_arena_point (SPCanvasItem *item, Geom::Point p, SPCanvasItem **actual_item)
 {
@@ -285,64 +231,14 @@ sp_canvas_arena_point (SPCanvasItem *item, Geom::Point p, SPCanvasItem **actual_
 }
 
 static void
-sp_canvas_arena_visible_area_changed (SPCanvasItem *item, Geom::IntRect const &old_area, Geom::IntRect const &new_area)
+sp_canvas_arena_viewbox_changed (SPCanvasItem *item, Geom::IntRect const &new_area)
 {
     SPCanvasArena *arena = SP_CANVAS_ARENA(item);
-
-    cairo_surface_t *new_cache = cairo_image_surface_create(CAIRO_FORMAT_ARGB32,
-        new_area.width(), new_area.height());
-    cairo_t *ct = cairo_create(new_cache);
-    cairo_set_source_surface(ct, arena->cache, old_area.left() - new_area.left(), old_area.top() - new_area.top());
-    cairo_set_operator(ct, CAIRO_OPERATOR_SOURCE);
-    cairo_paint(ct);
-    cairo_destroy(ct);
-    cairo_surface_destroy(arena->cache);
-    arena->cache = new_cache;
-    arena->cache_area = new_area;
-
-    cairo_rectangle_int_t crect;
-    crect.x = new_area.left();
-    crect.y = new_area.top();
-    crect.width = new_area.width();
-    crect.height = new_area.height();
-    cairo_region_intersect_rectangle(arena->dirty, &crect);
-
-    // invalidate newly exposed areas
-    /*
-     * +----------------------+
-     * |      top strip       |
-     * +-------+------+-------+
-     * |       |      |       |
-     * | left  | old  | right |
-     * | strip | area | strip |
-     * |       |      |       |
-     * +-------+------+-------+
-     * |     bottom strip     |
-     * +----------------------+
-     */
-    
-    // top strip
-    if (new_area.top() < old_area.top()) {
-        NRRectL top_strip(new_area.left(), new_area.top(), new_area.right(), old_area.top());
-        sp_canvas_arena_dirty_cache(arena, &top_strip);
-    }
-    // left strip
-    if (new_area.left() < old_area.left()) {
-        NRRectL left_strip(new_area.left(), std::max(new_area.top(), old_area.top()),
-            old_area.left(), std::min(new_area.bottom(), old_area.bottom()));
-        sp_canvas_arena_dirty_cache(arena, &left_strip);
-    }
-    // right strip
-    if (new_area.right() > old_area.right()) {
-        NRRectL right_strip(old_area.right(), std::max(new_area.top(), old_area.top()),
-            new_area.right(), std::min(new_area.bottom(), old_area.bottom()));
-        sp_canvas_arena_dirty_cache(arena, &right_strip);
-    }
-    // bottom strip
-    if (new_area.bottom() > old_area.bottom()) {
-        NRRectL bottom_strip(new_area.left(), old_area.bottom(), new_area.right(), new_area.bottom());
-        sp_canvas_arena_dirty_cache(arena, &bottom_strip);
-    }
+    // make the cache limit larger than screen to facilitate smooth scrolling
+    Geom::IntRect expanded = new_area;
+    Geom::IntPoint expansion(new_area.width()/2, new_area.height()/2);
+    expanded.expandBy(expansion);
+    nr_arena_set_cache_limit(arena->arena, expanded);
 }
 
 static gint
@@ -445,7 +341,6 @@ static void
 sp_canvas_arena_request_render (NRArena */*arena*/, NRRectL *area, void *data)
 {
     if (!area) return;
-    sp_canvas_arena_dirty_cache (SP_CANVAS_ARENA(data), area);
     sp_canvas_request_redraw (SP_CANVAS_ITEM (data)->canvas, area->x0, area->y0, area->x1, area->y1);
 }