[librsvg] rsvg-cairo-draw: Take 'invisible' objects into account for bounding boxes

[Federico Mena Quintero <federico src gnome org>]

commit 9957956c423d2eeac6b3300cb0fc223a34e70f12
Author: Federico Mena Quintero <federico gnome org>
Date:   Tue Aug 11 07:42:22 2015 -0500

    rsvg-cairo-draw: Take 'invisible' objects into account for bounding boxes
    
    Bounding boxes were computed only for objects that have a fill or a stroke.  However,
    for symbolic icons (e.g. adwaita-icon-theme/src/symbolic/gnome-stencils.svg) we can have
    fill-less and stroke-less rectangles that are just used to center the actual icons on
    the area they are allocated.  In that case we need to compute the full bounding box
    for the allocated area, i.e. the fill-less/stroke-less rectangles.
    
    This should not affect 'normal' SVGs where all objects have a fill or a stroke.

 rsvg-cairo-draw.c |   17 +++++++++++++----
 1 files changed, 13 insertions(+), 4 deletions(-)
---
diff --git a/rsvg-cairo-draw.c b/rsvg-cairo-draw.c
index 15d6bbc..6c3b2eb 100644
--- a/rsvg-cairo-draw.c
+++ b/rsvg-cairo-draw.c
@@ -457,9 +457,6 @@ rsvg_cairo_render_path (RsvgDrawingCtx * ctx, const cairo_path_t *path)
     RsvgBbox bbox;
     double backup_tolerance;
 
-    if (state->fill == NULL && state->stroke == NULL)
-        return;
-
     need_tmpbuf = ((state->fill != NULL) && (state->stroke != NULL) && state->opacity != 0xff)
         || state->clip_path_ref || state->mask || state->filter
         || (state->comp_op != CAIRO_OPERATOR_OVER);
@@ -490,7 +487,15 @@ rsvg_cairo_render_path (RsvgDrawingCtx * ctx, const cairo_path_t *path)
        _rendering_ time speedups, are these rather expensive operations
        really needed here? */
 
-    if (state->fill != NULL) {
+    /* Bounding box for fill
+     *
+     * Unlike the case for stroke, for fills we always compute the bounding box.
+     * In GNOME we have SVGs for symbolic icons where each icon has a bounding
+     * rectangle with no fill and no stroke, and inside it there are the actual
+     * paths for the icon's shape.  We need to be able to compute the bounding
+     * rectangle's extents, even when it has no fill nor stroke.
+     */
+    {
         RsvgBbox fb;
         rsvg_bbox_init (&fb, &state->affine);
         cairo_fill_extents (cr, &fb.rect.x, &fb.rect.y, &fb.rect.width, &fb.rect.height);
@@ -499,6 +504,8 @@ rsvg_cairo_render_path (RsvgDrawingCtx * ctx, const cairo_path_t *path)
         fb.virgin = 0;
         rsvg_bbox_insert (&bbox, &fb);
     }
+
+    /* Bounding box for stroke */
     if (state->stroke != NULL) {
         RsvgBbox sb;
         rsvg_bbox_init (&sb, &state->affine);
@@ -549,6 +556,8 @@ rsvg_cairo_render_path (RsvgDrawingCtx * ctx, const cairo_path_t *path)
         cairo_stroke (cr);
     }
 
+    cairo_new_path (cr); /* clear the path in case stroke == fill == NULL; otherwise we leave it around from 
computing the bounding box */
+
     if (need_tmpbuf)
         rsvg_cairo_pop_discrete_layer (ctx);
 }