Rebased a long outstanding inkscape patch. Original: https://bugs.launchpad.net/inkscape/+bug/169623/+attachment/1185169/+files/CanvasColor4.patch

CanvasColor4-fixed.patch

# Bazaar merge directive format 2 (Bazaar 0.90)
# revision_id: nathan.f77@gmail.com-20110921150425-ir9m3ot05rozkttf
# target_branch: http://bazaar.launchpad.net/~inkscape.dev/inkscape\
#   /trunk/
# testament_sha1: 1946394c022a88fa90e090cef6e0f7991a88d338
# timestamp: 2011-09-21 23:05:02 +0800
# base_revision_id: juca@members.fsf.org-20110919175042-\
#   532nbha31h5sb498
# 
# Begin patch
=== modified file 'src/desktop.cpp'
--- src/desktop.cpp	2011-08-27 14:58:22 +0000
+++ src/desktop.cpp	2011-09-21 15:04:25 +0000
@@ -1715,9 +1715,9 @@
     if (flags & SP_OBJECT_MODIFIED_FLAG) {
 
         /* Show/hide page background */
-        if (nv->pagecolor & 0xff) {
+        if (nv->pagecolor | 0xff != 0xffffffff) {
             sp_canvas_item_show (desktop->table);
-            ((CtrlRect *) desktop->table)->setColor(0x00000000, true, nv->pagecolor);
+            ((CtrlRect *) desktop->table)->setColor(0x00000000, true, nv->pagecolor | 0xff);
             sp_canvas_item_move_to_z (desktop->table, 0);
         } else {
             sp_canvas_item_hide (desktop->table);
@@ -1756,11 +1756,10 @@
         }
 
         Inkscape::Preferences *prefs = Inkscape::Preferences::get();
-        if (SP_RGBA32_A_U(nv->pagecolor) < 128 ||
-            (SP_RGBA32_R_U(nv->pagecolor) +
-             SP_RGBA32_G_U(nv->pagecolor) +
-             SP_RGBA32_B_U(nv->pagecolor)) >= 384) {
-            // the background color is light or transparent, use black outline
+        if (SP_RGBA32_R_U(nv->pagecolor) +
+            SP_RGBA32_G_U(nv->pagecolor) +
+            SP_RGBA32_B_U(nv->pagecolor) >= 384) {
+            // the background color is light, use black outline
             SP_CANVAS_ARENA (desktop->drawing)->drawing.outlinecolor = prefs->getInt("/options/wireframecolors/onlight", 0xff);
         } else { // use white outline
             SP_CANVAS_ARENA (desktop->drawing)->drawing.outlinecolor = prefs->getInt("/options/wireframecolors/ondark", 0xffffffff);
@@ -1847,3 +1846,4 @@
   End:
 */
 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :
+

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