1 files changed, 78 insertions, 0 deletions
diff --git a/src/grid-snapper.cpp b/src/grid-snapper.cpp
new file mode 100644
index 000000000..61bfa30d4
--- /dev/null
+++ b/src/grid-snapper.cpp
@@ -0,0 +1,78 @@
+/**
+ *  \file grid-snapper.cpp
+ *  \brief Snapping things to grids.
+ *
+ * Authors:
+ *   Lauris Kaplinski <lauris@kaplinski.com>
+ *   Frank Felfe <innerspace@iname.com>
+ *   Carl Hetherington <inkscape@carlh.net>
+ *
+ * Copyright (C) 1999-2002 Authors 
+ *
+ * Released under GNU GPL, read the file 'COPYING' for more information
+ */
+
+#include "sp-namedview.h"
+#include "display/canvas-grid.h"
+
+/**
+ * \return x rounded to the nearest multiple of c1 plus c0.
+ *
+ * \note
+ * If c1==0 (and c0 is finite), then returns +/-inf.  This makes grid spacing of zero
+ * mean "ignore the grid in this dimention".  We're currently discussing "good" semantics
+ * for guide/grid snapping.
+ */
+
+/* FIXME: move this somewhere else, perhaps */
+static double round_to_nearest_multiple_plus(double x, double const c1, double const c0)
+{
+    return floor((x - c0) / c1 + .5) * c1 + c0;
+}
+
+Inkscape::GridSnapper::GridSnapper(SPNamedView const *nv, NR::Coord const d) : LineSnapper(nv, d)
+{
+
+}
+
+Inkscape::LineSnapper::LineList Inkscape::GridSnapper::_getSnapLines(NR::Point const &p) const
+{
+    LineList s;
+
+    SPCGrid *griditem = NULL; 
+    for (GSList *l = _named_view->gridviews; l != NULL; l = l->next) {
+        // FIXME : this is a hack since there is only one view for now
+        //                 but when we'll handle multiple views, snapping should
+        //                 must be rethought and maybe only the current view
+        //                 should give back it's SHOWN lines to snap to
+        //                 For now, the last SPCGrid in _named_view->gridviews will be used.
+        griditem = SP_CGRID(l->data);
+    }
+
+    g_assert(griditem != NULL);
+    
+    for (unsigned int i = 0; i < 2; ++i) {
+
+        /* This is to make sure we snap to only visible grid lines */
+        double const scale = griditem->scaled[i] ? griditem->empspacing : 1;
+
+        NR::Coord const rounded = round_to_nearest_multiple_plus(p[i],
+                                                                 _named_view->gridspacing[i] * scale,
+                                                                 _named_view->gridorigin[i]);
+        
+        s.push_back(std::make_pair(NR::Dim2(i), rounded));
+    }
+
+    return s;
+}
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :