blender ruler enhancement

Index: source/blender/editors/include/ED_transform.h
===================================================================
--- source/blender/editors/include/ED_transform.h   (revision 56109)
+++ source/blender/editors/include/ED_transform.h   (working copy)
@@ -174,7 +174,8 @@
 typedef enum SnapMode {
    SNAP_ALL = 0,
    SNAP_NOT_SELECTED = 1,
-   SNAP_NOT_OBEDIT = 2
+   SNAP_NOT_OBEDIT = 2,
+   SNAP_ONLY_SELECTED = 3
 } SnapMode;

 #define SNAP_MIN_DISTANCE 30
Index: source/blender/editors/space_view3d/view3d_ruler.c
===================================================================
--- source/blender/editors/space_view3d/view3d_ruler.c  (revision 56109)
+++ source/blender/editors/space_view3d/view3d_ruler.c  (working copy)
@@ -61,7 +61,7 @@
 #include "ED_transform.h"

 static bool ED_view3d_snap_co(bContext *C, float r_co[3], const float co_ss[2], float r_no[3],
-                              bool use_vert, bool use_edge, bool use_face)
+                              bool snap_to_selected, bool use_vert, bool use_edge, bool use_face)
 {
    float dist_px = 12;  /* snap dist */
    float r_no_dummy[3];
@@ -72,19 +72,21 @@
    View3D *v3d = CTX_wm_view3d(C);
    ARegion *ar = CTX_wm_region(C);
    struct Object *obedit = CTX_data_edit_object(C);
+
+   SnapMode snap_mode = snap_to_selected ? SNAP_ONLY_SELECTED : SNAP_ALL;

    /* try snap edge, then face if it fails */
    if (use_vert) {
        ret = snapObjectsEx(scene, NULL, v3d, ar, obedit, SCE_SNAP_MODE_VERTEX,
-                           co_ss, &dist_px, r_co, r_no_ptr, SNAP_ALL);
+                           co_ss, &dist_px, r_co, r_no_ptr, snap_mode);
    }
    if (use_edge && (ret == false)) {
        ret = snapObjectsEx(scene, NULL, v3d, ar, obedit, SCE_SNAP_MODE_EDGE,
-                           co_ss, &dist_px, r_co, r_no_ptr, SNAP_ALL);
+                           co_ss, &dist_px, r_co, r_no_ptr, snap_mode);
    }
    if (use_face && (ret == false)) {
        ret = snapObjectsEx(scene, NULL, v3d, ar, obedit, SCE_SNAP_MODE_FACE,
-                           co_ss, &dist_px, r_co, r_no_ptr, SNAP_ALL);
+                           co_ss, &dist_px, r_co, r_no_ptr, snap_mode);
    }

    return ret;
@@ -156,6 +158,7 @@
    int flag;
    int snap_flag;
    int state;
+   int     snap_to_selected;

    /* --- */
    ARegion *ar;
@@ -685,7 +688,7 @@
            co_other = ruler_item->co[ruler_item->co_index == 0 ? 2 : 0];

            if (ED_view3d_snap_co(C, co, mval_fl, ray_normal,
-                                 false, false, true))
+                                 ruler_info->snap_to_selected, false, false, true))
            {
                negate_v3(ray_normal);
                /* add some bias */
@@ -697,7 +700,7 @@
        else if (do_snap) {
            const float mval_fl[2] = {UNPACK2(mval)};
            ED_view3d_snap_co(C, co, mval_fl, NULL,
-                             true, true, true);
+                             ruler_info->snap_to_selected, true, true, true);
        }
        return true;
    }
@@ -706,16 +709,23 @@
    }
 }

-static void view3d_ruler_header_update(ScrArea *sa)
+static void view3d_ruler_header_update(ScrArea *sa, RulerInfo *ruler_info)
 {
-   const char *text = "Ctrl+LMB: Add, "
-                      "Del: Remove, "
-                      "Ctrl+Drag: Snap, "
-                      "Shift+Drag: Thickness, "
-                      "Ctrl+C: Copy Value, "
-                      "Enter: Store,  "
-                      "Esc: Cancel";
+   char text[1024];
+   const char *snap_mode_str = ruler_info->snap_to_selected ? "To-Selected" : "To-All";
+   const char *template =
+       "Ctrl+LMB: Add, "
+       "Del: Remove, "
+       "Ctrl+Drag: Snap, "
+       "Shift+Drag: Thickness, "
+       "Ctrl+C: Copy Value, "
+       "Enter: Store,  "
+       "Esc: Cancel, "
+       "Ctrl+S: Toggle snap mode, "
+       "SnapMode: %s";

+   sprintf(text, template, snap_mode_str);
+
    ED_area_headerprint(sa, text);
 }

@@ -741,7 +751,7 @@
    ruler_info->draw_handle_pixel = ED_region_draw_cb_activate(ar->type, ruler_info_draw_pixel,
                                                               ruler_info, REGION_DRAW_POST_PIXEL);

-   view3d_ruler_header_update(sa);
+   view3d_ruler_header_update(sa, ruler_info);

    WM_cursor_modal(win, BC_CROSSCURSOR);
    WM_event_add_modal_handler(C, op);
@@ -866,6 +876,15 @@
                }
            }
            break;
+       case SKEY:
+       {
+           if (event->ctrl && event->val == KM_RELEASE) {
+               ruler_info->snap_to_selected = !ruler_info->snap_to_selected;
+               fprintf(stderr, "toggling snap_to_selected\n");
+               do_draw = true;
+           }
+           break;
+       }
        case CKEY:
        {
            if (event->ctrl) {
@@ -880,6 +899,7 @@
                    WM_clipboard_text_set((void *) numstr, false);
                }
            }
+           break;
        }
        case RIGHTCTRLKEY:
        case LEFTCTRLKEY:
@@ -934,7 +954,7 @@
    if (do_draw) {
        ScrArea *sa = CTX_wm_area(C);

-       view3d_ruler_header_update(sa);
+       view3d_ruler_header_update(sa, ruler_info);

        /* all 3d views draw rulers */
        WM_event_add_notifier(C, NC_SPACE | ND_SPACE_VIEW3D, NULL);
Index: source/blender/editors/transform/transform_snap.c
===================================================================
--- source/blender/editors/transform/transform_snap.c   (revision 56109)
+++ source/blender/editors/transform/transform_snap.c   (working copy)
@@ -1577,6 +1577,7 @@
            (base->flag & (BA_HAS_RECALC_OB | BA_HAS_RECALC_DATA)) == 0 &&

            ((mode == SNAP_NOT_SELECTED && (base->flag & (SELECT | BA_WAS_SEL)) == 0) ||
+            (mode == SNAP_ONLY_SELECTED && (base->flag & (SELECT | BA_WAS_SEL)) == 1) ||
             (ELEM(mode, SNAP_ALL, SNAP_NOT_OBEDIT) && base != base_act)))
        {
            Object *ob = base->object;