Merge pull request #883 from storytold/fix/812-guides-snap

Part of #812: ruler guides pull drawn points with Smart Guides on

crates/tools/src/guides.rs

@@ -365,11 +365,16 @@ impl Targets {
     /// View → Snap to Point: only these targets' anchors pull, and the ruler guides (shown and
     /// unlocked, as the selection tools pick them) pull the pointer into line where they run.
     fn for_snap_to_point(self, cx: &ToolContext) -> Self {
-        let mut t = self.anchors_only();
+        self.anchors_only().with_rulers(cx)
+    }
+
+    /// These targets and the ruler guides, when they are shown (and so unlocked to the selection
+    /// tools): they pull a point into line where they run.
+    fn with_rulers(mut self, cx: &ToolContext) -> Self {
         if cx.guides {
-            t.rulers = cx.doc.guides.iter().map(|g| Ruler { vertical: g.vertical, pos: g.pos, span: cx.doc.guide_span(g) }).collect();
+            self.rulers = cx.doc.guides.iter().map(|g| Ruler { vertical: g.vertical, pos: g.pos, span: cx.doc.guide_span(g) }).collect();
         }
-        t
+        self
     }
 
     /// What a dragged selection's grabbed point snaps to with View → Snap to Point and Smart
@@ -486,8 +491,10 @@ impl Targets {
             if d.abs() <= 1e-9 {
                 continue;
             }
+            // The ruler guides that way count as lines too (#812).
+            let rulers: Vec<(f64, Point, Kind)> = self.rulers.iter().filter(|r| r.vertical == vertical).filter_map(|r| r.line_at(q, reach)).collect();
             // A line that far across the way crosses it at least that far along.
-            for (t, from, _) in lines_near(lines, v, reach) {
+            for (t, from, _) in lines_near(lines, v, reach).iter().chain(&rulers) {
                 let s = (t - a) / d;
                 // Exactly on the line, whatever the rounding along the way.
                 let hit = if vertical { Point::new(*t, at.y + dir.y * s) } else { Point::new(at.x + dir.x * s, *t) };
@@ -827,7 +834,9 @@ impl PointSnap {
         let targets = if cx.snap_to_pixel || cx.snap_to_grid {
             None
         } else if cx.smart_guides {
-            Some((targets().styled(cx), cx.snapping_tolerance))
+            // Snap to Point keeps pulling points onto the ruler guides with Smart Guides on (#812).
+            let t = targets().styled(cx);
+            Some((if cx.snap_to_point { t.with_rulers(cx) } else { t }, cx.snapping_tolerance))
         } else if cx.snap_to_point {
             Some((targets().for_snap_to_point(cx), cx.snap_tolerance))
         } else {
@@ -1397,6 +1406,27 @@ mod tests {
         }
     }
 
+    /// #812: with Smart Guides on, ruler guides pull a drawn point too (Snap to Point), horizontal
+    /// and vertical alike, also while it slides along a construction guide or Shift's angle.
+    #[test]
+    fn drawn_points_snap_to_ruler_guides_with_smart_guides_on() {
+        let (mut d, _) = doc_with_rect();
+        d.guides.push(vectorcraft_doc::Guide::new(false, 313.0));
+        d.guides.push(vectorcraft_doc::Guide::new(true, 331.0));
+        let (s, p) = (Selection::default(), paint());
+        let c = cx(&d, &s, &p);
+        let mut snap = DrawSnap::default();
+        assert_eq!(snap.press(&c, Point::new(260.0, 315.0), &[], None), Point::new(260.0, 313.0), "the horizontal guide");
+        assert_eq!(snap.press(&c, Point::new(329.0, 260.0), &[], None), Point::new(331.0, 260.0), "the vertical guide");
+        // On the 45° construction guide from (210, 210), where the horizontal guide crosses it.
+        let from = Leave::segment(&c, Point::new(210.0, 210.0), false);
+        let q = snap.press(&c, Point::new(312.0, 311.0), &[], Some(&from));
+        assert!((q - Point::new(313.0, 313.0)).hypot() < 1e-9, "{q:?}");
+        // Snap to Point off: Smart Guides alone don't use the ruler guides.
+        let off = ToolContext { snap_to_point: false, ..cx(&d, &s, &p) };
+        assert_eq!(snap.press(&off, Point::new(260.0, 315.0), &[], None), Point::new(260.0, 315.0));
+    }
+
     /// A drawing tool's snapper reuses its targets while hovering over the same document state, and
     /// gathers them again when it changes, and on every press.
     #[test]