during l2p(v) when v falls into breaks, pick offset closest to it

... that way, positions that include some sort of offset
    (e.g. bar x0/x1, ohlc xo/xc) have the adequate
    px position.

Author: etpinard

src/plots/cartesian/set_convert.js

@@ -198,7 +198,12 @@ module.exports = function setConvert(ax, fullLayout) {
                 for(var i = 0; i < ax._breaks.length; i++) {
                     var brk = ax._breaks[i];
                     if(v <= brk.min) b = ax._B[i + 1];
-                    else if(v > brk.max) break;
+                    else if(v > brk.min && v < brk.max) {
+                        // when v falls into break, pick offset 'closest' to it
+                        if(v - brk.min <= brk.max - v) b = ax._B[i + 1];
+                        else b = ax._B[i];
+                        break;
+                    } else if(v > brk.max) break;
                 }
                 return _l2p(v, -ax._m2, b);
             };
@@ -223,7 +228,12 @@ module.exports = function setConvert(ax, fullLayout) {
                 for(var i = 0; i < ax._breaks.length; i++) {
                     var brk = ax._breaks[i];
                     if(v >= brk.max) b = ax._B[i + 1];
-                    else if(v < brk.min) break;
+                    else if(v > brk.min && v < brk.max) {
+                        // when v falls into break, pick offset 'closest' to it
+                        if(v - brk.min <= brk.max - v) b = ax._B[i];
+                        else b = ax._B[i + 1];
+                        break;
+                    } else if(v < brk.min) break;
                 }
                 return _l2p(v, ax._m2, b);
             };

test/image/baselines/axes_breaks-bars.png

@@ -0,0 +1,30 @@
+{
+  "data": [
+    {
+      "type": "bar",
+      "y": [ 0, 2 ],
+      "x": [ 1, 2 ],
+      "orientation": "h",
+      "marker": {
+        "color": ["purple", "orange"],
+        "opacity": [1, 0.5]
+      }
+    }
+  ],
+  "layout": {
+    "title": {
+      "text": "Bars centered on open breaks bounds<br>should show bars even though pos -/+ dPos falls within break",
+      "x": 0,
+      "xref": "paper",
+      "font": {"size": 12}
+    },
+    "yaxis": {
+      "breaks": [
+        {
+          "bounds": [ 0, 2 ],
+          "operation": "()"
+        }
+      ]
+    }
+  }
+}