Fixing a bug where the x,y of the arrow would be changed to stay on the chart, rather than render off screen when panned. Added corresponding annotation to image test.

Author: MFed

src/components/annotations/index.js

@@ -500,13 +500,17 @@ annotations.draw = function(gd, index, opt, value) {
         // and the annotation center are visible
         if(options.showarrow) {
             if(options.axref === options.xref) {
-                arrowX = Lib.constrain(annPosPx.x, 1, fullLayout.width - 1);
+                //we don't want to constrain if the tail is absolute
+                //or the slope (which is meaningful) will change.
+                arrowX = annPosPx.x;
             } else {
                 arrowX = Lib.constrain(annPosPx.x - options.ax, 1, fullLayout.width - 1);
             }
 
             if(options.ayref === options.yref) {
-                arrowY = Lib.constrain(annPosPx.y, 1, fullLayout.height - 1);
+                //we don't want to constrain if the tail is absolute
+                //or the slope (which is meaningful) will change.
+                arrowY = annPosPx.y;
             } else {
                 arrowY = Lib.constrain(annPosPx.y - options.ay, 1, fullLayout.height - 1);
             }

test/image/baselines/annotations.png

@@ -42,7 +42,8 @@
                 "font":{"color":"rgb(0, 0, 255)","size":20},
                 "arrowcolor":"rgb(166, 28, 0)","borderpad":3,"textangle":50,"x":5,"y":1
             },
-            {"text":"","showarrow":true,"borderwidth":1.2,"arrowhead":2,"axref":"x","ayref":"y","x":5,"y":5,"ax":4,"ay":3}
+            {"text":"","showarrow":true,"borderwidth":1.2,"arrowhead":2,"axref":"x","ayref":"y","x":5,"y":3,"ax":4,"ay":5},
+            {"text":"","showarrow":true,"borderwidth":1.2,"arrowhead":2,"axref":"x","ayref":"y","x":6,"y":2,"ax":3,"ay":3}
         ]
     }
 }