call ax.setScale in Annotations.drawOne

... which happens to be the first time it's called
    when annotations are present on autoranged axes on
    subplots w/o visible traces. This is important to avoid
    `transform:rotate(NaN)` errors as annotations require ax._offset
    to first-draw text to compute its bounds.

Author: etpinard

src/components/annotations/draw.js

@@ -67,6 +67,9 @@ function drawOne(gd, index) {
     var xa = Axes.getFromId(gd, options.xref);
     var ya = Axes.getFromId(gd, options.yref);
 
+    if(xa) xa.setScale();
+    if(ya) ya.setScale();
+
     drawRaw(gd, options, index, false, xa, ya);
 }
 

test/jasmine/tests/annotations_test.js

@@ -814,6 +814,28 @@ describe('annotations autorange', function() {
         .catch(failTest)
         .then(done);
     });
+
+    it('should not error out on subplots w/o visible traces', function(done) {
+        Plotly.plot(gd, [{}], {
+            annotations: [{
+                x: 0.1,
+                y: 0.1,
+                text: 't',
+                showarrow: false
+            }, {
+                x: 0.2,
+                y: 0.3,
+                text: 'a'
+            }]
+        })
+        .then(function() {
+            expect(gd._fullLayout.xaxis.range).toBeCloseToArray([0.099, 0.201], 1, 'x rng');
+            expect(gd._fullLayout.yaxis.range).toBeCloseToArray([0.091, 0.335], 1, 'y rng');
+            assertVisible([0, 1]);
+        })
+        .catch(failTest)
+        .then(done);
+    });
 });
 
 describe('annotation clicktoshow', function() {