cc.LabelTTF resolution issue

[pandamicro]

cc.LabelTTF's resolution varies with the design resolution policy.

How to reproduce:

1. Use a low definition device to see better the difference
2. Set the resolution size to twice of the device original resolution like (1280 * 656) on iphone 4s(640 * 328), draw a label on screen at font size 40.
3. Set the resolution size equal to the device original resolution like (640 * 328) on iphone 4s(640 * 328), draw a label on screen at font size 20.

Normally, as it's on the same device, and the real canvas size in pixel stays the same. Case 2, the whole scene will be scaled to a half. And the label should be exactly the same sharpness as in Case 3.
Though the results shows that the label in Case 2 is more fuzzy than in Case 3.

Hypothese:

The label have been rendered to a cached canvas, and then scaled. So the scale of a cached label texture will cause itself more fuzzy.