1. A method for a device to enlarge a displayed font, comprising: receiving an instruction for enlarging a currently displayed font; acquiring a size of the currently displayed font; when the size of the currently displayed font is smaller than a preset maximum threshold, enlarging the currently displayed font based on a curve enlargement rule with a first enlargement coefficient configured by an operating system of the device and a second enlargement coefficient configured by a current application; when the size of the currently displayed font is larger than or equal to the preset maximum threshold, enlarging the currently displayed font based on a linear enlargement rule with a third enlargement coefficient configured by the operating system; and displaying the enlarged font.
1. A method for a device to enlarge a displayed font, comprising: receiving an instruction for enlarging a currently displayed font; acquiring a size of the currently displayed font; when the size of the currently displayed font is smaller than a preset maximum threshold, enlarging the currently displayed font based on a curve enlargement rule with a first enlargement coefficient configured by an operating system of the device and a second enlargement coefficient configured by a current application; when the size of the currently displayed font is larger than or equal to the preset maximum threshold, enlarging the currently displayed font based on a linear enlargement rule with a third enlargement coefficient configured by the operating system; and displaying the enlarged font. 6. The method according to claim 1 , wherein the enlarging of the currently displayed font based on the linear enlargement rule comprises: enlarging the currently displayed font based on the following equation: 
 y=k 3* x, x≧T; wherein y is a size of the enlarged font, x is the size of the currently displayed font, k3 is the third enlargement coefficient configured by the operating system, and T is the preset maximum threshold.