measureText 计算 fontSize 有误

[tony chen]

zrender/src/core/platform.ts

Lines 75 to 79 in e5d275f

 text = text || ''; 
 font = font || DEFAULT_FONT; 
 // Use font size if there is no other method can be used. 
 const res = /^([0-9]*?)px$/.exec(font); 
 const fontSize = +(res && res[1]) || DEFAULT_FONT_SIZE; 

DEFAULT_FONT 为 12px sans-serif

运行时为 normal normal 12px sans-serif

font = font || DEFAULT_FONT;
const res = /^([0-9]*?)px$/.exec(font);
const fontSize = +(res && res[1]) || DEFAULT_FONT_SIZE;

res 为 null, fontSize 只能为 DEFAULT_FONT_SIZE

[Wenli Zhang]

normal normal 12px sans-serif 是怎么来的？请提供一个调用时的代码