条码生成器

这几种码制只编码十进制数字,别的都不行。输入里出现字母、空格或连字符,通常意味着复制时把格式一起带过来了,或者它压根不是一个 GTIN。

修复: 把非数字的字符全部去掉,然后重新核对位数。

来源: Derived from the module-encoding tables of each symbology, which this package implements and self-proves: the generator ships an independent decoder, and our tests round-trip thousands of random values through encode and decode to show the tables are right.

号码的位数决定用哪种码制:EAN-13 取 13 位,UPC-A 取 12 位,EAN-8 取 8 位,ITF-14 取 14 位。其他位数没法画成这几类线性条码。

修复: 先看看是不是丢了前导零 —— 11 位的值极常见地是被表格软件剪掉一位的 UPC-A。

来源: Derived from the module-encoding tables of each symbology, which this package implements and self-proves: the generator ships an independent decoder, and our tests round-trip thousands of random values through encode and decode to show the tables are right.

校验位对不上时,生成器拒绝出图。这是最要紧的一条:用错号码画出来的条码扫起来毫无异常,只是解析成了另一件商品 —— 或者什么都不是 —— 而你要等它印上包装之后才会发现。

修复: 在生成之前重算校验位,而不是在印刷之后。

来源: Derived from the module-encoding tables of each symbology, which this package implements and self-proves: the generator ships an independent decoder, and our tests round-trip thousands of random values through encode and decode to show the tables are right.

条杠两侧的空白边距不是装饰 —— 扫描器靠它找到码的起点和终点。渲染出来的图形已经把静区包含在内,所以一张紧贴条杠裁切的条码,即使看着完整,也会读得不稳。

修复: 把图形放进版面时,保留它四周的留白。

来源: Derived from the module-encoding tables of each symbology, which this package implements and self-proves: the generator ships an independent decoder, and our tests round-trip thousands of random values through encode and decode to show the tables are right.

把数字变成条杠的模块表,是生成器唯一可能悄悄出错的地方 —— 因为一张错的表照样能画出看着很像样的条码。本包自带一个独立的解码器,测试里拿随机值走一遍编码再解码,所以这些表是被证明过的,不是假定正确的。

来源: Derived from the module-encoding tables of each symbology, which this package implements and self-proves: the generator ships an independent decoder, and our tests round-trip thousands of random values through encode and decode to show the tables are right.