PDF字形间距和TJ运算符 [英] PDF glyph spacing and TJ operator

问题描述

我是PDF的新手，我想操纵文件中字符之间的空格. 我已经阅读了PDFReference并理解了其中的一些内容. 现在，我的问题是如何计算文本渲染的空间.

I am new to PDF, and i want to manipulate the space between the characters in a file. I have read the PDFReference and understood some of it. Now, the problem I have is how to calculate the spaces for the text rendering.

例如，我有

1 0 0 1 0 188.28799438 cm
BT 
/F2 11.04 Tf
1 0 0 -1 0 9.38000011 Tm 
(Some)Tj ( )Tj 
21.24200058 0 Td 
(text)Tj ( )Tj 

我想变成这个:

1 0 0 1 0 188.28799438 cm
BT 
/F2 11.04 Tf
1 0 0 -1 0 9.38000011 Tm 
[(S)10(o)10(m)10(e)( )]TJ 
21.24200058 0 Td 
[(t)10(e)10(x)10(t)( )]TJ 

添加空格，然后可以对其进行操作.但是我想知道如何使用这些附加值来计算ctm和行矩阵.

To add the spaces and then be able to manipulate them. However I was wondering how to calculate the ctm and the line matrix with those added values.

我知道我们将cm与上一个连接起来.

I know that we concatenate cm with the previous one.

cm2 x cm1

cm2 x cm1

Tms未连接Tm2代替Tm1.

The Tms are not concatenated Tm2 replaces Tm1.

我被td运算符和我添加的新空格所困扰.有任何线索吗?

I am stuck with the td operator and the new spaces I added. Any clue?

推荐答案

正如评论中所阐明的，OP并未要求 TJ 数字对当前转换矩阵的影响或文本行矩阵，但改为在文本矩阵 T _m 上.

As clarified in comments, the OP is not asking for effects of the TJ numbers on the current transformation matrix or text line matrix but instead on the text matrix T_m.

在规范ISO 32000-1(等效于ISO 32000-2)的第9.4.4节"文本空间详细信息"中对此进行了说明:绘制字形后(可能后面跟一个数字) TJ 指令数组参数)，文本矩阵应更新如下:

This is explained in the specification ISO 32000-1 (and equivalently in ISO 32000-2) in section 9.4.4 Text Space Details: After drawing a glyph (probably followed by a number in a TJ instruction array argument), the text matrix shall be updated as follows:

在水平模式下， t _x 是位移，在垂直模式下， t _y 为零> t _x 为零， t _y 为位移.适用值的计算方式为

In horizontal mode t_x is the displacement and t_y is zero, in vertical mode t_x is zero and t_y is the displacement. The applicable value is calculated as

即如果您在处理 TJ 指令时进行了此计算，并且当前绘制的字形的字符代码后面有一个数字，则该数字在此处被视为参数 T _j .

I.e. if you do this calculation while processing a TJ instruction and there is a number following the character code for the currently drawn glyph, that number is considered here as the parameterT_j.

因此，如果要确定仅由 TJ 数组参数的数字元素引起的位移，例如如果 TJ 数组参数中的 first 元素是一个数字，或者 TJ 数组参数中有多个连续的数字元素，并且您想知道每个人的效果-以上简化为

Thus, if you want to determine the displacement caused by a number element of a TJ array argument alone — e.g. if the first element in the TJ array argument is a number or if there are multiple consecutive number elements in the TJ array argument and you want to know the effect of each one — the above reduces to

t _x =(-T _j /1000)×T _fs ×T _h

t_x = (−T_j / 1000) × T_fs × T_h

t _y =(-T _j /1000)×T _fs

t_y = (−T_j / 1000) × T_fs

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