The text plane represents the visible characters of the presentation space. Non-display fields are shown in the text plane. The value of each element of the text plane corresponds to the Unicode value of the displayed character. The text plane does not contain binary zero (null) character values. Any null characters in the presentation space (such as null-padded input fields) are represented as Unicode blank (0x0020) characters.
When dealing with DBCS languages, the text plane has some unique characteristics. Because each double-byte character takes up two positions in the presentation space, the text plane actually contains two of the same Unicode DBCS characters at the positions corresponding to the two positions the single character occupies in the presentation space. This characteristic is analogous to the two bytes required to represent a double-byte character in the ASCII and EBCDIC character sets. The DBCS Plane can be used to determine whether a character is the first or second in these pairs of duplicate characters.
Note that HACL provides two sets of methods in ECLPS and ECLField which handle double-byte characters differently depending on the needs of an applet. In general the methods ending in String will handle duplicating double-byte characters to be stored in the text plane or removing duplicate double-byte characters which are returned. The methods ending in Screen and Text will return text plane data with duplicated double-byte characters still intact or will only accept data that contains appropriately duplicated double-byte characters. In single-byte environments, the two sets of methods function the same.
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