Appendix B. ECL Planes -- Format and Content

This appendix describes the format and contents of the different data planes in the ECL presentation space model. Each plane represents a distinct aspect of the host presentation space, such as its character contents, color specifications, field attributes, and so on. The ECL::GetScreen methods and others return data from the different presentation space planes.

Each plane contains one byte per host presentation space character position. Each plane is described in the following sections in terms of its logical contents and data format. The plane types are enumerated in the ECLPS.HPP header file.

TextPlane

The text plane represents the visible characters of the presentation space. Non-display fields are shown in the text plane. The byte value of each element of the text plane corresponds to the ASCII value of the displayed character. The text plane does not contain any binary zero (null) character values. Any null characters in the presentation space (such as null-padded input fields) are represented as ASCII blank (0x20) characters.

FieldPlane

The field plane represents the field positions and their attributes in the presentation space. This plane is meaningful only for field-formatted presentation spaces. (For example, VT connections are not formatted).

This plane is a sparse-array of field attribute values. All values in this plane are binary zero except for where field attribute characters are present in the presentation space. At those positions, the values are the attributes of the field which starts at that location. The length of a field is the linear distance between the field attribute position and the next field attribute in the presentation space, not including the attribute position itself.

The value of the field attribute positions are as shown in the following tables.

Note:
Attribute values are different for different types of connections.
Table 4. 3270 Field Attributes
Bit Position (0 is least significant bit) Meaning
7 Always "1"
6 Always "1"
5
0
Unprotected
1
Protected
4
0
Alphanumeric data
1
Numeric data only
3, 2
0, 0
Normal intensity, not pen detectable
0, 1
Normal intensity, pen detectable
1, 0
High intensity, pen detectable
1, 1
Nondisplay, not pen detectable
1 Reserved
0
0
Field has not been modified
1
Unprotected field has been modified

Table 5. 5250 Field Attributes
Bit Position (0 is least significant bit) Meaning
7 Always "1"
6
0
Nondisplay
1
Display
5
0
Unprotected
1
Protected
4
0
Normal intensity
1
High intensity
3, 2, 1
0, 0, 0
Alphanumeric data
0, 0, 1
Alpha only
0, 1, 0
Numeric shift
0, 1, 1
Numeric data plus numeric specials
1, 0, 1
Numeric only
1, 1, 0
Magnetic stripe reading device data only
1, 1, 1
Signed numeric only
0
0
Field has not been modified
1
Unprotected field has been modified

Table 6 defines the various mask values:

Table 6. Mask Values
Mnemonic Mask Description
FATTR_MDT 0x01 Modified field
FATTR_PEN_MASK 0x0C Pen detectable field
FATTR_BRIGHT 0x08 Intensified field
FATTR_DISPLAY 0x0C Visible field
FATTR_ALPHA 0x10 Alphanumeric field
FATTR_NUMERIC 0x10 Numeric only field
FATTR_PROTECTED 0x20 Protected field
FATTR_PRESENT 0x80 Field attribute present
FATTR_52_BRIGHT 0x10 5250 intensified field
FATTR_52_DISP 0x40 5250 visible field

ColorPlane

The color plane contains color information for each character of the presentation space. The foreground and background color of each character is represented as it is specified in the host data stream. The colors in the color plane are not modified by any color display mapping of the emulator window. Each byte of the color plane contains the following color information.

Table 7. Color Plane Information
Bit Position (0 is least significant bit) Meaning
7 - 4 Background character color
0x0
Blank
0x1
Blue
0x2
Green
0x3
Cyan
0x4
Red
0x5
Magenta
0x6
Brown (3270), Yellow (5250)
0x7
White
3-0 Foreground character color
0x0
Blank
0x1
Blue
0x2
Green
0x3
Cyan
0x4
Red
0x5
Magenta
0x6
Brown (3270), Yellow (5250)
0x7
White (normal intensity)
0x8
Gray
0x9
Light blue
0xA
Light green
0xB
Light cyan
0xC
Light red
0xD
Light magenta
0xE
Yellow
0xF
White (high intensity)

ExfieldPlane

This plane contains extended character attribute data.

This plane is a sparse-array of extended character attribute values. All values in the array are binary zero except for character in the presentation space for which the host has specified extended character attributes. The meaning of the extended character attribute values are as follows.

Table 8. 3270 Extended Character Attributes
Bit Position (0 is least significant bit) Meaning
7, 6 Character highlighting
0, 0
Normal
0, 1
Blink
1, 0
Reverse video
1, 1
Underline
5, 4, 3 Character color
0, 0, 0
Default
0, 0, 1
Blue
0, 1, 0
Red
0, 1, 1
Pink
1, 0, 0
Green
1, 0, 1
Turquoise
1, 1, 0
Yellow
1, 1, 1
White
2, 1 Character attribute
00
Default
11
Double byte character
0 Reserved

Table 9. 5250 Extended Character Attributes
Bit Position (0 is least significant bit) Meaning
7
0
Normal image
1
Reverse image
6
0
No underline
1
Underline
5
0
No blink
1
Blink
4
0
No column separator
1
Column separator
3, 2, 1, 0 Reserved