The graPHIGS Programming Interface: Technical Reference

Appendix B. Event Data Formats

Event Summary

The following table summarizes all events supported by the graPHIGS APIscreen In this table, columns titled as "major" and "minor" show the contents of major and minor code parameters for various event related functions. When the column has "None", the corresponding parameter is not set by the graPHIGS APIscreen The last column shows a GET function to be used for retrieving the detail event data of each event. When it has "None", the event has no event data to be retrieved. In this case, a GET function will result in an error.

Class	Meaning	Major	Minor	Data
1	Locator	Workstation ID	Device number	Locator
2	Stroke	Workstation ID	Device number	Stroke
3	Valuator	Workstation ID	Device number	Valuator
4	Choice	Workstation ID	Device number	Choice
5	Pick	Workstation ID	Device number	(Extended) Pick
6	String	Workstation ID	Device number	String
11	Locator_Break Event	Workstation ID	Device Number	None
12	Stroke_Break Event	Workstation ID	Device Number	None
13	Valuator_Break Event	Workstation ID	Device Number	None
14	Choice_Break Event	Workstation ID	Device Number	None
15	Pick_Break Event	Workstation ID	Device Number	None
16	String_Break Event	Workstation ID	Device Number	None
101	Link switch out	Workstation ID	0	None
102	Link switch in	Workstation ID	0	None
103	Update completion	Workstation ID	Display status	None
104	Input overflow events	Workstation ID	0	None
105	Window Resize Notification Event	Workstation ID	0	None
106	Window Exposure Notification Event	Workstation ID	0	Exposure data
107	Window Deletion Notification Event	Workstation ID	0	None
201	Broadcast message	Sender supplied	Sender supplied	Message
202	Private message	Sender supplied	Sender supplied	Message
301	Threshold Exceeded	Structure Store ID	Threshold value	None
401	Error Event	Error Number	0	None

Event Data Format

When the application specifies an event exit routine, the following event data and its length are also passed to the routine.

Locator Event (Event Class 1)

                    ---------------------
     WORD  1        |       view        |  Fullword integer
                    ---------------------
           2-4      |       position    |  3 short floating-point numbers
                    ---------------------

view: View index in which the locator position resides.
position: Locator 3-D position in world coordinates.

The length of this event data is always 16.

Stroke Event (Event Class 2)

                    ---------------------
     WORD  1        |       view        |  Fullword integer
                    ---------------------
           2        |       number      |  Fullword integer
                    ---------------------
           3-n      |       plist       |  Array of 3 short
                    /                   /  floating-point numbers
                    |                   |
                    ---------------------

view: View index in which the stroke points reside.
number: Number of points in the stroke point list.
plist: A list of 3-D points in world coordinates.

The length of this event data is n x 12 + 8.

Valuator Event (Event Class 3)

                    ---------------------
     WORD  1        |       value       |  Short floating-point number
                    ---------------------

value: Valuator value.
The length of this event data is always 4.

Choice Event (Event Class 4)

                    ---------------------
     WORD  1        |       status      |  Fullword integer
                    ---------------------
           2        |       choice      |  Fullword integer
                    ---------------------

status

Choice device status. This parameter takes one of the following values.

1 =: NO_CHOICE
2 =: OK

choice

Choice alternative. When the choice status is 2 = OK , this parameter includes one of the choice alternatives available on the choice device. Otherwise, this parameter may contain any number.

The length of this event data is always 8.

Pick Event (Event Class 5)

                    ---------------------
     WORD  1        |       status      |  Fullword integer
                    ---------------------
 
                    ---------------------
     WORD  1        |       status      |  Fullword integer
                    ---------------------
           2        |       depth       |  Fullword integer
                    ---------------------
           3-n      |       n-path      |  Array of 3 fullword integers
                    /                   /
                    |                   |
                    ---------------------
 
                    ---------------------
     WORD  1        |       status      |  Fullword integer
                    ---------------------
           2        |       view        |  Fullword integer
                    ---------------------
           3-18     |       modelx      |  16 short floating-point numbers
                    |                   |
                    ---------------------
          19-21     |       pos         |  3 short floating-point numbers
                    |                   |
                    ---------------------
          22        |       depth       |  Fullword integer
                    ---------------------
          23-n      |       x-path      |  Array of 4 fullword integers
                    /                   /
                    |                   |
                    ---------------------

status

Pick status. This parameter takes one of the following values and specifies which format is actually used.

0 =: NO_PICK
1 =: OK_NORMAL PICK
2 =: OK_EXTENDED PICK

When the pick status is 0 = NO PICK , the first format is used and so the length of the event data is 4. Otherwise, the event data is represented by the second or third format according to the pick device's type. If the device is the normal pick device, the second format is used. If the device is the extended pick device, the third format is used.

depth

Pick path depth.

n-path

Normal pick path. This parameter is a list of pick path triplets, -- a structure identifier, a pick identifier and an element number.

view

View index of a view in which the picked primitive resides.

modelx

Composite modeling transformation applied to the picked primitive. Elements of the transformation matrix are returned in the order M₁₁ ,M₁₂ ,M₁₃ ,M₁₄ ...

pos

3-D position in NPC where the center of pick aperture existed when the pick occurred.

x-path

Extended pick path. This parameter is a list of pick path quadruples, -- a structure identifier, a pick identifier, a label identifier and a structure element number.

String Event (Event Class 6)

                    ---------------------
     WORD  1        |       length      |  Fullword integer
                    ---------------------
           2-n      |       string      |  Character string
                    /                   /
                    |                   |
                    ---------------------

length: Length of the character string in bytes (does not include the length field itself).
string: Character string. When the length of this character string is not a multiple of 4, up to 3 padding bytes are supplied. Therefore, the length of this event data is ((length+7) /4)x4.

Window Exposure Event (Event Class 106)

                    ---------------------
     WORD  1        |   Exposure data   |  0-31 bits
                    ---------------------
     WORD  2        |   Exposure data   |  32-63 bits
                    ---------------------

exposure data

64 bits of data indicating which of the views in numerical order are affected by the exposure event. Bit 0 is the flag for view 0 and is the most significant bit. Each bit is set as follows:

0 =: NOT_AFFECTED_BY_EXPOSURE
1 =: IS_AFFECTED_BY_EXPOSURE

Application Message Event (Event Class 201 and 202)

                    ---------------------
     WORD  1        |       length      |  Fullword integer
                    ---------------------
           2-n      |  message data     |  Byte string
                    /                   /
                    |                   |
                    ---------------------

length: Length of the character string in bytes (does not include the length field itself).
message data: A byte string supplied by the sender. When the length of this data is not a multiple of 4, up to 3 padding bytes are supplied. Therefore, the length of this event data is ((length+7) /4)x4.