# X11 INPUT SYNTHESIS EXTENSION PROPOSAL

X Consortium Standard

Version 1.0
Larry Woestman
Member of Technical Staff Hewlett Packard
1993 X Consortium

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This is a proposal for an extension to the X11 server and Xlib.

## Introduction

This is a proposal for an extension to the X11 server and Xlib. It provides two capabilities:

- It allows a client to generate user input actions in the server without requiring a user to be present.

- It also allows a client to control the handling of user input actions by the server.

The capability to allow a client to generate user input actions in the server will be used by some of the X Testing Consortium Xlib tests. Both capabilities will be used by the X Testing Consortium client exerciser program. These capabilities may also be useful in other programs.

This extension requires modification to device-dependent code in the server. Therefore it is not a 'portable' extension as defined by the X11 Server Extensions document. However, the majority of the code and functionality of this extension will be implementation-independent.

## Conventions Used In This Document

The naming conventions used in the Xlib documentation are followed with these additions:

- The names of all functions defined in this extension begin with 'XTest', with the first letter of each additional word capitalized.

- The names of the protocol request structures follow the Xlib convention of 'x<name>Req'.

- The names of the protocol request minor type codes follow the Xlib convention of 'X_<name>'.

- The names of all other constants defined in this extension begin with 'XTest', with the rest of the name in upper case letters.

- All constants and structures defined in this extension will have their values specified in the 'xtestext1.h' file (listed in section 5).

## Definition Of Terms

### Input Actions

Input actions are pointer movements, button presses and releases, and key presses and releases. They can be generated by a user or by a client (using functions in this extension).

### User Input Actions

User input actions are input actions that are generated by the user moving a pointing device (typically a mouse), pressing and releasing buttons on the pointing device, and pressing and releasing keys on the keyboard.

## What Does This Extension Do?

Without this extension, user input actions are processed by the server, and are converted into normal X events that are sent to the appropriate client or clients.

This extension adds the following capabilities:

- Input actions may be sent from a client to the server to be processed just as if the user had physically performed them. The input actions are provided to the server in the form of X protocol requests defined by this extension. The information provided to the server includes what action should be performed, and how long to delay before processing the action in the server.

- User input actions may be diverted to a client before being processed by the server. The effect on the server is as if the user had performed no input action. The user input actions are provided to the client in the form of X events defined by this extension. The information provided to the client includes what user input action occurred and the delay between this user input action and the previous user input action. The client may then do anything it wishes with this information.

- User input actions may be copied, with one copy going to the server in the normal way, and the other copy being sent to a client as described above.

## Functions In This Extension

### High Level Functions

These functions are built on top of the low level functions described later.

#### XTestMovePointer

int `XTestMovePointer` Display *display int device_id unsigned long delay int x int y unsigned int count

display

  Specifies the connection to the X server.

device_id

  Specifies which pointer device was supposed to have caused the input action. This is a provision for future support of multiple (distinguishable) pointer devices, and should always be set to 0 for now.

delay

  Specifies the time (in milliseconds) to wait before each movement of the pointer.

x, y

  Specifies the x and y coordinates to move the pointer to relative to the root window for the specified display.

count

  Specifies the number of 'delay, x, y' triplets contained in the delay, x and y arrays.

The `XTestMovePointer` function creates input actions to be sent to the the server. The input actions will be accumulated in a request defined by this extension until the request is full or the XTestFlush function is called. They will then be sent to the server. When the input actions are sent to the server, the input actions will cause the server to think that the pointer was moved to the specified position(s), with the specified delay before each input action.

The `XTestMovePointer` function will return -1 if there is an error, and 0 otherwise.

#### XTestPressButton

int `XTestPressButton` Display *display int device_id unsigned long delay unsigned int button_number unsigned int button_action

display

  Specifies the connection to the X server.

device_id

  Specifies which button device was supposed to have caused the input action. This is a provision for future support of multiple (distinguishable) button devices, and should always be set to 0 for now.

delay

  Specifies the time (in milliseconds) to wait before the input action.

button_number

  Specifies which button is being acted upon.

button_action

  Specifies the action to be performed (one of XTestPRESS, XTestRELEASE, or XTestSTROKE).

The `XTestPressButton` function creates input actions to be sent to the the server. The input actions will be accumulated in a request defined by this extension until the request is full or the XTestFlush function is called. They will then be sent to the server. When the input actions are sent to the server, the input actions will cause the server to think that the specified button was moved as specified.

The `XTestPressButton` function will return -1 if there is an error, and 0 otherwise.

#### XTestPressKey

int `XTestPressKey` Display *display int device_id unsigned long delay unsigned int keycode unsigned int key_action

display

  Specifies the connection to the X server.

device_id

  Specifies which keyboard device was supposed to have caused the input action. This is a provision for future support of multiple (distinguishable) keyboard devices, and should always be set to 0 for now.

delay

  Specifies the time (in milliseconds) to wait before the input action.

keycode

  Specifies which keycode is being acted upon.

key_action

  Specifies the action to be performed (one of XTestPRESS, XTestRELEASE, or XTestSTROKE).

The `XTestPressKey` function creates input actions to be sent to the the server. The input actions will be accumulated in a request defined by this extension until the request is full or the XTestFlush function is called. They will then be sent to the server. When the input actions are sent to the server, the input actions will cause the server to think that the specified key on the keyboard was moved as specified.

The `XTestPressKey` function will return -1 if there is an error, and 0 otherwise.

#### XTestFlush

int `XTestFlush` Display *display

display

  Specifies the connection to the X server.

The `XTestFlush` will send any remaining input actions to the server.

The `XTestFlush` function will return -1 if there is an error, and 0 otherwise.

### Low Level Functions

#### XTestGetInput

int `XTestGetInput` Display *display int action_handling

display

  Specifies the connection to the X server.

action_handling

  Specifies to the server what to do with the user input actions. (one of 0, XTestPACKED_MOTION or XTestPACKED_ACTIONS; optionally 'or'ed with XTestEXCLUSIVE).

The `XTestGetInput` function tells the server to begin putting information about user input actions into events to be sent to the client that called this function. These events can be read via the Xlib `XNextEvent`fR function.

The server assigns an event type of XTestInputActionType to these events to distinguish them from other events. Since the actual value of the event type may vary depending on how many extensions are included with an X11 implementation, XTestInputActionType is a variable that will be contained in the Xlib part of this extension. It may be referenced as follows:

extern int XTestInputActionType;

- An action_handling value of 0 causes the server to send one user input action in each XTestInputActionType event. This can sometimes cause performance problems.

- An action_handling value of XTestPACKED_ACTIONS causes the server to pack as many user input actions as possible into a XTestInputActionType event. This is needed if user input actions are happening rapidly (such as when the user moves the pointer) to keep performance at a reasonable level.

- An action_handling value of XTestPACKED_MOTION causes the server to pack only user input actions associated with moving the pointer. This allows the client to receive button and key motions as they happen without waiting for the event to fill up, while still keeping performance at a reasonable level.

- An action_handling value with XTestEXCLUSIVE 'or'ed in causes the server to send user input actions only to the client. The effect on the server is as if the user had performed no input actions.

- An action_handling value without XTestEXCLUSIVE causes the server to copy user input actions, sending one copy to the client, and handling the other copy normally (as it would if this extension were not installed).

There are four types of input actions that are passed from the server to the client. They are:

key/button~state~change

  This type of input action contains the keycode of the key or button that changed state; whether the key or button is up or down, and the time delay between this input action and the previous input action.

pointer~motions

  This type of input action contains information about the motion of the pointer when the pointer has only moved a short distance. If the pointer has moved a long distance, the pointer jump input action is used.

pointer~jumps

  This type of input action contains information about the motion of the pointer when the pointer has moved a long distance.

delays

  This type of input action is used when the delay between input actions is too large to be held in the other input actions.

The `XTestGetInput` function will return -1 if there is an error, and 0 otherwise.

An error code of BadAccess means that another client has already requested that user input actions be sent to it.

#### XTestStopInput

int `XTestStopInput` Display *display

display

  Specifies the connection to the X server.

The `XTestStopInput` function tells the server to stop putting information about user input actions into events. The server will process user input actions normally (as it would if this extension were not in the server).

The `XTestStopInput` function will return -1 if there is an error, and 0 otherwise.

An error code of BadAccess means that a request was made to stop input when input has never been started.

#### XTestFakeInput

int `XTestFakeInput` Display *display char *action_list_addr int action_list_size int ack_flag

display

  Specifies the connection to the X server.

action_list_addr

  Specifies the address of an list of input actions to be sent to the server.

action_list_size

  Specifies the size (in bytes) of the list of input actions. It may be no larger than XTestMAX_ACTION_LIST_SIZE bytes.

ack_flag

  Specifies whether the server needs to send an event to indicate that its input action buffer is empty (one of XTestFAKE_ACK_NOT_NEEDED or XTestFAKE_ACK_REQUEST).

The `XTestFakeInput` function tells the server to take the specified user input actions and process them as if the user had physically performed them.

The server can only accept a limited number of input actions at one time. This limit can be determined by the `XTestQueryInputSize` function in this extension.

The client should set ack_flag to XTestFAKE_ACK_NOT_NEEDED on calls to XTestFakeInput that do not reach this limit.

The client should set ack_flag to XTestFAKE_ACK_REQUEST on the call to XTestFakeInput that reaches this limit.

When the server sees an ack_flag value of XTestFAKE_ACK_REQUEST it finishes processing its input action buffer, then sends an event with type XTestFakeAckType to the client. When the client reads this event, it knows that it is safe to resume sending input actions to the server.

Since the actual value of the event type may vary depending on how many extensions are included with an X11 implementation, XTestFakeAckType is a variable that is contained in the Xlib part of this extension. It may be referenced as follows:

extern int XTestFakeAckType;

There are four types of input actions that are passed from the client to the server. They are:

key/button~state~change

  This type of input action contains the keycode of the key or button that is to change state; whether the key or button is to be up or down, and the time to delay before changing the state of the key or button.

pointer~motions

  This type of input action contains information about the motion of the pointer when the pointer is to be moved a short distance, and the time to delay before moving the pointer. If the pointer is to be moved a long distance, the pointer jump input action must be used.

pointer~jumps

  This type of input action contains information about the motion of the pointer when the pointer is to be moved a long distance, and the time to delay before moving the pointer.

delays

  This type of input action is used when the delay between input actions is too large to be held in the other input actions.

The `XTestFakeInput` function will return -1 if there is an error, and 0 otherwise.

An error code of \fIBadAccess\fR means that another client has already sent user input actions to the server, and the server has not finished processing the user input actions.

#### XTestQueryInputSize

int `XTestQueryInputSize` Display *display unsigned long size_return

display

  Specifies the connection to the X server.

size_return

  Returns the number of input actions that the server's input action buffer can hold.

The `XTestQueryInputSize` function asks the server to return the number of input actions that it can hold in its input action buffer in the unsigned long pointed to by \fIsize_return\fR.

The `XTestQueryInputSize` function will return -1 if there is an error, and 0 otherwise.

#### XTestReset

int `XTestReset` Display *display

display

  Specifies the connection to the X server.

The `XTestReset` function tells the server to set everything having to do with this extension back to its initial state. After this call the server will act as if this extension were not installed until one of the extension functions is called by a client. This function is not normally needed, but is included in case a client wishes to clean up the server state, such as after a serious error.

The `XTestReset` function will return -1 if there is an error, and 0 otherwise.