XmText and XmTextField Resource

Xm CTL extends XmText and XmTextField by adding a parallel set of movement and deletion actions that operate visually, patterned after the Motif 2.0 CSText widget. The standard Motif 2.1 Text and TextField do not distinguish between logical and physical order: next and forward mean “to the right,” while previous and backward mean “to the left.” CSText, however, makes the proper distinction and defines a new set of actions with strictly physical names (for example, left-character(), delete-right-word(), and so on). These action routines are defined to be sensitive to the XmNlayoutDirection of the widget and to call the appropriate next- or previous- action.

The Xm CTL extensions are slightly more complex than the CSText extensions. The Xm CTL extensions are sensitive not to the global orientation of the widget, but to the specific directionality of the physical characters surrounding the cursor, as determined by the pseudo-XOC, including neutral stabilization.

The new resource name enables you to control selection policy, to provide a rendition tag, and to control alignment.

The set of new Xm CTL actions is roughly the cross product of {Move,Delete,Kill} by {Left,Right} by {Character,Word}. The action set is listed in the following table.

Table 6–2 New Resources in Xm CTL

Name	Class/Type	Access	Default Value
XmNrenditionTag	XmCRenditionTag/XmRString	CSG	XmFONTLIST_DEFAULT_TAG
XmNalignment	XmCAlignment/XmRAlignment	CSG	XmALIGNMENT_BEGINNING
XmNeditPolicy	XmCEditPolicy/XmREditPolicy	CSG	XmEDIT_LOGICAL

XmNrenditionTag

Specifies the rendition tag of the XmRendition that is in the XmNrenderTable resource, used for a widget.

XmNalignment

Specifies the text alignment used in the widget. Only XmALIGNMENT_END and XmALIGNMENT_CENTER are supported.

XmNeditPolicy

Specifies the editing policy used for the widget, either XmEDIT_LOGICAL or XmEDIT_VISUAL. In the case of XmEDIT_VISUAL, selection, cursor movement, and deletion are in a visual style. Setting this resource also changes the translations for the standard keyboard movement and deletion events either to the new “visual” actions list or to the existing logical actions.

Character Orientation Action Routines

The forward-cell() and backward-cell() actions query the orientation of the character in the direction specified. If the direction is left-to-right, these actions call the corresponding next-/forward- or previous-/backward- variants.

Character Orientation Additional Behavior

The actions determine the orientation of characters by using the Layout Services transformation OutToInp and Property buffers for the nesting level. The widget's behavior is therefore dependent on the locale-specific transformation. If the information in the OutToInp or, especially, Property buffers is inaccurate, the widget might behave unexpectedly. Moreover, as the locale-specific modules fall outside of the scope of this specification, bidirectional editing behavior can differ from platform to platform for the same text, application, resource values, and LayoutObject configuration.

The visual mode actions result in a display of cell-based behavior. The logical mode actions result in logical character-based behavior. For example, the delete-right-character() operation deletes the input buffer characters that correspond to the display cell. That is, one input buffer character whole LayoutObject transformation “property” byte “new cell indicator” is 1, and all succeeding characters whose “new cell indicator” is 0.

For more information on the Property buffer, see the specification for m_transform_layout() in CAE Specification.

Similarly, for backward-character(), the insertion point is moved backward one character in the input buffer, and the cursor is redrawn at the visual location corresponding to the associated output buffer character. Therefore, several keystrokes are required to move across a composite display cell. The cursor does not actually change display location as the insertion point moves across input buffer characters such as diacritics or ligature fragments whose “new cell indicator” is 0.

This behavior means that deletion operates either from the logical/input buffer side, or from the display cell level of the physical/output side. No mode exists for a strict, physical character-by-character deletion because no one-to-one correspondence exists between the input and output buffers. A given physical character can represent only a fragment of a logical character, for example.

XmText Action Routines

The following list describes the XmText action routines.

left-character(extend)

If the XmNeditPolicy is XmEDIT_LOGICAL and it is called without arguments, the insertion cursor moves back logically by a character. If the insertion cursor is at the beginning of the line, the insertion cursor moves to the logical last character of the previous line, if one exists. Otherwise, the insertion cursor position doesn't change.

If the XmNeditPolicy is XmEDIT_VISUAL, then the cursor moves to the left of the cursor position. If the insertion cursor is at the beginning of the line, then it moves to the end character of the previous line, if one exists.

If left-character() is called with an extend argument, the insertion cursor moves as in the case of no argument, and extends the current selection.

The left-character() action produces calls to the XmNmotionVerifyCallback procedures with the reason value XmCR_MOVING_INSERT_CURSOR. If called with an extend argument, this action can produce calls to the XmNgainPrimaryCallback procedures. See the callback description in the Motif Programmer's Reference for more information.

right-character(extend)

If the XmNeditPolicy is XmEDIT_LOGICAL and it is called without any arguments, the insertion cursor moves logically forward by a character. If the insertion cursor is at the logical end of the line, this action moves the insertion cursor to the logical start of the next line, if one exists.

If the XmNeditPolicy is XmEDIT_VISUAL, then the cursor moves to the right of the cursor position. If the insertion cursor is at the end of the line, it moves the insertion cursor to the starting of the next line, if one exists.

If called with an argument of extend, XmNeditPolicy moves the insertion cursor as in the case of no argument, and extends the current selection.

The right-character() action produces calls to the XmNmotionVerifyCallback procedures with the reason value XmCR_MOVING_INSERT_CURSOR. If called with extend argument, this action can produce calls to the XmNgainPrimaryCallback procedures. See the callback description in the Motif Programmer's Reference for more information.

right-word(extend)

If the XmNeditPolicy is XmEDIT_LOGICAL and it is called without any arguments, the insertion cursor moves to the logical starting character of the logical succeeding word, if one exists. Otherwise, the cursor moves to the logical end of the current word. If the insertion cursor is at the logical end of the line or in the logical last word of the line, the cursor moves to the logical first word in the next line, if one exists. Otherwise, the cursor moves to the logical end of the current word.

If the XmNeditPolicy is XmEDIT_VISUAL and it is called without arguments, the insertion cursor moves to the first non whitespace character after the first white space character to the right or after the end of the line.

If called with an argument of extend, the insertion cursor moves as in the case of no argument and extends the current selection.

The left-word() action produces calls to the XmNmotionVerifyCallback procedures with the reason value XmCR_MOVING_INSERT_CURSOR. If called with extend argument, this action can produce calls to the XmNgainPrimaryCallback procedures. See the callback description in the Motif Programmer's Reference for more information.

delete-left-character()

If the XmNeditPolicy is XmEDIT_LOGICAL, it is equivalent to delete-previous-char(). If the XmNeditPolicy is XmEDIT_VISUAL, then in normal mode, if the selection is non-null, it deletes the selection. Otherwise this action deletes the character to the left of the insertion cursor. In add mode, if the selection is non-null, the cursor is not disjointed from the selection, and XmNpendingDelete is set to True, this action deletes the selection. Otherwise, the action deletes the character to the left of the insertion cursor, which can affect the selection.

The delete-left-character() action produces calls to the XmNmodifyVerifyCallback procedures with the reason value XmCR_MODIFYING_TEXT_VALUE and the XmNvalueChangedCallback procedures with the reason value XmCR_VALUE_CHANGED.

delete-right-character()

If the XmNeditPolicy is XmEDIT_VISUAL, it is equivalent to delete-next-character(). If the XmNeditPolicy is XmEDIT_VISUAL, then in normal mode, if the selection is a non-null, it deletes the selection. Otherwise, it deletes the character to the right of the insertion cursor. In add mode, if there is a non-null selection and the cursor is not disjointed from the selection, the XmNpendingDelete is set to True and the selection is deleted. Otherwise, the character to the right of the insertion cursor is deleted. This action can affect the selection.

The delete-right-character() action produces calls to the XmNmodifyVerify-Callback procedures with reason value XmCR_MODIFYING_TEXT_VALUE, and the XmNvalue-ChangedCallback procedures with reason value XmCR_VALUE_CHANGED.

A few cell-based routines are implemented to support character composition, ligatures, and diacritics. In other words, two or more characters might be represented by a single glyph occupying one presentation cell.

The XmText cell action routines are as described in the following list.

backward-cell(extend)

Moves the insertion cursor back one cell. If the XmNeditPolicy is XmEDIT_LOGICAL, then the insertion cursor is moved to the start of the cell that precedes the current cell logically, if one exists. Otherwise, the cursor moves to the start of the current cell.

If the XmNeditPolicy is XmEDIT_VISUAL, then the cursor moves to the start of cell to the left of the cursor, if one exists. The prev-cell() action produces calls to the XmNmotionVerifyCallback procedures with the reason value XmCR_MOVING_INSERT_CURSOR. If called with an extend argument, this action can produce calls to the XmNgainPrimaryCallback procedures. See the callback description in the Motif Programmer's Reference for more information.

forward-cell(extend)

Moves the insertion cursor to the start of the logical next cell, if one exists. Otherwise this action moves the cursor to the end of the cell. If the XmNeditPolicy is XmEDIT_LOGICAL, then the cursor moves forward one cell.

If the XmNeditPolicy is XmEDIT_VISUAL, then the cursor moves to the start of the cell to the right of the cursor position, if one exists; otherwise, it moves to the end of the current cell. The forward-cell() action produces calls to the XmNmotionVerifyCallback procedures with the reason value XmCR_MOVING_INSERT_CURSOR. If called with an extend argument, this action can produce calls to the XmNgainPrimaryCallback procedures. See the callback description in the Motif Programmer's Reference for more information.