The `wmarkentry` Widget

by

Trevor Williams

phase1geo@gmail.com

Reference

NAME

wmarkentry::wmarkentry - Create and manipulate wmarkentry widgets

SYNOPSIS

wmarkentry::wmarkentry pathName ?options?

STANDARD OPTIONS

-background or -bg
-borderwidth or -bd
-cursor
-exportselection
-font
-foreground or -fg
-highlightbackground
-highlightcolor
-highlightthickness
-insertbackground
-insertborderwidth
-insertofftime
-insertontime
-insertwidth
-justify
-relief
-selectbackground
-selectborderwidth
-selectforeground
-takefocus
-textvariable
-xscrollcommand

ENTRY-SPECIFIC OPTIONS

-disabledbackground
-disabledforeground
-invalidcommand or -invcmd
-readonlybackground
-show
-state
-validate
-validatecommand or -vcmd
-width

WIDGET-SPECIFIC OPTIONS

-watermark text
-watermarkforeground color

DESCRIPTION

WIDGET COMMANDS

pathName bbox
        index

pathName cget
        option

pathName configure
        ?option? ?value option value ...?

pathName delete
        first ?last?

pathName entrytag

pathName get

pathName icursor
        index

pathName index
        index

pathName insert
        index string

pathName scan
          option args

pathName scan mark
            x

pathName scan dragto
            x

pathName selection
          option arg

pathName selection adjust
            index

pathName selection clear

pathName selection from
            index

pathName selection present

pathName selection range
            start end

pathName selection to
            index

pathName validate

pathName xview 
          args

pathName xview

pathName xview index

pathName xview moveto fraction

pathName xview scroll number what

DEFAULT BINDINGS

KEYWORDS

Detailed Reference

NAME

wmarkentry::wmarkentry - Create and manipulate wmarkentry widgets

SYNOPSIS

wmarkentry::wmarkentry pathName ?options?

STANDARD_OPTIONS

-background or -bg
-borderwidth or -bd
-cursor
-exportselection
-font
-foreground or -fg
-highlightbackground
-highlightcolor
-highlightthickness
-insertbackground
-insertborderwidth
-insertofftime
-insertontime
-insertwidth
-justify
-relief
-selectbackground
-selectborderwidth
-selectforeground
-takefocus
-textvariable
-xscrollcommand

See the options manual entry for details on the standard options.

ENTRY-SPECIFIC OPTIONS

-disabledbackground
-disabledforeground
-invalidcommand or -invcmd
-readonlybackground
-show
-state
-validate
-validatecommand or -vcmd
-width

WIDGET-SPECIFIC OPTIONS

Command-Line Name:	`-watermark`
Database Name:	`watermark`
Database Class:	`Watermark`

Specifies a textual string that will be used as a watermark in the entry field. The watermark string cannot be copied or selected and only is visible when the entry field is empty. Once the user begins to type in the entry field, the watermark string is cleared and the user's input data is visible. By default, no watermark is displayed in the entry field. The watermark can be cleared by setting this option to the empty string.

Command-Line Name:	`-watermarkforeground`
Database Name:	`watermarkForeground`
Database Class:	`Foreground`

Specifies the foreground color to use when a watermark is to be displayed in the entry field.

DESCRIPTION

The wmarkentry::wmarkentry command creates a new window named pathName and of the class WMarkEntry, and makes it into a wmarkentry widget. Additional options, described above, may be specified on the command-line or in the option database to configure aspects of the tokenentry sucah as its colors, font, and sizing. The wmarkentry::wmarkentry command returns its pathName argument. At the time this command is invoked, there must not exist a window named pathName, but pathName's parent must exist.

The wmarkentry widget is an entry widget that provides the additional capability of a watermark within the widget when no user data has been entered. The watermark can be any text string and it can also be given its own foreground color. Watermark text is not selectable or copyable, not returned as text when the entry get command is invoked, not navigable (via the insertion cursor), automatically disappears when user text is entered, and automatically reappears when user text is completely removed from the widget. In all other ways, the widget behaves the same as the standard entry widget in Tk.

WIDGET COMMANDS

The wmarkentry::wmarkentry command creates a new Tcl command whose name is pathName. This command may be used to invoke various operations on the widget. It has the following general form:

pathName option ?arg arg ...?

option and the arg determine the exact behavior of the command. The following commands are possible for tokenentry widgets:

pathName bbox index

Returns a list of four numbers describing the bounding box of the character given by index. The first two elements of the list give the x and y coordinates of the upper-left corner of the screen area covered by the character (in pixels relative to the widget) and the last two elements give the width and height of the character, in pixels. The bounding box may refer to a region outside the visible area of the window.

pathName cget option

Returns the current value of the configuration option given by option. Option may have any of the values accepted by the Tk entry command.

pathName configure ?option? ?value option value ...?

Query or modify the configuration options of the widget. If no option is specified, returns a list describing all of the available options for pathName (see Tk_ConfigureInfo for information on the format of this list). If option is specified with no value, then the command returns a list describing the one named option (this list will be identical to the corresponding sublist of the value returned if no option is specified). If one or more option-value pairs are specified, then the command modifies the given widget option(s) to have the given value(s); in this case the command returns an empty string. Option may have any of the values accepted by the Tk entry command.

pathName delete first ?last?

Delete one or more elements of the entry. First is the index of the first character to delete, and last is the index of the character just after the last one to delete. If last is not specified it defaults to first+1, i.e. a single character is deleted. This command returns an empty string.

pathName get

Returns the entry's string.

pathName entrytag

Returns the name of a binding tag whose name depends on the path name of the wmarkentry widget and which is associated with the wmarkentry's entry field. This binding tag precedes the tag WMarkEntryEntry in the list of binding tags of the wmarkentry descendants mentioned above and is designed to be used when defining individual binding scripts for wmarkentry widgets.

pathName icursor index

Arrange for the insertion cursor to be displayed just before the character given by index. Returns an empty string.

pathName index index

Returns the numerical index corresponding to index.

pathName insert index string

Insert the characters of string just before the character indicated by index. Returns an empty string.

pathName scan option args

This command is used to implement scanning on entries. It has two forms, depending on option:

pathName scan mark x: Records x and the current view in the entry window; used in conjunction with later scan dragto commands. Typically this command is associated with a mouse button press in the widget. It returns an empty string.
pathName scan dragto x: This command computes the difference between its x argument and the x argument to the last scan mark command for the widget. It then adjusts the view left or right by 10 times the difference in x-coordinates. This command is typically associated with mouse motion events in the widget, to produce the effect of dragging the entry at high speed through the window. The return value is an empty string.

pathName selection option arg

This command is used to adjust the selection within an entry. It has several forms, depending on option:

pathName selection adjust index: Locate the end of the selection nearest to the character given by index, and adjust that end of the selection to be at index (i.e. including but not going beyond index). The other end of the selection is made the anchor point for future select to commands. If the selection is not currently in the entry, then a new selection is created to include the characters between index and the most recent selection anchor point, inclusive. Returns an empty string.
pathName selection clear: Clear the selection if it is currently in this widget. If the selection is not in this widget then the command has no effect. Returns an empty string.
pathName selection from index: Set the selection anchor point to just before the character given by index. Does not change the selection. Returns an empty string.
pathName selection present: Returns 1 if there is are characters selected in the entry, 0 if nothing is selected.
pathName selection range start end: Sets the selection to include the characters starting with the one indexed by start and ending with the one just before end. If end refers to the same character as start or an earlier one, then the entry's selection is cleared.
pathName selection to index: If index is before the anchor point, set the selection to the characters from index up to but not including the anchor point. If index is the same as the anchor point, do nothing. If index is after the anchor point, set the selection to the characters from the anchor point up to but not including index. The anchor point is determined by the most recent select from or select adjust command in this widget. If the selection is not in this widget then a new selection is created using the most recent anchor point specified for the widget. Returns an empty string.

pathName validate

This command is used to force an evaluation of the validateCommand independent of the conditions specified by the validate option. This is done by temporarily setting the validate option to all. It returns 0 or 1.

pathName xview args

This command is used to query and change the horizontal position of the text in the widget's window. It can take any of the following forms:

pathName xview: Returns a list containing two elements. Each element is a real fraction between 0 and 1; together they describe the horizontal span that is visible in the window. For example, if the first element is .2 and the second element is .6, 20% of the entry's text is off-screen to the left, the middle 40% is visible in the window, and 40% of the text is off-screen to the right. These are the same values passed to scrollbars via the -xscrollcommand option.
pathName xview index: Adjusts the view in the window so that the character given by index is displayed at the left edge of the window.
pathName xview moveto fraction: Adjusts the view in the window so that the character fraction of the way through the text appears at the left edge of the window. Fraction must be a fraction between 0 and 1.
pathName xview scroll number what: This command shifts the view in the window left or right according to number and what. Number must be an integer. What must be either units or pages or an abbreviation of one of these. If what is units, the view adjusts left or right by number average-width characters on the display; if it is pages then the view adjusts by number screenfuls. If number is negative then characters farther to the left become visible; if it is positive then characters farther to the right become visible.

DEFAULT BINDINGS

Tk automatically creates class bindings for entries that give them the following default behavior. In the descriptions below, “word” refers to a contiguous group of letters, digits, or “_” characters, or any single character other than these.

Clicking mouse button 1 positions the insertion cursor just before the character underneath the mouse cursor, sets the input focus to this widget, and clears any selection in the widget. Dragging with mouse button 1 strokes out a selection between the insertion cursor and the character under the mouse.

Double-clicking with mouse button 1 selects the word under the mouse and positions the insertion cursor at the end of the word. Dragging after a double click will stroke out a selection consisting of whole words.

Triple-clicking with mouse button 1 selects all of the text in the entry and positions the insertion cursor at the end of the line.

The ends of the selection can be adjusted by dragging with mouse button 1 while the Shift key is down; this will adjust the end of the selection that was nearest to the mouse cursor when button 1 was pressed. If the button is double-clicked before dragging then the selection will be adjusted in units of whole words.

Clicking mouse button 1 with the Control key down will position the insertion cursor in the entry without affecting the selection.

If any normal printing characters are typed in an entry, they are inserted at the point of the insertion cursor.

The view in the entry can be adjusted by dragging with mouse button 2. If mouse button 2 is clicked without moving the mouse, the selection is copied into the entry at the position of the mouse cursor.

If the mouse is dragged out of the entry on the left or right sides while button 1 is pressed, the entry will automatically scroll to make more text visible (if there is more text off-screen on the side where the mouse left the window).

The Left and Right keys move the insertion cursor one character to the left or right; they also clear any selection in the entry and set the selection anchor. If Left or Right is typed with the Shift key down, then the insertion cursor moves and the selection is extended to include the new character. Control-Left and Control-Right move the insertion cursor by words, and Control-Shift-Left and Control-Shift-Right move the insertion cursor by words and also extend the selection. Control-b and Control-f behave the same as Left and Right, respectively. Meta-b and Meta-f behave the same as Control-Left and Control-Right, respectively.

The Home key, or Control-a, will move the insertion cursor to the beginning of the entry and clear any selection in the entry. Shift-Home moves the insertion cursor to the beginning of the entry and also extends the selection to that point.

The End key, or Control-e, will move the insertion cursor to the end of the entry and clear any selection in the entry. Shift-End moves the cursor to the end and extends the selection to that point.

The Select key and Control-Space set the selection anchor to the position of the insertion cursor. They do not affect the current selection. Shift-Select and Control-Shift-Space adjust the selection to the current position of the insertion cursor, selecting from the anchor to the insertion cursor if there was not any selection previously.

Control-/ selects all the text in the entry.

Control-\ clears any selection in the entry.

The F16 key (labelled Copy on many Sun workstations) or Meta-w copies the selection in the widget to the clipboard, if there is a selection.

The F20 key (labelled Cut on many Sun workstations) or Control-w copies the selection in the widget to the clipboard and deletes the selection. If there is no selection in the widget then these keys have no effect.

The F18 key (labelled Paste on many Sun workstations) or Control-y inserts the contents of the clipboard at the position of the insertion cursor.

The Delete key deletes the selection, if there is one in the entry. If there is no selection, it deletes the character to the right of the insertion cursor.

The BackSpace key and Control-h delete the selection, if there is one in the entry. If there is no selection, it deletes the character to the left of the insertion cursor.

Control-d deletes the character to the right of the insertion cursor.

Meta-d deletes the word to the right of the insertion cursor.

Control-k deletes all the characters to the right of the insertion cursor.

Control-t reverses the order of the two characters to the right of the insertion cursor.

If the entry is empty and only the watermark is displayed, the bindings will work as if the entry is empty.

If the entry is disabled using the -state option, then the entry's view can still be adjusted and text in the entry can still be selected, but no insertion cursor will be displayed and no text modifications will take place except if the entry is linked to a variable using the -textvariable option, in which case any changes to the variable are reflected by the entry whatever the value of its -state option.

The behavior of entries can be changed by defining new bindings for individual widgets or by redefining the class bindings.

KEYWORDS

entry, widget

The wmarkentry Widget

by

Trevor Williams

Reference

Detailed Reference

The `wmarkentry` Widget