1scale(n) Tk Built-In Commands scale(n)
2______________________________________________________________________________
6
8 scale - Create and manipulate scale widgets
9
11 scale pathName ?options?
12
14 -activebackground -foreground -relief
15 -background -highlightbackground -repeatdelay
16 -borderwidth -highlightcolor -repeatinterval
17 -cursor -highlightthickness -takefocus
18 -font -orient -troughcolor
19 See the options manual entry for details on the standard options.
21
23 [-bigincrement bigIncrement] Some interactions with the scale cause its
24 value to change by “large” increments; this option specifies the size
25 of the large increments. If specified as 0, the large increments
26 default to 1/10 the range of the scale. [-command command] Specifies
27 the prefix of a Tcl command to invoke whenever the scale's value is
28 changed via a widget command. The actual command consists of this
29 option followed by a space and a real number indicating the new value
30 of the scale. [-digits digits] An integer specifying how many signifi‐
31 cant digits should be retained when converting the value of the scale
32 to a string. If the number is less than or equal to zero, then the
33 scale picks the smallest value that guarantees that every possible
34 slider position prints as a different string. [-from from] A real
35 value corresponding to the left or top end of the scale.
36 [-label label] A string to display as a label for the scale. For ver‐
37 tical scales the label is displayed just to the right of the top end of
38 the scale. For horizontal scales the label is displayed just above the
39 left end of the scale. If the option is specified as an empty string,
40 no label is displayed. [-length length] Specifies the desired long
41 dimension of the scale in screen units (i.e. any of the forms accept‐
42 able to Tk_GetPixels). For vertical scales this is the scale's height;
43 for horizontal scales it is the scale's width. [-resolution resolu‐
44 tion] A real value specifying the resolution for the scale. If this
45 value is greater than zero then the scale's value will always be
46 rounded to an even multiple of this value, as will tick marks and the
47 endpoints of the scale. If the value is less than zero then no round‐
48 ing occurs. Defaults to 1 (i.e., the value will be integral). [-show‐
49 value showValue] Specifies a boolean value indicating whether or not
50 the current value of the scale is to be displayed. [-slider‐
51 length sliderLength] Specifies the size of the slider, measured in
52 screen units along the slider's long dimension. The value may be spec‐
53 ified in any of the forms acceptable to Tk_GetPixels. [-sliderre‐
54 lief sliderRelief] Specifies the relief to use when drawing the slider,
55 such as raised or sunken. [-state state] Specifies one of three states
56 for the scale: normal, active, or disabled. If the scale is disabled
57 then the value may not be changed and the scale will not activate. If
58 the scale is active, the slider is displayed using the color specified
59 by the activeBackground option. [-tickinterval tickInterval] Must be a
60 real value. Determines the spacing between numerical tick marks dis‐
61 played below or to the left of the slider. If 0, no tick marks will be
62 displayed. [-to to] Specifies a real value corresponding to the right
63 or bottom end of the scale. This value may be either less than or
64 greater than the from option. [-variable variable] Specifies the name
65 of a global variable to link to the scale. Whenever the value of the
66 variable changes, the scale will update to reflect this value. When‐
67 ever the scale is manipulated interactively, the variable will be modi‐
68 fied to reflect the scale's new value. [-width width] Specifies the
69 desired narrow dimension of the trough in screen units (i.e. any of the
70 forms acceptable to Tk_GetPixels). For vertical scales this is the
71 trough's width; for horizontal scales this is the trough's height.
72_________________________________________________________________
73
76 The scale command creates a new window (given by the pathName argument)
77 and makes it into a scale widget. Additional options, described above,
78 may be specified on the command line or in the option database to con‐
79 figure aspects of the scale such as its colors, orientation, and
80 relief. The scale command returns its pathName argument. At the time
81 this command is invoked, there must not exist a window named pathName,
82 but pathName's parent must exist.
83 A scale is a widget that displays a rectangular trough and a small
85 slider. The trough corresponds to a range of real values (determined
86 by the from, to, and resolution options), and the position of the
87 slider selects a particular real value. The slider's position (and
88 hence the scale's value) may be adjusted with the mouse or keyboard as
89 described in the BINDINGS section below. Whenever the scale's value is
90 changed, a Tcl command is invoked (using the command option) to notify
91 other interested widgets of the change. In addition, the value of the
92 scale can be linked to a Tcl variable (using the variable option), so
93 that changes in either are reflected in the other.
94 Three annotations may be displayed in a scale widget: a label appear‐
96 ing at the top right of the widget (top left for horizontal scales), a
97 number displayed just to the left of the slider (just above the slider
98 for horizontal scales), and a collection of numerical tick marks just
99 to the left of the current value (just below the trough for horizontal
100 scales). Each of these three annotations may be enabled or disabled
101 using the configuration options.
102
104 The scale command creates a new Tcl command whose name is pathName.
105 This command may be used to invoke various operations on the widget.
106 It has the following general form:
107 pathName option ?arg arg ...?
108 Option and the args determine the exact behavior of the command. The
109 following commands are possible for scale widgets:
110 pathName cget option
112 Returns the current value of the configuration option given by
113 option. Option may have any of the values accepted by the scale
114 command.
115 pathName configure ?option? ?value option value ...?
117 Query or modify the configuration options of the widget. If no
118 option is specified, returns a list describing all of the avail‐
119 able options for pathName (see Tk_ConfigureInfo for information
120 on the format of this list). If option is specified with no
121 value, then the command returns a list describing the one named
122 option (this list will be identical to the corresponding sublist
123 of the value returned if no option is specified). If one or
124 more option-value pairs are specified, then the command modifies
125 the given widget option(s) to have the given value(s); in this
126 case the command returns an empty string. Option may have any
127 of the values accepted by the scale command.
128 pathName coords ?value?
130 Returns a list whose elements are the x and y coordinates of the
131 point along the centerline of the trough that corresponds to
132 value. If value is omitted then the scale's current value is
133 used.
134 pathName get ?x y?
136 If x and y are omitted, returns the current value of the scale.
137 If x and y are specified, they give pixel coordinates within the
138 widget; the command returns the scale value corresponding to
139 the given pixel. Only one of x or y is used: for horizontal
140 scales y is ignored, and for vertical scales x is ignored.
141 pathName identify x y
143 Returns a string indicating what part of the scale lies under
144 the coordinates given by x and y. A return value of slider
145 means that the point is over the slider; trough1 means that the
146 point is over the portion of the slider above or to the left of
147 the slider; and trough2 means that the point is over the portion
148 of the slider below or to the right of the slider. If the point
149 is not over one of these elements, an empty string is returned.
150 pathName set value
152 This command is invoked to change the current value of the
153 scale, and hence the position at which the slider is displayed.
154 Value gives the new value for the scale. The command has no
155 effect if the scale is disabled.
156
158 Tk automatically creates class bindings for scales that give them the
159 following default behavior. Where the behavior is different for verti‐
160 cal and horizontal scales, the horizontal behavior is described in
161 parentheses.
162 [1] If button 1 is pressed in the trough, the scale's value will be
164 incremented or decremented by the value of the resolution option
165 so that the slider moves in the direction of the cursor. If the
166 button is held down, the action auto-repeats.
167 [2] If button 1 is pressed over the slider, the slider can be
169 dragged with the mouse.
170 [3] If button 1 is pressed in the trough with the Control key down,
172 the slider moves all the way to the end of its range, in the
173 direction towards the mouse cursor.
174 [4] If button 2 is pressed, the scale's value is set to the mouse
176 position. If the mouse is dragged with button 2 down, the
177 scale's value changes with the drag.
178 [5] The Up and Left keys move the slider up (left) by the value of
180 the resolution option.
181 [6] The Down and Right keys move the slider down (right) by the
183 value of the resolution option.
184 [7] Control-Up and Control-Left move the slider up (left) by the
186 value of the bigIncrement option.
187 [8] Control-Down and Control-Right move the slider down (right) by
189 the value of the bigIncrement option.
190 [9] Home moves the slider to the top (left) end of its range.
192 [10] End moves the slider to the bottom (right) end of its range.
194 If the scale is disabled using the state option then none of the above
196 bindings have any effect.
197 The behavior of scales can be changed by defining new bindings for
199 individual widgets or by redefining the class bindings.
200
203 scale, slider, trough, widget
204Tk 4.1 scale(n)