| 1 | # Copyright (c) 1990-1994 The Regents of the University of California. |
| 2 | # Copyright (c) 1994-1996 Sun Microsystems, Inc. |
| 3 | # See the file "license.terms" for information on usage and redistribution |
| 4 | # of this file, and for a DISCLAIMER OF ALL WARRANTIES. |
| 5 | # |
| 6 | # |
| 7 | |
| 8 | =head1 NAME |
| 9 | |
| 10 | Tk::Scale - Create and manipulate Scale widgets |
| 11 | |
| 12 | =for category Tk Widget Classes |
| 13 | |
| 14 | =head1 SYNOPSIS |
| 15 | |
| 16 | I<$scale> = I<$parent>-E<gt>B<Scale>(?I<options>?); |
| 17 | |
| 18 | =head1 STANDARD OPTIONS |
| 19 | |
| 20 | B<-activebackground> B<-font> B<-highlightthickness> B<-repeatinterval> |
| 21 | B<-background> B<-foreground> B<-orient> B<-takefocus> |
| 22 | B<-borderwidth> B<-highlightbackground> B<-relief> B<-troughcolor> |
| 23 | B<-cursor> B<-highlightcolor> B<-repeatdelay> |
| 24 | |
| 25 | See L<Tk::options> for details of the standard options. |
| 26 | |
| 27 | =head1 WIDGET-SPECIFIC OPTIONS |
| 28 | |
| 29 | =over 4 |
| 30 | |
| 31 | =item Name: B<bigIncrement> |
| 32 | |
| 33 | =item Class: B<BigIncrement> |
| 34 | |
| 35 | =item Switch: B<-bigincrement> |
| 36 | |
| 37 | Some interactions with the scale cause its value to change by |
| 38 | ``large'' increments; this option specifies the size of the |
| 39 | large increments. If specified as 0, the large increments default |
| 40 | to 1/10 the range of the scale. |
| 41 | |
| 42 | =item Name: B<command> |
| 43 | |
| 44 | =item Class: B<Command> |
| 45 | |
| 46 | =item Switch: B<-command> |
| 47 | |
| 48 | Specifies the prefix of a L<perl/Tk callback|Tk::callbacks> to invoke whenever the scale's |
| 49 | value is changed via a method. |
| 50 | The actual command consists |
| 51 | of this option followed by a space and a real number indicating the |
| 52 | new value of the scale. |
| 53 | |
| 54 | =item Name: B<digits> |
| 55 | |
| 56 | =item Class: B<Digits> |
| 57 | |
| 58 | =item Switch: B<-digits> |
| 59 | |
| 60 | An integer specifying how many significant digits should be retained |
| 61 | when converting the value of the scale to a string. |
| 62 | If the number is less than or equal to zero, then the scale picks |
| 63 | the smallest value that guarantees that every possible slider |
| 64 | position prints as a different string. |
| 65 | |
| 66 | =item Name: B<from> |
| 67 | |
| 68 | =item Class: B<From> |
| 69 | |
| 70 | =item Switch: B<-from> |
| 71 | |
| 72 | A real value corresponding to the left or top end of the scale. |
| 73 | |
| 74 | =item Name: B<label> |
| 75 | |
| 76 | =item Class: B<Label> |
| 77 | |
| 78 | =item Switch: B<-label> |
| 79 | |
| 80 | A string to display as a label for the scale. For |
| 81 | vertical scales the label is displayed just to the right of the |
| 82 | top end of the scale. For horizontal scales the label is displayed |
| 83 | just above the left end of the scale. If the option is specified |
| 84 | as an empty string, no label is displayed. |
| 85 | |
| 86 | =item Name: B<length> |
| 87 | |
| 88 | =item Class: B<Length> |
| 89 | |
| 90 | =item Switch: B<-length> |
| 91 | |
| 92 | Specifies the desired long dimension of the scale in screen units |
| 93 | (i.e. any of the forms acceptable to B<Tk_GetPixels>). |
| 94 | For vertical scales this is the scale's height; for horizontal scales |
| 95 | it is the scale's width. |
| 96 | |
| 97 | =item Name: B<resolution> |
| 98 | |
| 99 | =item Class: B<Resolution> |
| 100 | |
| 101 | =item Switch: B<-resolution> |
| 102 | |
| 103 | A real value specifying the resolution for the scale. |
| 104 | If this value is greater than zero then the scale's value will always be |
| 105 | rounded to an even multiple of this value, as will tick marks and |
| 106 | the endpoints of the scale. If the value is less than zero then no |
| 107 | rounding occurs. Defaults to 1 (i.e., the value will be integral). |
| 108 | |
| 109 | =item Name: B<showValue> |
| 110 | |
| 111 | =item Class: B<ShowValue> |
| 112 | |
| 113 | =item Switch: B<-showvalue> |
| 114 | |
| 115 | Specifies a boolean value indicating whether or not the current |
| 116 | value of the scale is to be displayed. |
| 117 | |
| 118 | =item Name: B<sliderLength> |
| 119 | |
| 120 | =item Class: B<SliderLength> |
| 121 | |
| 122 | =item Switch: B<-sliderlength> |
| 123 | |
| 124 | Specfies the size of the slider, measured in screen units along the slider's |
| 125 | long dimension. The value may be specified in any of the forms acceptable |
| 126 | to B<Tk_GetPixels>. |
| 127 | |
| 128 | =item Name: B<sliderRelief> |
| 129 | |
| 130 | =item Class: B<SliderRelief> |
| 131 | |
| 132 | =item Switch: B<-sliderrelief> |
| 133 | |
| 134 | Specifies the relief to use when drawing the slider, such as B<raised> |
| 135 | or B<sunken>. |
| 136 | |
| 137 | =item Name: B<state> |
| 138 | |
| 139 | =item Class: B<State> |
| 140 | |
| 141 | =item Switch: B<-state> |
| 142 | |
| 143 | Specifies one of three states for the scale: B<normal>, |
| 144 | B<active>, or B<disabled>. |
| 145 | If the scale is disabled then the value may not be changed and the scale |
| 146 | won't activate. |
| 147 | If the scale is active, the slider is displayed using the color |
| 148 | specified by the B<activeBackground> option. |
| 149 | |
| 150 | =item Name: B<tickInterval> |
| 151 | |
| 152 | =item Class: B<TickInterval> |
| 153 | |
| 154 | =item Switch: B<-tickinterval> |
| 155 | |
| 156 | Must be a real value. |
| 157 | Determines the spacing between numerical |
| 158 | tick marks displayed below or to the left of the slider. |
| 159 | If 0, no tick marks will be displayed. |
| 160 | |
| 161 | =item Name: B<to> |
| 162 | |
| 163 | =item Class: B<To> |
| 164 | |
| 165 | =item Switch: B<-to> |
| 166 | |
| 167 | Specifies a real value corresponding |
| 168 | to the right or bottom end of the scale. |
| 169 | This value may be either less than or greater than the B<from> option. |
| 170 | |
| 171 | =item Name: B<variable> |
| 172 | |
| 173 | =item Class: B<Variable> |
| 174 | |
| 175 | =item Switch: B<-variable> |
| 176 | |
| 177 | Specifies the name of a global variable to link to the scale. Whenever the |
| 178 | value of the variable changes, the scale will update to reflect this |
| 179 | value. |
| 180 | Whenever the scale is manipulated interactively, the variable |
| 181 | will be modified to reflect the scale's new value. |
| 182 | |
| 183 | =item Name: B<width> |
| 184 | |
| 185 | =item Class: B<Width> |
| 186 | |
| 187 | =item Switch: B<-width> |
| 188 | |
| 189 | Specifies the desired narrow dimension of the trough in screen units |
| 190 | (i.e. any of the forms acceptable to B<Tk_GetPixels>). |
| 191 | For vertical scales this is the trough's width; for horizontal scales |
| 192 | this is the trough's height. |
| 193 | |
| 194 | =back |
| 195 | |
| 196 | =head1 DESCRIPTION |
| 197 | |
| 198 | The B<Scale> method creates a new window (given by the |
| 199 | $widget argument) and makes it into a scale widget. |
| 200 | Additional |
| 201 | options, described above, may be specified on the command line |
| 202 | or in the option database |
| 203 | to configure aspects of the scale such as its colors, orientation, |
| 204 | and relief. The B<scale> command returns its |
| 205 | $widget argument. At the time this command is invoked, |
| 206 | there must not exist a window named $widget, but |
| 207 | $widget's parent must exist. |
| 208 | |
| 209 | A scale is a widget that displays a rectangular I<trough> and a |
| 210 | small I<slider>. The trough corresponds to a range |
| 211 | of real values (determined by the B<from>, B<to>, and |
| 212 | B<resolution> options), |
| 213 | and the position of the slider selects a particular real value. |
| 214 | The slider's position (and hence the scale's value) may be adjusted |
| 215 | with the mouse or keyboard as described in |
| 216 | the L<"BINDINGS"> section below. Whenever the scale's value is changed, a Tcl |
| 217 | command is invoked (using the B<command> option) to notify |
| 218 | other interested widgets of the change. |
| 219 | In addition, the value |
| 220 | of the scale can be linked to a Tcl variable (using the B<variable> |
| 221 | option), so that changes in either are reflected in the other. |
| 222 | |
| 223 | Three annotations may be displayed in a scale widget: a label |
| 224 | appearing at the top right of the widget (top left for horizontal |
| 225 | scales), a number displayed just to the left of the slider |
| 226 | (just above the slider for horizontal scales), and a collection |
| 227 | of numerical tick marks just to the left of the current value |
| 228 | (just below the trough for horizontal scales). Each of these three |
| 229 | annotations may be enabled or disabled using the |
| 230 | configuration options. |
| 231 | |
| 232 | =head1 WIDGET METHODS |
| 233 | |
| 234 | The B<Scale> method creates a widget object. |
| 235 | This object supports the B<configure> and B<cget> methods |
| 236 | described in L<Tk::options> which can be used to enquire and |
| 237 | modify the options described above. |
| 238 | The widget also inherits all the methods provided by the generic |
| 239 | L<Tk::Widget|Tk::Widget> class. |
| 240 | |
| 241 | The following additional methods are available for scale widgets: |
| 242 | |
| 243 | =over 4 |
| 244 | |
| 245 | =item I<$scale>-E<gt>B<coords>(?I<value>?) |
| 246 | |
| 247 | Returns a list whose elements are the x and y coordinates of |
| 248 | the point along the centerline of the trough that corresponds |
| 249 | to I<value>. |
| 250 | If I<value> is omitted then the scale's current value is used. |
| 251 | |
| 252 | =item I<$scale>-E<gt>B<get>(?I<x, y>?) |
| 253 | |
| 254 | If I<x> and I<y> are omitted, returns the current value |
| 255 | of the scale. If I<x> and I<y> are specified, they give |
| 256 | pixel coordinates within the widget; the command returns |
| 257 | the scale value corresponding to the given pixel. |
| 258 | Only one of I<x> or I<y> is used: for horizontal scales |
| 259 | I<y> is ignored, and for vertical scales I<x> is ignored. |
| 260 | |
| 261 | =item I<$scale>-E<gt>B<identify>(I<x, y>) |
| 262 | |
| 263 | Returns a string indicating what part of the scale lies under |
| 264 | the coordinates given by I<x> and I<y>. |
| 265 | A return value of B<slider> means that the point is over |
| 266 | the slider; B<trough1> means that the point is over the |
| 267 | portion of the slider above or to the left of the slider; |
| 268 | and B<trough2> means that the point is over the portion |
| 269 | of the slider below or to the right of the slider. |
| 270 | If the point isn't over one of these elements, an empty string |
| 271 | is returned. |
| 272 | |
| 273 | =item I<$scale>-E<gt>B<set>(I<value>) |
| 274 | |
| 275 | This command is invoked to change the current value of the scale, |
| 276 | and hence the position at which the slider is displayed. I<Value> |
| 277 | gives the new value for the scale. |
| 278 | The command has no effect if the scale is disabled. |
| 279 | |
| 280 | =back |
| 281 | |
| 282 | =head1 BINDINGS |
| 283 | |
| 284 | Tk automatically creates class bindings for scales that give them |
| 285 | the following default behavior. |
| 286 | Where the behavior is different for vertical and horizontal scales, |
| 287 | the horizontal behavior is described in parentheses. |
| 288 | |
| 289 | =over 4 |
| 290 | |
| 291 | =item [1] |
| 292 | |
| 293 | If button 1 is pressed in the trough, the scale's value will |
| 294 | be incremented or decremented by the value of the B<resolution> |
| 295 | option so that the slider moves in the direction of the cursor. |
| 296 | If the button is held down, the action auto-repeats. |
| 297 | |
| 298 | =item [2] |
| 299 | |
| 300 | If button 1 is pressed over the slider, the slider can be dragged |
| 301 | with the mouse. |
| 302 | |
| 303 | =item [3] |
| 304 | |
| 305 | If button 1 is pressed in the trough with the Control key down, |
| 306 | the slider moves all the way to the end of its range, in the |
| 307 | direction towards the mouse cursor. |
| 308 | |
| 309 | =item [4] |
| 310 | |
| 311 | If button 2 is pressed, the scale's value is set to the mouse |
| 312 | position. If the mouse is dragged with button 2 down, the scale's |
| 313 | value changes with the drag. |
| 314 | |
| 315 | =item [5] |
| 316 | |
| 317 | The Up and Left keys move the slider up (left) by the value |
| 318 | of the B<resolution> option. |
| 319 | |
| 320 | =item [6] |
| 321 | |
| 322 | The Down and Right keys move the slider down (right) by the value |
| 323 | of the B<resolution> option. |
| 324 | |
| 325 | =item [7] |
| 326 | |
| 327 | Control-Up and Control-Left move the slider up (left) by the |
| 328 | value of the B<bigIncrement> option. |
| 329 | |
| 330 | =item [8] |
| 331 | |
| 332 | Control-Down and Control-Right move the slider down (right) by the |
| 333 | value of the B<bigIncrement> option. |
| 334 | |
| 335 | =item [9] |
| 336 | |
| 337 | Home moves the slider to the top (left) end of its range. |
| 338 | |
| 339 | =item [10] |
| 340 | |
| 341 | End moves the slider to the bottom (right) end of its range. |
| 342 | |
| 343 | If the scale is disabled using the B<state> option then |
| 344 | none of the above bindings have any effect. |
| 345 | |
| 346 | The behavior of scales can be changed by defining new bindings for |
| 347 | individual widgets or by redefining the class bindings. |
| 348 | |
| 349 | =back |
| 350 | |
| 351 | =head1 KEYWORDS |
| 352 | |
| 353 | scale, slider, trough, widget |
| 354 | |
| 355 | =cut |
| 356 | |