| 1 | '\" |
| 2 | '\" Copyright (c) 1994 The Australian National University |
| 3 | '\" Copyright (c) 1994-1997 Sun Microsystems, Inc. |
| 4 | '\" |
| 5 | '\" See the file "license.terms" for information on usage and redistribution |
| 6 | '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. |
| 7 | '\" |
| 8 | '\" Author: Paul Mackerras (paulus@cs.anu.edu.au), |
| 9 | '\" Department of Computer Science, |
| 10 | '\" Australian National University. |
| 11 | '\" |
| 12 | '\" RCS: @(#) $Id: photo.n,v 1.14.2.4 2004/10/28 12:25:22 dkf Exp $ |
| 13 | '\" |
| 14 | '\" The definitions below are for supplemental macros used in Tcl/Tk |
| 15 | '\" manual entries. |
| 16 | '\" |
| 17 | '\" .AP type name in/out ?indent? |
| 18 | '\" Start paragraph describing an argument to a library procedure. |
| 19 | '\" type is type of argument (int, etc.), in/out is either "in", "out", |
| 20 | '\" or "in/out" to describe whether procedure reads or modifies arg, |
| 21 | '\" and indent is equivalent to second arg of .IP (shouldn't ever be |
| 22 | '\" needed; use .AS below instead) |
| 23 | '\" |
| 24 | '\" .AS ?type? ?name? |
| 25 | '\" Give maximum sizes of arguments for setting tab stops. Type and |
| 26 | '\" name are examples of largest possible arguments that will be passed |
| 27 | '\" to .AP later. If args are omitted, default tab stops are used. |
| 28 | '\" |
| 29 | '\" .BS |
| 30 | '\" Start box enclosure. From here until next .BE, everything will be |
| 31 | '\" enclosed in one large box. |
| 32 | '\" |
| 33 | '\" .BE |
| 34 | '\" End of box enclosure. |
| 35 | '\" |
| 36 | '\" .CS |
| 37 | '\" Begin code excerpt. |
| 38 | '\" |
| 39 | '\" .CE |
| 40 | '\" End code excerpt. |
| 41 | '\" |
| 42 | '\" .VS ?version? ?br? |
| 43 | '\" Begin vertical sidebar, for use in marking newly-changed parts |
| 44 | '\" of man pages. The first argument is ignored and used for recording |
| 45 | '\" the version when the .VS was added, so that the sidebars can be |
| 46 | '\" found and removed when they reach a certain age. If another argument |
| 47 | '\" is present, then a line break is forced before starting the sidebar. |
| 48 | '\" |
| 49 | '\" .VE |
| 50 | '\" End of vertical sidebar. |
| 51 | '\" |
| 52 | '\" .DS |
| 53 | '\" Begin an indented unfilled display. |
| 54 | '\" |
| 55 | '\" .DE |
| 56 | '\" End of indented unfilled display. |
| 57 | '\" |
| 58 | '\" .SO |
| 59 | '\" Start of list of standard options for a Tk widget. The |
| 60 | '\" options follow on successive lines, in four columns separated |
| 61 | '\" by tabs. |
| 62 | '\" |
| 63 | '\" .SE |
| 64 | '\" End of list of standard options for a Tk widget. |
| 65 | '\" |
| 66 | '\" .OP cmdName dbName dbClass |
| 67 | '\" Start of description of a specific option. cmdName gives the |
| 68 | '\" option's name as specified in the class command, dbName gives |
| 69 | '\" the option's name in the option database, and dbClass gives |
| 70 | '\" the option's class in the option database. |
| 71 | '\" |
| 72 | '\" .UL arg1 arg2 |
| 73 | '\" Print arg1 underlined, then print arg2 normally. |
| 74 | '\" |
| 75 | '\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $ |
| 76 | '\" |
| 77 | '\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. |
| 78 | .if t .wh -1.3i ^B |
| 79 | .nr ^l \n(.l |
| 80 | .ad b |
| 81 | '\" # Start an argument description |
| 82 | .de AP |
| 83 | .ie !"\\$4"" .TP \\$4 |
| 84 | .el \{\ |
| 85 | . ie !"\\$2"" .TP \\n()Cu |
| 86 | . el .TP 15 |
| 87 | .\} |
| 88 | .ta \\n()Au \\n()Bu |
| 89 | .ie !"\\$3"" \{\ |
| 90 | \&\\$1 \\fI\\$2\\fP (\\$3) |
| 91 | .\".b |
| 92 | .\} |
| 93 | .el \{\ |
| 94 | .br |
| 95 | .ie !"\\$2"" \{\ |
| 96 | \&\\$1 \\fI\\$2\\fP |
| 97 | .\} |
| 98 | .el \{\ |
| 99 | \&\\fI\\$1\\fP |
| 100 | .\} |
| 101 | .\} |
| 102 | .. |
| 103 | '\" # define tabbing values for .AP |
| 104 | .de AS |
| 105 | .nr )A 10n |
| 106 | .if !"\\$1"" .nr )A \\w'\\$1'u+3n |
| 107 | .nr )B \\n()Au+15n |
| 108 | .\" |
| 109 | .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n |
| 110 | .nr )C \\n()Bu+\\w'(in/out)'u+2n |
| 111 | .. |
| 112 | .AS Tcl_Interp Tcl_CreateInterp in/out |
| 113 | '\" # BS - start boxed text |
| 114 | '\" # ^y = starting y location |
| 115 | '\" # ^b = 1 |
| 116 | .de BS |
| 117 | .br |
| 118 | .mk ^y |
| 119 | .nr ^b 1u |
| 120 | .if n .nf |
| 121 | .if n .ti 0 |
| 122 | .if n \l'\\n(.lu\(ul' |
| 123 | .if n .fi |
| 124 | .. |
| 125 | '\" # BE - end boxed text (draw box now) |
| 126 | .de BE |
| 127 | .nf |
| 128 | .ti 0 |
| 129 | .mk ^t |
| 130 | .ie n \l'\\n(^lu\(ul' |
| 131 | .el \{\ |
| 132 | .\" Draw four-sided box normally, but don't draw top of |
| 133 | .\" box if the box started on an earlier page. |
| 134 | .ie !\\n(^b-1 \{\ |
| 135 | \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' |
| 136 | .\} |
| 137 | .el \}\ |
| 138 | \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' |
| 139 | .\} |
| 140 | .\} |
| 141 | .fi |
| 142 | .br |
| 143 | .nr ^b 0 |
| 144 | .. |
| 145 | '\" # VS - start vertical sidebar |
| 146 | '\" # ^Y = starting y location |
| 147 | '\" # ^v = 1 (for troff; for nroff this doesn't matter) |
| 148 | .de VS |
| 149 | .if !"\\$2"" .br |
| 150 | .mk ^Y |
| 151 | .ie n 'mc \s12\(br\s0 |
| 152 | .el .nr ^v 1u |
| 153 | .. |
| 154 | '\" # VE - end of vertical sidebar |
| 155 | .de VE |
| 156 | .ie n 'mc |
| 157 | .el \{\ |
| 158 | .ev 2 |
| 159 | .nf |
| 160 | .ti 0 |
| 161 | .mk ^t |
| 162 | \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' |
| 163 | .sp -1 |
| 164 | .fi |
| 165 | .ev |
| 166 | .\} |
| 167 | .nr ^v 0 |
| 168 | .. |
| 169 | '\" # Special macro to handle page bottom: finish off current |
| 170 | '\" # box/sidebar if in box/sidebar mode, then invoked standard |
| 171 | '\" # page bottom macro. |
| 172 | .de ^B |
| 173 | .ev 2 |
| 174 | 'ti 0 |
| 175 | 'nf |
| 176 | .mk ^t |
| 177 | .if \\n(^b \{\ |
| 178 | .\" Draw three-sided box if this is the box's first page, |
| 179 | .\" draw two sides but no top otherwise. |
| 180 | .ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c |
| 181 | .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c |
| 182 | .\} |
| 183 | .if \\n(^v \{\ |
| 184 | .nr ^x \\n(^tu+1v-\\n(^Yu |
| 185 | \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c |
| 186 | .\} |
| 187 | .bp |
| 188 | 'fi |
| 189 | .ev |
| 190 | .if \\n(^b \{\ |
| 191 | .mk ^y |
| 192 | .nr ^b 2 |
| 193 | .\} |
| 194 | .if \\n(^v \{\ |
| 195 | .mk ^Y |
| 196 | .\} |
| 197 | .. |
| 198 | '\" # DS - begin display |
| 199 | .de DS |
| 200 | .RS |
| 201 | .nf |
| 202 | .sp |
| 203 | .. |
| 204 | '\" # DE - end display |
| 205 | .de DE |
| 206 | .fi |
| 207 | .RE |
| 208 | .sp |
| 209 | .. |
| 210 | '\" # SO - start of list of standard options |
| 211 | .de SO |
| 212 | .SH "STANDARD OPTIONS" |
| 213 | .LP |
| 214 | .nf |
| 215 | .ta 5.5c 11c |
| 216 | .ft B |
| 217 | .. |
| 218 | '\" # SE - end of list of standard options |
| 219 | .de SE |
| 220 | .fi |
| 221 | .ft R |
| 222 | .LP |
| 223 | See the \\fBoptions\\fR manual entry for details on the standard options. |
| 224 | .. |
| 225 | '\" # OP - start of full description for a single option |
| 226 | .de OP |
| 227 | .LP |
| 228 | .nf |
| 229 | .ta 4c |
| 230 | Command-Line Name: \\fB\\$1\\fR |
| 231 | Database Name: \\fB\\$2\\fR |
| 232 | Database Class: \\fB\\$3\\fR |
| 233 | .fi |
| 234 | .IP |
| 235 | .. |
| 236 | '\" # CS - begin code excerpt |
| 237 | .de CS |
| 238 | .RS |
| 239 | .nf |
| 240 | .ta .25i .5i .75i 1i |
| 241 | .. |
| 242 | '\" # CE - end code excerpt |
| 243 | .de CE |
| 244 | .fi |
| 245 | .RE |
| 246 | .. |
| 247 | .de UL |
| 248 | \\$1\l'|0\(ul'\\$2 |
| 249 | .. |
| 250 | .TH photo n 4.0 Tk "Tk Built-In Commands" |
| 251 | .BS |
| 252 | '\" Note: do not modify the .SH NAME line immediately below! |
| 253 | .SH NAME |
| 254 | photo \- Full-color images |
| 255 | .SH SYNOPSIS |
| 256 | \fBimage create photo \fR?\fIname\fR? ?\fIoptions\fR? |
| 257 | .BE |
| 258 | |
| 259 | .SH DESCRIPTION |
| 260 | .PP |
| 261 | A photo is an image whose pixels can display any color or be |
| 262 | transparent. A photo image is stored internally in full color (32 |
| 263 | bits per pixel), and is displayed using dithering if necessary. Image |
| 264 | data for a photo image can be obtained from a file or a string, or it |
| 265 | can be supplied from |
| 266 | C code through a procedural interface. At present, only GIF and PPM/PGM |
| 267 | formats are supported, but an interface exists to allow additional |
| 268 | image file formats to be added easily. A photo image is transparent |
| 269 | in regions where no image data has been supplied |
| 270 | .VS 8.4 |
| 271 | or where it has been set transparent by the \fBtransparency set\fR |
| 272 | subcommand. |
| 273 | .VE 8.4 |
| 274 | .SH "CREATING PHOTOS" |
| 275 | .PP |
| 276 | Like all images, photos are created using the \fBimage create\fR |
| 277 | command. |
| 278 | Photos support the following \fIoptions\fR: |
| 279 | .TP |
| 280 | \fB\-data \fIstring\fR |
| 281 | Specifies the contents of the image as a string. The string can |
| 282 | contain base64 encoded data or binary data. The format of the |
| 283 | string must be one of those for which there is an image file format |
| 284 | handler that will accept string data. If both the \fB\-data\fR |
| 285 | and \fB\-file\fR options are specified, the \fB\-file\fR option takes |
| 286 | precedence. |
| 287 | .TP |
| 288 | \fB\-format \fIformat-name\fR |
| 289 | Specifies the name of the file format for the data specified with the |
| 290 | \fB\-data\fR or \fB\-file\fR option. |
| 291 | .TP |
| 292 | \fB\-file \fIname\fR |
| 293 | \fIname\fR gives the name of a file that is to be read to supply data |
| 294 | for the photo image. The file format must be one of those for which |
| 295 | there is an image file format handler that can read data. |
| 296 | .TP |
| 297 | \fB\-gamma \fIvalue\fR |
| 298 | Specifies that the colors allocated for displaying this image in a |
| 299 | window should be corrected for a non-linear display with the specified |
| 300 | gamma exponent value. (The intensity produced by most |
| 301 | CRT displays is a power function of the input value, to a good |
| 302 | approximation; gamma is the exponent and is typically around 2). |
| 303 | The value specified must be greater than zero. The default |
| 304 | value is one (no correction). In general, values greater than one |
| 305 | will make the image lighter, and values less than one will make it |
| 306 | darker. |
| 307 | .TP |
| 308 | \fB\-height \fInumber\fR |
| 309 | Specifies the height of the image, in pixels. This option is useful |
| 310 | primarily in situations where the user wishes to build up the contents |
| 311 | of the image piece by piece. A value of zero (the default) allows the |
| 312 | image to expand or shrink vertically to fit the data stored in it. |
| 313 | .TP |
| 314 | \fB\-palette \fIpalette-spec\fR |
| 315 | Specifies the resolution of the color cube to be allocated for |
| 316 | displaying this image, and thus the number of colors used from the |
| 317 | colormaps of the windows where it is displayed. The |
| 318 | \fIpalette-spec\fR string may be either a single decimal number, |
| 319 | specifying the number of shades of gray to use, or three decimal |
| 320 | numbers separated by slashes (/), specifying the number of shades of |
| 321 | red, green and blue to use, respectively. If the first form (a single |
| 322 | number) is used, the image will be displayed in monochrome (i.e., |
| 323 | grayscale). |
| 324 | .TP |
| 325 | \fB\-width \fInumber\fR |
| 326 | Specifies the width of the image, in pixels. This option is useful |
| 327 | primarily in situations where the user wishes to build up the contents |
| 328 | of the image piece by piece. A value of zero (the default) allows the |
| 329 | image to expand or shrink horizontally to fit the data stored in it. |
| 330 | .SH "IMAGE COMMAND" |
| 331 | .PP |
| 332 | When a photo image is created, Tk also creates a new command |
| 333 | whose name is the same as the image. |
| 334 | This command may be used to invoke various operations |
| 335 | on the image. |
| 336 | It has the following general form: |
| 337 | .CS |
| 338 | \fIimageName option \fR?\fIarg arg ...\fR? |
| 339 | .CE |
| 340 | \fIOption\fR and the \fIarg\fRs |
| 341 | determine the exact behavior of the command. |
| 342 | .PP |
| 343 | Those options that write data to the image generally expand the size |
| 344 | of the image, if necessary, to accommodate the data written to the |
| 345 | image, unless the user has specified non-zero values for the |
| 346 | \fB\-width\fR and/or \fB\-height\fR configuration options, in which |
| 347 | case the width and/or height, respectively, of the image will not be |
| 348 | changed. |
| 349 | .PP |
| 350 | The following commands are possible for photo images: |
| 351 | .TP |
| 352 | \fIimageName \fBblank\fR |
| 353 | Blank the image; that is, set the entire image to have no data, so it |
| 354 | will be displayed as transparent, and the background of whatever |
| 355 | window it is displayed in will show through. |
| 356 | .TP |
| 357 | \fIimageName \fBcget\fR \fIoption\fR |
| 358 | Returns the current value of the configuration option given |
| 359 | by \fIoption\fR. |
| 360 | \fIOption\fR may have any of the values accepted by the |
| 361 | \fBimage create photo\fR command. |
| 362 | .TP |
| 363 | \fIimageName \fBconfigure\fR ?\fIoption\fR? ?\fIvalue option value ...\fR? |
| 364 | Query or modify the configuration options for the image. |
| 365 | If no \fIoption\fR is specified, returns a list describing all of |
| 366 | the available options for \fIimageName\fR (see \fBTk_ConfigureInfo\fR for |
| 367 | information on the format of this list). If \fIoption\fR is specified |
| 368 | with no \fIvalue\fR, then the command returns a list describing the |
| 369 | one named option (this list will be identical to the corresponding |
| 370 | sublist of the value returned if no \fIoption\fR is specified). If |
| 371 | one or more \fIoption\-value\fR pairs are specified, then the command |
| 372 | modifies the given option(s) to have the given value(s); in |
| 373 | this case the command returns an empty string. |
| 374 | \fIOption\fR may have any of the values accepted by the |
| 375 | \fBimage create photo\fR command. |
| 376 | .TP |
| 377 | \fIimageName \fBcopy\fR \fIsourceImage\fR ?\fIoption value(s) ...\fR? |
| 378 | Copies a region from the image called \fIsourceImage\fR (which must |
| 379 | be a photo image) to the image called \fIimageName\fR, possibly with |
| 380 | pixel zooming and/or subsampling. If no options are specified, this |
| 381 | command copies the whole of \fIsourceImage\fR into \fIimageName\fR, |
| 382 | starting at coordinates (0,0) in \fIimageName\fR. The following |
| 383 | options may be specified: |
| 384 | .RS |
| 385 | .TP |
| 386 | \fB\-from \fIx1 y1 x2 y2\fR |
| 387 | Specifies a rectangular sub-region of the source image to be copied. |
| 388 | (\fIx1,y1\fR) and (\fIx2,y2\fR) specify diagonally opposite corners of |
| 389 | the rectangle. If \fIx2\fR and \fIy2\fR are not specified, the |
| 390 | default value is the bottom-right corner of the source image. The |
| 391 | pixels copied will include the left and top edges of the specified |
| 392 | rectangle but not the bottom or right edges. If the \fB\-from\fR |
| 393 | option is not given, the default is the whole source image. |
| 394 | .TP |
| 395 | \fB\-to \fIx1 y1 x2 y2\fR |
| 396 | Specifies a rectangular sub-region of the destination image to be |
| 397 | affected. (\fIx1,y1\fR) and (\fIx2,y2\fR) specify diagonally opposite |
| 398 | corners of the rectangle. If \fIx2\fR and \fIy2\fR are not specified, |
| 399 | the default value is (\fIx1,y1\fR) plus the size of the source |
| 400 | region (after subsampling and zooming, if specified). If \fIx2\fR and |
| 401 | \fIy2\fR are specified, the source region will be replicated if |
| 402 | necessary to fill the destination region in a tiled fashion. |
| 403 | .TP |
| 404 | \fB\-shrink\fR |
| 405 | Specifies that the size of the destination image should be reduced, if |
| 406 | necessary, so that the region being copied into is at the bottom-right |
| 407 | corner of the image. This option will not affect the width or height |
| 408 | of the image if the user has specified a non-zero value for the |
| 409 | \fB\-width\fR or \fB\-height\fR configuration option, respectively. |
| 410 | .TP |
| 411 | \fB\-zoom \fIx y\fR |
| 412 | Specifies that the source region should be magnified by a factor of |
| 413 | \fIx\fR in the X direction and \fIy\fR in the Y direction. If \fIy\fR |
| 414 | is not given, the default value is the same as \fIx\fR. With this |
| 415 | option, each pixel in the source image will be expanded into a block |
| 416 | of \fIx\fR x \fIy\fR pixels in the destination image, all the same |
| 417 | color. \fIx\fR and \fIy\fR must be greater than 0. |
| 418 | .TP |
| 419 | \fB\-subsample \fIx y\fR |
| 420 | Specifies that the source image should be reduced in size by using |
| 421 | only every \fIx\fRth pixel in the X direction and \fIy\fRth pixel in |
| 422 | the Y direction. Negative values will cause the image to be flipped |
| 423 | about the Y or X axes, respectively. If \fIy\fR is not given, the |
| 424 | default value is the same as \fIx\fR. |
| 425 | .TP |
| 426 | \fB\-compositingrule \fIrule\fR |
| 427 | .VS 8.4 |
| 428 | Specifies how transparent pixels in the source image are combined with |
| 429 | the destination image. When a compositing rule of \fIoverlay\fR is |
| 430 | set, the old contents of the destination image are visible, as if the |
| 431 | source image were printed on a piece of transparent film and placed |
| 432 | over the top of the destination. When a compositing rule of \fIset\fR |
| 433 | is set, the old contents of the destination image are discarded and |
| 434 | the source image is used as-is. The default compositing rule is |
| 435 | \fIoverlay\fR. |
| 436 | .VE 8.4 |
| 437 | .RE |
| 438 | .TP |
| 439 | \fIimageName \fBdata ?\fIoption value(s) ...\fR? |
| 440 | Returns image data in the form of a string. The following options |
| 441 | may be specified: |
| 442 | .RS |
| 443 | .TP |
| 444 | \fB\-background\fI color\fR |
| 445 | If the color is specified, the data will not contain any transparency |
| 446 | information. In all transparent pixels the color will be replaced by |
| 447 | the specified color. |
| 448 | .TP |
| 449 | \fB\-format\fI format-name\fR |
| 450 | Specifies the name of the image file format handler to be used. |
| 451 | Specifically, this subcommand searches |
| 452 | for the first handler whose name matches an initial substring of |
| 453 | \fIformat-name\fR and which has the capability to read this image data. |
| 454 | If this option is not given, this subcommand uses the first |
| 455 | handler that has the capability to read the image data. |
| 456 | .TP |
| 457 | \fB\-from \fIx1 y1 x2 y2\fR |
| 458 | Specifies a rectangular region of \fIimageName\fR to be returned. |
| 459 | If only \fIx1\fR and \fIy1\fR are specified, the region |
| 460 | extends from \fI(x1,y1)\fR to the bottom-right corner of |
| 461 | \fIimageName\fR. If all four coordinates are given, they specify |
| 462 | diagonally opposite corners of the rectangular region, including x1,y1 |
| 463 | and excluding x2,y2. The default, if this option is not given, is the |
| 464 | whole image. |
| 465 | .TP |
| 466 | \fB\-grayscale\fR |
| 467 | If this options is specified, the data will not contain color |
| 468 | information. All pixel data will be transformed into grayscale. |
| 469 | .RE |
| 470 | .TP |
| 471 | \fIimageName \fBget\fR \fIx y\fR |
| 472 | Returns the color of the pixel at coordinates (\fIx\fR,\fIy\fR) in the |
| 473 | image as a list of three integers between 0 and 255, representing the |
| 474 | red, green and blue components respectively. |
| 475 | .TP |
| 476 | \fIimageName \fBput\fR \fIdata\fR ?\fIoption value(s) ...\fR? |
| 477 | Sets pixels in \fI imageName\fR to the data specified in \fIdata\fR. |
| 478 | This command first searches the list of image file format handlers for |
| 479 | a handler that can interpret the data in \fIdata\fR, and then reads |
| 480 | the image encoded within into \fIimageName\fR (the destination image). |
| 481 | If \fIdata\fR does not match any known format, an attempt to interpret |
| 482 | it as a (top-to-bottom) list of scan-lines is made, with each |
| 483 | scan-line being a (left-to-right) list of pixel colors (see |
| 484 | \fBTk_GetColor\fR for a description of valid colors.) Every scan-line |
| 485 | must be of the same length. Note that when \fIdata\fR is a single |
| 486 | color name, you are instructing Tk to fill a rectangular region with |
| 487 | that color. The following options may be specified: |
| 488 | .RS |
| 489 | .TP |
| 490 | \fB\-format \fIformat-name\fR |
| 491 | Specifies the format of the image data in \fIdata\fR. |
| 492 | Specifically, only image file format handlers whose names begin with |
| 493 | \fIformat-name\fR will be used while searching for an image data |
| 494 | format handler to read the data. |
| 495 | .TP |
| 496 | \fB\-to \fIx1 y1\fR ?\fIx2 y2\fR? |
| 497 | Specifies the coordinates of the top-left corner (\fIx1\fR,\fIy1\fR) |
| 498 | of the region of \fIimageName\fR into which data from \fIfilename\fR |
| 499 | are to be read. The default is (0,0). If \fIx2\fR,\fIy2\fR is given |
| 500 | and \fIdata\fR is not large enough to cover the rectangle specified by |
| 501 | this option, the image data extracted will be tiled so it covers the |
| 502 | entire destination rectangle. Note that if \fIdata\fR specifies a |
| 503 | single color value, then a region extending to the bottom-right corner |
| 504 | represented by (\fIx2\fR,\fIy2\fR) will be filled with that color. |
| 505 | .RE |
| 506 | .TP |
| 507 | \fIimageName \fBread\fR \fIfilename\fR ?\fIoption value(s) ...\fR? |
| 508 | Reads image data from the file named \fIfilename\fR into the image. |
| 509 | This command first searches the list of |
| 510 | image file format handlers for a handler that can interpret the data |
| 511 | in \fIfilename\fR, and then reads the image in \fIfilename\fR into |
| 512 | \fIimageName\fR (the destination image). The following options may be |
| 513 | specified: |
| 514 | .RS |
| 515 | .TP |
| 516 | \fB\-format \fIformat-name\fR |
| 517 | Specifies the format of the image data in \fIfilename\fR. |
| 518 | Specifically, only image file format handlers whose names begin with |
| 519 | \fIformat-name\fR will be used while searching for an image data |
| 520 | format handler to read the data. |
| 521 | .TP |
| 522 | \fB\-from \fIx1 y1 x2 y2\fR |
| 523 | Specifies a rectangular sub-region of the image file data to be copied |
| 524 | to the destination image. If only \fIx1\fR and \fIy1\fR are |
| 525 | specified, the region extends from (\fIx1,y1\fR) to the bottom-right |
| 526 | corner of the image in the image file. If all four coordinates are |
| 527 | specified, they specify diagonally opposite corners or the region. |
| 528 | The default, if this option is not specified, is the whole of the |
| 529 | image in the image file. |
| 530 | .TP |
| 531 | \fB\-shrink\fR |
| 532 | If this option, the size of \fIimageName\fR will be reduced, if |
| 533 | necessary, so that the region into which the image file data are read |
| 534 | is at the bottom-right corner of the \fIimageName\fR. This option |
| 535 | will not affect the width or height of the image if the user has |
| 536 | specified a non-zero value for the \fB\-width\fR or \fB\-height\fR |
| 537 | configuration option, respectively. |
| 538 | .TP |
| 539 | \fB\-to \fIx y\fR |
| 540 | Specifies the coordinates of the top-left corner of the region of |
| 541 | \fIimageName\fR into which data from \fIfilename\fR are to be read. |
| 542 | The default is (0,0). |
| 543 | .RE |
| 544 | .TP |
| 545 | \fIimageName \fBredither\fR |
| 546 | The dithering algorithm used in displaying photo images propagates |
| 547 | quantization errors from one pixel to its neighbors. |
| 548 | If the image data for \fIimageName\fR is supplied in pieces, the |
| 549 | dithered image may not be exactly correct. Normally the difference is |
| 550 | not noticeable, but if it is a problem, this command can be used to |
| 551 | recalculate the dithered image in each window where the image is |
| 552 | displayed. |
| 553 | .TP |
| 554 | \fIimageName \fBtransparency \fIsubcommand ?arg arg ...?\fR |
| 555 | .VS 8.4 |
| 556 | Allows examination and manipulation of the transparency information in |
| 557 | the photo image. Several subcommands are available: |
| 558 | .RS |
| 559 | .TP |
| 560 | \fIimageName \fBtransparency get \fIx y\fR |
| 561 | Returns a boolean indicating if the pixel at (\fIx\fR,\fIy\fR) is |
| 562 | transparent. |
| 563 | .TP |
| 564 | \fIimageName \fBtransparency set \fIx y boolean\fR |
| 565 | Makes the pixel at (\fIx\fR,\fIy\fR) transparent if \fIboolean\fR is |
| 566 | true, and makes that pixel opaque otherwise. |
| 567 | .RE |
| 568 | .VE 8.4 |
| 569 | .TP |
| 570 | \fIimageName \fBwrite \fIfilename\fR ?\fIoption value(s) ...\fR? |
| 571 | Writes image data from \fIimageName\fR to a file named \fIfilename\fR. |
| 572 | The following options may be specified: |
| 573 | .RS |
| 574 | .TP |
| 575 | \fB\-background\fI color\fR |
| 576 | If the color is specified, the data will not contain any transparency |
| 577 | information. In all transparent pixels the color will be replaced by |
| 578 | the specified color. |
| 579 | .TP |
| 580 | \fB\-format\fI format-name\fR |
| 581 | Specifies the name of the image file format handler to be used to |
| 582 | write the data to the file. Specifically, this subcommand searches |
| 583 | for the first handler whose name matches an initial substring of |
| 584 | \fIformat-name\fR and which has the capability to write an image |
| 585 | file. If this option is not given, this subcommand uses the first |
| 586 | handler that has the capability to write an image file. |
| 587 | .TP |
| 588 | \fB\-from \fIx1 y1 x2 y2\fR |
| 589 | Specifies a rectangular region of \fIimageName\fR to be written to the |
| 590 | image file. If only \fIx1\fR and \fIy1\fR are specified, the region |
| 591 | extends from \fI(x1,y1)\fR to the bottom-right corner of |
| 592 | \fIimageName\fR. If all four coordinates are given, they specify |
| 593 | diagonally opposite corners of the rectangular region. The default, |
| 594 | if this option is not given, is the whole image. |
| 595 | .TP |
| 596 | \fB\-grayscale\fR |
| 597 | If this options is specified, the data will not contain color |
| 598 | information. All pixel data will be transformed into grayscale. |
| 599 | .RE |
| 600 | .SH "IMAGE FORMATS" |
| 601 | .PP |
| 602 | The photo image code is structured to allow handlers for additional |
| 603 | image file formats to be added easily. The photo image code maintains |
| 604 | a list of these handlers. Handlers are added to the list by |
| 605 | registering them with a call to \fBTk_CreatePhotoImageFormat\fR. The |
| 606 | standard Tk distribution comes with handlers for PPM/PGM and GIF formats, |
| 607 | which are automatically registered on initialization. |
| 608 | .PP |
| 609 | When reading an image file or processing |
| 610 | string data specified with the \fB\-data\fR configuration option, the |
| 611 | photo image code invokes each handler in turn until one is |
| 612 | found that claims to be able to read the data in the file or string. |
| 613 | Usually this will find the correct handler, but if it doesn't, the |
| 614 | user may give a format name with the \fB\-format\fR option to specify |
| 615 | which handler to use. In fact the photo image code will try those |
| 616 | handlers whose names begin with the string specified for the |
| 617 | \fB\-format\fR option (the comparison is case-insensitive). For |
| 618 | example, if the user specifies \fB\-format gif\fR, then a handler |
| 619 | named GIF87 or GIF89 may be invoked, but a handler |
| 620 | named JPEG may not (assuming that such handlers had been |
| 621 | registered). |
| 622 | .PP |
| 623 | When writing image data to a file, the processing of the |
| 624 | \fB\-format\fR option is slightly different: the string value given |
| 625 | for the \fB\-format\fR option must begin with the complete name of the |
| 626 | requested handler, and may contain additional information following |
| 627 | that, which the handler can use, for example, to specify which variant |
| 628 | to use of the formats supported by the handler. |
| 629 | .VS 8.4 |
| 630 | Note that not all image handlers may support writing transparency data |
| 631 | to a file, even where the target image format does. |
| 632 | .VE 8.4 |
| 633 | .SH "COLOR ALLOCATION" |
| 634 | .PP |
| 635 | When a photo image is displayed in a window, the photo image code |
| 636 | allocates colors to use to display the image and dithers the image, if |
| 637 | necessary, to display a reasonable approximation to the image using |
| 638 | the colors that are available. The colors are allocated as a color |
| 639 | cube, that is, the number of colors allocated is the product of the |
| 640 | number of shades of red, green and blue. |
| 641 | .PP |
| 642 | Normally, the number of |
| 643 | colors allocated is chosen based on the depth of the window. For |
| 644 | example, in an 8-bit PseudoColor window, the photo image code will |
| 645 | attempt to allocate seven shades of red, seven shades of green and |
| 646 | four shades of blue, for a total of 198 colors. In a 1-bit StaticGray |
| 647 | (monochrome) window, it will allocate two colors, black and white. In |
| 648 | a 24-bit DirectColor or TrueColor window, it will allocate 256 shades |
| 649 | each of red, green and blue. Fortunately, because of the way that |
| 650 | pixel values can be combined in DirectColor and TrueColor windows, |
| 651 | this only requires 256 colors to be allocated. If not all of the |
| 652 | colors can be allocated, the photo image code reduces the number of |
| 653 | shades of each primary color and tries again. |
| 654 | .PP |
| 655 | The user can exercise some control over the number of colors that a |
| 656 | photo image uses with the \fB\-palette\fR configuration option. If |
| 657 | this option is used, it specifies the maximum number of shades of |
| 658 | each primary color to try to allocate. It can also be used to force |
| 659 | the image to be displayed in shades of gray, even on a color display, |
| 660 | by giving a single number rather than three numbers separated by |
| 661 | slashes. |
| 662 | .SH CREDITS |
| 663 | .PP |
| 664 | The photo image type was designed and implemented by Paul Mackerras, |
| 665 | based on his earlier photo widget and some suggestions from |
| 666 | John Ousterhout. |
| 667 | .SH EXAMPLE |
| 668 | Load an image from a file and tile it to the size of a window, which |
| 669 | is useful for producing a tiled background: |
| 670 | .CS |
| 671 | # These lines should be called once |
| 672 | \fBimage create photo\fR untiled -file "theFile.ppm" |
| 673 | \fBimage create photo\fR tiled |
| 674 | |
| 675 | # These lines should be called whenever .someWidget changes |
| 676 | # size; a <Configure> binding is useful here |
| 677 | set width [winfo width .someWidget] |
| 678 | set height [winfo height .someWidget] |
| 679 | tiled \fBcopy\fR untiled \-to 0 0 $width $height \-shrink |
| 680 | .CE |
| 681 | |
| 682 | .SH "SEE ALSO" |
| 683 | image(n) |
| 684 | |
| 685 | .SH KEYWORDS |
| 686 | photo, image, color |