| '\" |
| '\" Copyright (c) 1996 Sun Microsystems, Inc. |
| '\" |
| '\" See the file "license.terms" for information on usage and redistribution |
| '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. |
| '\" |
| '\" RCS: @(#) $Id: MeasureChar.3,v 1.4 1999/12/21 23:54:17 hobbs Exp $ |
| '\" |
| '\" The definitions below are for supplemental macros used in Tcl/Tk |
| '\" manual entries. |
| '\" |
| '\" .AP type name in/out ?indent? |
| '\" Start paragraph describing an argument to a library procedure. |
| '\" type is type of argument (int, etc.), in/out is either "in", "out", |
| '\" or "in/out" to describe whether procedure reads or modifies arg, |
| '\" and indent is equivalent to second arg of .IP (shouldn't ever be |
| '\" needed; use .AS below instead) |
| '\" |
| '\" .AS ?type? ?name? |
| '\" Give maximum sizes of arguments for setting tab stops. Type and |
| '\" name are examples of largest possible arguments that will be passed |
| '\" to .AP later. If args are omitted, default tab stops are used. |
| '\" |
| '\" .BS |
| '\" Start box enclosure. From here until next .BE, everything will be |
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| '\" .BE |
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| '\" .CS |
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| '\" |
| '\" .VS ?version? ?br? |
| '\" Begin vertical sidebar, for use in marking newly-changed parts |
| '\" of man pages. The first argument is ignored and used for recording |
| '\" the version when the .VS was added, so that the sidebars can be |
| '\" found and removed when they reach a certain age. If another argument |
| '\" is present, then a line break is forced before starting the sidebar. |
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| '\" .SO |
| '\" Start of list of standard options for a Tk widget. The |
| '\" options follow on successive lines, in four columns separated |
| '\" by tabs. |
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| '\" End of list of standard options for a Tk widget. |
| '\" |
| '\" .OP cmdName dbName dbClass |
| '\" Start of description of a specific option. cmdName gives the |
| '\" option's name as specified in the class command, dbName gives |
| '\" the option's name in the option database, and dbClass gives |
| '\" the option's class in the option database. |
| '\" |
| '\" .UL arg1 arg2 |
| '\" Print arg1 underlined, then print arg2 normally. |
| '\" |
| '\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $ |
| '\" |
| '\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. |
| .if t .wh -1.3i ^B |
| .nr ^l \n(.l |
| .ad b |
| '\" # Start an argument description |
| .de AP |
| .ie !"\\$4"" .TP \\$4 |
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| . ie !"\\$2"" .TP \\n()Cu |
| . el .TP 15 |
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| .ta \\n()Au \\n()Bu |
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| \&\\$1 \\fI\\$2\\fP (\\$3) |
| .\".b |
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| .. |
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| .if !"\\$1"" .nr )A \\w'\\$1'u+3n |
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| .nr )C \\n()Bu+\\w'(in/out)'u+2n |
| .. |
| .AS Tcl_Interp Tcl_CreateInterp in/out |
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| \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' |
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| \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' |
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| '\" # box/sidebar if in box/sidebar mode, then invoked standard |
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| .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c |
| .\} |
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| \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c |
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| '\" # SO - start of list of standard options |
| .de SO |
| .SH "STANDARD OPTIONS" |
| .LP |
| .nf |
| .ta 5.5c 11c |
| .ft B |
| .. |
| '\" # SE - end of list of standard options |
| .de SE |
| .fi |
| .ft R |
| .LP |
| See the \\fBoptions\\fR manual entry for details on the standard options. |
| .. |
| '\" # OP - start of full description for a single option |
| .de OP |
| .LP |
| .nf |
| .ta 4c |
| Command-Line Name: \\fB\\$1\\fR |
| Database Name: \\fB\\$2\\fR |
| Database Class: \\fB\\$3\\fR |
| .fi |
| .IP |
| .. |
| '\" # CS - begin code excerpt |
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| .ta .25i .5i .75i 1i |
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| .de CE |
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| .RE |
| .. |
| .de UL |
| \\$1\l'|0\(ul'\\$2 |
| .. |
| .TH Tk_MeasureChars 3 8.1 Tk "Tk Library Procedures" |
| .BS |
| .SH NAME |
| Tk_MeasureChars, Tk_TextWidth, Tk_DrawChars, Tk_UnderlineChars \- routines to measure and display simple single-line strings. |
| .SH SYNOPSIS |
| .nf |
| \fB#include <tk.h>\fR |
| .sp |
| int |
| \fBTk_MeasureChars(\fItkfont, string, numBytes, maxPixels, flags, lengthPtr\fB)\fR |
| .sp |
| int |
| \fBTk_TextWidth(\fItkfont, string, numBytes\fB)\fR |
| .sp |
| void |
| \fBTk_DrawChars(\fIdisplay, drawable, gc, tkfont, string, numBytes, x, y\fB)\fR |
| .sp |
| void |
| \fBTk_UnderlineChars(\fIdisplay, drawable, gc, tkfont, string, x, y, firstByte, lastByte\fB)\fR |
| .sp |
| .SH ARGUMENTS |
| .AS "const char" firstChar |
| .AP Tk_Font tkfont in |
| Token for font in which text is to be drawn or measured. Must have been |
| returned by a previous call to \fBTk_GetFont\fR. |
| .AP "const char" *string in |
| Text to be measured or displayed. Need not be null terminated. Any |
| non-printing meta-characters in the string (such as tabs, newlines, and |
| other control characters) will be measured or displayed in a |
| platform-dependent manner. |
| .VS 8.1 |
| .AP int numBytes in |
| The maximum number of bytes to consider when measuring or drawing |
| \fIstring\fR. Must be greater than or equal to 0. |
| .VE 8.1 |
| .AP int maxPixels in |
| If \fImaxPixels\fR is >= 0, it specifies the longest permissible |
| line length in pixels. Characters from \fIstring\fR are processed only |
| until this many pixels have been covered. If \fImaxPixels\fR is < 0, then |
| the line length is unbounded and the \fIflags\fR argument is ignored. |
| .AP int flags in |
| Various flag bits OR-ed together: TK_PARTIAL_OK means include a character |
| as long as any part of it fits in the length given by \fImaxPixels\fR; |
| otherwise, a character must fit completely to be considered. |
| TK_WHOLE_WORDS means stop on a word boundary, if possible. If |
| TK_AT_LEAST_ONE is set, it means return at least one character even if no |
| characters could fit in the length given by \fImaxPixels\fR. If |
| TK_AT_LEAST_ONE is set and TK_WHOLE_WORDS is also set, it means that if |
| not even one word fits on the line, return the first few letters of the |
| word that did fit; if not even one letter of the word fit, then the first |
| letter will still be returned. |
| .AP int *lengthPtr out |
| Filled with the number of pixels occupied by the number of characters |
| returned as the result of \fBTk_MeasureChars\fR. |
| .AP Display *display in |
| Display on which to draw. |
| .AP Drawable drawable in |
| Window or pixmap in which to draw. |
| .AP GC gc in |
| Graphics context for drawing characters. The font selected into this GC |
| must be the same as the \fItkfont\fR. |
| .AP int "x, y" in |
| Coordinates at which to place the left edge of the baseline when displaying |
| \fIstring\fR. |
| .VS 8.1 |
| .AP int firstByte in |
| The index of the first byte of the first character to underline in the |
| \fIstring\fR. Underlining begins at the left edge of this character. |
| .AP int lastByte in |
| The index of the first byte of the last character up to which the |
| underline will be drawn. The character specified by \fIlastByte\fR |
| will not itself be underlined. |
| .VE 8.1 |
| .BE |
| |
| .SH DESCRIPTION |
| .PP |
| These routines are for measuring and displaying simple single-font, |
| single-line, strings. To measure and display single-font, multi-line, |
| justified text, refer to the documentation for \fBTk_ComputeTextLayout\fR. |
| There is no programming interface in the core of Tk that supports |
| multi-font, multi-line text; support for that behavior must be built on |
| top of simpler layers. |
| .VS 8.1 |
| Note that the interfaces described here are |
| byte-oriented not character-oriented, so index values coming from Tcl |
| scripts need to be converted to byte offsets using the |
| \fBTcl_UtfAtIndex\fR and related routines. |
| .VE 8.1 |
| .PP |
| A glyph is the displayable picture of a letter, number, or some other |
| symbol. Not all character codes in a given font have a glyph. |
| Characters such as tabs, newlines/returns, and control characters that |
| have no glyph are measured and displayed by these procedures in a |
| platform-dependent manner; under X, they are replaced with backslashed |
| escape sequences, while under Windows and Macintosh hollow or solid boxes |
| may be substituted. Refer to the documentation for |
| \fBTk_ComputeTextLayout\fR for a programming interface that supports the |
| platform-independent expansion of tab characters into columns and |
| newlines/returns into multi-line text. |
| .PP |
| \fBTk_MeasureChars\fR is used both to compute the length of a given |
| string and to compute how many characters from a string fit in a given |
| amount of space. The return value is the number of bytes from |
| \fIstring\fR that fit in the space specified by \fImaxPixels\fR subject to |
| the conditions described by \fIflags\fR. If all characters fit, the return |
| value will be \fInumBytes\fR. \fI*lengthPtr\fR is filled with the computed |
| width, in pixels, of the portion of the string that was measured. For |
| example, if the return value is 5, then \fI*lengthPtr\fR is filled with the |
| distance between the left edge of \fIstring\fR[0] and the right edge of |
| \fIstring\fR[4]. |
| .PP |
| \fBTk_TextWidth\fR is a wrapper function that provides a simpler interface |
| to the \fBTk_MeasureChars\fR function. The return value is how much |
| space in pixels the given \fIstring\fR needs. |
| .PP |
| \fBTk_DrawChars\fR draws the \fIstring\fR at the given location in the |
| given \fIdrawable\fR. |
| .PP |
| \fBTk_UnderlineChars\fR underlines the given range of characters in the |
| given \fIstring\fR. It doesn't draw the characters (which are assumed to |
| have been displayed previously by \fBTk_DrawChars\fR); it just draws the |
| underline. This procedure is used to underline a few characters without |
| having to construct an underlined font. To produce natively underlined |
| text, the appropriate underlined font should be constructed and used. |
| |
| .SH KEYWORDS |
| font |