/*
* tkFont.c --
*
* This file maintains a database of looked-up fonts for the Tk
* toolkit, in order to avoid round-trips to the server to map
* font names to XFontStructs.
*
* Copyright 1990 Regents of the University of California
* Permission to use, copy, modify, and distribute this
* software and its documentation for any purpose and without
* fee is hereby granted, provided that the above copyright
* notice appear in all copies. The University of California
* makes no representations about the suitability of this
* software for any purpose. It is provided "as is" without
* express or implied warranty.
*/
#ifndef lint
static char rcsid[] = "$Header: /user6/ouster/wish/RCS/tkFont.c,v 1.21 92/06/15 14:00:19 ouster Exp $ SPRITE (Berkeley)";
#endif
#include "tkConfig.h"
#include "tkInt.h"
/*
* This module caches extra information about fonts in addition to
* what X already provides. The extra information is used by the
* TkMeasureChars procedure, and consists of two parts: a type and
* a width. The type is one of the following:
*
* NORMAL: Standard character.
* TAB: Tab character: output enough space to
* get to next tab stop.
* NEWLINE: Newline character: don't output anything more
* on this line (character has infinite width).
* REPLACE: This character doesn't print: instead of
* displaying character, display a replacement
* sequence of the form "\xdd" where dd is the
* hex equivalent of the character.
* SKIP: Don't display anything for this character. This
* is only used where the font doesn't contain
* all the characters needed to generate
* replacement sequences.
* The width gives the total width of the displayed character or
* sequence: for replacement sequences, it gives the width of the
* sequence.
*/
#define NORMAL 1
#define TAB 2
#define NEWLINE 3
#define REPLACE 4
#define SKIP 5
/*
* One of the following data structures exists for each font that is
* currently active. The structure is indexed with two hash tables,
* one based on font name and one based on XFontStruct address.
*/
typedef struct {
XFontStruct *fontStructPtr; /* X information about font. */
Display *display; /* Display to which font belongs. */
int refCount; /* Number of active uses of this font. */
char *types; /* Malloc'ed array giving types of all
* chars in the font (may be NULL). */
unsigned char *widths; /* Malloc'ed array giving widths of all
* chars in the font (may be NULL). */
int tabWidth; /* Width of tabs in this font. */
Tcl_HashEntry *nameHashPtr; /* Entry in name-based hash table (needed
* when deleting this structure). */
} TkFont;
/*
* Hash table for name -> TkFont mapping, and key structure used to
* index into that table:
*/
static Tcl_HashTable nameTable;
typedef struct {
Tk_Uid name; /* Name of font. */
Display *display; /* Display for which font is valid. */
} NameKey;
/*
* Hash table for font struct -> TkFont mapping. This table is
* indexed by the XFontStruct address.
*/
static Tcl_HashTable fontTable;
static int initialized = 0; /* 0 means static structures haven't been
* initialized yet. */
/*
* To speed up TkMeasureChars, the variables below keep the last
* mapping from (XFontStruct *) to (TkFont *).
*/
static TkFont *lastFontPtr = NULL;
static XFontStruct *lastFontStructPtr = NULL;
/*
* Characters used when displaying control sequences as their
* hex equivalents.
*/
static char hexChars[] = "0123456789abcdefx\\";
/*
* Forward declarations for procedures defined in this file:
*/
static void FontInit _ANSI_ARGS_((void));
static void SetFontMetrics _ANSI_ARGS_((TkFont *fontPtr));
/*
*----------------------------------------------------------------------
*
* Tk_GetFontStruct --
*
* Given a string name for a font, map the name to an XFontStruct
* describing the font.
*
* Results:
* The return value is normally a pointer to the font description
* for the desired font. If an error occurs in mapping the string
* to a font, then an error message will be left in interp->result
* and NULL will be returned.
*
* Side effects:
* The font is added to an internal database with a reference count.
* For each call to this procedure, there should eventually be a call
* to Tk_FreeFontStruct, so that the database is cleaned up when fonts
* aren't in use anymore.
*
*----------------------------------------------------------------------
*/
XFontStruct *
Tk_GetFontStruct(interp, tkwin, name)
Tcl_Interp *interp; /* Place to leave error message if
* font can't be found. */
Tk_Window tkwin; /* Window in which font will be used. */
Tk_Uid name; /* Name of font (in form suitable for
* passing to XLoadQueryFont). */
{
NameKey nameKey;
Tcl_HashEntry *nameHashPtr, *fontHashPtr;
int new;
register TkFont *fontPtr;
XFontStruct *fontStructPtr;
if (!initialized) {
FontInit();
}
/*
* First, check to see if there's already a mapping for this font
* name.
*/
nameKey.name = name;
nameKey.display = Tk_Display(tkwin);
nameHashPtr = Tcl_CreateHashEntry(&nameTable, (char *) &nameKey, &new);
if (!new) {
fontPtr = (TkFont *) Tcl_GetHashValue(nameHashPtr);
fontPtr->refCount++;
return fontPtr->fontStructPtr;
}
/*
* The name isn't currently known. Map from the name to a font, and
* add a new structure to the database.
*/
fontStructPtr = XLoadQueryFont(nameKey.display, name);
if (fontStructPtr == NULL) {
Tcl_DeleteHashEntry(nameHashPtr);
Tcl_AppendResult(interp, "font \"", name, "\" doesn't exist",
(char *) NULL);
return NULL;
}
fontPtr = (TkFont *) ckalloc(sizeof(TkFont));
fontPtr->display = nameKey.display;
fontPtr->fontStructPtr = fontStructPtr;
fontPtr->refCount = 1;
fontPtr->types = NULL;
fontPtr->widths = NULL;
fontPtr->nameHashPtr = nameHashPtr;
fontHashPtr = Tcl_CreateHashEntry(&fontTable, (char *) fontStructPtr, &new);
if (!new) {
panic("XFontStruct already registered in Tk_GetFontStruct");
}
Tcl_SetHashValue(nameHashPtr, fontPtr);
Tcl_SetHashValue(fontHashPtr, fontPtr);
return fontPtr->fontStructPtr;
}
/*
*--------------------------------------------------------------
*
* Tk_NameOfFontStruct --
*
* Given a font, return a textual string identifying it.
*
* Results:
* If font was created by Tk_GetFontStruct, then the return
* value is the "string" that was used to create it.
* Otherwise the return value is a string giving the X
* identifier for the font. The storage for the returned
* string is only guaranteed to persist up until the next
* call to this procedure.
*
* Side effects:
* None.
*
*--------------------------------------------------------------
*/
char *
Tk_NameOfFontStruct(fontStructPtr)
XFontStruct *fontStructPtr; /* Font whose name is desired. */
{
Tcl_HashEntry *fontHashPtr;
TkFont *fontPtr;
static char string[20];
if (!initialized) {
printid:
sprintf(string, "font id 0x%x", fontStructPtr->fid);
return string;
}
fontHashPtr = Tcl_FindHashEntry(&fontTable, (char *) fontStructPtr);
if (fontHashPtr == NULL) {
goto printid;
}
fontPtr = (TkFont *) Tcl_GetHashValue(fontHashPtr);
return ((NameKey *) fontPtr->nameHashPtr->key.words)->name;
}
/*
*----------------------------------------------------------------------
*
* Tk_FreeFontStruct --
*
* This procedure is called to release a font allocated by
* Tk_GetFontStruct.
*
* Results:
* None.
*
* Side effects:
* The reference count associated with font is decremented, and
* the font is officially deallocated if no-one is using it
* anymore.
*
*----------------------------------------------------------------------
*/
void
Tk_FreeFontStruct(fontStructPtr)
XFontStruct *fontStructPtr; /* Font to be released. */
{
Tcl_HashEntry *fontHashPtr;
register TkFont *fontPtr;
if (!initialized) {
panic("Tk_FreeFontStruct called before Tk_GetFontStruct");
}
fontHashPtr = Tcl_FindHashEntry(&fontTable, (char *) fontStructPtr);
if (fontHashPtr == NULL) {
panic("Tk_FreeFontStruct received unknown font argument");
}
fontPtr = (TkFont *) Tcl_GetHashValue(fontHashPtr);
fontPtr->refCount--;
if (fontPtr->refCount == 0) {
XFreeFont(fontPtr->display, fontPtr->fontStructPtr);
Tcl_DeleteHashEntry(fontPtr->nameHashPtr);
Tcl_DeleteHashEntry(fontHashPtr);
if (fontPtr->types != NULL) {
ckfree(fontPtr->types);
}
if (fontPtr->widths != NULL) {
ckfree((char *) fontPtr->widths);
}
ckfree((char *) fontPtr);
lastFontStructPtr = NULL;
}
}
/*
*----------------------------------------------------------------------
*
* FontInit --
*
* Initialize the structure used for font management.
*
* Results:
* None.
*
* Side effects:
* Read the code.
*
*----------------------------------------------------------------------
*/
static void
FontInit()
{
initialized = 1;
Tcl_InitHashTable(&nameTable, sizeof(NameKey)/sizeof(int));
Tcl_InitHashTable(&fontTable, TCL_ONE_WORD_KEYS);
}
/*
*--------------------------------------------------------------
*
* SetFontMetrics --
*
* This procedure is called to fill in the "widths" and "types"
* arrays for a font.
*
* Results:
* None.
*
* Side effects:
* FontPtr gets modified to hold font metric information.
*
*--------------------------------------------------------------
*/
static void
SetFontMetrics(fontPtr)
register TkFont *fontPtr; /* Font structure in which to
* set metrics. */
{
int i, replaceOK, baseWidth;
register XFontStruct *fontStructPtr = fontPtr->fontStructPtr;
char *p;
/*
* Pass 1: initialize the arrays.
*/
fontPtr->types = (char *) ckalloc(256);
fontPtr->widths = (unsigned char *) ckalloc(256);
for (i = 0; i < 256; i++) {
fontPtr->types[i] = REPLACE;
}
/*
* Pass 2: for all characters that exist in the font and are
* not control characters, fill in the type and width
* information.
*/
for (i = ' '; i < 256; i++) {
if ((i == 0177) || (i < fontStructPtr->min_char_or_byte2)
|| (i > fontStructPtr->max_char_or_byte2)) {
continue;
}
fontPtr->types[i] = NORMAL;
if (fontStructPtr->per_char == NULL) {
fontPtr->widths[i] = fontStructPtr->min_bounds.width;
} else {
fontPtr->widths[i] = fontStructPtr->per_char[i
- fontStructPtr->min_char_or_byte2].width;
}
}
/*
* Pass 3: fill in information for characters that have to
* be replaced with "\xhh" strings. If the font doesn't
* have the characters needed for this, then just use the
* font's default character.
*/
replaceOK = 1;
baseWidth = fontPtr->widths['\\'] + fontPtr->widths['x'];
for (p = hexChars; *p != 0; p++) {
if (fontPtr->types[*p] != NORMAL) {
replaceOK = 0;
break;
}
}
for (i = 0; i < 256; i++) {
if (fontPtr->types[i] != REPLACE) {
continue;
}
if (replaceOK) {
fontPtr->widths[i] = baseWidth
+ fontPtr->widths[hexChars[i & 0xf]]
+ fontPtr->widths[hexChars[(i>>4) & 0xf]];
} else {
fontPtr->types[i] = SKIP;
fontPtr->widths[i] = 0;
}
}
/*
* Lastly, fill in special information for newline and tab.
*/
fontPtr->types['\n'] = NEWLINE;
fontPtr->widths['\n'] = 0;
fontPtr->types['\t'] = TAB;
fontPtr->widths['\t'] = 0;
if (fontPtr->types['0'] == NORMAL) {
fontPtr->tabWidth = 8*fontPtr->widths['0'];
} else {
fontPtr->tabWidth = 8*fontStructPtr->max_bounds.width;
}
/*
* Make sure the tab width isn't zero (some fonts may not have enough
* information to set a reasonable tab width).
*/
if (fontPtr->tabWidth == 0) {
fontPtr->tabWidth = 1;
}
}
/*
*--------------------------------------------------------------
*
* TkMeasureChars --
*
* Measure the number of characters from a string that
* will fit in a given horizontal span. The measurement
* is done under the assumption that TkDisplayChars will
* be used to actually display the characters.
*
* Results:
* The return value is the number of characters from source
* that fit in the span given by startX and maxX. *nextXPtr
* is filled in with the x-coordinate at which the first
* character that didn't fit would be drawn, if it were to
* be drawn.
*
* Side effects:
* None.
*
*--------------------------------------------------------------
*/
int
TkMeasureChars(fontStructPtr, source, maxChars, startX, maxX, flags, nextXPtr)
XFontStruct *fontStructPtr; /* Font in which to draw characters. */
char *source; /* Characters to be displayed. Need not
* be NULL-terminated. */
int maxChars; /* Maximum # of characters to consider from
* source. */
int startX; /* X-position at which first character will
* be drawn. */
int maxX; /* Don't consider any character that would
* cross this x-position. */
int flags; /* Various flag bits OR-ed together.
* TK_WHOLE_WORDS means stop on a word boundary
* (just before a space character) if
* possible. TK_AT_LEAST_ONE means always
* return a value of at least one, even
* if the character doesn't fit.
* TK_PARTIAL_OK means it's OK to display only
* a part of the last character in the line.
* TK_NEWLINES_NOT_SPECIAL means that newlines
* are treated just like other control chars:
* they don't terminate the line,*/
int *nextXPtr; /* Return x-position of terminating
* character here. */
{
register TkFont *fontPtr;
register char *p; /* Current character. */
register int c;
char *term; /* Pointer to most recent character that
* may legally be a terminating character. */
int termX; /* X-position just after term. */
int curX; /* X-position corresponding to p. */
int newX; /* X-position corresponding to p+1. */
int type;
/*
* Find the TkFont structure for this font, and make sure its
* font metrics exist.
*/
if (lastFontStructPtr == fontStructPtr) {
fontPtr = lastFontPtr;
} else {
Tcl_HashEntry *fontHashPtr;
if (!initialized) {
badArg:
panic("TkMeasureChars received unknown font argument");
}
fontHashPtr = Tcl_FindHashEntry(&fontTable, (char *) fontStructPtr);
if (fontHashPtr == NULL) {
goto badArg;
}
fontPtr = (TkFont *) Tcl_GetHashValue(fontHashPtr);
lastFontStructPtr = fontPtr->fontStructPtr;
lastFontPtr = fontPtr;
}
if (fontPtr->types == NULL) {
SetFontMetrics(fontPtr);
}
/*
* Scan the input string one character at a time, until a character
* is found that crosses maxX.
*/
newX = curX = startX;
termX = 0; /* Not needed, but eliminates compiler warning. */
term = source;
for (p = source, c = *p & 0xff; maxChars > 0; p++, maxChars--) {
type = fontPtr->types[c];
if (type == NORMAL) {
newX += fontPtr->widths[c];
} else if (type == TAB) {
newX += fontPtr->tabWidth;
newX -= newX % fontPtr->tabWidth;
} else if (type == REPLACE) {
replaceType:
newX += fontPtr->widths['\\'] + fontPtr->widths['x']
+ fontPtr->widths[hexChars[(c >> 4) & 0xf]]
+ fontPtr->widths[hexChars[c & 0xf]];
} else if (type == NEWLINE) {
if (flags & TK_NEWLINES_NOT_SPECIAL) {
goto replaceType;
}
break;
} else if (type != SKIP) {
panic("Unknown type %d in TkMeasureChars", type);
}
if (newX > maxX) {
break;
}
c = p[1] & 0xff;
if (isspace(c) || (c == 0)) {
term = p+1;
termX = newX;
}
curX = newX;
}
/*
* P points to the first character that doesn't fit in the desired
* span. Use the flags to figure out what to return.
*/
if ((flags & TK_PARTIAL_OK) && (curX < maxX)) {
curX = newX;
p++;
}
if ((flags & TK_AT_LEAST_ONE) && (term == source) && (maxChars > 0)
& !isspace(*term)) {
term = p;
termX = curX;
if (term == source) {
term++;
termX = newX;
}
} else if ((maxChars == 0) || !(flags & TK_WHOLE_WORDS)) {
term = p;
termX = curX;
}
*nextXPtr = termX;
return term-source;
}
/*
*--------------------------------------------------------------
*
* TkDisplayChars --
*
* Draw a string of characters on the screen, converting
* tabs to the right number of spaces and control characters
* to sequences of the form "\xhh" where hh are two hex
* digits.
*
* Results:
* None.
*
* Side effects:
* Information gets drawn on the screen.
*
*--------------------------------------------------------------
*/
void
TkDisplayChars(display, drawable, gc, fontStructPtr, string, numChars,
x, y, flags)
Display *display; /* Display on which to draw. */
Drawable drawable; /* Window or pixmap in which to draw. */
GC gc; /* Graphics context for actually drawing
* characters. */
XFontStruct *fontStructPtr; /* Font used in GC; must have been allocated
* by Tk_GetFontStruct. Used to compute sizes
* of tabs, etc. */
char *string; /* Characters to be displayed. */
int numChars; /* Number of characters to display from
* string. */
int x, y; /* Coordinates at which to draw string. */
int flags; /* Flags to control display. Only
* TK_NEWLINES_NOT_SPECIAL is supported right
* now. See TkMeasureChars for information
* about it. */
{
register TkFont *fontPtr;
register char *p; /* Current character being scanned. */
register int c;
int type;
char *start; /* First character waiting to be displayed. */
int startX; /* X-coordinate corresponding to start. */
int curX; /* X-coordinate corresponding to p. */
char replace[10];
/*
* Find the TkFont structure for this font, and make sure its
* font metrics exist.
*/
if (lastFontStructPtr == fontStructPtr) {
fontPtr = lastFontPtr;
} else {
Tcl_HashEntry *fontHashPtr;
if (!initialized) {
badArg:
panic("TkDisplayChars received unknown font argument");
}
fontHashPtr = Tcl_FindHashEntry(&fontTable, (char *) fontStructPtr);
if (fontHashPtr == NULL) {
goto badArg;
}
fontPtr = (TkFont *) Tcl_GetHashValue(fontHashPtr);
lastFontStructPtr = fontPtr->fontStructPtr;
lastFontPtr = fontPtr;
}
if (fontPtr->types == NULL) {
SetFontMetrics(fontPtr);
}
/*
* Scan the string one character at a time. Display control
* characters immediately, but delay displaying normal characters
* in order to pass many characters to the server all together.
*/
startX = curX = x;
start = string;
for (p = string; numChars > 0; numChars--, p++) {
c = *p & 0xff;
type = fontPtr->types[c];
if (type == NORMAL) {
curX += fontPtr->widths[c];
continue;
}
if (p != start) {
XDrawString(display, drawable, gc, startX, y, start, p - start);
startX = curX;
}
if (type == TAB) {
curX += fontPtr->tabWidth;
curX -= curX % fontPtr->tabWidth;
} else if (type == REPLACE) {
doReplace:
replace[0] = '\\';
replace[1] = 'x';
replace[2] = hexChars[(c >> 4) & 0xf];
replace[3] = hexChars[c & 0xf];
XDrawString(display, drawable, gc, startX, y, replace, 4);
curX += fontPtr->widths[replace[0]]
+ fontPtr->widths[replace[1]]
+ fontPtr->widths[replace[2]]
+ fontPtr->widths[replace[3]];
} else if (type == NEWLINE) {
if (flags & TK_NEWLINES_NOT_SPECIAL) {
goto doReplace;
}
y += fontStructPtr->ascent + fontStructPtr->descent;
curX = x;
} else if (type != SKIP) {
panic("Unknown type %d in TkDisplayChars", type);
}
startX = curX;
start = p+1;
}
/*
* At the very end, there may be one last batch of normal characters
* to display.
*/
if (p != start) {
XDrawString(display, drawable, gc, startX, y, start, p - start);
}
}
/*
*----------------------------------------------------------------------
*
* TkUnderlineChars --
*
* This procedure draws an underline for a given range of characters
* in a given string, using appropriate information for the string's
* font. It doesn't draw the characters (which are assumed to have
* been displayed previously); it just draws the underline.
*
* Results:
* None.
*
* Side effects:
* Information gets displayed in "drawable".
*
*----------------------------------------------------------------------
*/
void
TkUnderlineChars(display, drawable, gc, fontStructPtr, string, x, y,
flags, firstChar, lastChar)
Display *display; /* Display on which to draw. */
Drawable drawable; /* Window or pixmap in which to draw. */
GC gc; /* Graphics context for actually drawing
* underline. */
XFontStruct *fontStructPtr; /* Font used in GC; must have been allocated
* by Tk_GetFontStruct. Used to character
* dimensions, etc. */
char *string; /* String containing characters to be
* underlined. */
int x, y; /* Coordinates at which first character of
* string is drawn. */
int flags; /* Flags that were passed to TkDisplayChars. */
int firstChar; /* Index of first character to underline. */
int lastChar; /* Index of last character to underline. */
{
int xUnder, yUnder, width, height;
unsigned long value;
/*
* First compute the vertical span of the underline, using font
* properties if they exist.
*/
if (XGetFontProperty(fontStructPtr, XA_UNDERLINE_POSITION, &value)) {
yUnder = y + value;
} else {
yUnder = y + fontStructPtr->max_bounds.descent/2;
}
if (XGetFontProperty(fontStructPtr, XA_UNDERLINE_THICKNESS, &value)) {
height = value;
} else {
height = 2;
}
/*
* Now compute the horizontal span of the underline.
*/
TkMeasureChars(fontStructPtr, string, firstChar, x, (int) 1000000, flags,
&xUnder);
TkMeasureChars(fontStructPtr, string+firstChar, lastChar+1-firstChar,
xUnder, (int) 1000000, flags, &width);
width -= xUnder;
XFillRectangle(display, drawable, gc, xUnder, yUnder,
(unsigned int) width, (unsigned int) height);
}