/* * tkUnixFont.c -- * * Contains the Unix implementation of the platform-independant * font package interface. * * 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. * * SCCS: @(#) tkUnixFont.c 1.16 97/10/23 12:47:53 */ #include "tkPort.h" #include "tkInt.h" #include "tkUnixInt.h" #include "tkFont.h" #ifndef ABS #define ABS(n) (((n) < 0) ? -(n) : (n)) #endif /* * The following structure represents Unix's implementation of a font. */ typedef struct UnixFont { TkFont font; /* Stuff used by generic font package. Must * be first in structure. */ Display *display; /* The display to which font belongs. */ XFontStruct *fontStructPtr; /* X information about font. */ char types[256]; /* Array giving types of all characters in * the font, used when displaying control * characters. See below for definition. */ int widths[256]; /* Array giving widths of all possible * characters in the font. */ int underlinePos; /* Offset from baseline to origin of * underline bar (used for simulating a native * underlined font). */ int barHeight; /* Height of underline or overstrike bar * (used for simulating a native underlined or * strikeout font). */ } UnixFont; /* * Possible values for entries in the "types" field in a UnixFont structure, * which classifies the types of all characters in the given font. This * information is used when measuring and displaying characters. * * NORMAL: Standard character. * REPLACE: This character doesn't print: instead of * displaying character, display a replacement * sequence like "\n" (for those characters where * ANSI C defines such a sequence) or a 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. */ #define NORMAL 0 #define REPLACE 1 #define SKIP 2 /* * Characters used when displaying control sequences. */ static char hexChars[] = "0123456789abcdefxtnvr\\"; /* * The following table maps some control characters to sequences like '\n' * rather than '\x10'. A zero entry in the table means no such mapping * exists, and the table only maps characters less than 0x10. */ static char mapChars[] = { 0, 0, 0, 0, 0, 0, 0, 'a', 'b', 't', 'n', 'v', 'f', 'r', 0 }; static UnixFont * AllocFont _ANSI_ARGS_((TkFont *tkFontPtr, Tk_Window tkwin, XFontStruct *fontStructPtr, CONST char *fontName)); static void DrawChars _ANSI_ARGS_((Display *display, Drawable drawable, GC gc, UnixFont *fontPtr, CONST char *source, int numChars, int x, int y)); static int GetControlCharSubst _ANSI_ARGS_((int c, char buf[4])); /* *--------------------------------------------------------------------------- * * TkpGetNativeFont -- * * Map a platform-specific native font name to a TkFont. * * Results: * The return value is a pointer to a TkFont that represents the * native font. If a native font by the given name could not be * found, the return value is NULL. * * Every call to this procedure returns a new TkFont structure, * even if the name has already been seen before. The caller should * call TkpDeleteFont() when the font is no longer needed. * * The caller is responsible for initializing the memory associated * with the generic TkFont when this function returns and releasing * the contents of the generic TkFont before calling TkpDeleteFont(). * * Side effects: * None. * *--------------------------------------------------------------------------- */ TkFont * TkpGetNativeFont(tkwin, name) Tk_Window tkwin; /* For display where font will be used. */ CONST char *name; /* Platform-specific font name. */ { XFontStruct *fontStructPtr; fontStructPtr = XLoadQueryFont(Tk_Display(tkwin), name); if (fontStructPtr == NULL) { return NULL; } return (TkFont *) AllocFont(NULL, tkwin, fontStructPtr, name); } /* *--------------------------------------------------------------------------- * * TkpGetFontFromAttributes -- * * Given a desired set of attributes for a font, find a font with * the closest matching attributes. * * Results: * The return value is a pointer to a TkFont that represents the * font with the desired attributes. If a font with the desired * attributes could not be constructed, some other font will be * substituted automatically. * * Every call to this procedure returns a new TkFont structure, * even if the specified attributes have already been seen before. * The caller should call TkpDeleteFont() to free the platform- * specific data when the font is no longer needed. * * The caller is responsible for initializing the memory associated * with the generic TkFont when this function returns and releasing * the contents of the generic TkFont before calling TkpDeleteFont(). * * Side effects: * None. * *--------------------------------------------------------------------------- */ TkFont * TkpGetFontFromAttributes(tkFontPtr, tkwin, faPtr) TkFont *tkFontPtr; /* If non-NULL, store the information in * this existing TkFont structure, rather than * allocating a new structure to hold the * font; the existing contents of the font * will be released. If NULL, a new TkFont * structure is allocated. */ Tk_Window tkwin; /* For display where font will be used. */ CONST TkFontAttributes *faPtr; /* Set of attributes to match. */ { int numNames, score, i, scaleable, pixelsize, xaPixelsize; int bestIdx, bestScore, bestScaleableIdx, bestScaleableScore; TkXLFDAttributes xa; char buf[256]; UnixFont *fontPtr; char **nameList; XFontStruct *fontStructPtr; CONST char *fmt, *family; double d; family = faPtr->family; if (family == NULL) { family = "*"; } pixelsize = -faPtr->pointsize; if (pixelsize < 0) { d = -pixelsize * 25.4 / 72; d *= WidthOfScreen(Tk_Screen(tkwin)); d /= WidthMMOfScreen(Tk_Screen(tkwin)); d += 0.5; pixelsize = (int) d; } /* * Replace the standard Windows and Mac family names with the names that * X likes. */ if ((strcasecmp("Times New Roman", family) == 0) || (strcasecmp("New York", family) == 0)) { family = "Times"; } else if ((strcasecmp("Courier New", family) == 0) || (strcasecmp("Monaco", family) == 0)) { family = "Courier"; } else if ((strcasecmp("Arial", family) == 0) || (strcasecmp("Geneva", family) == 0)) { family = "Helvetica"; } /* * First try for the Q&D exact match. */ #if 0 sprintf(buf, "-*-%.200s-%s-%c-normal-*-*-%d-*-*-*-*-iso8859-1", family, ((faPtr->weight > TK_FW_NORMAL) ? "bold" : "medium"), ((faPtr->slant == TK_FS_ROMAN) ? 'r' : (faPtr->slant == TK_FS_ITALIC) ? 'i' : 'o'), faPtr->pointsize * 10); fontStructPtr = XLoadQueryFont(Tk_Display(tkwin), buf); #else fontStructPtr = NULL; #endif if (fontStructPtr != NULL) { goto end; } /* * Couldn't find exact match. Now fall back to other available * physical fonts. */ fmt = "-*-%.240s-*-*-*-*-*-*-*-*-*-*-*-*"; sprintf(buf, fmt, family); nameList = XListFonts(Tk_Display(tkwin), buf, 10000, &numNames); if (numNames == 0) { /* * Try getting some system font. */ sprintf(buf, fmt, "fixed"); nameList = XListFonts(Tk_Display(tkwin), buf, 10000, &numNames); if (numNames == 0) { getsystem: fontStructPtr = XLoadQueryFont(Tk_Display(tkwin), "fixed"); if (fontStructPtr == NULL) { fontStructPtr = XLoadQueryFont(Tk_Display(tkwin), "*"); if (fontStructPtr == NULL) { panic("TkpGetFontFromAttributes: cannot get any font"); } } goto end; } } /* * Inspect each of the XLFDs and pick the one that most closely * matches the desired attributes. */ bestIdx = 0; bestScore = INT_MAX; bestScaleableIdx = 0; bestScaleableScore = INT_MAX; for (i = 0; i < numNames; i++) { score = 0; scaleable = 0; if (TkParseXLFD(nameList[i], &xa) != TCL_OK) { continue; } xaPixelsize = -xa.fa.pointsize; /* * Since most people used to use -adobe-* in their XLFDs, * preserve the preference for "adobe" foundry. Otherwise * some applications looks may change slightly if another foundry * is chosen. */ if (strcasecmp(xa.foundry, "adobe") != 0) { score += 3000; } if (xa.fa.pointsize == 0) { /* * A scaleable font is almost always acceptable, but the * corresponding bitmapped font would be better. */ score += 10; scaleable = 1; } else { /* * A font that is too small is better than one that is too * big. */ if (xaPixelsize > pixelsize) { score += (xaPixelsize - pixelsize) * 120; } else { score += (pixelsize - xaPixelsize) * 100; } } score += ABS(xa.fa.weight - faPtr->weight) * 30; score += ABS(xa.fa.slant - faPtr->slant) * 25; if (xa.slant == TK_FS_OBLIQUE) { /* * Italic fonts are preferred over oblique. */ score += 4; } if (xa.setwidth != TK_SW_NORMAL) { /* * The normal setwidth is highly preferred. */ score += 2000; } if (xa.charset == TK_CS_OTHER) { /* * The standard character set is highly preferred over * foreign languages charsets (because we don't support * other languages yet). */ score += 11000; } if ((xa.charset == TK_CS_NORMAL) && (xa.encoding != 1)) { /* * The '1' encoding for the characters above 0x7f is highly * preferred over the other encodings. */ score += 8000; } if (scaleable) { if (score < bestScaleableScore) { bestScaleableIdx = i; bestScaleableScore = score; } } else { if (score < bestScore) { bestIdx = i; bestScore = score; } } if (score == 0) { break; } } /* * Now we know which is the closest matching scaleable font and the * closest matching bitmapped font. If the scaleable font was a * better match, try getting the scaleable font; however, if the * scalable font was not actually available in the desired * pointsize, fall back to the closest bitmapped font. */ fontStructPtr = NULL; if (bestScaleableScore < bestScore) { char *str, *rest; /* * Fill in the desired pointsize info for this font. */ tryscale: str = nameList[bestScaleableIdx]; for (i = 0; i < XLFD_PIXEL_SIZE - 1; i++) { str = strchr(str + 1, '-'); } rest = str; for (i = XLFD_PIXEL_SIZE - 1; i < XLFD_REGISTRY; i++) { rest = strchr(rest + 1, '-'); } *str = '\0'; sprintf(buf, "%.240s-*-%d-*-*-*-*-*%s", nameList[bestScaleableIdx], pixelsize, rest); *str = '-'; fontStructPtr = XLoadQueryFont(Tk_Display(tkwin), buf); bestScaleableScore = INT_MAX; } if (fontStructPtr == NULL) { strcpy(buf, nameList[bestIdx]); fontStructPtr = XLoadQueryFont(Tk_Display(tkwin), buf); if (fontStructPtr == NULL) { /* * This shouldn't happen because the font name is one of the * names that X gave us to use, but it does anyhow. */ if (bestScaleableScore < INT_MAX) { goto tryscale; } else { XFreeFontNames(nameList); goto getsystem; } } } XFreeFontNames(nameList); end: fontPtr = AllocFont(tkFontPtr, tkwin, fontStructPtr, buf); fontPtr->font.fa.underline = faPtr->underline; fontPtr->font.fa.overstrike = faPtr->overstrike; return (TkFont *) fontPtr; } /* *--------------------------------------------------------------------------- * * TkpDeleteFont -- * * Called to release a font allocated by TkpGetNativeFont() or * TkpGetFontFromAttributes(). The caller should have already * released the fields of the TkFont that are used exclusively by * the generic TkFont code. * * Results: * None. * * Side effects: * TkFont is deallocated. * *--------------------------------------------------------------------------- */ void TkpDeleteFont(tkFontPtr) TkFont *tkFontPtr; /* Token of font to be deleted. */ { UnixFont *fontPtr; fontPtr = (UnixFont *) tkFontPtr; XFreeFont(fontPtr->display, fontPtr->fontStructPtr); ckfree((char *) fontPtr); } /* *--------------------------------------------------------------------------- * * TkpGetFontFamilies -- * * Return information about the font families that are available * on the display of the given window. * * Results: * interp->result is modified to hold a list of all the available * font families. * * Side effects: * None. * *--------------------------------------------------------------------------- */ void TkpGetFontFamilies(interp, tkwin) Tcl_Interp *interp; Tk_Window tkwin; { int i, new, numNames; char *family, *end, *p; Tcl_HashTable familyTable; Tcl_HashEntry *hPtr; Tcl_HashSearch search; char **nameList; Tcl_InitHashTable(&familyTable, TCL_STRING_KEYS); nameList = XListFonts(Tk_Display(tkwin), "*", 10000, &numNames); for (i = 0; i < numNames; i++) { if (nameList[i][0] != '-') { continue; } family = strchr(nameList[i] + 1, '-'); if (family == NULL) { continue; } family++; end = strchr(family, '-'); if (end == NULL) { continue; } *end = '\0'; for (p = family; *p != '\0'; p++) { if (isupper(UCHAR(*p))) { *p = tolower(UCHAR(*p)); } } Tcl_CreateHashEntry(&familyTable, family, &new); } hPtr = Tcl_FirstHashEntry(&familyTable, &search); while (hPtr != NULL) { #ifdef STk_CODE Tcl_AppendElement(interp,STk_stringify(Tcl_GetHashKey(&familyTable,hPtr),0)); #else Tcl_AppendElement(interp, Tcl_GetHashKey(&familyTable, hPtr)); #endif hPtr = Tcl_NextHashEntry(&search); } Tcl_DeleteHashTable(&familyTable); XFreeFontNames(nameList); } /* *--------------------------------------------------------------------------- * * Tk_MeasureChars -- * * Determine the number of characters from the string that will fit * in the given horizontal span. The measurement is done under the * assumption that Tk_DrawChars() will be used to actually display * the characters. * * Results: * The return value is the number of characters from source that * fit into the span that extends from 0 to maxLength. *lengthPtr is * filled with the x-coordinate of the right edge of the last * character that did fit. * * Side effects: * None. * *--------------------------------------------------------------------------- */ int Tk_MeasureChars(tkfont, source, numChars, maxLength, flags, lengthPtr) Tk_Font tkfont; /* Font in which characters will be drawn. */ CONST char *source; /* Characters to be displayed. Need not be * '\0' terminated. */ int numChars; /* Maximum number of characters to consider * from source string. */ int maxLength; /* If > 0, maxLength specifies the longest * permissible line length; don't consider any * character that would cross this * x-position. If <= 0, then line length is * unbounded and the flags argument is * ignored. */ int flags; /* Various flag bits OR-ed together: * TK_PARTIAL_OK means include the last char * which only partially fit on this line. * TK_WHOLE_WORDS means stop on a word * boundary, if possible. * TK_AT_LEAST_ONE means return at least one * character even if no characters fit. */ int *lengthPtr; /* Filled with x-location just after the * terminating character. */ { UnixFont *fontPtr; CONST char *p; /* Current character. */ CONST 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 c, sawNonSpace; fontPtr = (UnixFont *) tkfont; if (numChars == 0) { *lengthPtr = 0; return 0; } if (maxLength <= 0) { maxLength = INT_MAX; } newX = curX = termX = 0; p = term = source; sawNonSpace = !isspace(UCHAR(*p)); /* * Scan the input string one character at a time, calculating width. */ for (c = UCHAR(*p); ; ) { newX += fontPtr->widths[c]; if (newX > maxLength) { break; } curX = newX; numChars--; p++; if (numChars == 0) { term = p; termX = curX; break; } c = UCHAR(*p); if (isspace(c)) { if (sawNonSpace) { term = p; termX = curX; sawNonSpace = 0; } } else { sawNonSpace = 1; } } /* * 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) && (numChars > 0) && (curX < maxLength)) { /* * Include the first character that didn't quite fit in the desired * span. The width returned will include the width of that extra * character. */ numChars--; curX = newX; p++; } if ((flags & TK_AT_LEAST_ONE) && (term == source) && (numChars > 0)) { term = p; termX = curX; if (term == source) { term++; termX = newX; } } else if ((numChars == 0) || !(flags & TK_WHOLE_WORDS)) { term = p; termX = curX; } *lengthPtr = termX; return term-source; } /* *--------------------------------------------------------------------------- * * Tk_DrawChars, DrawChars -- * * Draw a string of characters on the screen. Tk_DrawChars() * expands control characters that occur in the string to \X or * \xXX sequences. DrawChars() just draws the strings. * * Results: * None. * * Side effects: * Information gets drawn on the screen. * *--------------------------------------------------------------------------- */ void Tk_DrawChars(display, drawable, gc, tkfont, source, numChars, x, y) Display *display; /* Display on which to draw. */ Drawable drawable; /* Window or pixmap in which to draw. */ GC gc; /* Graphics context for drawing characters. */ Tk_Font tkfont; /* Font in which characters will be drawn; * must be the same as font used in GC. */ CONST char *source; /* Characters to be displayed. Need not be * '\0' terminated. All Tk meta-characters * (tabs, control characters, and newlines) * should be stripped out of the string that * is passed to this function. If they are * not stripped out, they will be displayed as * regular printing characters. */ int numChars; /* Number of characters in string. */ int x, y; /* Coordinates at which to place origin of * string when drawing. */ { UnixFont *fontPtr; CONST char *p; int i, type; char buf[4]; fontPtr = (UnixFont *) tkfont; p = source; for (i = 0; i < numChars; i++) { type = fontPtr->types[UCHAR(*p)]; if (type != NORMAL) { DrawChars(display, drawable, gc, fontPtr, source, p - source, x, y); x += XTextWidth(fontPtr->fontStructPtr, source, p - source); if (type == REPLACE) { DrawChars(display, drawable, gc, fontPtr, buf, GetControlCharSubst(UCHAR(*p), buf), x, y); x += fontPtr->widths[UCHAR(*p)]; } source = p + 1; } p++; } DrawChars(display, drawable, gc, fontPtr, source, p - source, x, y); } static void DrawChars(display, drawable, gc, fontPtr, source, numChars, x, y) Display *display; /* Display on which to draw. */ Drawable drawable; /* Window or pixmap in which to draw. */ GC gc; /* Graphics context for drawing characters. */ UnixFont *fontPtr; /* Font in which characters will be drawn; * must be the same as font used in GC. */ CONST char *source; /* Characters to be displayed. Need not be * '\0' terminated. All Tk meta-characters * (tabs, control characters, and newlines) * should be stripped out of the string that * is passed to this function. If they are * not stripped out, they will be displayed as * regular printing characters. */ int numChars; /* Number of characters in string. */ int x, y; /* Coordinates at which to place origin of * string when drawing. */ { /* * Perform a quick sanity check to ensure we won't overflow the X * coordinate space. */ if ((x + (fontPtr->fontStructPtr->max_bounds.width * numChars) > 0x7fff)) { int length; /* * The string we are being asked to draw is too big and would overflow * the X coordinate space. Unfortunatley X servers aren't too bright * and so they won't deal with this case cleanly. We need to truncate * the string before sending it to X. */ numChars = Tk_MeasureChars((Tk_Font) fontPtr, source, numChars, 0x7fff - x, 0, &length); } XDrawString(display, drawable, gc, x, y, source, numChars); if (fontPtr->font.fa.underline != 0) { XFillRectangle(display, drawable, gc, x, y + fontPtr->underlinePos, (unsigned) XTextWidth(fontPtr->fontStructPtr, source, numChars), (unsigned) fontPtr->barHeight); } if (fontPtr->font.fa.overstrike != 0) { y -= fontPtr->font.fm.descent + (fontPtr->font.fm.ascent) / 10; XFillRectangle(display, drawable, gc, x, y, (unsigned) XTextWidth(fontPtr->fontStructPtr, source, numChars), (unsigned) fontPtr->barHeight); } } /* *--------------------------------------------------------------------------- * * AllocFont -- * * Helper for TkpGetNativeFont() and TkpGetFontFromAttributes(). * Allocates and intializes the memory for a new TkFont that * wraps the platform-specific data. * * Results: * Returns pointer to newly constructed TkFont. * * The caller is responsible for initializing the fields of the * TkFont that are used exclusively by the generic TkFont code, and * for releasing those fields before calling TkpDeleteFont(). * * Side effects: * Memory allocated. * *--------------------------------------------------------------------------- */ static UnixFont * AllocFont(tkFontPtr, tkwin, fontStructPtr, fontName) TkFont *tkFontPtr; /* If non-NULL, store the information in * this existing TkFont structure, rather than * allocating a new structure to hold the * font; the existing contents of the font * will be released. If NULL, a new TkFont * structure is allocated. */ Tk_Window tkwin; /* For display where font will be used. */ XFontStruct *fontStructPtr; /* X information about font. */ CONST char *fontName; /* The string passed to XLoadQueryFont() to * construct the fontStructPtr. */ { UnixFont *fontPtr; unsigned long value; int i, width, firstChar, lastChar, n, replaceOK; char *name, *p; char buf[4]; TkXLFDAttributes xa; double d; if (tkFontPtr != NULL) { fontPtr = (UnixFont *) tkFontPtr; XFreeFont(fontPtr->display, fontPtr->fontStructPtr); } else { fontPtr = (UnixFont *) ckalloc(sizeof(UnixFont)); } /* * Encapsulate the generic stuff in the TkFont. */ fontPtr->font.fid = fontStructPtr->fid; if (XGetFontProperty(fontStructPtr, XA_FONT, &value) && (value != 0)) { name = Tk_GetAtomName(tkwin, (Atom) value); TkInitFontAttributes(&xa.fa); if (TkParseXLFD(name, &xa) == TCL_OK) { goto ok; } } TkInitFontAttributes(&xa.fa); if (TkParseXLFD(fontName, &xa) != TCL_OK) { TkInitFontAttributes(&fontPtr->font.fa); fontPtr->font.fa.family = Tk_GetUid(fontName); } else { ok: fontPtr->font.fa = xa.fa; } if (fontPtr->font.fa.pointsize < 0) { d = -fontPtr->font.fa.pointsize * 72 / 25.4; d *= WidthMMOfScreen(Tk_Screen(tkwin)); d /= WidthOfScreen(Tk_Screen(tkwin)); d += 0.5; fontPtr->font.fa.pointsize = (int) d; } fontPtr->font.fm.ascent = fontStructPtr->ascent; fontPtr->font.fm.descent = fontStructPtr->descent; fontPtr->font.fm.maxWidth = fontStructPtr->max_bounds.width; fontPtr->font.fm.fixed = 1; fontPtr->display = Tk_Display(tkwin); fontPtr->fontStructPtr = fontStructPtr; /* * Classify the characters. */ firstChar = fontStructPtr->min_char_or_byte2; lastChar = fontStructPtr->max_char_or_byte2; for (i = 0; i < 256; i++) { if ((i == 0177) || (i < firstChar) || (i > lastChar)) { fontPtr->types[i] = REPLACE; } else { fontPtr->types[i] = NORMAL; } } /* * Compute the widths for all the normal characters. Any other * characters are given an initial width of 0. Also, this determines * if this is a fixed or variable width font, by comparing the widths * of all the normal characters. */ width = 0; for (i = 0; i < 256; i++) { if (fontPtr->types[i] != NORMAL) { n = 0; } else if (fontStructPtr->per_char == NULL) { n = fontStructPtr->max_bounds.width; } else { n = fontStructPtr->per_char[i - firstChar].width; } fontPtr->widths[i] = n; if (n != 0) { if (width == 0) { width = n; } else if (width != n) { fontPtr->font.fm.fixed = 0; } } } /* * Compute the widths of the characters that should be replaced with * control character expansions. If the appropriate chars are not * available in this font, then control character expansions will not * be used; control chars will be invisible & zero-width. */ replaceOK = 1; for (p = hexChars; *p != '\0'; p++) { if ((UCHAR(*p) < firstChar) || (UCHAR(*p) > lastChar)) { replaceOK = 0; break; } } for (i = 0; i < 256; i++) { if (fontPtr->types[i] == REPLACE) { if (replaceOK) { n = GetControlCharSubst(i, buf); for ( ; --n >= 0; ) { fontPtr->widths[i] += fontPtr->widths[UCHAR(buf[n])]; } } else { fontPtr->types[i] = SKIP; } } } if (XGetFontProperty(fontStructPtr, XA_UNDERLINE_POSITION, &value)) { fontPtr->underlinePos = value; } else { /* * If the XA_UNDERLINE_POSITION property does not exist, the X * manual recommends using the following value: */ fontPtr->underlinePos = fontStructPtr->descent / 2; } fontPtr->barHeight = 0; if (XGetFontProperty(fontStructPtr, XA_UNDERLINE_THICKNESS, &value)) { /* * Sometimes this is 0 even though it shouldn't be. */ fontPtr->barHeight = value; } if (fontPtr->barHeight == 0) { /* * If the XA_UNDERLINE_THICKNESS property does not exist, the X * manual recommends using the width of the stem on a capital * letter. I don't know of a way to get the stem width of a letter, * so guess and use 1/3 the width of a capital I. */ fontPtr->barHeight = fontPtr->widths['I'] / 3; if (fontPtr->barHeight == 0) { fontPtr->barHeight = 1; } } if (fontPtr->underlinePos + fontPtr->barHeight > fontStructPtr->descent) { /* * If this set of cobbled together values would cause the bottom of * the underline bar to stick below the descent of the font, jack * the underline up a bit higher. */ fontPtr->barHeight = fontStructPtr->descent - fontPtr->underlinePos; if (fontPtr->barHeight == 0) { fontPtr->underlinePos--; fontPtr->barHeight = 1; } } return fontPtr; } /* *--------------------------------------------------------------------------- * * GetControlCharSubst -- * * When displaying text in a widget, a backslashed escape sequence * is substituted for control characters that occur in the text. * Given a control character, fill in a buffer with the replacement * string that should be displayed. * * Results: * The return value is the length of the substitute string. buf is * filled with the substitute string; it is not '\0' terminated. * * Side effects: * None. * *--------------------------------------------------------------------------- */ static int GetControlCharSubst(c, buf) int c; /* The control character to be replaced. */ char buf[4]; /* Buffer that gets replacement string. It * only needs to be 4 characters long. */ { buf[0] = '\\'; if ((c < sizeof(mapChars)) && (mapChars[c] != 0)) { buf[1] = mapChars[c]; return 2; } else { buf[1] = 'x'; buf[2] = hexChars[(c >> 4) & 0xf]; buf[3] = hexChars[c & 0xf]; return 4; } }