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Diffstat (limited to 'lib/libpbmfont1.c')
| -rw-r--r-- | lib/libpbmfont1.c | 359 |
1 files changed, 359 insertions, 0 deletions
diff --git a/lib/libpbmfont1.c b/lib/libpbmfont1.c new file mode 100644 index 00000000..2d269da7 --- /dev/null +++ b/lib/libpbmfont1.c @@ -0,0 +1,359 @@ +/* +** +** Routines for loading a PBM sheet font file +** +** Copyright (C) 1991 by Jef Poskanzer. +** +** 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 and that both that +** copyright notice and this permission notice appear in supporting +** documentation. This software is provided "as is" without express or +** implied warranty. +*/ + +#include <assert.h> +#include <string.h> + +#include "netpbm/pm_c_util.h" +#include "netpbm/mallocvar.h" +#include "netpbm/nstring.h" + +#include "pbm.h" +#include "pbmfont.h" + + +/*---------------------------------------------------------------------------- + + The routines in this file reads a font bitmap representing + the following text: + + (0,0) + M ",/^_[`jpqy| M + + / !"#$%&'()*+ / + < ,-./01234567 < + > 89:;<=>?@ABC > + @ DEFGHIJKLMNO @ + _ PQRSTUVWXYZ[ _ + { \]^_`abcdefg { + } hijklmnopqrs } + ~ tuvwxyz{|}~ ~ + + M ",/^_[`jpqy| M + + The bitmap must be cropped exactly to the edges. + + The characters in the border you see are irrelevant except for + character size compuations. The 12 x 8 array in the center is + the font. The top left character there belongs to code point + 0, and the code points increase in standard reading order, so + the bottom right character is code point 127. You can't define + code points < 32 or > 127 with this font format. + + The characters in the top and bottom border rows must include a + character with the lowest reach of any in the font (e.g. "y", + "_") and one with the highest reach (e.g. '"'). The characters + in the left and right border columns must include characters + with the rightmost and leftmost reach of any in the font + (e.g. "M" for both). + + The border must be separated from the font by one blank text + row or text column. +-----------------------------------------------------------------------------*/ + + +static unsigned int const firstCodePoint = 32; + /* This is the code point of the first character in a pbmfont font. + In ASCII, it is a space. + */ + +static unsigned int const nCharsInFont = 96; + /* The number of characters in a pbmfont font. A pbmfont font defines + characters at position 32 (ASCII space) through 127, so that's 96. + */ + + +static void +findFirstBlankRow(const bit ** const font, + unsigned int const fcols, + unsigned int const frows, + unsigned int * const browP) { + + unsigned int row; + bool foundBlank; + + for (row = 0, foundBlank = false; row < frows / 6 && !foundBlank; ++row) { + unsigned int col; + bit col0Value = font[row][0]; + bool rowIsBlank; + rowIsBlank = true; /* initial assumption */ + for (col = 1; col < fcols; ++col) + if (font[row][col] != col0Value) + rowIsBlank = false; + + if (rowIsBlank) { + foundBlank = true; + *browP = row; + } + } + + if (!foundBlank) + pm_error("couldn't find blank pixel row in font"); +} + + + +static void +findFirstBlankCol(const bit ** const font, + unsigned int const fcols, + unsigned int const frows, + unsigned int * const bcolP) { + + unsigned int col; + bool foundBlank; + + for (col = 0, foundBlank = false; col < fcols / 6 && !foundBlank; ++col) { + unsigned int row; + bit row0Value = font[0][col]; + bool colIsBlank; + colIsBlank = true; /* initial assumption */ + for (row = 1; row < frows; ++row) + if (font[row][col] != row0Value) + colIsBlank = false; + + if (colIsBlank) { + foundBlank = true; + *bcolP = col; + } + } + + if (!foundBlank) + pm_error("couldn't find blank pixel column in font"); +} + + + +static void +computeCharacterSize(const bit ** const font, + unsigned int const fcols, + unsigned int const frows, + unsigned int * const cellWidthP, + unsigned int * const cellHeightP, + unsigned int * const charWidthP, + unsigned int * const charHeightP) { + + unsigned int firstBlankRow; + unsigned int firstBlankCol; + unsigned int heightLast11Rows; + + findFirstBlankRow(font, fcols, frows, &firstBlankRow); + + findFirstBlankCol(font, fcols, frows, &firstBlankCol); + + heightLast11Rows = frows - firstBlankRow; + + if (heightLast11Rows % 11 != 0) + pm_error("The rows of characters in the font do not appear to " + "be all the same height. The last 11 rows are %u pixel " + "rows high (from pixel row %u up to %u), " + "which is not a multiple of 11.", + heightLast11Rows, firstBlankRow, frows); + else { + unsigned int widthLast15Cols; + + *cellHeightP = heightLast11Rows / 11; + + widthLast15Cols = fcols - firstBlankCol; + + if (widthLast15Cols % 15 != 0) + pm_error("The columns of characters in the font do not appear to " + "be all the same width. " + "The last 15 columns are %u pixel " + "columns wide (from pixel col %u up to %u), " + "which is not a multiple of 15.", + widthLast15Cols, firstBlankCol, fcols); + else { + *cellWidthP = widthLast15Cols / 15; + + *charWidthP = firstBlankCol; + *charHeightP = firstBlankRow; + } + } +} + + + +struct font* +pbm_dissectfont(const bit ** const fontsheet, + unsigned int const frows, + unsigned int const fcols) { +/*---------------------------------------------------------------------------- + Dissect PBM sheet font data, create a font structre, + load bitmap data into it. + + Return value is a pointer to the newly created font structure + + The input bitmap data is in memory, in one byte per pixel format. + + The dissection works by finding the first blank row and column; + i.e the lower right corner of the "M" in the upper left corner + of the matrix. That gives the height and width of the + maximum-sized character, which is not too useful. But the + distance from there to the opposite side is an integral + multiple of the cell size, and that's what we need. Then it's + just a matter of filling in all the coordinates. + + Struct font has fields 'oldfont', 'fcols', 'frows' for backward + compability. If there is any need to load data stored in this format + feed the above three, in order, as arguments to this function: + + pbm_dissectfont(oldfont, fcols, frows); + ----------------------------------------------------------------------------*/ + + unsigned int cellWidth, cellHeight; + /* Dimensions in pixels of each cell of the font -- that + includes the glyph and the white space above and to the + right of it. Each cell is a tile of the font image. The + top character row and left character row don't count -- + those cells are smaller because they are missing the white + space. + */ + unsigned int charWidth, charHeight; + /* Maximum dimensions of glyph itself, inside its cell */ + + int row, col, ch, r, c, i; + struct font * fn; + + computeCharacterSize(fontsheet, fcols, frows, + &cellWidth, &cellHeight, &charWidth, &charHeight); + + /* Now convert to a general font */ + + MALLOCVAR(fn); + if (fn == NULL) + pm_error("out of memory allocating font structure"); + + fn->maxwidth = charWidth; + fn->maxheight = charHeight; + fn->x = fn->y = 0; + + fn->oldfont = fontsheet; + fn->frows = frows; + fn->fcols = fcols; + + /* Now fill in the 0,0 coords. */ + row = cellHeight * 2; + col = cellWidth * 2; + + /* Load individual glyphs */ + for ( ch = 0; ch < nCharsInFont; ++ch ) { + /* Allocate memory separately for each glyph. + pbm_loadbdffont2() does this in exactly the same manner. + */ + struct glyph * const glyph = + (struct glyph *) malloc (sizeof (struct glyph)); + char * const bmap = (char*) malloc(fn->maxwidth * fn->maxheight); + + if ( bmap == NULL || glyph == NULL ) + pm_error( "out of memory allocating glyph data" ); + + glyph->width = fn->maxwidth; + glyph->height = fn->maxheight; + glyph->x = glyph->y = 0; + glyph->xadd = cellWidth; + + for ( r = 0; r < glyph->height; ++r ) + for ( c = 0; c < glyph->width; ++c ) + bmap[r * glyph->width + c] = fontsheet[row + r][col + c]; + + glyph->bmap = bmap; + fn->glyph[firstCodePoint + ch] = glyph; + + col += cellWidth; + if ( col >= cellWidth * 14 ) { + col = cellWidth * 2; + row += cellHeight; + } + } + + /* Initialize all remaining character positions to "undefined." */ + for (i = 0; i < firstCodePoint; ++i) + fn->glyph[i] = NULL; + + for (i = firstCodePoint + nCharsInFont; i <= PM_FONT_MAXGLYPH; ++i) + fn->glyph[i] = NULL; + + return fn; +} + + + + +struct font * +pbm_loadpbmfont(const char * const filename) { +/*---------------------------------------------------------------------------- + Read PBM font sheet data from file 'filename'. + Load data into font structure. + + When done with object, free with pbm_destroybdffont(). +-----------------------------------------------------------------------------*/ + + FILE * ifP; + bit ** fontsheet; + int fcols, frows; + struct font * retval; + + ifP = pm_openr(filename); + + fontsheet = pbm_readpbm(ifP, &fcols, &frows); + + if ((fcols - 1) / 16 >= pbm_maxfontwidth() || + (frows - 1) / 12 >= pbm_maxfontheight()) + pm_error("Absurdly large PBM font file: %s", filename); + else if (fcols < 31 || frows < 23) { + /* Need at least one pixel per character, and this is too small to + have that. + */ + pm_error("PBM font file '%s' too small to be a font file: %u x %u. " + "Minimum sensible size is 31 x 23", + filename, fcols, frows); + } + + pm_close(ifP); + + retval = pbm_dissectfont((const bit **)fontsheet, frows, fcols); + return (retval); + +} + + + +struct font2 * +pbm_loadpbmfont2(const char * const filename) { +/*---------------------------------------------------------------------------- + Like pbm_loadpbmfont, but return a pointer to struct font2. + + When done with object, free with pbm_destroybdffont2(). +-----------------------------------------------------------------------------*/ + + const struct font * const pbmfont = pbm_loadpbmfont(filename); + struct font2 * const retval = pbm_expandbdffont(pbmfont); + + free ((void *)pbmfont); + + /* Overwrite some fields */ + + retval->load_fn = LOAD_PBMSHEET; + retval->default_char = (PM_WCHAR) ' '; + retval->default_char_defined = TRUE; + retval->name = pm_strdup("(PBM sheet font has no name)"); + retval->charset = ISO646_1991_IRV; + retval->charset_string = pm_strdup("ASCII"); + retval->total_chars = retval->chars = nCharsInFont; + + return(retval); +} + + + |