plfreetype.c

/* $Id: plfreetype.c 9477 2009-02-08 22:34:26Z andrewross $
 *
 * Copyright (C) 2002, 2004, 2005  Andrew Roach
 * Copyright (C) 2002  Maurice LeBrun
 * Copyright (C) 2002, 2004, 2005  Alan W. Irwin
 * Copyright (C) 2003, 2004  Joao Cardoso
 * Copyright (C) 2003, 2004, 2005  Rafael Laboissiere
 * Copyright (C) 2004  Andrew Ross
 *
 * This file is part of PLplot.
 *
 * PLplot is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Library Public License as published
 * by the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * PLplot is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with PLplot; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *
 *
 *                  Support routines for freetype font engine
 *
 *  This file contains a series of support routines for drivers interested
 *  in using freetype rendered fonts instead of plplot plotter fonts.
 *  Freetype supports a gerth of font formats including TrueType, OpenType,
 *  Adobe Type1, Type42 etc... the list seems almost endless. Any bitmap
 *  driver should be able to use any of these freetype fonts from plplot if
 *  these routines are properly initialised.
 *
 *  Freetype support is not intended to be a "feature" of the common API,
 *  but is  implemented as a driver-specific optional extra invoked via the
 *  -drvopt command line toggle. It is intended to be used in the context of
 *  "PLESC_HAS_TEXT" for any bitmap drivers without native font support.
 *  Implementing freetype in this manner minimise changes to the overall
 *  API. Because of this approach, there is not a "wealth" of font options
 *  available to the programmer. You can not do anything you can't do for a
 *  normal freetype plotter font like boldface. You can do most of the
 *  things that you can do with a plotter font however, like greek
 *  characters superscripting, and selecting one of the four "pre-defined"
 *  plplot font types. At present underlining and overlining are not
 *  supported.
 *
 *  To give the user some level of control over the fonts that are used,
 *  environmental variables can be set to over-ride the definitions used by
 *  the five default plplot fonts.
 *
 *  The exact syntax for evoking freetype fonts is dependant on each
 *  driver, but for the GD and GNUSVGA drivers I have followed the syntax of
 *  the PS driver and use the command-line switch of "-drvopt text" to
 *  activate the feature, and suggest other programmers do the same for
 *  commonality.
 *
 *  Both anti-aliased and monochrome font rendering is supported by these
 *  routines. How these are evoked depends on the programmer, but with the
 *  GD and GNUSVGA driver families I have used the command-line switch
 *  "-drvopt smooth" to activate the feature; but, considering you also need
 *  to turn freetype on, it would probably really be more like "-drvopt
 *  text,smooth".
 *
 */

#if !defined(WIN32) || defined(__GNUC__)
  #include <unistd.h>
#else
  #define F_OK 1
  #include <stdio.h>
  int access( char *filename, int flag ) {
      FILE *infile ;
      infile = fopen( filename, "r" ) ;
      if ( infile != NULL ) {
          fclose(infile) ;
          return 0 ;
      } else {
          return 1 ;
      }
  }
#endif

#define makeunixslash( b ) do { char *I; for (I=b;*I!=0;*I++) if (*I=='\\') *I='/';}while(0)

#include "plDevs.h"
#include "plplotP.h"
#include "drivers.h"
#ifdef HAVE_FREETYPE
#include "plfreetype.h"
#include "plfci-truetype.h"

#define FT_Data _FT_Data_

/* Font lookup table that is constructed in plD_FreeType_init*/
PLDLLIMPEXP_DATA(FCI_to_FontName_Table) FontLookup[N_TrueTypeLookup];
/*              TOP LEVEL DEFINES       */

/*  Freetype lets you set the text size absolutely. It also takes into
 *  account the DPI when doing so. So does plplot. Why, then, is it that the
 *  size of the text drawn by plplot is bigger than the text drawn by
 *  freetype when given IDENTICAL parameters ? Perhaps I am missing
 *  something somewhere, but to fix this up we use TEXT_SCALING_FACTOR to
 *  set a scaling factor to try and square things up a bit.
 */

#define TEXT_SCALING_FACTOR .7

/* default size of temporary text buffer */
/* If we wanted to be fancy we could add sizing, but this should be big enough */

#define NTEXT_ALLOC 1024

/*--------------------------------------------------------------------------*\
 *  Some debugging macros
\*--------------------------------------------------------------------------*/

#define Debug6(a,b,c,d,e,f) do {if (pls->debug){fprintf(stderr,a,b,c,d,e,f);}}while(0)


/*              FUNCTION PROTOTYPES    */

/*  Public prototypes, generally available to the API  */

void plD_FreeType_init(PLStream *pls);
void plD_render_freetype_text (PLStream *pls, EscText *args);
void plD_FreeType_Destroy(PLStream *pls);
void pl_set_extended_cmap0(PLStream *pls, int ncol0_width, int ncol0_org);
void pl_RemakeFreeType_text_from_buffer (PLStream *pls);
void plD_render_freetype_sym (PLStream *pls, EscText *args);

/*  Private prototypes for use in this file only */

static void FT_PlotChar(PLStream *pls,FT_Data *FT, FT_GlyphSlot  slot, int x, int y, short colour );
static void FT_SetFace( PLStream *pls, PLUNICODE fci );
static PLFLT CalculateIncrement( int bg, int fg, int levels);

/* These are never defined, maybe they will be used in the future?

static void pl_save_FreeType_text_to_buffer (PLStream *pls, EscText *args);
static FT_ULong hershey_to_unicode (char in);

*/

static void FT_WriteStrW(PLStream *pls,const PLUNICODE  *text, short len, int x, int y);
static void FT_StrX_YW(PLStream *pls,const PLUNICODE *text, short len, int *xx, int *yy);

/*----------------------------------------------------------------------*\
 * FT_StrX_YW()
 *
 * Returns the dimensions of the text box. It does this by fully parsing
 * the supplied text through the rendering engine. It does everything
 * but draw the text. This seems, to me, the easiest and most accurate
 * way of determining the text's dimensions. If/when caching is added,
 * the CPU hit for this "double processing" will be minimal.
\*----------------------------------------------------------------------*/

void
FT_StrX_YW(PLStream *pls, const PLUNICODE *text, short len, int *xx, int *yy)
{
    FT_Data *FT=(FT_Data *)pls->FT;
    short i=0;
    FT_Vector  akerning;
    int x=0,y=0;
    char esc;

    plgesc(&esc);

/*
 * Things seems to work better with this line than without it;
 * I guess because there is no vertical kerning or advancement for most
 * non-transformed fonts, so we need to define *something* for the y height,
 * and this is the best thing I could think of.
 */

    y -= FT->face->size->metrics.height;

/* walk through the text character by character */
    for (i=0;i<len;i++) {
    if ((text[i]==esc)&&(text[i-1]!=esc)) {
        if (text[i+1]==esc) continue;

        switch(text[i+1]) {

        case 'u': /* super script */
        case 'd': /* subscript */
        case 'U':
        case 'D':
                i++;
                break;
        }

        } else if (text[i] & PL_FCI_MARK) {
       /* FCI in text stream; change font accordingly. */
       FT_SetFace(pls , text[i]);
        } else {

    /* see if we have kerning for the particular character pair */
        if ((i>0)&&FT_HAS_KERNING(FT->face)) {
        FT_Get_Kerning( FT->face,
                text[i-1],
                text[i],
                ft_kerning_default,
                &akerning );
        x+= (akerning.x >> 6);        /* add (or subtract) the kerning */
        }

     /*
      * Next we load the char. This also draws the char, transforms it, and
      * converts it to a bitmap. At present this is a bit wasteful, but
      * if/when I add cache support, then this data won't go to waste.
      * Since there is no sense in going to the trouble of doing anti-aliasing
      * calculations since we aren't REALLY plotting anything, we will render
      * this as monochrome since it is probably marginally quicker. If/when
      * cache support is added, naturally this will have to change.
      */

        FT_Load_Char( FT->face, text[i], FT_LOAD_MONOCHROME+FT_LOAD_RENDER);

     /*
      * Add in the "advancement" needed to position the cursor for the next
      * character. Unless the text is transformed, "y" will always be zero.
      * Y is negative because freetype does things upside down
      */

        x += (FT->face->glyph->advance.x);
        y -= (FT->face->glyph->advance.y);
    }
    }

/*
 * Convert from unit of 1/64 of a pixel to pixels, and do it real fast with
 * a bitwise shift (mind you, any decent compiler SHOULD optimise /64 this way
 * anyway...)
 */

/* (RL, on 2005-01-23) Removed the shift bellow to avoid truncation errors
 * later.
    *yy=y>> 6;
    *xx=x>> 6;
 */
    *yy = y;
    *xx = x;

}

/*----------------------------------------------------------------------*\
 * FT_WriteStrW()
 *
 * Writes a string of FT text at the current cursor location.
 * most of the code here is identical to "FT_StrX_Y" and I will probably
 * collapse the two into some more efficient code eventually.
\*----------------------------------------------------------------------*/

void
FT_WriteStrW(PLStream *pls, const PLUNICODE *text, short len, int x, int y)
{
    FT_Data *FT=(FT_Data *)pls->FT;
    short i=0,last_char=-1;
    FT_Vector  akerning, adjust;
    char esc;

    plgesc(&esc);


/*
 *  Adjust for the descender - make sure the font is nice and centred
 *  vertically. Freetype assumes we have a base-line, but plplot thinks of
 *  centre-lines, so that's why we have to do this. Since this is one of our
 *  own adjustments, rather than a freetype one, we have to run it through
 *  the transform matrix manually.
 *
 *  For some odd reason, this works best if we triple the
 *  descender's height and then adjust the height later on...
 *  Don't ask me why, 'cause I don't know. But it does seem to work.
 *
 *  I really wish I knew *why* it worked better though...
 *
 *   y-=FT->face->descender >> 6;
 */

#ifdef DODGIE_DECENDER_HACK
    adjust.y= (FT->face->descender >> 6)*3;
#else
    adjust.y= (FT->face->descender >> 6);
#endif

/* (RL) adjust.y is zeroed below,, making the code above (around
 * DODGIE_DECENDER_HACK) completely useless.  This is necessary for
 * getting the vertical alignment of text right, which is coped with
 * in function plD_render_freetype_text now.
 */

    adjust.x=0;
    adjust.y=0;
    FT_Vector_Transform( &adjust, &FT->matrix);
    x+=adjust.x;
    y-=adjust.y;

/* (RL, on 2005-01-25) The computation of cumulated glyph width within
 * the text is done now with full precision, using 26.6 Freetype
 * arithmetics.  We should then shift the x and y variables by 6 bits,
 * as below.  Inside the character for loop, all operations regarding
 * x and y will be done in 26.6 mode and  these variables will be
 * converted to integers when passed to FT_PlotChar.  Notrice that we
 * are using ROUND and float division instead of ">> 6" now.  This
 * minimizes truncation errors.
*/

    x <<= 6;
    y <<= 6;

/* walk through the text character by character */

    for (i=0; i<len; i++) {
    if ((text[i]==esc)&&(text[i-1]!=esc)) {
        if (text[i+1]==esc) continue;

        switch(text[i+1]) {

/*
 *  We run the OFFSET for the super-script and sub-script through the
 *  transformation matrix so we can calculate nice and easy the required
 *  offset no matter what's happened rotation wise. Everything else, like
 *  kerning and advancing from character to character is transformed
 *  automatically by freetype, but since the superscript/subscript is a
 *  feature of plplot, and not freetype, we have to make allowances.
 */

        case 'u': /* super script */
        case 'U': /* super script */
                adjust.y = FT->face->size->metrics.height / 2;
                adjust.x=0;
                FT_Vector_Transform( &adjust, &FT->matrix);
                x+=adjust.x;
                y-=adjust.y;
                i++;
                break;

        case 'd': /* subscript */
        case 'D': /* subscript */
                adjust.y = -FT->face->size->metrics.height / 2;
                adjust.x=0;
                FT_Vector_Transform( &adjust, &FT->matrix);
                x+=adjust.x;
                y-=adjust.y;
                i++;
                break;
        }

        } else if (text[i] & PL_FCI_MARK) {
       /* FCI in text stream; change font accordingly. */
       FT_SetFace(pls , text[i]);
       FT=(FT_Data *)pls->FT;
       FT_Set_Transform( FT->face, &FT->matrix, &FT->pos );
        } else {
    /* see if we have kerning for the particular character pair */
        if ((last_char!=-1)&&(i>0)&&FT_HAS_KERNING(FT->face)) {
        FT_Get_Kerning( FT->face,
                text[last_char],
                text[i],
                ft_kerning_default, &akerning );
        x += akerning.x;        /* add (or subtract) the kerning */
                y -= akerning.y;        /* Do I need this in case of rotation ? */

            }


       FT_Load_Char( FT->face, text[i], (FT->smooth_text==0) ? FT_LOAD_MONOCHROME+FT_LOAD_RENDER : FT_LOAD_RENDER|FT_LOAD_FORCE_AUTOHINT);
       FT_PlotChar(pls,FT, FT->face->glyph,
                   ROUND (x / 64.0), ROUND (y / 64.0), 2 ); /* render the text */

        x += FT->face->glyph->advance.x;
            y -= FT->face->glyph->advance.y;

        last_char=i;
    }
    } /* end for */
}

/*----------------------------------------------------------------------*\
 * FT_PlotChar()
 *
 * Plots an individual character. I know some of this stuff, like colour
 * could be parsed from plstream, but it was just quicker this way.
\*----------------------------------------------------------------------*/

void
FT_PlotChar(PLStream *pls, FT_Data *FT, FT_GlyphSlot slot,
        int x, int y, short colour )
{
    unsigned char bittest;
    short i,k,j;
    int n=slot->bitmap.pitch;
    int current_pixel_colour;
    int R,G,B;
    PLFLT alpha_a,alpha_b;
    int xx;
    short imin, imax, kmin, kmax;

    /* Corners of the clipping rectangle */
    PLINT clipxmin, clipymin, clipxmax,clipymax, tmp;
    PLINT clpxmi, clpxma, clpymi, clpyma;

    /* Convert clipping box into normal coordinates */
    clipxmin=pls->clpxmi;
    clipxmax=pls->clpxma;
    clipymin=pls->clpymi;
    clipymax=pls->clpyma;

    if (plsc->difilt) {
      difilt(&clipxmin,&clipymin,1,&clpxmi,&clpxma,&clpymi,&clpyma);
      difilt(&clipxmax,&clipymax,1,&clpxmi,&clpxma,&clpymi,&clpyma);
    }


    if( FT->scale!=0.0 ) {  /* scale was set */
      clipxmin = clipxmin/FT->scale;
      clipxmax = clipxmax/FT->scale;
      if (FT->invert_y==1) {
    clipymin=FT->ymax-(clipymin/FT->scale);
    clipymax=FT->ymax-(clipymax/FT->scale);
      }
      else {
    clipymin=clipymin/FT->scale;
    clipymax=clipymax/FT->scale;
      }
    } 
    else {
      clipxmin=clipxmin/FT->scalex;
      clipxmax=clipxmax/FT->scalex;
      
      if (FT->invert_y==1) {
    clipymin=FT->ymax-(clipymin/FT->scaley);
    clipymax=FT->ymax-(clipymax/FT->scaley);
      } 
      else {
    clipymin=clipymin/FT->scaley;
    clipymax=clipymax/FT->scaley;
      }
    }
    if (clipxmin > clipxmax) {
      tmp = clipxmax;
      clipxmax = clipxmin;
      clipxmin = tmp;
    }
    if (clipymin > clipymax) {
      tmp = clipymax;
      clipymax = clipymin;
      clipymin = tmp;
    }

    /* Comment this out as it fails for cases where we want to plot text
     * in the background font, i.e. example 24. 
     */
    /*if ((slot->bitmap.pixel_mode==ft_pixel_mode_mono)||(pls->icol0==0)) {*/
    if (slot->bitmap.pixel_mode==ft_pixel_mode_mono) {
    x+=slot->bitmap_left;
    y-=slot->bitmap_top;

        imin = MAX(0,clipymin-y);
        imax = MIN(slot->bitmap.rows,clipymax-y);
    for(i=imin;i<imax;i++) {
        for (k=0;k<n;k++) {
        bittest=128;
        for (j=0;j<8;j++) {
            if ((bittest&(unsigned char)slot->bitmap.buffer[(i*n)+k])==bittest) {
            xx = x+(k*8)+j;
            if ( (xx >= clipxmin) && (xx <= clipxmax) )
              FT->pixel(pls, xx, y+i);
                    }
            bittest>>=1;
        }
            }
        }
    }

/* this is the anti-aliased stuff */

    else {
           x+=slot->bitmap_left;
           y-=slot->bitmap_top;

          imin = MAX(0,clipymin-y);
          imax = MIN(slot->bitmap.rows,clipymax-y);
          kmin = MAX(0,clipxmin-x);
          kmax = MIN(slot->bitmap.width,clipxmax-x);
           for(i=imin;i<imax;i++)
              {
                for (k=kmin;k<kmax;k++)
                  {
                    FT->shade=(slot->bitmap.buffer[(i*slot->bitmap.width)+k]);
                    if (FT->shade>0)
                      {
                        if ((FT->BLENDED_ANTIALIASING==1)&&(FT->read_pixel!=NULL))
                          /* The New anti-aliasing technique */
                          {
                            if (FT->shade==255)
                              {
                                FT->pixel(pls,x+k,y+i);
                              }
                            else
                              {
                                current_pixel_colour=FT->read_pixel(pls,x+k,y+i);

                                G=GetGValue(current_pixel_colour);
                                R=GetRValue(current_pixel_colour);
                                B=GetBValue(current_pixel_colour);
                                alpha_a=(float)FT->shade/255.0;

                                /* alpha_b=1.0-alpha_a;
                                R=(plsc->cmap0[pls->icol0].r*alpha_a)+(R*alpha_b);
                                G=(plsc->cmap0[pls->icol0].g*alpha_a)+(G*alpha_b);
                                B=(plsc->cmap0[pls->icol0].b*alpha_a)+(B*alpha_b);
                                 */

                                /*  This next bit of code is, I *think*, computationally
                                 *  more efficient than the bit above. It results in
                                 *  an indistinguishable plot, but file sizes are different
                                 *  suggesting subtle variations doubtless caused by rounding
                                 *  and/or floating point conversions. Questions are - which is
                                 *  better ? Which is more "correct" ? Does it make a difference ?
                                 *  Is one faster than the other so that you'd ever notice ?
                                 */

                                R=(((plsc->cmap0[pls->icol0].r-R)*alpha_a)+R);
                                G=(((plsc->cmap0[pls->icol0].g-G)*alpha_a)+G);
                                B=(((plsc->cmap0[pls->icol0].b-B)*alpha_a)+B);

                                FT->set_pixel(pls,x+k,y+i,RGB(R>255 ? 255 : R,G>255 ? 255 : G,B>255 ? 255 : B));
                              }
                          }
                        else /* The old anti-aliasing technique */
                          {
                            FT->col_idx=FT->ncol0_width-((FT->ncol0_width*FT->shade)/255);
                            FT->last_icol0=pls->icol0;
                            plcol0(pls->icol0+(FT->col_idx*(FT->ncol0_org-1)));
                            FT->pixel(pls,x+k,y+i);
                            plcol0(FT->last_icol0);
                          }
                      }
                  }
              }
        }
}

/*----------------------------------------------------------------------*\
 * plD_FreeType_init()
 *
 * Allocates memory to Freetype structure
 * Initialises the freetype library.
 * Initialises freetype structure
\*----------------------------------------------------------------------*/

void plD_FreeType_init(PLStream *pls)
{
    FT_Data *FT;
    char *a;
/* font paths and file names can be long so leave generous (1024) room */
    char font_dir[PLPLOT_MAX_PATH];
    /* N.B. must be in exactly same order as TrueTypeLookup */
    const char *env_font_names[N_TrueTypeLookup] = {
         "PLPLOT_FREETYPE_SANS_FONT",
         "PLPLOT_FREETYPE_SERIF_FONT",
         "PLPLOT_FREETYPE_MONO_FONT",
         "PLPLOT_FREETYPE_SCRIPT_FONT",
         "PLPLOT_FREETYPE_SYMBOL_FONT",
         "PLPLOT_FREETYPE_SANS_ITALIC_FONT",
         "PLPLOT_FREETYPE_SERIF_ITALIC_FONT",
         "PLPLOT_FREETYPE_MONO_ITALIC_FONT",
         "PLPLOT_FREETYPE_SCRIPT_ITALIC_FONT",
         "PLPLOT_FREETYPE_SYMBOL_ITALIC_FONT",
         "PLPLOT_FREETYPE_SANS_OBLIQUE_FONT",
         "PLPLOT_FREETYPE_SERIF_OBLIQUE_FONT",
         "PLPLOT_FREETYPE_MONO_OBLIQUE_FONT",
         "PLPLOT_FREETYPE_SCRIPT_OBLIQUE_FONT",
         "PLPLOT_FREETYPE_SYMBOL_OBLIQUE_FONT",
         "PLPLOT_FREETYPE_SANS_BOLD_FONT",
         "PLPLOT_FREETYPE_SERIF_BOLD_FONT",
         "PLPLOT_FREETYPE_MONO_BOLD_FONT",
         "PLPLOT_FREETYPE_SCRIPT_BOLD_FONT",
         "PLPLOT_FREETYPE_SYMBOL_BOLD_FONT",
         "PLPLOT_FREETYPE_SANS_BOLD_ITALIC_FONT",
         "PLPLOT_FREETYPE_SERIF_BOLD_ITALIC_FONT",
         "PLPLOT_FREETYPE_MONO_BOLD_ITALIC_FONT",
         "PLPLOT_FREETYPE_SCRIPT_BOLD_ITALIC_FONT",
         "PLPLOT_FREETYPE_SYMBOL_BOLD_ITALIC_FONT",
         "PLPLOT_FREETYPE_SANS_BOLD_OBLIQUE_FONT",
         "PLPLOT_FREETYPE_SERIF_BOLD_OBLIQUE_FONT",
         "PLPLOT_FREETYPE_MONO_BOLD_OBLIQUE_FONT",
         "PLPLOT_FREETYPE_SCRIPT_BOLD_OBLIQUE_FONT",
         "PLPLOT_FREETYPE_SYMBOL_BOLD_OBLIQUE_FONT"
    };
    short i;

#if defined(MSDOS) || defined(WIN32)
    static char *default_font_names[]={"arial.ttf","times.ttf","timesi.ttf","arial.ttf",
                       "symbol.ttf"};
    char WINDIR_PATH[PLPLOT_MAX_PATH];
    char *b;
    b=getenv("WINDIR");
    strncpy(WINDIR_PATH,b,PLPLOT_MAX_PATH-1);
    WINDIR_PATH[PLPLOT_MAX_PATH-1] = '\0';
#else
    const char *default_unix_font_dir=PL_FREETYPE_FONT_DIR;
#endif


    if (pls->FT) {
    plwarn("Freetype seems already to have been initialised!");
    return;
    }

    if ((pls->FT=calloc(1, (size_t)sizeof(FT_Data)))==NULL)
    plexit("Could not allocate memory for Freetype");

    FT=(FT_Data *)pls->FT;

    if ((FT->textbuf=calloc(NTEXT_ALLOC, 1))==NULL)
    plexit("Could not allocate memory for Freetype text buffer");

    if ( FT_Init_FreeType( &FT->library ) )
    plexit("Could not initialise Freetype library");

    /* set to an impossible value for an FCI */
    FT->fci=PL_FCI_IMPOSSIBLE;

#if defined(MSDOS) || defined(WIN32)

/*
 * Work out if we have Win95+ or Win3.?... sort of.
 * Actually, this just tries to find the place where the fonts live by looking
 * for arial, which should be on all windows machines.
 * At present, it only looks in two places, on one drive. I might change this
 * soon.
 */
    if (WINDIR_PATH==NULL)
    {
        if (access("c:\\windows\\fonts\\arial.ttf", F_OK)==0) {
            strcpy(font_dir,"c:/windows/fonts/");
        }
        else if ( access("c:\\windows\\system\\arial.ttf", F_OK)==0) {
            strcpy(font_dir,"c:/windows/system/");
        }
        else
        plwarn("Could not find font path; I sure hope you have defined fonts manually !");
    }
    else
    {
      strncat(WINDIR_PATH,"\\fonts\\arial.ttf",PLPLOT_MAX_PATH-1-strlen(WINDIR_PATH));
      if (access(WINDIR_PATH, F_OK)==0)
        {
          b=strrchr(WINDIR_PATH,'\\');
          b++;
          *b=0;
          makeunixslash(WINDIR_PATH);
          strcpy(font_dir,WINDIR_PATH);
        }
      else
        plwarn("Could not find font path; I sure hope you have defined fonts manually !");
    }

    if (pls->debug) fprintf( stderr, "%s\n", font_dir ) ;
#else

/*
 *  For Unix systems, we will set the font path up a little differently in
 *  that the configured PL_FREETYPE_FONT_DIR has been set as the default path,
 *  but the user can override this by setting the environmental variable
 *  "PLPLOT_FREETYPE_FONT_DIR" to something else.
 *  NOTE WELL - the trailing slash must be added for now !
 */

    if ((a = getenv("PLPLOT_FREETYPE_FONT_DIR")) != NULL)
        strncpy(font_dir,a,PLPLOT_MAX_PATH-1);
    else
        strncpy(font_dir,default_unix_font_dir,PLPLOT_MAX_PATH-1);

    font_dir[PLPLOT_MAX_PATH-1] = '\0';
#endif

/*
 * The driver looks for N_TrueTypeLookup  environmental variables
 * where the path and name of these fonts can be OPTIONALLY set,
 * overriding the configured default values.
 */

    for (i=0; i<N_TrueTypeLookup; i++) {
    if ((a = getenv(env_font_names[i])) != NULL) {

/*
 *  Work out if we have been given an absolute path to a font name, or just
 *  a font name sans-path. To do this we will look for a directory separator
 *  character, which means some system specific junk. DJGPP is all wise, and
 *  understands both Unix and DOS conventions. DOS only knows DOS, and
 *  I assume everything else knows Unix-speak. (Why Bill, didn't you just
 *  pay the extra 15c and get a REAL separator???)
 */

#ifdef MSDOS
        if (a[1]==':') /* check for MS-DOS absolute path */
#else
        if ((a[0]=='/')||(a[0]=='~')) /* check for unix abs path */
#endif
        strncpy(FT->font_name[i],a,PLPLOT_MAX_PATH-1);

        else {
        strncpy(FT->font_name[i],font_dir,PLPLOT_MAX_PATH-1);
        strncat(FT->font_name[i],a,PLPLOT_MAX_PATH-1-strlen(FT->font_name[i]));
        }

    } else {
        strncpy(FT->font_name[i],font_dir,PLPLOT_MAX_PATH-1);
        strncat(FT->font_name[i],(char *)TrueTypeLookup[i].pfont,PLPLOT_MAX_PATH-1-strlen(FT->font_name[i]));
    }
        FT->font_name[i][PLPLOT_MAX_PATH-1] = '\0';

   {
   FILE *infile ;
    if ( (infile=fopen(FT->font_name[i], "r"))==NULL) {
        char msgbuf[1024];
        snprintf(msgbuf, 1024,
            "plD_FreeType_init: Could not find the freetype compatible font:\n %s",
            FT->font_name[i]);
        plwarn(msgbuf);
    } else {
        fclose(infile);
   }
   }
        FontLookup[i].fci = TrueTypeLookup[i].fci;
        FontLookup[i].pfont = (unsigned char *)FT->font_name[i];
    }
/*
 * Next, we check to see if -drvopt has been used on the command line to
 * over-ride any settings
 */

}


/*----------------------------------------------------------------------*\
 * FT_SetFace( PLStream *pls, PLUNICODE fci )
 *
 * Sets up the font face and size
\*----------------------------------------------------------------------*/

void FT_SetFace( PLStream *pls, PLUNICODE fci)
{
   FT_Data *FT=(FT_Data *)pls->FT;
   double font_size = pls->chrht * 72/25.4; /* font_size in points, chrht is in mm */

   /* save a copy of character height and resolution */
   FT->chrht=pls->chrht;
   FT->xdpi=pls->xdpi;
   FT->ydpi=pls->ydpi;

   if (fci != FT->fci) {
      char *font_name = plP_FCI2FontName(fci, FontLookup, N_TrueTypeLookup);
      if (font_name == NULL) {
     if (FT->fci == PL_FCI_IMPOSSIBLE)
       plexit("FT_SetFace: Bad FCI and no previous valid font to fall back on");
     else
       plwarn("FT_SetFace: Bad FCI.  Falling back to previous font.");
      } else {
     FT->fci=fci;

     if (FT->face!=NULL) {
        FT_Done_Face(FT->face);
        FT->face=NULL;
     }

     if (FT->face==NULL) {
        if (FT_New_Face( FT->library,font_name, 0,&FT->face))
          plexit("FT_SetFace: Error loading a font in freetype");
     }
      }
   }
   FT_Set_Char_Size(FT->face,0,
            font_size * 64/TEXT_SCALING_FACTOR,pls->xdpi,
            pls->ydpi );
}

/*----------------------------------------------------------------------*\
 * plD_render_freetype_text()
 *
 * Transforms the font
 * calculates real-world bitmap coordinates from plplot ones
 * renders text using freetype
\*----------------------------------------------------------------------*/

void plD_render_freetype_text (PLStream *pls, EscText *args)
{
    FT_Data *FT=(FT_Data *)pls->FT;
    int x,y;
    int w=0,h=0;
    PLFLT *t = args->xform;
    FT_Matrix matrix;
    PLFLT angle=PI*pls->diorot/2;
/*
  Used later in a commented out section (See Rotate The Page), if that
  section will never be used again, remove these as well.
    PLINT clxmin, clxmax, clymin, clymax; 
*/
    PLFLT Sin_A,Cos_A;
    FT_Vector adjust;
    PLUNICODE fci;
    FT_Fixed height;
    PLFLT height_factor;

if ((args->string!=NULL)||(args->unicode_array_len>0))
{

/*
 *   Work out if either the font size, the font face or the
 *   resolution has changed.
 *   If either has, then we will reload the font face.
 */
    plgfci(&fci);
    if ((FT->fci!=fci)||(FT->chrht!=pls->chrht)||(FT->xdpi!=pls->xdpi)||(FT->ydpi!=pls->ydpi))
        FT_SetFace(pls,fci);


/*  this will help work out underlining and overlining*/

    Debug6("%s %d %d %d %d\n","plD_render_freetype_text:",
       FT->face->underline_position>>6,
       FT->face->descender>>6,
       FT->face->ascender>>6,
       ((FT->face->underline_position*-1)+FT->face->ascender)>>6);



/*
 *  Now we work out how long the text is (for justification etc...) and how
 *  high the text is. This is done on UN-TRANSFORMED text, since we will
 *  apply our own transformations on it later, so it's necessary for us
 *  to to turn all transformations off first, before calling the function
 *  that calculates the text size.
 */

    FT->matrix.xx =0x10000;
    FT->matrix.xy =0x00000;
    FT->matrix.yx =0x00000;
    FT->matrix.yy =0x10000;

    FT_Vector_Transform( &FT->pos, &FT->matrix);
    FT_Set_Transform( FT->face, &FT->matrix, &FT->pos );

    FT_StrX_YW(pls,args->unicode_array,args->unicode_array_len,&w, &h);

/*
 *      Set up the transformation Matrix
 *
 * Fortunately this is almost identical to plplot's own transformation matrix;
 * you have NO idea how much effort that saves ! Some params are in a
 * different order, and Freetype wants integers whereas plplot likes floats,
 * but such differences are quite trivial.
 *
 * For some odd reason, this needs to be set a different way for DJGPP. Why ?
 * I wish I knew.
 */

/* (RL, on 2005-01-21) The height_factor variable is introduced below.
 * It is used here and farther below when computing the vertical
 * adjustment.  The rationale for its introduction is as follow: up to
 * now, the text produced with Hershey fonts was systematically taller
 * than the same text produced with TT fonts, and tha by a factor of
 * around 1.125 (I discovered this empirically).  This corresponds
 * roughly to the ratio between total height and the ascender of some
 * TT faces.  Hence the computation below.  Remember that descender is
 * always a negative quantity.
 */

    height_factor = (PLFLT) (FT->face->ascender - FT->face->descender)
                    / FT->face->ascender;
    height = (FT_Fixed) (0x10000 * height_factor);

#ifdef DJGPP
    FT->matrix.xx = height * t[0];
    FT->matrix.xy = height * t[2];
    FT->matrix.yx = height * t[1];
    FT->matrix.yy = height * t[3];
#else
    FT->matrix.xx = height * t[0];
    FT->matrix.xy = height * t[1];
    FT->matrix.yx = height * t[2];
    FT->matrix.yy = height * t[3];
#endif


/*                            Rotate the Font
 *
 *  If the page has been rotated using -ori, this is where we rotate the
 *  font to point in the right direction. To make things nice and easy, we
 *  will use freetypes matrix math stuff to do this for us.
 */

    Cos_A=cos(angle);
    Sin_A=sin(angle);

    matrix.xx =(FT_Fixed)0x10000*Cos_A;

#ifdef DJGPP
    matrix.xy =(FT_Fixed)0x10000*Sin_A*-1;
    matrix.yx =(FT_Fixed)0x10000*Sin_A;
#else
    matrix.xy =(FT_Fixed)0x10000*Sin_A;
    matrix.yx =(FT_Fixed)0x10000*Sin_A*-1;
#endif

    matrix.yy =(FT_Fixed)0x10000*Cos_A;

    FT_Matrix_Multiply(&matrix,&FT->matrix);


/*       Calculate a Vector from the matrix
 *
 * This is closely related to the "transform matrix".
 * The matrix is used for rendering the glyph, while the vector is used for
 * calculating offsets of the text box, so we need both. Why ? I dunno, but
 * we have to live with it, and it works...
 */


    FT_Vector_Transform( &FT->pos, &FT->matrix);


/*    Transform the font face
 *
 * This is where our matrix transformation is calculated for the font face.
 * This is only done once for each unique transformation since it is "sticky"
 * within the font. Font rendering is done later, using the supplied matrix,
 * but invisibly to us from here on. I don't believe the vector is used, but
 * it is asked for.
 */

    FT_Set_Transform( FT->face, &FT->matrix, &FT->pos );


/*                            Rotate the Page
 *
 *  If the page has been rotated using -ori, this is we recalculate the
 *  reference point for the text using plplot functions.
 */

/*   difilt(&args->x, &args->y, 1, &clxmin, &clxmax, &clymin, &clymax); */


/*
 *   Convert into normal coordinates from virtual coordinates
 */

  if( FT->scale!=0.0 ) {  /* scale was set */
      x=args->x/FT->scale;

     if (FT->invert_y==1)
        y=FT->ymax-(args->y/FT->scale);
     else
        y=args->y/FT->scale;
  } else {
      x=args->x/FT->scalex;

     if (FT->invert_y==1)
        y=FT->ymax-(args->y/FT->scaley);
     else
        y=args->y/FT->scaley;
 }

 /*          Adjust for the justification and character height
  *
  *  Eeeksss... this wasn't a nice bit of code to work out, let me tell you.
  *  I could not work out an entirely satisfactory solution that made
  *  logical sense, so came up with an "illogical" one as well.
  *  The logical one works fine for text in the normal "portrait"
  *  orientation, and does so for reasons you might expect it to work; But
  *  for all other orientations, the text's base line is either a little
  *  high, or a little low. This is because of the way the base-line pos
  *  is calculated from the decender height. The "dodgie" way of calculating
  *  the position is to use the character height here, then adjust for the
  *  decender height by a three-fold factor later on. That approach seems to
  *  work a little better for rotated pages, but why it should be so, I
  *  don't understand. You can compile in or out which way you want it by
  *  defining "DODGIE_DECENDER_HACK".
  *
  *  note: the logic of the page rotation coming up next is that we pump in
  *  the justification factor and then use freetype to rotate and transform
  *  the values, which we then use to change the plotting location.
  */


#ifdef DODGIE_DECENDER_HACK
    adjust.y=h;
#else
    adjust.y=0;
#endif

/* (RL, on 2005-01-24) The code below uses floating point and division
 * operations instead of integer shift used before. This is slower but
 * gives accurate placement of text in plots.
 */

/* (RL, on 2005-01-21) The hack below is intended to align single
 * glyphs being generated via plpoin.  The way to detect this
 * situation is completely hackish, I must admit, by checking whether the
 * length of the Unicode array is equal 2 and whether the first
 * character is actually a font-changing command to font number 4 (for
 * symbols).  This is ugly because it depends on definitions set
 * elsewhere, but it works.
 *
 * The computation of the vertical and horizontal adjustments are
 * based on the bouding box of the glyph being loaded (since there is
 * only one glyph in the string in this case, we are okay here).
 */

    if ((args->unicode_array_len == 2)
      && (args->unicode_array[0] == (PL_FCI_MARK |0x004)))
    {
        adjust.x = args->just * ROUND (FT->face->glyph->metrics.width / 64.0);
        adjust.y = (FT_Pos) ROUND (FT->face->glyph->metrics.height / 128.0);
    }
    else
    {

/* (RL, on 2005-01-21) The vertical adjustment is set below, making
 * the DODGIE conditional moot.  I use the value of h as return by FT_StrX_YW,
 * which should correspond to the total height of the text being
 * drawn.  Freetype aligns text around the baseline, while PLplot
 * aligns to the center of the ascender portion.  We must then adjust
 * by half of the ascender and this is why there is a division by
 * height_factor below.
 */

      adjust.y = (FT_Pos)
          ROUND (FT->face->size->metrics.height / height_factor / 128.0);
      adjust.x = (FT_Pos) (args->just * ROUND (w / 64.0));

    }

    FT_Vector_Transform( &adjust, &FT->matrix);    /* was /&matrix); -  was I using the wrong matrix all this time ?*/

    x-=adjust.x;
    y+=adjust.y;

    FT_WriteStrW(pls,args->unicode_array,args->unicode_array_len,x,y); /* write it out */
}
else
{
plD_render_freetype_sym (pls, args);
}

}

/*----------------------------------------------------------------------*\
 * plD_FreeType_Destroy()
 *
 * Restores cmap0 if it had been modifed for anti-aliasing
 * closes the freetype library.
 * Deallocates memory to the Freetype structure
\*----------------------------------------------------------------------*/

void plD_FreeType_Destroy(PLStream *pls)
{
    FT_Data *FT=(FT_Data *)pls->FT;
    extern int FT_Done_Library( FT_Library  library );

    if (FT) {
    if ((FT->smooth_text==1)&&(FT->BLENDED_ANTIALIASING==0)) plscmap0n(FT->ncol0_org);
        if (FT->textbuf)
          free(FT->textbuf);
    FT_Done_Library(FT->library);
    free(pls->FT);
    pls->FT=NULL;
    }
}

/*----------------------------------------------------------------------*\
 * PLFLT CalculateIncrement( int bg, int fg, int levels)
 *
 * Takes the value of the foreground, and the background, and when
 * given the number of desired steps, calculates how much to incriment
 * a value to transition from fg to bg.
 * This function only does it for one colour channel at a time.
\*----------------------------------------------------------------------*/

static PLFLT CalculateIncrement( int bg, int fg, int levels)
{
    PLFLT ret=0;

    if (levels>1) {
    if (fg>bg)
        ret=((fg+1)-bg)/levels;
    else if (fg<bg)
        ret=(((fg-1)-bg)/levels);
    }
    return(ret);
}

/*----------------------------------------------------------------------*\
 * void pl_set_extended_cmap0(PLStream *pls, int ncol0_width, int ncol0_org)
 *
 *  ncol0_width - how many greyscale levels to accolate to each CMAP0 entry
 *  ncol0_org - the originl number of CMAP0 entries.
 *
 *  This function calcualtes and sets an extended CMAP0 entry for the
 *  driver. It is assumed that the caller has checked to make sure there is
 *  room for extending CMAP0 already.
 *
 *  NOTES
 *  We don't bother calculating an entry for CMAP[0], the background.
 *  It is assumed the caller has already expanded the size of CMAP[0]
\*----------------------------------------------------------------------*/

void pl_set_extended_cmap0(PLStream *pls, int ncol0_width, int ncol0_org)
{
    int i,j,k;
    int r,g,b;
    PLFLT r_inc,g_inc,b_inc;

    for (i=1;i<ncol0_org;i++) {

    r=pls->cmap0[i].r;
    g=pls->cmap0[i].g;
    b=pls->cmap0[i].b;

    r_inc=CalculateIncrement(pls->cmap0[0].r,r,ncol0_width);
    g_inc=CalculateIncrement(pls->cmap0[0].g,g,ncol0_width);
    b_inc=CalculateIncrement(pls->cmap0[0].b,b,ncol0_width);

    for (j=0,k=ncol0_org+i-1;j<ncol0_width;j++,k+=(ncol0_org-1)) {
        r-=r_inc;
        g-=g_inc;
        b-=b_inc;
        if ((r<0)||(g<0)||(b<0))
        plscol0 (k, 0, 0, 0);
        else
        plscol0 (k, (r > 0xff ? 0xff : r), (g > 0xff ? 0xff : g), (b > 0xff ? 0xff : b));
        }
    }
}


/*----------------------------------------------------------------------*\
 * plD_render_freetype_sym( PLStream *pls, EscText *args )
 *   PLStream *pls - pointer to plot stream
 *   EscText *args - pointer to standard "string" object.
 *
 *  This function is a simple rendering function which draws a single
 *  character at a time. The function is an alternative to the text
 *  functions which are considerably, and needlessly, more complicated
 *  than what we need here.
\*----------------------------------------------------------------------*/


void plD_render_freetype_sym (PLStream *pls, EscText *args)
{
    FT_Data *FT=(FT_Data *)pls->FT;
    int x,y;
    FT_Vector  adjust;
    PLUNICODE fci;

    if( FT->scale!=0.0 ) {  /* scale was set */
      x=args->x/FT->scale;

      if (FT->invert_y==1)
        y=FT->ymax-(args->y/FT->scale);
      else
        y=args->y/FT->scale;
    } else {
      x=args->x/FT->scalex;

      if (FT->invert_y==1)
        y=FT->ymax-(args->y/FT->scaley);
      else
        y=args->y/FT->scaley;
    }


/*
 *  Adjust for the descender - make sure the font is nice and centred
 *  vertically. Freetype assumes we have a base-line, but plplot thinks of
 *  centre-lines, so that's why we have to do this. Since this is one of our
 *  own adjustments, rather than a freetype one, we have to run it through
 *  the transform matrix manually.
 *
 *  For some odd reason, this works best if we triple the
 *  descender's height and then adjust the height later on...
 *  Don't ask me why, 'cause I don't know. But it does seem to work.
 *
 *  I really wish I knew *why* it worked better though...
 *
 *   y-=FT->face->descender >> 6;
 */

#ifdef DODGIE_DECENDER_HACK
    adjust.y= (FT->face->descender >> 6)*3;
#else
    adjust.y= (FT->face->descender >> 6);
#endif

    adjust.x=0;
    FT_Vector_Transform( &adjust, &FT->matrix);
    x+=adjust.x;
    y-=adjust.y;

    plgfci(&fci);
    FT_SetFace(pls,fci);

    FT=(FT_Data *)pls->FT;
    FT_Set_Transform( FT->face, &FT->matrix, &FT->pos );

    FT_Load_Char( FT->face, args->unicode_char, (FT->smooth_text==0) ? FT_LOAD_MONOCHROME+FT_LOAD_RENDER : FT_LOAD_RENDER|FT_LOAD_FORCE_AUTOHINT );

/*
 * Now we have to try and componsate for the fact that the freetype glyphs are left
 * justified, and plplot's glyphs are centred. To do this, we will just work out the
 * advancment, halve it, and take it away from the x position. This wont be 100%
 * accurate because "spacing" is factored into the right hand side of the glyph,
 * but it is as good a way as I can think of.
 */

    x -= (FT->face->glyph->advance.x >> 6)/2;
    FT_PlotChar(pls,FT, FT->face->glyph,  x, y, pls->icol0 ); /* render the text */

}




#else
int
plfreetype()
{
    return 0;
}

#endif

---