- document the values for the read() and write() method type

[imager.git] / font.c

#include "image.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include <stdio.h>
#include <stdlib.h>






/*
=head1 NAME

font.c - implements font handling functions for t1 and truetype fonts

=head1 SYNOPSIS

  i_init_fonts();

  #ifdef HAVE_LIBT1
  fontnum = i_t1_new(path_to_pfb, path_to_afm);
  i_t1_bbox(fontnum, points, "foo", 3, int cords[6]);
  rc = i_t1_destroy(fontnum);
  #endif

  #ifdef HAVE_LIBTT
  handle = i_tt_new(path_to_ttf);
  rc = i_tt_bbox(handle, points, "foo", 3, int cords[6]);
  i_tt_destroy(handle);

  // and much more

=head1 DESCRIPTION

font.c implements font creation, rendering, bounding box functions and
more for Imager.

=head1 FUNCTION REFERENCE

Some of these functions are internal.

=over

=cut

*/









/* 
=item i_init_fonts()

Initialize font rendering libraries if they are avaliable.

=cut
*/

undef_int 
i_init_fonts(int t1log) {
  mm_log((1,"Initializing fonts\n"));

#ifdef HAVE_LIBT1
  i_init_t1(t1log);
#endif
  
#ifdef HAVE_LIBTT
  i_init_tt();
#endif

#ifdef HAVE_FT2
  if (!i_ft2_init())
    return 0;
#endif

  return(1); /* FIXME: Always true - check the return values of the init_t1 and init_tt functions */
}




#ifdef HAVE_LIBT1



/* 
=item i_init_t1(t1log)

Initializes the t1lib font rendering engine.

=cut
*/

undef_int
i_init_t1(int t1log) {
  int init_flags = IGNORE_CONFIGFILE|IGNORE_FONTDATABASE;
  mm_log((1,"init_t1()\n"));
  
  if (t1log)
    init_flags |= LOGFILE;
  if ((T1_InitLib(init_flags) == NULL)){
    mm_log((1,"Initialization of t1lib failed\n"));
    return(1);
  }
  T1_SetLogLevel(T1LOG_DEBUG);
  i_t1_set_aa(1); /* Default Antialias value */
  return(0);
}


/* 
=item i_close_t1()

Shuts the t1lib font rendering engine down.

  This it seems that this function is never used.

=cut
*/

void
i_close_t1(void) {
  T1_CloseLib();
}


/*
=item i_t1_new(pfb, afm)

Loads the fonts with the given filenames, returns its font id

 pfb -  path to pfb file for font
 afm -  path to afm file for font

=cut
*/

int
i_t1_new(char *pfb,char *afm) {
  int font_id;
  mm_log((1,"i_t1_new(pfb %s,afm %s)\n",pfb,(afm?afm:"NULL")));
  font_id = T1_AddFont(pfb);
  if (font_id<0) {
    mm_log((1,"i_t1_new: Failed to load pfb file '%s' - return code %d.\n",pfb,font_id));
    return font_id;
  }
  
  if (afm != NULL) {
    mm_log((1,"i_t1_new: requesting afm file '%s'.\n",afm));
    if (T1_SetAfmFileName(font_id,afm)<0) mm_log((1,"i_t1_new: afm loading of '%s' failed.\n",afm));
  }
  return font_id;
}

/*
=item i_t1_destroy(font_id)

Frees resources for a t1 font with given font id.

   font_id - number of the font to free

=cut
*/

int
i_t1_destroy(int font_id) {
  mm_log((1,"i_t1_destroy(font_id %d)\n",font_id));
  return T1_DeleteFont(font_id);
}


/*
=item i_t1_set_aa(st)

Sets the antialiasing level of the t1 library.

   st - 0 =  NONE, 1 = LOW, 2 =  HIGH.

=cut
*/

void
i_t1_set_aa(int st) {
  int i;
  unsigned long cst[17];
  switch(st) {
  case 0:
    T1_AASetBitsPerPixel( 8 );
    T1_AASetLevel( T1_AA_NONE );
    T1_AANSetGrayValues( 0, 255 );
    mm_log((1,"setting T1 antialias to none\n"));
    break;
  case 1:
    T1_AASetBitsPerPixel( 8 );
    T1_AASetLevel( T1_AA_LOW );
    T1_AASetGrayValues( 0,65,127,191,255 );
    mm_log((1,"setting T1 antialias to low\n"));
    break;
  case 2:
    T1_AASetBitsPerPixel(8);
    T1_AASetLevel(T1_AA_HIGH);
    for(i=0;i<17;i++) cst[i]=(i*255)/16;
    T1_AAHSetGrayValues( cst );
    mm_log((1,"setting T1 antialias to high\n"));
  }
}


/* 
=item i_t1_cp(im, xb, yb, channel, fontnum, points, str, len, align)

Interface to text rendering into a single channel in an image

   im        pointer to image structure
   xb        x coordinate of start of string
   yb        y coordinate of start of string ( see align )
   channel - destination channel
   fontnum - t1 library font id
   points  - number of points in fontheight
   str     - string to render
   len     - string length
   align   - (0 - top of font glyph | 1 - baseline )

=cut
*/

undef_int
i_t1_cp(i_img *im,int xb,int yb,int channel,int fontnum,float points,char* str,int len,int align) {
  GLYPH *glyph;
  int xsize,ysize,x,y;
  i_color val;

  unsigned int ch_mask_store;
  
  if (im == NULL) { mm_log((1,"i_t1_cp: Null image in input\n")); return(0); }

  glyph=T1_AASetString( fontnum, str, len, 0, T1_KERNING, points, NULL);
  if (glyph == NULL)
    return 0;

  mm_log((1,"metrics: ascent: %d descent: %d\n",glyph->metrics.ascent,glyph->metrics.descent));
  mm_log((1," leftSideBearing: %d rightSideBearing: %d\n",glyph->metrics.leftSideBearing,glyph->metrics.rightSideBearing));
  mm_log((1," advanceX: %d  advanceY: %d\n",glyph->metrics.advanceX,glyph->metrics.advanceY));
  mm_log((1,"bpp: %d\n",glyph->bpp));
  
  xsize=glyph->metrics.rightSideBearing-glyph->metrics.leftSideBearing;
  ysize=glyph->metrics.ascent-glyph->metrics.descent;
  
  mm_log((1,"width: %d height: %d\n",xsize,ysize));

  ch_mask_store=im->ch_mask;
  im->ch_mask=1<<channel;

  if (align==1) { xb+=glyph->metrics.leftSideBearing; yb-=glyph->metrics.ascent; }
  
  for(y=0;y<ysize;y++) for(x=0;x<xsize;x++) {
    val.channel[channel]=glyph->bits[y*xsize+x];
    i_ppix(im,x+xb,y+yb,&val);
  }
  
  im->ch_mask=ch_mask_store;
  return 1;
}


/*
=item i_t1_bbox(handle, fontnum, points, str, len, cords)

function to get a strings bounding box given the font id and sizes

   handle  - pointer to font handle   
   fontnum - t1 library font id
   points  - number of points in fontheight
   str     - string to measure
   len     - string length
   cords   - the bounding box (modified in place)

=cut
*/

void
i_t1_bbox(int fontnum,float points,char *str,int len,int cords[6]) {
  BBox bbox;
  BBox gbbox;
  
  mm_log((1,"i_t1_bbox(fontnum %d,points %.2f,str '%.*s', len %d)\n",fontnum,points,len,str,len));
  T1_LoadFont(fontnum);  /* FIXME: Here a return code is ignored - haw haw haw */ 
  bbox = T1_GetStringBBox(fontnum,str,len,0,T1_KERNING);
  gbbox = T1_GetFontBBox(fontnum);
  
  mm_log((1,"bbox: (%d,%d,%d,%d)\n",
	  (int)(bbox.llx*points/1000),
	  (int)(gbbox.lly*points/1000),
	  (int)(bbox.urx*points/1000),
	  (int)(gbbox.ury*points/1000),
	  (int)(bbox.lly*points/1000),
	  (int)(bbox.ury*points/1000) ));


  cords[0]=((float)bbox.llx*points)/1000;
  cords[2]=((float)bbox.urx*points)/1000;

  cords[1]=((float)gbbox.lly*points)/1000;
  cords[3]=((float)gbbox.ury*points)/1000;

  cords[4]=((float)bbox.lly*points)/1000;
  cords[5]=((float)bbox.ury*points)/1000;
}


/*
=item i_t1_text(im, xb, yb, cl, fontnum, points, str, len, align)

Interface to text rendering in a single color onto an image

   im      - pointer to image structure
   xb      - x coordinate of start of string
   yb      - y coordinate of start of string ( see align )
   cl      - color to draw the text in
   fontnum - t1 library font id
   points  - number of points in fontheight
   str     - char pointer to string to render
   len     - string length
   align   - (0 - top of font glyph | 1 - baseline )

=cut
*/

undef_int
i_t1_text(i_img *im,int xb,int yb,i_color *cl,int fontnum,float points,char* str,int len,int align) {
  GLYPH *glyph;
  int xsize,ysize,x,y,ch;
  i_color val;
  unsigned char c,i;

  if (im == NULL) { mm_log((1,"i_t1_cp: Null image in input\n")); return(0); }

  glyph=T1_AASetString( fontnum, str, len, 0, T1_KERNING, points, NULL);
  if (glyph == NULL)
    return 0;

  mm_log((1,"metrics:  ascent: %d descent: %d\n",glyph->metrics.ascent,glyph->metrics.descent));
  mm_log((1," leftSideBearing: %d rightSideBearing: %d\n",glyph->metrics.leftSideBearing,glyph->metrics.rightSideBearing));
  mm_log((1," advanceX: %d advanceY: %d\n",glyph->metrics.advanceX,glyph->metrics.advanceY));
  mm_log((1,"bpp: %d\n",glyph->bpp));
  
  xsize=glyph->metrics.rightSideBearing-glyph->metrics.leftSideBearing;
  ysize=glyph->metrics.ascent-glyph->metrics.descent;
  
  mm_log((1,"width: %d height: %d\n",xsize,ysize));

  if (align==1) { xb+=glyph->metrics.leftSideBearing; yb-=glyph->metrics.ascent; }
  
  for(y=0;y<ysize;y++) for(x=0;x<xsize;x++) {
    c=glyph->bits[y*xsize+x];
    i=255-c;
    i_gpix(im,x+xb,y+yb,&val);
    for(ch=0;ch<im->channels;ch++) val.channel[ch]=(c*cl->channel[ch]+i*val.channel[ch])/255;
    i_ppix(im,x+xb,y+yb,&val);
  }
  return 1;
}


#endif /* HAVE_LIBT1 */










/* Truetype font support */

#ifdef HAVE_LIBTT


/* Defines */

#define USTRCT(x) ((x).z)
#define TT_VALID( handle )  ( ( handle ).z != NULL )


/* Prototypes */

static  int i_tt_get_instance( TT_Fonthandle *handle, int points, int smooth );
static void i_tt_init_raster_map( TT_Raster_Map* bit, int width, int height, int smooth );
static void i_tt_done_raster_map( TT_Raster_Map *bit );
static void i_tt_clear_raster_map( TT_Raster_Map* bit );
static void i_tt_blit_or( TT_Raster_Map *dst, TT_Raster_Map *src,int x_off, int y_off );
static  int i_tt_get_glyph( TT_Fonthandle *handle, int inst, unsigned char j );
static void i_tt_render_glyph( TT_Glyph glyph, TT_Glyph_Metrics* gmetrics, TT_Raster_Map *bit, TT_Raster_Map *small_bit, int x_off, int y_off, int smooth );
static void i_tt_render_all_glyphs( TT_Fonthandle *handle, int inst, TT_Raster_Map *bit, TT_Raster_Map *small_bit, int cords[6], char* txt, int len, int smooth );
static void i_tt_dump_raster_map2( i_img* im, TT_Raster_Map* bit, int xb, int yb, i_color *cl, int smooth );
static void i_tt_dump_raster_map_channel( i_img* im, TT_Raster_Map* bit, int xb, int yb, int channel, int smooth );
static  int i_tt_rasterize( TT_Fonthandle *handle, TT_Raster_Map *bit, int cords[6], float points, char* txt, int len, int smooth );
static undef_int i_tt_bbox_inst( TT_Fonthandle *handle, int inst ,const char *txt, int len, int cords[6] );


/* static globals needed */

static TT_Engine    engine;
static int  LTT_dpi    = 72; /* FIXME: this ought to be a part of the call interface */
static int  LTT_hinted = 1;  /* FIXME: this too */


/*
 * FreeType interface
 */


/*
=item init_tt()

Initializes the freetype font rendering engine

=cut
*/

undef_int
i_init_tt() {
  TT_Error  error;
  mm_log((1,"init_tt()\n"));
  error = TT_Init_FreeType( &engine );
  if ( error ){
    mm_log((1,"Initialization of freetype failed, code = 0x%x\n",error));
    return(1);
  }
  return(0);
}


/* 
=item i_tt_get_instance(handle, points, smooth)

Finds a points+smooth instance or if one doesn't exist in the cache
allocates room and returns its cache entry

   fontname - path to the font to load
   handle   - handle to the font.
   points   - points of the requested font
   smooth   - boolean (True: antialias on, False: antialias is off)

=cut
*/

static
int
i_tt_get_instance( TT_Fonthandle *handle, int points, int smooth ) {
  int i,idx;
  TT_Error error;
  
  mm_log((1,"i_tt_get_instance(handle 0x%X, points %d, smooth %d)\n",handle,points,smooth));
  
  if (smooth == -1) { /* Smooth doesn't matter for this search */
    for(i=0;i<TT_CHC;i++) if (handle->instanceh[i].ptsize==points) {
      mm_log((1,"i_tt_get_instance: in cache - (non selective smoothing search) returning %d\n",i));
      return i;
    }
    smooth=1; /* We will be adding a font - add it as smooth then */
  } else { /* Smooth doesn't matter for this search */
    for(i=0;i<TT_CHC;i++) if (handle->instanceh[i].ptsize==points && handle->instanceh[i].smooth==smooth) {
      mm_log((1,"i_tt_get_instance: in cache returning %d\n",i));
      return i;
    }
  }
  
  /* Found the instance in the cache - return the cache index */
  
  for(idx=0;idx<TT_CHC;idx++) if (!(handle->instanceh[idx].order)) break; /* find the lru item */

  mm_log((1,"i_tt_get_instance: lru item is %d\n",idx));
  mm_log((1,"i_tt_get_instance: lru pointer 0x%X\n",USTRCT(handle->instanceh[idx].instance) ));
  
  if ( USTRCT(handle->instanceh[idx].instance) ) {
    mm_log((1,"i_tt_get_instance: freeing lru item from cache %d\n",idx));
    /* Free cached glyphs */

    for(i=0;i<256;i++)
      if ( USTRCT(handle->instanceh[idx].glyphs[i]) )
	TT_Done_Glyph( handle->instanceh[idx].glyphs[i] );

    for(i=0;i<256;i++) USTRCT(handle->instanceh[idx].glyphs[i])=NULL;    
    TT_Done_Instance( handle->instanceh[idx].instance ); /* Free instance if needed */
    
  }
  
  /* create and initialize instance */
  /* FIXME: probably a memory leak on fail */
  
  (void) (( error = TT_New_Instance( handle->face, &handle->instanceh[idx].instance ) ) || 
	  ( error = TT_Set_Instance_Resolutions( handle->instanceh[idx].instance, LTT_dpi, LTT_dpi ) ) ||
	  ( error = TT_Set_Instance_CharSize( handle->instanceh[idx].instance, points*64 ) ) );
  
  if ( error ) {
    mm_log((1, "Could not create and initialize instance: error 0x%x.\n",error ));
    return -1;
  }
  
  /* Now that the instance should the inplace we need to lower all of the
     ru counts and put `this' one with the highest entry */
  
  for(i=0;i<TT_CHC;i++) handle->instanceh[i].order--;

  handle->instanceh[idx].order=TT_CHC-1;
  handle->instanceh[idx].ptsize=points;
  handle->instanceh[idx].smooth=smooth;
  TT_Get_Instance_Metrics( handle->instanceh[idx].instance, &(handle->instanceh[idx].imetrics) );

  /* Zero the memory for the glyph storage so they are not thought as cached if they haven't been cached
     since this new font was loaded */

  for(i=0;i<256;i++) USTRCT(handle->instanceh[idx].glyphs[i])=NULL;
  
  return idx;
}


/*
=item i_tt_new(fontname)

Creates a new font handle object, finds a character map and initialise the
the font handle's cache

   fontname - path to the font to load

=cut
*/

TT_Fonthandle*
i_tt_new(char *fontname) {
  TT_Error error;
  TT_Fonthandle *handle;
  unsigned short i,n;
  unsigned short platform,encoding;
  
  mm_log((1,"i_tt_new(fontname '%s')\n",fontname));
  
  /* allocate memory for the structure */
  
  handle = mymalloc( sizeof(TT_Fonthandle) );

  /* load the typeface */
  error = TT_Open_Face( engine, fontname, &handle->face );
  if ( error ) {
    if ( error == TT_Err_Could_Not_Open_File ) { mm_log((1, "Could not find/open %s.\n", fontname )) }
    else { mm_log((1, "Error while opening %s, error code = 0x%x.\n",fontname, error )); }
    return NULL;
  }
  
  TT_Get_Face_Properties( handle->face, &(handle->properties) );
  /* First, look for a Unicode charmap */
  
  n = handle->properties.num_CharMaps;
  USTRCT( handle->char_map )=NULL; /* Invalidate character map */
  
  for ( i = 0; i < n; i++ ) {
    TT_Get_CharMap_ID( handle->face, i, &platform, &encoding );
    if ( (platform == 3 && encoding == 1 ) || (platform == 0 && encoding == 0 ) ) {
      mm_log((2,"i_tt_new - found char map platform %u encoding %u\n", platform, encoding));
      TT_Get_CharMap( handle->face, i, &(handle->char_map) );
      break;
    }
  }
  if (!USTRCT(handle->char_map) && n != 0) {
    /* just use the first one */
    TT_Get_CharMap( handle->face, 0, &(handle->char_map));
  }

  /* Zero the pointsizes - and ordering */
  
  for(i=0;i<TT_CHC;i++) {
    USTRCT(handle->instanceh[i].instance)=NULL;
    handle->instanceh[i].order=i;
    handle->instanceh[i].ptsize=0;
    handle->instanceh[i].smooth=-1;
  }

  mm_log((1,"i_tt_new <- 0x%X\n",handle));
  return handle;
}



/*