most numeric parameters to the XS implementation now throw an exception if supplied...

[imager.git] / fontft1.c

#include "imager.h"
#include "imrender.h"

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

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


/*
=head1 NAME

fontft1.c - Freetype 1.x font driver for Imager

=head1 SYNOPSIS

  handle = i_tt_new(path_to_ttf);
  rc = i_tt_bbox(handle, points, "foo", 3, int cords[6], utf8);
  i_tt_destroy(handle);

  // and much more

=head1 DESCRIPTION

fontft1.c implements font creation, rendering, bounding box functions and
more for Imager using Freetype 1.x.

In general this driver should be ignored in favour of the FT2 driver.

=head1 FUNCTION REFERENCE

Some of these functions are internal.

=over

=cut

*/


/* Truetype font support */
/* These are enabled by default when configuring Freetype 1.x
   I haven't a clue how to reliably detect it at compile time.

   We need a compilation probe in Makefile.PL
*/
#define FTXPOST 1
#define FTXERR18 1

#include <freetype.h>
#define TT_CHC 5

#ifdef FTXPOST
#include <ftxpost.h>
#endif

#ifdef FTXERR18
#include <ftxerr18.h>
#endif

/* some versions of FT1.x don't seem to define this - it's font defined
   so it won't change */
#ifndef TT_MS_LANGID_ENGLISH_GENERAL
#define TT_MS_LANGID_ENGLISH_GENERAL 0x0409
#endif

static im_slot_t slot = -1;

/* convert a code point into an index in the glyph cache */
#define TT_HASH(x) ((x) & 0xFF)

typedef struct {
  int initialized;
  TT_Engine engine;
} i_tt_engine;

typedef struct i_glyph_entry_ {
  TT_Glyph glyph;
  unsigned long ch;
} i_tt_glyph_entry;

#define TT_NOCHAR (~0UL)

struct TT_Instancehandle_ {
  TT_Instance instance;
  TT_Instance_Metrics imetrics;
  TT_Glyph_Metrics gmetrics[256];
  i_tt_glyph_entry glyphs[256];
  int smooth;
  int order;
  i_img_dim ptsize;
};

typedef struct TT_Instancehandle_ TT_Instancehandle;

struct TT_Fonthandle_ {
  TT_Face face;
  TT_Face_Properties properties;
  TT_Instancehandle instanceh[TT_CHC];
  TT_CharMap char_map;
#ifdef FTXPOST
  int loaded_names;
  TT_Error load_cond;
#endif
};

/* Defines */

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

static void i_tt_push_error(TT_Error rc);
static void i_tt_uninit(void *);

/* Prototypes */

static  int i_tt_get_instance( TT_Fonthandle *handle, i_img_dim points, int smooth );
static void i_tt_init_raster_map( TT_Raster_Map* bit, i_img_dim width, i_img_dim 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,i_img_dim x_off, i_img_dim y_off );
static  int i_tt_get_glyph( TT_Fonthandle *handle, int inst, unsigned long j );
static void 
i_tt_render_glyph( TT_Glyph glyph, TT_Glyph_Metrics* gmetrics, 
                   TT_Raster_Map *bit, TT_Raster_Map *small_bit, 
                   i_img_dim x_off, i_img_dim y_off, int smooth );
static int
i_tt_render_all_glyphs( TT_Fonthandle *handle, int inst, TT_Raster_Map *bit, 
                        TT_Raster_Map *small_bit, i_img_dim cords[6], 
                        char const* txt, size_t len, int smooth, int utf8 );
static void i_tt_dump_raster_map2( i_img* im, TT_Raster_Map* bit, i_img_dim xb, i_img_dim yb, const i_color *cl, int smooth );
static void i_tt_dump_raster_map_channel( i_img* im, TT_Raster_Map* bit, i_img_dim xb, i_img_dim yb, int channel, int smooth );
static  int
i_tt_rasterize( TT_Fonthandle *handle, TT_Raster_Map *bit, i_img_dim cords[6], 
                double points, char const* txt, size_t len, int smooth, int utf8 );
static undef_int i_tt_bbox_inst( TT_Fonthandle *handle, int inst ,const char *txt, size_t len, i_img_dim cords[6], int utf8 );


/* static globals needed */

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
 */

void
i_tt_start(void) {
  if (slot == -1)
    slot = im_context_slot_new(i_tt_uninit);
}


/*
=item init_tt()

Initializes the freetype font rendering engine (if needed)

=cut
*/

static i_tt_engine *
i_init_tt(void) {
  TT_Error  error;
  im_context_t ctx = im_get_context();
  TT_Byte palette[] = { 0, 64, 127, 191, 255 };
  i_tt_engine *result = im_context_slot_get(ctx, slot);

  i_clear_error();

  if (result == NULL) {
    result = mymalloc(sizeof(i_tt_engine));
    memset(result, 0, sizeof(*result));
    im_context_slot_set(ctx, slot, result);
    mm_log((1, "allocated FT1 state %p\n", result));
  }

  mm_log((1,"init_tt()\n"));

  if (result->initialized)
    return result;

  error = TT_Init_FreeType( &result->engine );
  if ( error ){
    mm_log((1,"Initialization of freetype failed, code = 0x%x\n",
	    (unsigned)error));
    i_tt_push_error(error);
    i_push_error(0, "Could not initialize freetype 1.x");
    return NULL;
  }

#ifdef FTXPOST
  error = TT_Init_Post_Extension( result->engine );
  if (error) {
    mm_log((1, "Initialization of Post extension failed = 0x%x\n",
	    (unsigned)error));
    
    i_tt_push_error(error);
    i_push_error(0, "Could not initialize FT 1.x POST extension");
    return NULL;
  }
#endif

  error = TT_Set_Raster_Gray_Palette(result->engine, palette);
  if (error) {
    mm_log((1, "Initialization of gray levels failed = 0x%x\n",
	    (unsigned)error));
    i_tt_push_error(error);
    i_push_error(0, "Could not initialize FT 1.x POST extension");
    return NULL;
  }

  mm_log((1, "initialized FT1 state %p\n", result));

  result->initialized = 1;

  return result;
}

static void
i_tt_uninit(void *p) {
  i_tt_engine *tteng = p;

  if (tteng->initialized) {
    mm_log((1, "finalizing FT1 state %p\n", tteng));
    TT_Done_FreeType(tteng->engine);
  }
  mm_log((1, "freeing FT1 state %p\n", tteng));
  myfree(tteng);
}

/* 
=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, i_img_dim points, int smooth ) {
  int i,idx;
  TT_Error error;
  
  mm_log((1,"i_tt_get_instance(handle %p, points %" i_DF ", smooth %d)\n",
          handle, i_DFc(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 %p\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].glyph) )
	TT_Done_Glyph( handle->instanceh[idx].glyphs[i].glyph );

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

    /* Free instance if needed */
    TT_Done_Instance( handle->instanceh[idx].instance );
  }
  
  /* 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 %x.\n",
	    (unsigned)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++) {
    handle->instanceh[idx].glyphs[i].ch = TT_NOCHAR;
    USTRCT(handle->instanceh[idx].glyphs[i].glyph)=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(const char *fontname) {
  TT_Error error;
  TT_Fonthandle *handle;
  unsigned short i,n;
  unsigned short platform,encoding;
  i_tt_engine *tteng;

  if ((tteng = i_init_tt()) == NULL) {
    i_push_error(0, "Could not initialize FT1 engine");
    return NULL;
  }

  i_clear_error();
  
  mm_log((1,"i_tt_new(fontname '%s')\n",fontname));
  
  /* allocate memory for the structure */
  
  handle = mymalloc( sizeof(TT_Fonthandle) ); /* checked 5Nov05 tonyc */

  /* load the typeface */
  error = TT_Open_Face( tteng->engine, fontname, &handle->face );
  if ( error ) {
    myfree(handle);
    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, 
              (unsigned)error )); 
    }
    i_tt_push_error(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;
  }

#ifdef FTXPOST
  handle->loaded_names = 0;
#endif

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



/*