[dense] Add optimization for division

* src/dense/ftdense.c: FT_UDIV, FT_UDIVPREP macros taken from smooth
rasterizer, help optimize fixed-point division

CMakeLists.txt

@@ -405,6 +405,7 @@ set(BASE_SRCS
   src/cache/ftcache.c
   src/cff/cff.c
   src/cid/type1cid.c
+  src/dense/dense.c
   src/gzip/ftgzip.c
   src/lzw/ftlzw.c
   src/pcf/pcf.c

include/freetype/config/ftmodule.h

@@ -24,6 +24,7 @@ FT_USE_MODULE( FT_Module_Class, psaux_module_class )
 FT_USE_MODULE( FT_Module_Class, psnames_module_class )
 FT_USE_MODULE( FT_Module_Class, pshinter_module_class )
 FT_USE_MODULE( FT_Module_Class, sfnt_module_class )
+FT_USE_MODULE( FT_Renderer_Class, ft_dense_renderer_class )
 FT_USE_MODULE( FT_Renderer_Class, ft_smooth_renderer_class )
 FT_USE_MODULE( FT_Renderer_Class, ft_raster1_renderer_class )
 FT_USE_MODULE( FT_Renderer_Class, ft_sdf_renderer_class )

modules.cfg

@@ -93,6 +93,9 @@ HINTING_MODULES += pshinter
 #### raster modules -- at least one is required for vector font formats
 ####
 
+# Dense Rasterizer
+RASTER_MODULES += dense
+
 # Anti-aliasing rasterizer.
 RASTER_MODULES += smooth
 

src/dense/dense.c

@@ -0,0 +1,6 @@
+/** For building a single object of the entire module */
+#define FT_MAKE_OPTION_SINGLE_OBJECT
+
+#include "ftdense.c"
+#include "ftdenserend.c"
+/* END */

src/dense/ftdense.c

@@ -0,0 +1,554 @@
+/** The rasterizer for the 'dense' renderer */
+
+#undef FT_COMPONENT
+#define FT_COMPONENT dense
+
+#include <freetype/ftoutln.h>
+#include <freetype/internal/ftcalc.h>
+#include <freetype/internal/ftdebug.h>
+#include <freetype/internal/ftobjs.h>
+#include <math.h>
+
+#include "ftdense.h"
+#include "ftdenseerrs.h"
+
+#if defined( __SSE4_1__ )                          || \
+    defined( __x86_64__ )                        || \
+    defined( _M_AMD64 )                          || \
+    ( defined( _M_IX86_FP ) && _M_IX86_FP >= 2 )
+#  define FT_SSE4_1 1
+#else
+#  define FT_SSE4_1 0
+#endif
+
+
+#if FT_SSE4_1
+
+    #include <immintrin.h>
+
+#endif
+
+#define PIXEL_BITS 8
+
+#define ONE_PIXEL  ( 1 << PIXEL_BITS )
+#define TRUNC( x ) (int)( ( x ) >> PIXEL_BITS )
+
+#define UPSCALE( x )   ( ( x ) * ( ONE_PIXEL >> 6 ) )
+#define DOWNSCALE( x ) ( ( x ) >> ( PIXEL_BITS - 6 ) )
+
+#define FT_SWAP(a, b)   { (a) = (a) + (b); (b) = (a) - (b); (a) = (a) - (b);}
+#define FT_MIN( a, b )  ( (a) < (b) ? (a) : (b) )
+#define FT_MAX( a, b )  ( (a) > (b) ? (a) : (b) )
+#define FT_ABS( a )     ( (a) < 0 ? -(a) : (a) )
+
+// TODO: Fix types
+#define FT_UDIVPREP( c, b )                                \
+  FT26D6  b ## _r = c ? (FT26D6)0xFFFFFFFF / ( b ) : 0
+#define FT_UDIV( a, b )                                           \
+  (FT26D6)( ( (FT26D6)( a ) * (FT26D6)( b ## _r ) ) >> 32 )
+
+typedef struct dense_TRaster_
+{
+  void* memory;
+
+} dense_TRaster, *dense_PRaster;
+
+/* Linear interpolation between P0 and P1 */
+static FT_Vector
+Lerp( float T, FT_Vector P0, FT_Vector P1 )
+{
+  FT_Vector p;
+  p.x = P0.x + T * ( P1.x - P0.x );
+  p.y = P0.y + T * ( P1.y - P0.y );
+  return p;
+}
+
+static int
+dense_move_to( const FT_Vector* to, dense_worker* worker )
+{
+  FT_Pos x, y;
+
+  x              = UPSCALE( to->x );
+  y              = UPSCALE( to->y );
+  worker->prev_x = x;
+  worker->prev_y = y;
+  return 0;
+}
+
+static int
+dense_line_to( const FT_Vector* to, dense_worker* worker )
+{
+  dense_render_line( worker, UPSCALE( to->x ), UPSCALE( to->y ) );
+  dense_move_to( to, worker );
+  return 0;
+}
+
+void
+dense_render_line( dense_worker* worker, FT_Pos tox, FT_Pos toy )
+{
+
+  FT26D6 fx = worker->prev_x>>2;
+  FT26D6 fy = worker->prev_y>>2;
+
+  FT26D6 from_x = fx;
+  FT26D6 from_y = fy;
+
+
+  FT26D6 tx = tox>>2;
+  FT26D6 ty = toy>>2;
+
+  if ( fy == ty )
+    return;
+
+  FT26D6 to_x = tx;
+  FT26D6 to_y = ty;
+
+  int dir = 1;
+  if ( from_y >= to_y )
+  {
+    dir = -1;
+    FT_SWAP(from_x, to_x);
+    FT_SWAP(from_y, to_y);
+  }
+
+  // Clip to the height.
+  if ( from_y >= worker->m_h<<6 || to_y <= 0 )
+    return;
+
+  FT26D6 deltax,deltay;
+  deltax = to_x - from_x;
+  deltay = to_y - from_y;
+
+    FT_UDIVPREP(from_x != to_x, deltax);
+
+    FT_UDIVPREP(from_y != to_y, deltay);
+
+  if ( from_y < 0 )
+  {
+    from_x -= from_y * deltax/deltay;
+    from_y = 0;
+  }
+
+  if ( to_y > worker->m_h<<6 )
+  {
+    to_x -= (( to_y - worker->m_h<<6 ) * deltax/deltay);
+    to_y = worker->m_h<<6;
+  }
+
+
+  if(deltax == 0){
+    FT26D6 x       = from_x;
+    int   x0i    = x>>6;
+    FT26D6 x0floor = x0i<<6;
+
+    // y-coordinate of first pixel of line
+    int    y0      = from_y>>6;
+
+    // y-coordinate of last pixel of line
+    int    y_limit = (to_y + 0x3f)>>6;
+    FT20D12* m_a   = worker->m_a;
+
+
+
+    for ( int y = y0; y < y_limit; y++ )
+    {
+      int linestart = y * worker->m_w;
+
+     FT26D6 dy   = min( (y + 1)<<6, to_y ) - max( y<<6, from_y );
+
+      m_a[linestart + x0i] += dir*dy*(64 - x + x0floor);
+      m_a[linestart + ( x0i + 1 )] += dir*dy*(x-x0floor);
+
+    }
+  }
+  else
+  {
+    int    x       = from_x;
+    int    y0      = from_y>>6;
+    int    y_limit = (to_y + 0x3f)>>6;
+
+    FT20D12* m_a     = worker->m_a;
+
+    for ( int y = y0; y < y_limit; y++ )
+    {
+      int   linestart = y * worker->m_w;
+      FT26D6 dy        = FT_MIN( (y + 1)<<6, to_y ) - FT_MAX( y<<6, from_y );
+      FT26D6 xnext     = x + FT_UDIV((dy*deltax), deltay);
+      FT26D6 d         = dy * dir;
+
+      FT26D6 x0, x1;
+      if ( x < xnext )
+      {
+        x0 = x;
+        x1 = xnext;
+      }
+      else
+      {
+        x0 = xnext;
+        x1 = x;
+      }
+
+
+      int   x0i    = x0>>6;
+      FT26D6 x0floor = x0i<<6;
+
+
+      int   x1i    = (x1+0x3f)>>6;
+      FT26D6 x1ceil =  x1i <<6;
+
+      if ( x1i <= x0i + 1 )
+      {
+        FT26D6 xmf = ( ( x + xnext )>>1) - x0floor;
+        m_a[linestart + x0i] += d * ((1<<6) - xmf);
+        m_a[linestart + ( x0i + 1 )] += d * xmf;
+      }
+      else
+      {
+
+        FT26D6 oneOverS = x1 - x0;
+
+        FT_UDIVPREP(x1 != x0, oneOverS);
+
+        FT26D6 x0f = x0 - x0floor;
+
+
+        FT26D6 oneMinusX0f = (1<<6) - x0f;
+        FT26D6 a0 = FT_UDIV(((oneMinusX0f * oneMinusX0f) >> 1), oneOverS);
+        FT26D6 x1f = x1 - x1ceil + (1<<6);
+        FT26D6 am =  FT_UDIV(((x1f * x1f) >> 1) , oneOverS);
+
+        m_a[linestart + x0i] += d * a0;
+
+        if ( x1i == x0i + 2 )
+          m_a[linestart + ( x0i + 1 )] += d * ( (1<<6) - a0 - am );
+        else
+        {
+          FT26D6 a1 =  FT_UDIV((((1<<6) + (1<<5) - x0f) << 6) , oneOverS);
+          m_a[linestart + ( x0i + 1 )] += d * ( a1 - a0 );
+
+          FT26D6 dTimesS =  FT_UDIV((d << 12) , oneOverS);
+
+          for ( FT26D6 xi = x0i + 2; xi < x1i - 1; xi++ )
+            m_a[linestart + xi] += dTimesS;
+
+          FT26D6 a2 = a1 +  FT_UDIV((( x1i - x0i - 3 )<<12),oneOverS);
+          m_a[linestart + ( x1i - 1 )] += d * ( (1<<6) - a2 - am );
+        }
+        m_a[linestart + x1i] += d * am;
+      }
+      x = xnext;
+    }
+  }
+}
+
+
+static int
+dense_conic_to( const FT_Vector* control,
+                const FT_Vector* to,
+                dense_worker*    worker )
+{
+  dense_render_quadratic( worker, control, to );
+  return 0;
+}
+
+void
+dense_render_quadratic( dense_worker*    worker,
+                        FT_Vector* control,
+                        FT_Vector* to )
+{
+  /*
+  Calculate devsq as the square of four times the
+  distance from the control point to the midpoint of the curve.
+  This is the place at which the curve is furthest from the
+  line joining the control points.
+
+  4 x point on curve = p0 + 2p1 + p2
+  4 x midpoint = 4p1
+
+  The division by four is omitted to save time.
+  */
+
+  FT_Vector aP0 = { DOWNSCALE( worker->prev_x ), DOWNSCALE( worker->prev_y ) };
+  FT_Vector aP1 = { control->x, control->y };
+  FT_Vector aP2 = { to->x, to->y };
+
+  float devx  = aP0.x - aP1.x - aP1.x + aP2.x;
+  float devy  = aP0.y - aP1.y - aP1.y + aP2.y;
+  float devsq = devx * devx + devy * devy;
+
+  if ( devsq < 0.333f )
+  {
+    dense_line_to( &aP2, worker );
+    return;
+  }
+
+  /*
+  According to Raph Levien, the reason for the subdivision by n (instead of
+  recursive division by the Casteljau system) is that "I expect the flatness
+  computation to be semi-expensive (it's done once rather than on each potential
+  subdivision) and also because you'll often get fewer subdivisions. Taking a
+  circular arc as a simplifying assumption, where I get n, a recursive approach
+  would get 2^ceil(lg n), which, if I haven't made any horrible mistakes, is
+  expected to be 33% more in the limit".
+  */
+
+  const float tol = 3.0f;
+  int         n   = (int)floor( sqrt( sqrt( tol * devsq ) ) )/8;
+  FT_Vector p      = aP0;
+  float     nrecip = 1.0f / ( n + 1.0f );
+  float     t      = 0.0f;
+  for ( int i = 0; i < n; i++ )
+  {
+    t += nrecip;
+    FT_Vector next = Lerp( t, Lerp( t, aP0, aP1 ), Lerp( t, aP1, aP2 ) );
+    dense_line_to(&next, worker );
+    p              = next;
+  }
+
+  dense_line_to( &aP2, worker );
+}
+
+static int
+dense_cubic_to( const FT_Vector* control1,
+                const FT_Vector* control2,
+                const FT_Vector* to,
+                dense_worker*    worker )
+{
+  dense_render_cubic( worker, control1, control2, to );
+  return 0;
+}
+
+void
+dense_render_cubic( dense_worker* worker,
+                    FT_Vector*    control_1,
+                    FT_Vector*    control_2,
+                    FT_Vector*    to )
+{
+  FT_Vector aP0 = { DOWNSCALE( worker->prev_x ), DOWNSCALE( worker->prev_y ) };
+  FT_Vector aP1 = { control_1->x, control_1->y };
+  FT_Vector aP2 = { control_2->x, control_2->y };
+  FT_Vector aP3 = { to->x, to->y };
+
+  float     devx   = aP0.x - aP1.x - aP1.x + aP2.x;
+  float     devy   = aP0.y - aP1.y - aP1.y + aP2.y;
+  float     devsq0 = devx * devx + devy * devy;
+  devx             = aP1.x - aP2.x - aP2.x + aP3.x;
+  devy             = aP1.y - aP2.y - aP2.y + aP3.y;
+  float devsq1     = devx * devx + devy * devy;
+  float devsq      = fmax( devsq0, devsq1 );
+
+  if ( devsq < 0.333f )
+  {
+    dense_render_line( worker, aP3.x, aP3.y );
+    return;
+  }
+
+  const float tol    = 3.0f;
+  int         n      = (int)floor( sqrt( sqrt( tol * devsq ) ) ) / 8;
+  FT_Vector   p      = aP0;
+  float       nrecip = 1.0f / ( n + 1.0f );
+  float       t      = 0.0f;
+  for ( int i = 0; i < n; i++ )
+  {
+    t += nrecip;
+    FT_Vector a    = Lerp( t, Lerp( t, aP0, aP1 ), Lerp( t, aP1, aP2 ) );
+    FT_Vector b    = Lerp( t, Lerp( t, aP1, aP2 ), Lerp( t, aP2, aP3 ) );
+    FT_Vector next = Lerp( t, a, b );
+    dense_render_line( worker, next.x, next.y );
+    worker->prev_x = next.x;
+    worker->prev_y = next.y;
+    p              = next;
+  }
+
+  dense_line_to( &aP3, worker );
+}
+
+static int
+dense_raster_new( FT_Memory memory, dense_PRaster* araster )
+{
+  FT_Error      error;
+  dense_PRaster raster;
+
+  if ( !FT_NEW( raster ) )
+    raster->memory = memory;
+
+  *araster = raster;
+  return error;
+}
+
+static void
+dense_raster_done( FT_Raster raster )
+{
+  FT_Memory memory = (FT_Memory)( (dense_PRaster)raster )->memory;
+
+  FT_FREE( raster );
+}
+
+static void
+dense_raster_reset( FT_Raster      raster,
+                    unsigned char* pool_base,
+                    unsigned long  pool_size )
+{
+  FT_UNUSED( raster );
+  FT_UNUSED( pool_base );
+  FT_UNUSED( pool_size );
+}
+
+static int
+dense_raster_set_mode( FT_Raster raster, unsigned long mode, void* args )
+{
+  FT_UNUSED( raster );
+  FT_UNUSED( mode );
+  FT_UNUSED( args );
+
+  return 0; /* nothing to do */
+}
+
+FT_DEFINE_OUTLINE_FUNCS( dense_decompose_funcs,
+
+                         (FT_Outline_MoveTo_Func)dense_move_to,   /* move_to  */
+                         (FT_Outline_LineTo_Func)dense_line_to,   /* line_to  */
+                         (FT_Outline_ConicTo_Func)dense_conic_to, /* conic_to */
+                         (FT_Outline_CubicTo_Func)dense_cubic_to, /* cubic_to */
+
+                         0, /* shift    */
+                         0  /* delta    */
+)
+
+static int
+dense_render_glyph( dense_worker* worker, const FT_Bitmap* target )
+{
+  FT_Error error = FT_Outline_Decompose( &( worker->outline ),
+                                         &dense_decompose_funcs, worker );
+  // Render into bitmap
+  const FT20D12* source = worker->m_a;
+  unsigned char* dest     = target->buffer;
+  unsigned char* dest_end = target->buffer + worker->m_w * worker->m_h;
+
+#if FT_SSE4_1
+
+__m128i offset = _mm_setzero_si128();
+  __m128i mask   = _mm_set1_epi32( 0x0c080400 );
+
+  for (int i = 0; i < worker->m_h*worker->m_w; i += 4)
+  {
+    // load 4 floats from source
+
+    __m128i x = _mm_load_si128( (__m128i*)&source[i] );
+
+    x = _mm_add_epi32( x, _mm_slli_si128( x, 4 ) );
+
+    x = _mm_add_epi32(
+        x, _mm_castps_si128( _mm_shuffle_ps( _mm_setzero_ps(),
+                                             _mm_castsi128_ps( x ), 0x40 ) ) );
+
+    // add the prefsum of previous 4 floats to all current floats
+    x = _mm_add_epi32( x, offset );
+
+    // take absolute value
+    __m128i y = _mm_abs_epi32( x );  // fabs(x)
+
+    // cap max value to 1
+    y = _mm_min_epi32( y, _mm_set1_epi32( 4080 ) );
+
+    // reduce to 255
+    y = _mm_srli_epi32( y, 4 );
+
+    // shuffle
+    y = _mm_shuffle_epi8( y, mask );
+
+    _mm_store_ss( (float*)&dest[i], (__m128)y );
+
+    // store the current prefix sum in offset
+    offset = _mm_castps_si128( _mm_shuffle_ps( _mm_castsi128_ps( x ),
+                                               _mm_castsi128_ps( x ),
+                                               _MM_SHUFFLE( 3, 3, 3, 3 ) ) );
+  }
+
+#else /* FT_SSE4_1 */
+
+  FT20D12 value = 0;
+
+  while ( dest < dest_end )
+  {
+    value += *source++;
+
+    if(value > 0){
+      int n = value >>4;
+
+      if(n>255)n=255;
+      *dest = (unsigned char)n;
+    }else{
+      *dest = 0;
+    }
+    dest++;
+  }
+
+#endif /* FT_SSE4_1 */
+
+  free(worker->m_a);
+  return error;
+}
+
+static int
+dense_raster_render( FT_Raster raster, const FT_Raster_Params* params )
+{
+  const FT_Outline* outline    = (const FT_Outline*)params->source;
+  FT_Bitmap*  target_map = params->target;
+
+  dense_worker worker[1];
+
+  if ( !raster )
+    return FT_THROW( Invalid_Argument );
+
+  if ( !outline )
+    return FT_THROW( Invalid_Outline );
+
+  worker->outline = *outline;
+
+  if ( !target_map )
+    return FT_THROW( Invalid_Argument );
+
+  /* nothing to do */
+  if ( !target_map->width || !target_map->rows )
+    return 0;
+
+  if ( !target_map->buffer )
+    return FT_THROW( Invalid_Argument );
+
+  worker->m_origin_x = 0;
+  worker->m_origin_y = 0;
+  worker->m_w = target_map->pitch;
+  worker->m_h = target_map->rows;
+
+  int size = worker->m_w * worker->m_h + 4;
+
+  worker->m_a      = malloc( sizeof( FT20D12 ) * size );
+  worker->m_a_size = size;
+
+  memset( worker->m_a, 0, ( sizeof( FT20D12 ) * size ) );
+  /* exit if nothing to do */
+  if ( worker->m_w <= worker->m_origin_x || worker->m_h <= worker->m_origin_y )
+  {
+    return 0;
+  }
+
+  // Invert the pitch to account for different +ve y-axis direction in dense array
+  // (maybe temporary solution)
+  target_map->pitch *= -1;
+  return dense_render_glyph( worker, target_map );
+}
+
+FT_DEFINE_RASTER_FUNCS(
+    ft_dense_raster,
+
+    FT_GLYPH_FORMAT_OUTLINE,
+
+    (FT_Raster_New_Func)dense_raster_new,           /* raster_new      */
+    (FT_Raster_Reset_Func)dense_raster_reset,       /* raster_reset    */
+    (FT_Raster_Set_Mode_Func)dense_raster_set_mode, /* raster_set_mode */
+    (FT_Raster_Render_Func)dense_raster_render,     /* raster_render   */
+    (FT_Raster_Done_Func)dense_raster_done          /* raster_done     */
+)
+
+/* END */

src/dense/ftdense.h

@@ -0,0 +1,63 @@
+/* Dense rasterizer header*/
+
+#ifndef FTDENSE_H_
+#define FTDENSE_H_
+
+#include <ft2build.h>
+#include FT_CONFIG_CONFIG_H
+#include <freetype/ftimage.h>
+
+FT_BEGIN_HEADER
+
+#ifndef FT_EXPORT_VAR
+#define FT_EXPORT_VAR( x ) extern x
+#endif
+FT_EXPORT_VAR( const FT_Raster_Funcs ) ft_dense_raster;
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+
+  typedef signed long FT26D6;            /* 26.6 fixed-point representation  */
+  typedef signed int FT20D12;            /* 20.12 fixed-point representation  */
+
+  typedef struct
+  {
+    /** The array used to store signed area differences. */
+    float* m_a;
+    /** The number of elements in m_a. */
+    int m_a_size;
+    /** The width of the current raster in pixels. */
+    int m_w;
+    /** The height of the current raster in pixels. */
+    int m_h;
+    /** The x origin of the raster. */
+    int m_origin_x;
+    /** The y origin of the raster. */
+    int m_origin_y;
+
+    FT_Pos prev_x, prev_y;
+
+    FT_Outline outline;
+  } dense_worker;
+
+  void dense_render_line( dense_worker* worker, FT_Pos to_x, FT_Pos to_y );
+  void dense_render_quadratic( dense_worker* worker,
+                               FT_Vector* control,
+                               FT_Vector* to );
+  void dense_render_cubic( dense_worker* worker,
+                           FT_Vector*    control_1,
+                           FT_Vector*    control_2,
+                           FT_Vector*    to );
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+FT_END_HEADER
+
+#endif /* FTDENSE_H_ */
+
+/* END */

src/dense/ftdenseerrs.h

@@ -0,0 +1,17 @@
+/* Dense Renderer Error Codes */
+#ifndef FTDENSEERRS_H_
+#define FTDENSEERRS_H_
+
+#include <freetype/ftmoderr.h>
+
+#undef FTERRORS_H_
+
+#undef FT_ERR_PREFIX
+#define FT_ERR_PREFIX Dense_Err_
+#define FT_ERR_BASE   FT_Mod_Err_Dense
+
+#include <freetype/fterrors.h>
+
+#endif /* FTDENSEERRS_H_ */
+
+/* END */

src/dense/ftdenserend.c

@@ -0,0 +1,220 @@
+  /** The 'dense' renderer */
+
+#include <freetype/ftoutln.h>
+#include <freetype/internal/ftdebug.h>
+#include <freetype/internal/ftobjs.h>
+#include "ftdenserend.h"
+#include "ftdense.h"
+
+#include "ftdenseerrs.h"
+
+  /**************************************************************************
+   *
+   * The macro FT_COMPONENT is used in trace mode.  It is an implicit
+   * parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log
+   * messages during execution.
+   */
+#undef FT_COMPONENT
+#define FT_COMPONENT dense
+
+
+
+  /**************************************************************************
+   *
+   * interface functions
+   *
+   */
+
+  /* set render specific modes or attributes */
+  static FT_Error
+  ft_dense_set_mode( FT_Renderer render, FT_ULong mode_tag, FT_Pointer data )
+  {
+    /* pass it to the rasterizer */
+    return render->clazz->raster_class->raster_set_mode( render->raster, mode_tag,
+                                                         data );
+  }
+
+  /* transform the glyph using matrix and/or delta */
+  static FT_Error
+  ft_dense_transform( FT_Renderer      render,
+                      FT_GlyphSlot     slot,
+                      const FT_Matrix* matrix,
+                      const FT_Vector* delta )
+  {
+
+    FT_Error error = FT_Err_Ok;
+
+    if ( slot->format != render->glyph_format )
+    {
+      error = FT_THROW( Invalid_Argument );
+      goto Exit;
+    }
+
+    if ( matrix )
+      FT_Outline_Transform( &slot->outline, matrix );
+
+    if ( delta )
+      FT_Outline_Translate( &slot->outline, delta->x, delta->y );
+
+  Exit:
+    return error;
+  }
+
+  /* return the control box of a glyph's outline */
+  static void
+  ft_dense_get_cbox( FT_Renderer render, FT_GlyphSlot slot, FT_BBox* cbox )
+  {
+
+    FT_ZERO( cbox );
+
+    if ( slot->format == render->glyph_format )
+      FT_Outline_Get_CBox( &slot->outline, cbox );
+  }
+
+  static FT_Error
+  ft_dense_init( FT_Renderer render )
+  {
+    return FT_Err_Ok;
+  }
+
+  static void
+  ft_dense_done( FT_Renderer render )
+  {
+    FT_UNUSED( render );
+  }
+
+  /* generate bitmap from a glyph's slot image */
+  static FT_Error
+  ft_dense_render( FT_Renderer      render,
+                   FT_GlyphSlot     slot,
+                   FT_Render_Mode   mode,
+                   const FT_Vector* origin )
+  {
+    FT_Error    error   = FT_Err_Ok;
+    FT_Outline* outline = &slot->outline;
+    FT_Bitmap*  bitmap  = &slot->bitmap;
+
+    /* FT_FREE and FT_ALLOC_MULT macros need a variable named 'memory' */
+    FT_Memory   memory  = render->root.memory;
+
+    FT_Pos x_shift = 0;
+    FT_Pos y_shift = 0;
+
+    FT_Raster_Params params;
+
+    /* check whether slot format is correct before rendering */
+    if ( slot->format != render->glyph_format )
+    {
+      error = FT_THROW( Invalid_Glyph_Format );
+      goto Exit;
+    }
+
+    /* check mode */
+    if ( mode != FT_RENDER_MODE_NORMAL &&
+         mode != FT_RENDER_MODE_LIGHT  &&
+         mode != FT_RENDER_MODE_LCD    &&
+         mode != FT_RENDER_MODE_LCD_V  )
+    {
+      error = FT_THROW( Cannot_Render_Glyph );
+      goto Exit;
+    }
+
+
+    /* deallocate the previously allocated bitmap */
+    if ( slot->internal->flags & FT_GLYPH_OWN_BITMAP )
+    {
+      FT_FREE( bitmap->buffer );
+      slot->internal->flags &= ~FT_GLYPH_OWN_BITMAP;
+    }
+
+    /* preset the bitmap using the glyph's outline */
+    if ( ft_glyphslot_preset_bitmap( slot, mode, origin ) )
+    {
+      error = FT_THROW( Raster_Overflow );
+      goto Exit;
+    }
+
+    if ( !bitmap->rows || !bitmap->pitch )
+      goto Exit;
+
+
+    /* allocate new one */
+    if ( FT_ALLOC_MULT( bitmap->buffer, bitmap->rows, bitmap->pitch ) )
+      goto Exit;
+
+    slot->internal->flags |= FT_GLYPH_OWN_BITMAP;
+
+    /* Calculate shift in 26.6 format */
+    x_shift = 64 * -slot->bitmap_left;
+    y_shift = 64 * -slot->bitmap_top;
+
+    if ( bitmap->pixel_mode == FT_PIXEL_MODE_LCD_V )
+       y_shift += 64 * (FT_Int)bitmap->rows / 3;
+     else
+       y_shift += 64 * (FT_Int)bitmap->rows;
+
+
+    if ( origin )
+    {
+      x_shift += origin->x;
+      y_shift += origin->y;
+    }
+
+    /* translate outline to render it into the bitmap */
+    if ( x_shift || y_shift )
+      FT_Outline_Translate( outline, x_shift, y_shift );
+
+    /* set up parameters */
+    params.target = bitmap;
+    params.source = outline;
+
+    /* render the outline */
+    error =
+        render->raster_render( render->raster, (const FT_Raster_Params*)&params );
+
+  Exit:
+    if ( !error )
+    {
+      /* the glyph is successfully rendered to a bitmap */
+      slot->format = FT_GLYPH_FORMAT_BITMAP;
+    }
+    else if ( slot->internal->flags & FT_GLYPH_OWN_BITMAP )
+    {
+      FT_FREE( bitmap->buffer );
+      slot->internal->flags &= ~FT_GLYPH_OWN_BITMAP;
+    }
+
+    if ( x_shift || y_shift )
+      FT_Outline_Translate( outline, -x_shift, -y_shift );
+
+    return error;
+  }
+
+
+  FT_DEFINE_RENDERER(
+      ft_dense_renderer_class,
+
+      FT_MODULE_RENDERER,
+      sizeof( FT_RendererRec ),
+
+      "dense",
+      0x10000L,
+      0x20000L,
+
+      NULL,
+
+      (FT_Module_Constructor)ft_dense_init,
+      (FT_Module_Destructor)ft_dense_done,
+      (FT_Module_Requester)NULL,
+
+      FT_GLYPH_FORMAT_OUTLINE,
+
+      (FT_Renderer_RenderFunc)ft_dense_render,       /* render_glyph    */
+      (FT_Renderer_TransformFunc)ft_dense_transform, /* transform_glyph */
+      (FT_Renderer_GetCBoxFunc)ft_dense_get_cbox,    /* get_glyph_cbox  */
+      (FT_Renderer_SetModeFunc)ft_dense_set_mode,    /* set_mode        */
+
+      (FT_Raster_Funcs*)&ft_dense_raster /* raster_class    */
+  )
+
+  /* END */

src/dense/ftdenserend.h

@@ -0,0 +1,27 @@
+/* Dense renderer interface (specification) */
+#ifndef FTDENSEREND_H_
+#define FTDENSEREND_H_
+
+
+#include <freetype/ftmodapi.h>
+#include <freetype/ftrender.h>
+#include <freetype/internal/ftobjs.h>
+
+FT_BEGIN_HEADER
+
+/**************************************************************************
+ *
+ * @renderer:
+ *   ft_dense_renderer_class
+ *
+ * @description:
+ *   Renderer to convert @FT_Outline to bitmaps.
+ *
+ */
+FT_DECLARE_RENDERER( ft_dense_renderer_class )
+
+FT_END_HEADER
+
+#endif /* FTDENSEREND_H_ */
+
+/* END */

src/dense/module.mk

@@ -0,0 +1,23 @@
+#
+# FreeType 2 smooth renderer module definition
+#
+
+
+# Copyright (C) 1996-2021 by
+# David Turner, Robert Wilhelm, and Werner Lemberg.
+#
+# This file is part of the FreeType project, and may only be used, modified,
+# and distributed under the terms of the FreeType project license,
+# LICENSE.TXT.  By continuing to use, modify, or distribute this file you
+# indicate that you have read the license and understand and accept it
+# fully.
+
+
+FTMODULE_H_COMMANDS += DENSE_RENDERER
+
+define DENSE_RENDERER
+$(OPEN_DRIVER) FT_Renderer_Class, ft_dense_renderer_class $(CLOSE_DRIVER)
+$(ECHO_DRIVER)dense     $(ECHO_DRIVER_DESC)anti-aliased dense renderer$(ECHO_DRIVER_DONE)
+endef
+
+# EOF

src/dense/rules.mk

@@ -0,0 +1,73 @@
+#
+# FreeType 2 DENSE renderer module build rules
+#
+
+
+# Copyright (C) 1996-2021 by
+# David Turner, Robert Wilhelm, and Werner Lemberg.
+#
+# This file is part of the FreeType project, and may only be used, modified,
+# and distributed under the terms of the FreeType project license,
+# LICENSE.TXT.  By continuing to use, modify, or distribute this file you
+# indicate that you have read the license and understand and accept it
+# fully.
+
+
+# DENSE driver directory
+#
+DENSE_DIR := $(SRC_DIR)/dense
+
+
+# compilation flags for the driver
+#
+DENSE_COMPILE := $(CC) $(ANSIFLAGS)                               \
+                        $I$(subst /,$(COMPILER_SEP),$(DENSE_DIR)) \
+                        $(INCLUDE_FLAGS)                          \
+                        $(FT_CFLAGS)                              \
+                        "-msse4.1"
+
+# DENSE driver sources (i.e., C files)
+#
+DENSE_DRV_SRC := $(DENSE_DIR)/ftdense.c  \
+                  $(DENSE_DIR)/ftdenserend.c
+
+
+# DENSE driver headers
+#
+DENSE_DRV_H := $(DENSE_DRV_SRC:%c=%h)  \
+                $(DENSE_DIR)/ftdenseerrs.h
+
+
+# DENSE driver object(s)
+#
+#   DENSE_DRV_OBJ_M is used during `multi' builds.
+#   DENSE_DRV_OBJ_S is used during `single' builds.
+#
+DENSE_DRV_OBJ_M := $(DENSE_DRV_SRC:$(DENSE_DIR)/%.c=$(OBJ_DIR)/%.$O)
+DENSE_DRV_OBJ_S := $(OBJ_DIR)/dense.$O
+
+# DENSE driver source file for single build
+#
+DENSE_DRV_SRC_S := $(DENSE_DIR)/dense.c
+
+
+# DENSE driver - single object
+#
+$(DENSE_DRV_OBJ_S): $(DENSE_DRV_SRC_S) $(DENSE_DRV_SRC) \
+                     $(FREETYPE_H) $(DENSE_DRV_H)
+	$(DENSE_COMPILE) $T$(subst /,$(COMPILER_SEP),$@ $(DENSE_DRV_SRC_S))
+
+
+# DENSE driver - multiple objects
+#
+$(OBJ_DIR)/%.$O: $(DENSE_DIR)/%.c $(FREETYPE_H) $(DENSE_DRV_H)
+	$(DENSE_COMPILE) $T$(subst /,$(COMPILER_SEP),$@ $<)
+
+
+# update main driver object lists
+#
+DRV_OBJS_S += $(DENSE_DRV_OBJ_S)
+DRV_OBJS_M += $(DENSE_DRV_OBJ_M)
+
+
+# EOF