ftsmooth.c | Explore in Territory

/****************************************************************************
 *
 * ftsmooth.c
 *
 *   Anti-aliasing renderer interface (body).
 *
 * Copyright (C) 2000-2024 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.
 *
 */


#include <freetype/internal/ftdebug.h>
#include <freetype/internal/ftobjs.h>
#include <freetype/ftoutln.h>
#include "ftsmooth.h"
#include "ftgrays.h"

#include "ftsmerrs.h"


  /* sets render-specific mode */
  static FT_Error
  ft_smooth_set_mode( FT_Renderer  render,
                      FT_ULong     mode_tag,
                      FT_Pointer   data )
  { … }

  /* transform a given glyph image */
  static FT_Error
  ft_smooth_transform( FT_Renderer       render,
                       FT_GlyphSlot      slot,
                       const FT_Matrix*  matrix,
                       const FT_Vector*  delta )
  { … }


  /* return the glyph's control box */
  static void
  ft_smooth_get_cbox( FT_Renderer   render,
                      FT_GlyphSlot  slot,
                      FT_BBox*      cbox )
  { … }

  TOrigin;

#ifndef FT_CONFIG_OPTION_SUBPIXEL_RENDERING

  /* initialize renderer -- init its raster */
  static FT_Error
  ft_smooth_init( FT_Module  module )   /* FT_Renderer */
  {
    FT_Renderer  render = (FT_Renderer)module;

    FT_Vector*  sub = render->root.library->lcd_geometry;


    /* set up default subpixel geometry for striped RGB panels. */
    sub[0].x = -21;
    sub[0].y = 0;
    sub[1].x = 0;
    sub[1].y = 0;
    sub[2].x = 21;
    sub[2].y = 0;

    render->clazz->raster_class->raster_reset( render->raster, NULL, 0 );

    return 0;
  }


  /* This function writes every third byte in direct rendering mode */
  static void
  ft_smooth_lcd_spans( int             y,
                       int             count,
                       const FT_Span*  spans,
                       void*           target_ )   /* TOrigin* */
  {
    TOrigin*  target = (TOrigin*)target_;

    unsigned char*  dst_line = target->origin - y * target->pitch;
    unsigned char*  dst;
    unsigned short  w;


    for ( ; count--; spans++ )
      for ( dst = dst_line + spans->x * 3, w = spans->len; w--; dst += 3 )
        *dst = spans->coverage;
  }


  static FT_Error
  ft_smooth_raster_lcd( FT_Renderer  render,
                        FT_Outline*  outline,
                        FT_Bitmap*   bitmap )
  {
    FT_Error      error = FT_Err_Ok;
    FT_Vector*    sub   = render->root.library->lcd_geometry;
    FT_Pos        x, y;

    FT_Raster_Params   params;
    TOrigin            target;


    /* Render 3 separate coverage bitmaps, shifting the outline.  */
    /* Set up direct rendering to record them on each third byte. */
    params.source     = outline;
    params.flags      = FT_RASTER_FLAG_AA | FT_RASTER_FLAG_DIRECT;
    params.gray_spans = ft_smooth_lcd_spans;
    params.user       = &target;

    params.clip_box.xMin = 0;
    params.clip_box.yMin = 0;
    params.clip_box.xMax = bitmap->width;
    params.clip_box.yMax = bitmap->rows;

    if ( bitmap->pitch < 0 )
      target.origin = bitmap->buffer;
    else
      target.origin = bitmap->buffer
                      + ( bitmap->rows - 1 ) * (unsigned int)bitmap->pitch;

    target.pitch = bitmap->pitch;

    FT_Outline_Translate( outline,
                          -sub[0].x,
                          -sub[0].y );
    error = render->raster_render( render->raster, &params );
    x = sub[0].x;
    y = sub[0].y;
    if ( error )
      goto Exit;

    target.origin++;
    FT_Outline_Translate( outline,
                          sub[0].x - sub[1].x,
                          sub[0].y - sub[1].y );
    error = render->raster_render( render->raster, &params );
    x = sub[1].x;
    y = sub[1].y;
    if ( error )
      goto Exit;

    target.origin++;
    FT_Outline_Translate( outline,
                          sub[1].x - sub[2].x,
                          sub[1].y - sub[2].y );
    error = render->raster_render( render->raster, &params );
    x = sub[2].x;
    y = sub[2].y;

  Exit:
    FT_Outline_Translate( outline, x, y );

    return error;
  }


  static FT_Error
  ft_smooth_raster_lcdv( FT_Renderer  render,
                         FT_Outline*  outline,
                         FT_Bitmap*   bitmap )
  {
    FT_Error     error = FT_Err_Ok;
    int          pitch = bitmap->pitch;
    FT_Vector*   sub   = render->root.library->lcd_geometry;
    FT_Pos       x, y;

    FT_Raster_Params  params;


    params.target = bitmap;
    params.source = outline;
    params.flags  = FT_RASTER_FLAG_AA;

    /* Render 3 separate coverage bitmaps, shifting the outline. */
    /* Notice that the subpixel geometry vectors are rotated.    */
    /* Triple the pitch to render on each third row.            */
    bitmap->pitch *= 3;
    bitmap->rows  /= 3;

    FT_Outline_Translate( outline,
                          -sub[0].y,
                          sub[0].x );
    error = render->raster_render( render->raster, &params );
    x = sub[0].y;
    y = -sub[0].x;
    if ( error )
      goto Exit;

    bitmap->buffer += pitch;
    FT_Outline_Translate( outline,
                          sub[0].y - sub[1].y,
                          sub[1].x - sub[0].x );
    error = render->raster_render( render->raster, &params );
    x = sub[1].y;
    y = -sub[1].x;
    bitmap->buffer -= pitch;
    if ( error )
      goto Exit;

    bitmap->buffer += 2 * pitch;
    FT_Outline_Translate( outline,
                          sub[1].y - sub[2].y,
                          sub[2].x - sub[1].x );
    error = render->raster_render( render->raster, &params );
    x = sub[2].y;
    y = -sub[2].x;
    bitmap->buffer -= 2 * pitch;

  Exit:
    FT_Outline_Translate( outline, x, y );

    bitmap->pitch /= 3;
    bitmap->rows  *= 3;

    return error;
  }

#else   /* FT_CONFIG_OPTION_SUBPIXEL_RENDERING */

  /* initialize renderer -- init its raster */
  static FT_Error
  ft_smooth_init( FT_Module  module )   /* FT_Renderer */
  { … }


  static FT_Error
  ft_smooth_raster_lcd( FT_Renderer  render,
                        FT_Outline*  outline,
                        FT_Bitmap*   bitmap )
  { … }


  static FT_Error
  ft_smooth_raster_lcdv( FT_Renderer  render,
                         FT_Outline*  outline,
                         FT_Bitmap*   bitmap )
  { … }

#endif  /* FT_CONFIG_OPTION_SUBPIXEL_RENDERING */

/* Oversampling scale to be used in rendering overlaps */
#define SCALE …

  /* This function averages inflated spans in direct rendering mode */
  static void
  ft_smooth_overlap_spans( int             y,
                           int             count,
                           const FT_Span*  spans,
                           void*           target_ )
  { … }


  static FT_Error
  ft_smooth_raster_overlap( FT_Renderer  render,
                            FT_Outline*  outline,
                            FT_Bitmap*   bitmap )
  { … }

#undef SCALE

  static FT_Error
  ft_smooth_render( FT_Renderer       render,
                    FT_GlyphSlot      slot,
                    FT_Render_Mode    mode,
                    const FT_Vector*  origin )
  { … }


  FT_DEFINE_RENDERER(
    ft_smooth_renderer_class,

      FT_MODULE_RENDERER,
      sizeof ( FT_RendererRec ),

      "smooth",
      0x10000L,
      0x20000L,

      NULL,    /* module specific interface */

      (FT_Module_Constructor)ft_smooth_init,  /* module_init   */
      (FT_Module_Destructor) NULL,            /* module_done   */
      (FT_Module_Requester)  NULL,            /* get_interface */

    FT_GLYPH_FORMAT_OUTLINE,

    (FT_Renderer_RenderFunc)   ft_smooth_render,     /* render_glyph    */
    (FT_Renderer_TransformFunc)ft_smooth_transform,  /* transform_glyph */
    (FT_Renderer_GetCBoxFunc)  ft_smooth_get_cbox,   /* get_glyph_cbox  */
    (FT_Renderer_SetModeFunc)  ft_smooth_set_mode,   /* set_mode        */

    (FT_Raster_Funcs*)&ft_grays_raster               /* raster_class    */
  )


/* END */
chromium/third_party/freetype/src/src/smooth/ftsmooth.c
