renderer.c

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Hash : f0df85ba
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Date : 2000-06-22T00:17:42

- MAJOR INTERNAL REDESIGN: A lot of internal modifications have been performed lately on the source in order to provide the following enhancements: - more generic module support: The FT_Module type is now defined to represent a handle to a given module. The file <freetype/ftmodule.h> contains the FT_Module_Class definition, as well as the module-loading public API The FT_Driver type is still defined, and still represents a pointer to a font driver. Note that FT_Add_Driver is replaced by FT_Add_Module, FT_Get_Driver by FT_Get_Module, etc.. - support for generic glyph image types: The FT_Renderer type is a pointer to a module used to perform various operations on glyph image. Each renderer is capable of handling images in a single format (e.g. ft_glyph_format_outline). Its functions are used to: - transform an glyph image - render a glyph image into a bitmap - return the control box (dimensions) of a given glyph image The scan converters "ftraster.c" and "ftgrays.c" have been moved to the new directory "src/renderer", and are used to provide two default renderer modules. One corresponds to the "standard" scan-converter, the other to the "smooth" one. The current renderer can be set through the new function FT_Set_Renderer. The old raster-related function FT_Set_Raster, FT_Get_Raster and FT_Set_Raster_Mode have now disappeared, in favor of the new: FT_Get_Renderer FT_Set_Renderer see the file <freetype/ftrender.h> for more details.. These changes were necessary to properly support different scalable formats in the future, like bi-color glyphs, etc.. - glyph loader object: A new internal object, called a 'glyph loader' has been introduced in the base layer. It is used by all scalable format font drivers to load glyphs and composites. This object has been created to reduce the code size of each driver, as each one of them basically re-implemented its functionality. See <freetype/internal/ftobjs.h> and the FT_GlyphLoader type for more information.. - FT_GlyphSlot had new fields: In order to support extended features (see below), the FT_GlyphSlot structure has a few new fields: linearHoriAdvance: this field gives the linearly scaled (i.e. scaled but unhinted) advance width for the glyph, expressed as a 16.16 fixed pixel value. This is useful to perform WYSIWYG text. linearVertAdvance: this field gives the linearly scaled advance height for the glyph (relevant in vertical glyph layouts only). This is useful to perform WYSIWYG text. Note that the two above field replace the removed "metrics2" field in the glyph slot. advance: this field is a vector that gives the transformed advance for the glyph. By default, it corresponds to the advance width, unless FT_LOAD_VERTICAL_LAYOUT was specified when calling FT_Load_Glyph or FT_Load_Char bitmap_left: this field gives the distance in integer pixels from the current pen position to the left-most pixel of a glyph image WHEN IT IS A BITMAP. It is only valid when the "format" field is set to "ft_glyph_format_bitmap", for example, after calling the new function FT_Render_Glyph. bitmap_top: this field gives the distance in integer pixels from the current pen position (located on the baseline) to the top-most pixel of the glyph image WHEN IT IS A BITMAP. Positive values correspond to upwards Y. loader: this is a new private field for the glyph slot. Client applications should not touch it.. - support for transforms and direct rendering in FT_Load_Glyph: Most of the functionality found in <freetype/ftglyph.h> has been moved to the core library. Hence, the following: - a transform can be specified for a face through FT_Set_Transform. this transform is applied by FT_Load_Glyph to scalable glyph images (i.e. NOT TO BITMAPS) before the function returns, unless the bit flag FT_LOAD_IGNORE_TRANSFORM was set in the load flags.. - once a glyph image has been loaded, it can be directly converted to a bitmap by using the new FT_Render_Glyph function. Note that this function takes the glyph image from the glyph slot, and converts it to a bitmap whose properties are returned in "face.glyph.bitmap", "face.glyph.bitmap_left" and "face.glyph.bitmap_top". The original native image might be lost after the conversion. - when using the new bit flag FT_LOAD_RENDER, the FT_Load_Glyph and FT_Load_Char functions will call FT_Render_Glyph automatically when needed.

src/renderer/renderer.c

#include <freetype/internal/ftobjs.h>

 /* initialise renderer - init its raster */
  static FT_Error ft_renderer_init( FT_Renderer  render )
  {
    FT_Library  library = FT_MODULE_LIBRARY(render);
    
    render->clazz->raster_class->raster_reset( render->raster,
        library->raster_pool, library->raster_pool_size );

    return 0;
  }
  


 /* sets render-specific mode */
  static  FT_Error  ft_renderer_set_mode( FT_Renderer  render,
                                          FT_ULong     mode_tag,
                                          FT_Pointer   data )
  {
    /* we simply pass it to the raster */
    return render->clazz->raster_class->raster_set_mode(
                    render->raster, mode_tag, data );
  }                                          

 /* transform a given glyph image */
  static  FT_Error  ft_renderer_transform( FT_Renderer   render,
                                           FT_GlyphSlot  slot,
                                           FT_Matrix*    matrix,
                                           FT_Vector*    delta )
  {
    FT_Error error = FT_Err_Ok;
    
    if (slot->format != render->glyph_format)
    {
      error = FT_Err_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 glyph's control box */
  static  void  ft_renderer_get_cbox( FT_Renderer   render,
                                      FT_GlyphSlot  slot,
                                      FT_BBox      *cbox )
  {
    MEM_Set( cbox, 0, sizeof(*cbox) );

    if (slot->format == render->glyph_format)
      FT_Outline_Get_CBox( &slot->outline, cbox );
  }                                      
  

 /* convert a slot's glyph image into a bitmap */
  static  FT_Error  ft_renderer_render( FT_Renderer  render,
                                        FT_GlyphSlot slot,
                                        FT_UInt      mode,
                                        FT_Vector*   origin )
  {
    FT_Error     error;
    FT_Outline*  outline;
    FT_BBox      cbox;
    FT_UInt      width, height, pitch;
    FT_Bitmap*   bitmap;
    FT_Memory    memory;
    
    FT_Raster_Params  params;
    
    /* check glyph image format */
    if (slot->format != render->glyph_format)
    {
      error = FT_Err_Invalid_Argument;
      goto Exit;
    }
    
    outline = &slot->outline;
    
    /* translate the outline to the new origin if needed */
    if (origin)
      FT_Outline_Translate( outline, origin->x, origin->y );
    
    /* compute the control box, and grid fit it */
    FT_Outline_Get_CBox( outline, &cbox );
    
    cbox.xMin &= -64;
    cbox.yMin &= -64;
    cbox.xMax  = (cbox.xMax+63) & -64;
    cbox.yMax  = (cbox.yMax+63) & -64;

    width  = (cbox.xMax - cbox.xMin) >> 6;
    height = (cbox.yMax - cbox.yMin) >> 6;
    bitmap = &slot->bitmap;
    memory = slot->face->memory;
    
    /* release old bitmap buffer */
    if ((slot->flags & ft_glyph_own_bitmap))
    {
      FREE(bitmap->buffer);
      slot->flags &= ~ft_glyph_own_bitmap;
    }
      
    /* allocate new one, depends on pixel format */
    if ( mode & ft_render_mode_antialias )
    {
      pitch = width;
      bitmap->pixel_mode = ft_pixel_mode_grays;
      bitmap->num_grays  = 256;
    }
    else
    {
      pitch  = (width+7) >> 3;
      bitmap->pixel_mode = ft_pixel_mode_mono;
    }

    bitmap->width = width;
    bitmap->rows  = height;
    bitmap->pitch = pitch;
    
    if (ALLOC( bitmap->buffer, (FT_ULong)pitch * height ))
      goto Exit;

    slot->flags |= ft_glyph_own_bitmap;
    
    /* translate outline to render it into the bitmap */
    FT_Outline_Translate( outline, -cbox.xMin, -cbox.yMin );

    /* set up parameters */
    params.target = bitmap;
    params.source = outline;
    params.flags  = 0;

    if ( bitmap->pixel_mode == ft_pixel_mode_grays )
      params.flags |= ft_raster_flag_aa;

    /* render outline into the bitmap */
    error = render->raster_render( render->raster, &params );
    if (error) goto Exit;
    
    slot->format = ft_glyph_format_bitmap;
    slot->bitmap_left = cbox.xMin >> 6;
    slot->bitmap_top  = cbox.yMax >> 6;
    
  Exit:
    return error;
  }

#ifndef  FT_CONFIG_OPTION_NO_STD_RASTER

#include <freetype/ftraster.h>

  const FT_Renderer_Class   ft_standard_renderer_class =
  {
    {
      ft_module_renderer,
      sizeof( FT_RendererRec ),
      
      "standard renderer",
      0x10000,
      0x20000,
      
      0,    /* module specific interface */
      
      (FT_Module_Constructor)  ft_renderer_init,
      (FT_Module_Destructor)   0,
      (FT_Module_Requester)    0
    },
    
    ft_glyph_format_outline,
    
    (FTRenderer_render)       ft_renderer_render,
    (FTRenderer_transform)    ft_renderer_transform,
    (FTRenderer_getCBox)      ft_renderer_get_cbox,
    (FTRenderer_setMode)      ft_renderer_set_mode,
    
    (FT_Raster_Funcs*)        &ft_standard_raster
  };
  
#endif /* !FT_CONFIG_OPTION_NO_STD_RASTER */

#ifndef FT_CONFIG_OPTION_NO_SMOOTH_RASTER

#include <freetype/ftgrays.h>

  const FT_Renderer_Class  ft_smooth_renderer_class =
  {
    {
      ft_module_renderer,
      sizeof( FT_RendererRec ),
      
      "smooth renderer",
      0x10000,
      0x20000,
      
      0,    /* module specific interface */
      
      (FT_Module_Constructor)  ft_renderer_init,
      (FT_Module_Destructor)   0,
      (FT_Module_Requester)    0
    },

    ft_glyph_format_outline,
    
    (FTRenderer_render)       ft_renderer_render,
    (FTRenderer_transform)    ft_renderer_transform,
    (FTRenderer_getCBox)      ft_renderer_get_cbox,
    (FTRenderer_setMode)      ft_renderer_set_mode,
    
    (FT_Raster_Funcs*)        &ft_grays_raster
  };

#endif /* !FT_CONFIG_OPTION_NO_SMOOTH_RASTER */

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src/renderer/renderer.c