ref: 521e2bc8048c74127bfd69448cdf72f740bc0480
dir: /src/base/ftglyph.c/
/***************************************************************************/
/* */
/* ftglyph.c */
/* */
/* FreeType convenience functions to handle glyphs.. */
/* */
/* Copyright 1996-1999 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. */
/* */
/* This file contains the definition of several convenience functions */
/* that can be used by client applications to easily retrieve glyph */
/* bitmaps and outlines from a given face. */
/* */
/* These functions should be optional if you're writing a font server */
/* or text layout engine on top of FreeType. However, they are pretty */
/* handy for many other simple uses of the library.. */
/* */
/***************************************************************************/
#include <ftglyph.h>
#include <ftobjs.h>
static
void ft_prepare_glyph( FT_Glyph glyph,
FT_Face face,
FT_Bool vertical )
{
FT_Glyph_Metrics* metrics = &face->glyph->metrics;
glyph->memory = face->memory;
glyph->width = metrics->width;
glyph->height = metrics->height;
if (vertical)
{
glyph->bearingX = metrics->vertBearingX;
glyph->bearingY = metrics->vertBearingY;
glyph->advance = metrics->vertAdvance;
}
else
{
glyph->bearingX = metrics->horiBearingX;
glyph->bearingY = metrics->horiBearingY;
glyph->advance = metrics->horiAdvance;
}
}
/***********************************************************************
*
* <Function>
* FT_Get_Glyph_Bitmap
*
* <Description>
* A function used to directly return a monochrome bitmap glyph image
* from a face.
*
* <Input>
* face :: handle to source face object
* glyph_index :: glyph index in face
* load_flags :: load flags, see FT_LOAD_FLAG_XXXX constants..
* grays :: number of gray levels for anti-aliased bitmaps,
* set to 0 if you want to render a monochrome bitmap
* origin :: a pointer to the origin's position. Set to 0
* if the current transform is the identity..
*
* <Output>
* bitglyph :: pointer to the new bitmap glyph
*
* <Return>
* Error code. 0 means success.
*
* <Note>
* If the font contains glyph outlines, these will be automatically
* converted to a bitmap according to the value of "grays"
*
* If "grays" is set to 0, the result is a 1-bit monochrome bitmap
* otherwise, it is an 8-bit gray-level bitmap
*
* The number of gray levels in the result anti-aliased bitmap might
* not be "grays", depending on the current scan-converter implementation
*
* Note that it is not possible to generate 8-bit monochrome bitmaps
* with this function. Rather, use FT_Get_Glyph_Outline, then
* FT_Glyph_Render_Outline and provide your own span callbacks..
*
* When the face doesn't contain scalable outlines, this function will
* fail if the current transform is not the identity, or if the glyph
* origin's phase to the pixel grid is not 0 in both directions !!
*
***********************************************************************/
EXPORT_FUNC
FT_Error FT_Get_Glyph_Bitmap( FT_Face face,
FT_UInt glyph_index,
FT_UInt load_flags,
FT_Int grays,
FT_Vector* origin,
FT_BitmapGlyph *abitglyph )
{
FT_Error error;
FT_Memory memory;
FT_BitmapGlyph bitglyph;
FT_Glyph glyph;
FT_Pos origin_x = 0;
FT_Pos origin_y = 0;
*abitglyph = 0;
if (origin)
{
origin_x = origin->x & 63;
origin_y = origin->y & 63;
}
/* check arguments if the face's format is not scalable */
if ( !(face->face_flags & FT_FACE_FLAG_SCALABLE) && face->transform_flags )
{
/* we can't transform bitmaps, so return an error */
error = FT_Err_Unimplemented_Feature;
goto Exit;
}
/* check that NO_SCALE and NO_RECURSE are not set */
if (load_flags & (FT_LOAD_NO_SCALE|FT_LOAD_NO_RECURSE))
{
error = FT_Err_Invalid_Argument;
goto Exit;
}
/* disable embedded bitmaps for transformed images */
if ( face->face_flags & FT_FACE_FLAG_SCALABLE && face->transform_flags )
load_flags |= FT_LOAD_NO_BITMAP;
error = FT_Load_Glyph( face, glyph_index, load_flags );
if (error) goto Exit;
/* now, handle bitmap and outline glyph images */
memory = face->memory;
switch ( face->glyph->format )
{
case ft_glyph_format_bitmap:
{
FT_Long size;
FT_Bitmap* source;
if ( ALLOC( bitglyph, sizeof(*bitglyph) ) )
goto Exit;
glyph = (FT_Glyph)bitglyph;
glyph->glyph_type = ft_glyph_type_bitmap;
ft_prepare_glyph( glyph, face, 0 );
source = &face->glyph->bitmap;
size = source->rows * source->pitch;
if (size < 0) size = -size;
bitglyph->bitmap = *source;
if ( ALLOC( bitglyph->bitmap.buffer, size ) )
goto Fail;
/* copy the content of the source glyph */
MEM_Copy( bitglyph->bitmap.buffer, source->buffer, size );
}
break;
case ft_glyph_format_outline:
{
FT_BBox cbox;
FT_Int width, height, pitch;
FT_Long size;
/* transform the outline - note that the original metrics are NOT */
/* transformed by this.. only the outline points themselves.. */
FT_Outline_Transform( &face->glyph->outline, &face->transform_matrix );
FT_Outline_Translate( &face->glyph->outline,
face->transform_delta.x + origin_x,
face->transform_delta.y + origin_y );
/* compute the size in pixels of the outline */
FT_Outline_Get_CBox( &face->glyph->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;
/* allocate the pixel buffer for the glyph bitmap */
if (grays) pitch = (width+3) & -4; /* some raster implementation need this */
else pitch = (width+7) >> 3;
size = pitch * height;
if ( ALLOC( bitglyph, sizeof(*bitglyph) ) )
goto Exit;
glyph = (FT_Glyph)bitglyph;
glyph->glyph_type = ft_glyph_type_bitmap;
ft_prepare_glyph( glyph, face, 0 );
if ( ALLOC( bitglyph->bitmap.buffer, size ) )
goto Fail;
bitglyph->bitmap.width = width;
bitglyph->bitmap.rows = height;
bitglyph->bitmap.pitch = pitch;
bitglyph->bitmap.pixel_mode = grays ? ft_pixel_mode_grays
: ft_pixel_mode_mono;
bitglyph->bitmap.num_grays = (short)grays;
bitglyph->left = (cbox.xMin >> 6);
bitglyph->top = (cbox.yMax >> 6);
/* render the monochrome outline into the target buffer */
FT_Outline_Translate( &face->glyph->outline, -cbox.xMin, -cbox.yMin );
error = FT_Outline_Get_Bitmap( face->driver->library,
&face->glyph->outline,
&bitglyph->bitmap );
if (error)
{
FREE( bitglyph->bitmap.buffer );
goto Fail;
}
}
break;
default:
error = FT_Err_Invalid_Glyph_Index;
goto Exit;
}
*abitglyph = bitglyph;
Exit:
return error;
Fail:
FREE( glyph );
goto Exit;
}
/***********************************************************************
*
* <Function>
* FT_Get_Glyph_Outline
*
* <Description>
* A function used to directly return a bitmap glyph image from a
* face. This is faster than calling FT_Load_Glyph+FT_Get_Outline_Bitmap..
*
* <Input>
* face :: handle to source face object
* glyph_index :: glyph index in face
* load_flags :: load flags, see FT_LOAD_FLAG_XXXX constants..
*
* <Output>
* vecglyph :: pointer to the new outline glyph
*
* <Return>
* Error code. 0 means success.
*
* <Note>
* This function will fail if the load flags FT_LOAD_NO_OUTLINE and
* FT_LOAD_NO_RECURSE are set..
*
***********************************************************************/
EXPORT_FUNC
FT_Error FT_Get_Glyph_Outline( FT_Face face,
FT_UInt glyph_index,
FT_UInt load_flags,
FT_OutlineGlyph *vecglyph )
{
FT_Error error;
FT_Memory memory;
FT_OutlineGlyph glyph;
*vecglyph = 0;
/* check that NO_OUTLINE and NO_RECURSE are not set */
if (load_flags & (FT_LOAD_NO_OUTLINE|FT_LOAD_NO_RECURSE))
{
error = FT_Err_Invalid_Argument;
goto Exit;
}
/* disable the loading of embedded bitmaps */
load_flags |= FT_LOAD_NO_BITMAP;
error = FT_Load_Glyph( face, glyph_index, load_flags );
if (error) goto Exit;
/* check that we really loaded an outline */
if ( face->glyph->format != ft_glyph_format_outline )
{
error = FT_Err_Invalid_Glyph_Index;
goto Exit;
}
/* transform the outline - note that the original metrics are NOT */
/* transformed by this.. only the outline points themselves.. */
if ( face->transform_flags )
{
FT_Outline_Transform( &face->glyph->outline, &face->transform_matrix );
FT_Outline_Translate( &face->glyph->outline,
face->transform_delta.x,
face->transform_delta.y );
}
/* now, create a new outline glyph and copy everything there */
memory = face->memory;
if ( ALLOC( glyph, sizeof(*glyph) ) )
goto Exit;
ft_prepare_glyph( (FT_Glyph)glyph, face, 0 );
glyph->metrics.glyph_type = ft_glyph_type_outline;
error = FT_Outline_New( face->driver->library,
face->glyph->outline.n_points,
face->glyph->outline.n_contours,
&glyph->outline );
if (!error)
error = FT_Outline_Copy( &face->glyph->outline, &glyph->outline );
if (error) goto Fail;
*vecglyph = glyph;
Exit:
return error;
Fail:
FREE( glyph );
goto Exit;
}
/***********************************************************************
*
* <Function>
* FT_Set_Transform
*
* <Description>
* A function used to set the transform that is applied to glyph images
* just after they're loaded in the face's glyph slot, and before they're
* returned by either FT_Get_Glyph_Bitmap or FT_Get_Glyph_Outline
*
* <Input>
* face :: handle to source face object
* matrix :: pointer to the transform's 2x2 matrix. 0 for identity
* delta :: pointer to the transform's translation. 0 for null vector
*
* <Note>
* The transform is only applied to glyph outlines when they are found
* in a font face. It is unable to transform embedded glyph bitmaps
*
***********************************************************************/
EXPORT_FUNC
void FT_Set_Transform( FT_Face face,
FT_Matrix* matrix,
FT_Vector* delta )
{
face->transform_flags = 0;
if (!matrix)
{
face->transform_matrix.xx = 0x10000L;
face->transform_matrix.xy = 0;
face->transform_matrix.yx = 0L;
face->transform_matrix.yy = 0x10000L;
matrix = &face->transform_matrix;
}
else
face->transform_matrix = *matrix;
/* set transform_flags bit flag 0 if delta isn't the null vector */
if ( (matrix->xy | matrix->yx) ||
matrix->xx != 0x10000L ||
matrix->yy != 0x10000L )
face->transform_flags |= 1;
if (!delta)
{
face->transform_delta.x = 0;
face->transform_delta.y = 0;
delta = &face->transform_delta;
}
else
face->transform_delta = *delta;
/* set transform_flags bit flag 1 if delta isn't the null vector */
if ( delta->x | delta->y )
face->transform_flags |= 2;
}
/***********************************************************************
*
* <Function>
* FT_Done_Glyph
*
* <Description>
* Destroys a given glyph..
*
* <Input>
* glyph :: handle to target glyph object
*
***********************************************************************/
EXPORT_FUNC
void FT_Done_Glyph( FT_Glyph glyph )
{
if (glyph)
{
FT_Memory memory = glyph->memory;
if ( glyph->glyph_type == ft_glyph_type_bitmap )
{
FT_BitmapGlyph bit = (FT_BitmapGlyph)glyph;
FREE( bit->bitmap.buffer );
}
else if ( glyph->glyph_type == ft_glyph_type_outline )
{
FT_OutlineGlyph out = (FT_OutlineGlyph)glyph;
if (out->outline.flags & ft_outline_owner)
{
FREE( out->outline.points );
FREE( out->outline.contours );
FREE( out->outline.tags );
}
}
FREE( glyph );
}
}
/***********************************************************************
*
* <Function>
* FT_Glyph_Get_Box
*
* <Description>
* Returns the glyph image's bounding box in pixels.
*
* <Input>
* glyph :: handle to target glyph object
*
* <Output>
* box :: the glyph bounding box. Coordinates are expressed in
* _integer_ pixels, with exclusive max bounds
*
* <Note>
* Coordinates are relative to the glyph origin, using the Y-upwards
* convention..
*
* The width of the box in pixels is box.xMax-box.xMin
* The height is box.yMax - box.yMin
*
***********************************************************************/
EXPORT_DEF
void FT_Glyph_Get_Box( FT_Glyph glyph,
FT_BBox *box )
{
box->xMin = box->xMax = 0;
box->yMin = box->yMax = 0;
if (glyph) switch (glyph->glyph_type)
{
case ft_glyph_type_bitmap:
{
FT_BitmapGlyph bit = (FT_BitmapGlyph)glyph;
box->xMin = bit->left;
box->xMax = box->xMin + bit->bitmap.width;
box->yMax = bit->top;
box->yMin = box->yMax - bit->bitmap.rows;
}
break;
case ft_glyph_type_outline:
{
FT_OutlineGlyph out = (FT_OutlineGlyph)glyph;
FT_Outline_Get_CBox( &out->outline, box );
box->xMin >>= 6;
box->yMin >>= 6;
box->xMax = (box->xMax+63) >> 6;
box->yMax = (box->yMax+63) >> 6;
}
break;
default:
;
}
}