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/** The 'dense' renderer */
#include "ftdenserend.h"
#include <freetype/ftbitmap.h>
#include <freetype/ftoutln.h>
#include <freetype/internal/ftdebug.h>
#include <freetype/internal/ftobjs.h>
#include <freetype/internal/services/svprop.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
*
*/
/* @QUES: So, I think this is used for setting up the
initial properties of the renderer ??? */
static FT_Error
ft_dense_init( FT_Renderer render )
{
return FT_Err_Ok;
}
/* @QUES: A destructor probably. The smooth renderer doesn't have this
so, I guess this is unnecessary ??? */
static void
ft_dense_done( FT_Renderer render )
{
FT_UNUSED( render );
}
/* generate bitmap from a glyph's slot image */
/* @QUES: This method allocates the bitmap buffer, shifts the outlines
as required (Why exactly is shifting required?), and finally calls
raster_render interface methods with correct params */
static FT_Error
ft_dense_render( FT_Renderer render,
FT_GlyphSlot slot,
FT_Render_Mode mode,
const FT_Vector* origin )
{
// printf("ft_dense_render\n");
FT_Error error = FT_Err_Ok;
FT_Outline* outline = &slot->outline;
FT_Bitmap* bitmap = &slot->bitmap;
/* @QUES: You know, it should be a bit more clear that FT_FREE and FT_ALLOC_MULT macros
take a variable named `memory`. It can only be known if you follow the macros 3 level deep.*/
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;
/* @QUES: What does this flag mean ?*/
slot->internal->flags |= FT_GLYPH_OWN_BITMAP;
/* @QUES: Where can I read more about why x and y shift are required */
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;
/* @QUES: Why is my final bitmap upside down ??🤔*/
/* render the outline */
error =
render->raster_render( render->raster, (const FT_Raster_Params*)¶ms );
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;
}
/* transform the glyph using matrix and/or delta */
/* @QUES: This mthod isn't called, atleast in normal ftlint execution.
What is it for ?*/
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 */
/* @QUES: This method isn't called either in normal ftlint execution*/
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 );
}
/* set render specific modes or attributes */
/* @QUES: Isn't called in normal ftlint execution*/
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 );
}
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 */
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