[freetype2] GSoC-2020-anuj ed7d2f5 2/2: [sdf] Added the `sdf' renderer.

[Anuj Verma]

branch: GSoC-2020-anuj
commit ed7d2f5789c2a2772e965ded51ced909f67185eb
Author: Anuj Verma <anujv@iitbhilai.ac.in>
Commit: Anuj Verma <anujv@iitbhilai.ac.in>

    [sdf] Added the `sdf' renderer.
    
    * src/sdf/ftsdf.c (*): Added `sdf' renderer along with
      it's interface functions and functions to set and get
      properties.
---
 src/sdf/ftsdfrend.c | 398 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 398 insertions(+)

diff --git a/src/sdf/ftsdfrend.c b/src/sdf/ftsdfrend.c
index 93a4c65..1a2797c 100644
--- a/src/sdf/ftsdfrend.c
+++ b/src/sdf/ftsdfrend.c
@@ -1,3 +1,401 @@
 
+#include <freetype/internal/ftdebug.h>
+#include <freetype/internal/ftobjs.h>
+#include <freetype/internal/services/svprop.h>
+#include <freetype/ftoutln.h>
+#include <freetype/ftbitmap.h>
+#include "ftsdfrend.h"
+#include "ftsdf.h"
+
+#include "ftsdferrs.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  sdf
+
+  /**************************************************************************
+   *
+   * macros and default property values
+   *
+   */
+
+  #define SDF_RENDERER( rend ) ( (SDF_Renderer)rend )
+
+  /**************************************************************************
+   *
+   * for setting properties
+   *
+   */
+
+  /* property setter function */
+  static FT_Error
+  sdf_property_set( FT_Module    module,
+                    const char*  property_name,
+                    const void*  value,
+                    FT_Bool      value_is_string )
+  {
+    FT_Error      error  = FT_Err_Ok;
+    SDF_Renderer  render = SDF_RENDERER( FT_RENDERER( module ) );
+
+
+    FT_UNUSED( value_is_string );
+
+    if ( ft_strcmp( property_name, "spread" ) == 0 )
+    {
+      FT_Int  val = *(const FT_Int*)value;
+
+
+      if ( val > MAX_SPREAD || val < MIN_SPREAD )
+      {
+        FT_TRACE0(( "[sdf] sdf_property_set: "
+                    "the `spread' property can have a "
+                    "value within range [%d, %d] (value provided %d)\n",
+                    MIN_SPREAD, MAX_SPREAD, val ));
+        error = FT_THROW( Invalid_Argument );
+        goto Exit;
+      }
+      render->spread = (FT_UInt)val;
+      FT_TRACE7(( "[sdf] sdf_property_set: "
+                  "updated property `spread' to %d\n", val ));
+    }
+    else if ( ft_strcmp( property_name, "flip_sign" ) == 0 )
+    {
+      FT_Int  val = *(const FT_Int*)value;
+
+
+      render->flip_sign = val ? 1 : 0;
+      FT_TRACE7(( "[sdf] sdf_property_set: "
+                  "updated property `flip_sign' to %d\n", val ));
+    }
+    else if ( ft_strcmp( property_name, "flip_y" ) == 0 )
+    {
+      FT_Int  val = *(const FT_Int*)value;
+
+
+      render->flip_y = val ? 1 : 0;
+      FT_TRACE7(( "[sdf] sdf_property_set: "
+                  "updated property `flip_y' to %d\n", val ));
+    }
+    else if ( ft_strcmp( property_name, "overlaps" ) == 0 )
+    {
+      FT_Int  val = *(const FT_Int*)value;
+
+
+      render->overlaps = val;
+      FT_TRACE7(( "[sdf] sdf_property_set: "
+                  "updated property `overlaps' to %d\n", val ));
+    }
+    else
+    {
+      FT_TRACE0(( "[sdf] sdf_property_set: "
+                  "missing property `%s'\n", property_name ));
+      error = FT_THROW( Missing_Property );
+    }
+
+  Exit:
+    return error;
+  }
+
+  /* property getter function */
+  static FT_Error
+  sdf_property_get( FT_Module    module,
+                    const char*  property_name,
+                    void*        value )
+  {
+    FT_Error      error = FT_Err_Ok;
+    SDF_Renderer  render = SDF_RENDERER( FT_RENDERER( module ) );
+
+
+    if ( ft_strcmp( property_name, "spread" ) == 0 )
+    {
+      FT_Int*  val = (FT_Int*)value;
+
+
+      *val = render->spread;
+    }
+    else if ( ft_strcmp( property_name, "flip_sign" ) == 0 )
+    {
+      FT_Int*  val = (FT_Int*)value;
+
+
+      *val = render->flip_sign;
+    }
+    else if ( ft_strcmp( property_name, "flip_y" ) == 0 )
+    {
+      FT_Int*  val = (FT_Int*)value;
+
+
+      *val = render->flip_y;
+    }
+    else if ( ft_strcmp( property_name, "overlaps" ) == 0 )
+    {
+      FT_Int*  val = (FT_Int*)value;
+
+
+      *val = render->overlaps;
+    }
+    else
+    {
+      FT_TRACE0(( "[sdf] sdf_property_get: "
+                  "missing property `%s'\n", property_name ));
+      error = FT_THROW( Missing_Property );
+    }
+
+    return error;
+  }
+
+  FT_DEFINE_SERVICE_PROPERTIESREC(
+    sdf_service_properties,
+
+    (FT_Properties_SetFunc)sdf_property_set,        /* set_property */
+    (FT_Properties_GetFunc)sdf_property_get )       /* get_property */
+
+
+  FT_DEFINE_SERVICEDESCREC1(
+    sdf_services,
+
+    FT_SERVICE_ID_PROPERTIES, &sdf_service_properties )
+
+  static FT_Module_Interface
+  ft_sdf_requester( FT_Renderer  render,
+                    const char*  module_interface )
+  {
+    FT_UNUSED( render );
+
+    return ft_service_list_lookup( sdf_services, module_interface );
+  }
+
+  /**************************************************************************
+   *
+   * interface functions
+   *
+   */
+
+  static FT_Error
+  ft_sdf_init( FT_Renderer  render )
+  {
+    SDF_Renderer  sdf_render = SDF_RENDERER( render );
+
+
+    sdf_render->spread    = DEFAULT_SPREAD;
+    sdf_render->flip_sign = 0;
+    sdf_render->flip_y    = 0;
+    sdf_render->overlaps  = 0;
+
+    return FT_Err_Ok;
+  }
+
+  static FT_Error
+  ft_sdf_done( FT_Renderer  render )
+  {
+    FT_UNUSED( render );
+
+    return FT_Err_Ok;
+  }
+
+  /* generate signed distance field from a glyph's slot image */
+  static FT_Error
+  ft_sdf_render( FT_Renderer       module,
+                 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_Memory    memory  = NULL;
+    FT_Renderer  render  = NULL;
+    FT_Pos       x_shift = 0;
+    FT_Pos       y_shift = 0;
+
+    FT_Pos       x_pad   = 0;
+    FT_Pos       y_pad   = 0;
+
+    SDF_Raster_Params  params;
+    SDF_Renderer       sdf_module = SDF_RENDERER( module );
+
+
+    render = &sdf_module->root;
+    memory = render->root.memory;
+
+    /* check if slot format is correct before rendering */
+    if ( slot->format != render->glyph_format )
+    {
+      error = FT_THROW( Invalid_Glyph_Format );
+      goto Exit;
+    }
+
+    /* check if render mode is correct */
+    if ( mode != FT_RENDER_MODE_SDF )
+    {
+      FT_ERROR(( "[sdf] ft_sdf_render: "
+                 "sdf module only render when "
+                 "using `FT_RENDER_MODE_SDF'\n" ));
+      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;         */
+    /* the sdf bitmap is similar to an antialiased bitmap   */
+    /* with a slightly bigger size and different pixel mode */
+    if ( ft_glyphslot_preset_bitmap( slot, FT_RENDER_MODE_NORMAL, origin ) )
+    {
+      error = FT_THROW( Raster_Overflow );
+      goto Exit;
+    }
+
+    if ( !bitmap->rows || !bitmap->pitch )
+      goto Exit;
+
+    /* the padding will simply be equal to the `spread' */
+    x_pad = sdf_module->spread;
+    y_pad = sdf_module->spread;
+
+    /* apply the padding, will be in all the directions */
+    bitmap->rows  += y_pad * 2;
+    bitmap->width += x_pad * 2;
+
+    /* ignore the pitch, pixel mode and set custom */
+    bitmap->pixel_mode = FT_PIXEL_MODE_GRAY16;
+    bitmap->pitch = bitmap->width * 2;
+    bitmap->num_grays = 65535;
+
+    /* allocate new buffer */
+    if ( FT_ALLOC_MULT( bitmap->buffer, bitmap->rows, bitmap->pitch ) )
+      goto Exit;
+
+    slot->internal->flags |= FT_GLYPH_OWN_BITMAP;
+
+    x_shift  = 64 * -( slot->bitmap_left - x_pad );
+    y_shift  = 64 * -( slot->bitmap_top + y_pad );
+    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.root.target = bitmap;
+    params.root.source = outline;
+    params.root.flags  = FT_RASTER_FLAG_SDF;
+    params.spread      = sdf_module->spread;
+    params.flip_sign   = sdf_module->flip_sign;
+    params.flip_y      = sdf_module->flip_y;
+    params.overlaps    = sdf_module->overlaps;
+
+    /* 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;
+  }
+
+  /* transform the glyph using matrix and/or delta */
+  static FT_Error
+  ft_sdf_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;
+  }
+
+  /* returns the control box of glyph's outline */
+  static void
+  ft_sdf_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 */
+  static FT_Error
+  ft_sdf_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_sdf_renderer_class,
+
+    FT_MODULE_RENDERER,
+    sizeof( SDF_Renderer_Module ),
+
+    "sdf",
+    0x10000L,
+    0x20000L,
+
+    NULL,
+
+    (FT_Module_Constructor) ft_sdf_init,
+    (FT_Module_Destructor)  ft_sdf_done,
+    (FT_Module_Requester)   ft_sdf_requester,
+
+    FT_GLYPH_FORMAT_OUTLINE,
+
+    (FT_Renderer_RenderFunc)    ft_sdf_render,     /* render_glyph    */
+    (FT_Renderer_TransformFunc) ft_sdf_transform,  /* transform_glyph */
+    (FT_Renderer_GetCBoxFunc)   ft_sdf_get_cbox,   /* get_glyph_cbox  */
+    (FT_Renderer_SetModeFunc)   ft_sdf_set_mode,   /* set_mode        */
+
+    (FT_Raster_Funcs*)&ft_sdf_raster               /* raster_class    */
+  )
 
 /* END */