[Git][freetype/freetype][master] [raster] Fix linked profiles in contour

Alexei Podtelezhnikov pushed to branch master at FreeType / FreeType

Commits:

3fa5c845

by Alexei Podtelezhnikov (Алексей Подтележников) at 2023-10-17T23:56:23-04:00

[raster] Fix linked profiles in contour loops.

This fixes a subtle bug when the last profile in a contour was not
properly short-circuited if it was still empty at `End_Profile`.
We finalize all linking in `Finalize_Profile_List` now and do nothing
else there.  The turns are added in `End_Profile`.

* src/raster/ftraster.c (Insert_Y_Turn): Moved up unchanged.
(End_Profile): Take care of turns but set only preliminary linking.
(Finalize_Profile_Table): Take care of linking and null-termination.
(Convert_Glyph): Adjusted accordingly.

1 changed file:

src/raster/ftraster.c

Changes:

src/raster/ftraster.c

@@ -591,6 +591,62 @@
+   }
 +  /**************************************************************************
 +   *
 +   * @Function:
 +   *   Insert_Y_Turn
 +   *
 +   * @Description:
 +   *   Insert a salient into the sorted list placed on top of the render
 +   *   pool.
 +   *
 +   * @Input:
 +   *   New y scanline position.
 +   *
 +   * @Return:
 +   *   SUCCESS on success.  FAILURE in case of overflow.
 +   */
 +  static Bool
 +  Insert_Y_Turn( RAS_ARGS Int  y )
 +  {
 +    PLong  y_turns;
 +    Int    n;
++
++
 +    n       = ras.numTurns - 1;
 +    y_turns = ras.sizeBuff - ras.numTurns;
++
 +    /* look for first y value that is <= */
 +    while ( n >= 0 && y < y_turns[n] )
 +      n--;
++
 +    /* if it is <, simply insert it, ignore if == */
 +    if ( n >= 0 && y > y_turns[n] )
 +      do
 +      {
 +        Int  y2 = (Int)y_turns[n];
++
++
 +        y_turns[n] = y;
 +        y = y2;
 +      } while ( --n >= 0 );
++
 +    if ( n < 0 )
 +    {
 +      ras.maxBuff--;
 +      if ( ras.maxBuff <= ras.top )
 +      {
 +        ras.error = FT_THROW( Raster_Overflow );
 +        return FAILURE;
 +      }
 +      ras.numTurns++;
 +      ras.sizeBuff[-ras.numTurns] = y;
 +    }
++
 +    return SUCCESS;
 +  }
++
++
    /**************************************************************************
+    *
     * @Function:
@@ -687,10 +743,10 @@
    static Bool
    End_Profile( RAS_ARGS Bool  overshoot )
+   {
 -    Long  h;
+-
 +    PProfile  p = ras.cProfile;
 +    Long      h = (Long)( ras.top - p->offset );
 +    Int       bottom, top;
 -    h = (Long)( ras.top - ras.cProfile->offset );
      if ( h < 0 )
+     {
@@ -701,82 +757,45 @@
      if ( h > 0 )
+     {
 -      FT_TRACE7(( "  ending profile %p, start = %ld, height = %ld\n",
 -                  (void *)ras.cProfile, ras.cProfile->start, h ));
 +      FT_TRACE7(( "  ending profile %p, start = %2ld, height = %+3ld\n",
 +                  (void *)p, p->start, p->flags & Flow_Up ? h : -h ));
 -      ras.cProfile->height = h;
        if ( overshoot )
+       {
 -        if ( ras.cProfile->flags & Flow_Up )
 -          ras.cProfile->flags |= Overshoot_Top;
 +        if ( p->flags & Flow_Up )
 +          p->flags |= Overshoot_Top;
          else
 -          ras.cProfile->flags |= Overshoot_Bottom;
 +          p->flags |= Overshoot_Bottom;
+       }
 -      /* premature, the last profile in the contour must loop */
 -      ras.cProfile->next = (PProfile)ras.top;
+-
 -      ras.num_Profs++;
 -    }
+-
 -    ras.joint = FALSE;
+-
 -    return SUCCESS;
 -  }
+-
 +      p->height = h;
 -  /**************************************************************************
 -   *
 -   * @Function:
 -   *   Insert_Y_Turn
 -   *
 -   * @Description:
 -   *   Insert a salient into the sorted list placed on top of the render
 -   *   pool.
 -   *
 -   * @Input:
 -   *   New y scanline position.
 -   *
 -   * @Return:
 -   *   SUCCESS on success.  FAILURE in case of overflow.
 -   */
 -  static Bool
 -  Insert_Y_Turn( RAS_ARGS Int  y )
 -  {
 -    PLong  y_turns;
 -    Int    n;
+-
+-
 -    n       = ras.numTurns - 1;
 -    y_turns = ras.sizeBuff - ras.numTurns;
+-
 -    /* look for first y value that is <= */
 -    while ( n >= 0 && y < y_turns[n] )
 -      n--;
+-
 -    /* if it is <, simply insert it, ignore if == */
 -    if ( n >= 0 && y > y_turns[n] )
 -      do
 +      if ( p->flags & Flow_Up )
+       {
 -        Int  y2 = (Int)y_turns[n];
 +        bottom = (Int)p->start;
 +        top    = (Int)( p->start + h - 1 );
 +      }
 +      else
 +      {
 +        bottom     = (Int)( p->start - h + 1 );
 +        top        = (Int)p->start;
 +        p->start   = bottom;
 +        p->offset += h - 1;
 +      }
 +      if ( Insert_Y_Turn( RAS_VARS bottom )  ||
 +           Insert_Y_Turn( RAS_VARS top + 1 ) )
 +        return FAILURE;
 -        y_turns[n] = y;
 -        y = y2;
 -      } while ( --n >= 0 );
 +      /* preliminary values to be finalized */
 +      p->link = (PProfile)ras.top;
 +      p->next = ras.gProfile;
 -    if ( n < 0 )
 -    {
 -      ras.maxBuff--;
 -      if ( ras.maxBuff <= ras.top )
 -      {
 -        ras.error = FT_THROW( Raster_Overflow );
 -        return FAILURE;
 -      }
 -      ras.numTurns++;
 -      ras.sizeBuff[-ras.numTurns] = y;
 +      ras.num_Profs++;
+     }
 +    ras.joint = FALSE;
++
      return SUCCESS;
+   }
@@ -788,56 +807,28 @@
+    *
     * @Description:
     *   Adjust all links in the profiles list.
 -   *
 -   * @Return:
 -   *   SUCCESS on success.  FAILURE in case of overflow.
     */
 -  static Bool
 +  static void
    Finalize_Profile_Table( RAS_ARG )
+   {
 -    UShort    n;
 -    PProfile  p;
+-
 +    UShort    n = ras.num_Profs;
 +    PProfile  p = ras.fProfile;
 +    PProfile  q;
 -    n = ras.num_Profs;
 -    p = ras.fProfile;
 -    if ( n > 1 && p )
 +    while ( --n )
+     {
 -      do
 -      {
 -        Int  bottom, top;
+-
+-
 -        if ( n > 1 )
 -          p->link = (PProfile)( p->offset + p->height );
 -        else
 -          p->link = NULL;
+-
 -        if ( p->flags & Flow_Up )
 -        {
 -          bottom = (Int)p->start;
 -          top    = (Int)( p->start + p->height - 1 );
 -        }
 -        else
 -        {
 -          bottom     = (Int)( p->start - p->height + 1 );
 -          top        = (Int)p->start;
 -          p->start   = bottom;
 -          p->offset += p->height - 1;
 -        }
 +      q = p->link;
 -        if ( Insert_Y_Turn( RAS_VARS bottom )  ||
 -             Insert_Y_Turn( RAS_VARS top + 1 ) )
 -          return FAILURE;
 +      /* fix the contour loop */
 +      if ( q->next == p->next )
 +        p->next = q;
 -        p = p->link;
 -      } while ( --n );
 +      p = q;
+     }
 -    else
 -      ras.fProfile = NULL;
 -    return SUCCESS;
 +    /* null-terminate */
 +    p->link = NULL;
+   }
@@ -2001,17 +1992,14 @@
        if ( End_Profile( RAS_VARS o ) )
          return FAILURE;
 -      /* loop the last profile in the contour */
 -      ras.cProfile->next = ras.gProfile;
+-
 -      if ( !ras.fProfile )
 +      if ( !ras.fProfile && ras.num_Profs )
          ras.fProfile = ras.gProfile;
+     }
 -    if ( Finalize_Profile_Table( RAS_VAR ) )
 -      return FAILURE;
 +    if ( ras.num_Profs )
 +      Finalize_Profile_Table( RAS_VAR );
 -    return (Bool)( ras.top < ras.maxBuff ? SUCCESS : FAILURE );
 +    return SUCCESS;
+   }

From:	Alexei Podtelezhnikov (@apodtele)
Subject:	[Git][freetype/freetype][master] [raster] Fix linked profiles in contour loops.
Date:	Wed, 18 Oct 2023 04:16:54 +0000