[Git][freetype/freetype][master] [raster] Keep only bottom y-turns.

Alexei Podtelezhnikov pushed to branch master at FreeType / FreeType

Commits:

050a3207

by Alexei Podtelezhnikov (Алексей Подтележников) at 2023-11-15T23:41:56-05:00

[raster] Keep only bottom y-turns.

This results in noticeable performance improvement.

* src/raster/ftraster.c (Insert_Y_Turns): All bottom y-turns are still
sorted and stored; only the maximum top y-turn is recorded now. The
function is renamed.
(End_Profile): Updated accordingly.
(Convert_Glyph): Reserve space for the top value.

1 changed file:

src/raster/ftraster.c

Changes:

src/raster/ftraster.c

@@ -116,8 +116,8 @@
     *   generated until the end of the outline.
+    *
     *   Note that, for all generated profiles, the function End_Profile()
 -   *   is used to record their bottom-most scanline as well as the
 -   *   scanline above its upmost boundary.  These positions are called
 +   *   is used to record all their bottom-most scanlines as well as the
 +   *   scanline above their upmost boundary.  These positions are called
     *   `y-turns' because they (sort of) correspond to local extrema.
     *   They are stored in a sorted list built from the top of the render
     *   pool as a downwards stack:
@@ -579,12 +579,17 @@
     *   SUCCESS on success.  FAILURE in case of overflow.
     */
    static Bool
 -  Insert_Y_Turn( RAS_ARGS Int  y )
 +  Insert_Y_Turns( RAS_ARGS Int  y,
 +                           Int  top )
+   {
      Int    n       = ras.numTurns;
      PLong  y_turns = ras.maxBuff;
 +    /* update top value */
 +    if ( n == 0 || top > y_turns[n] )
 +      y_turns[n] = top;
++
      /* look for first y value that is <= */
      while ( n-- && y < y_turns[n] )
+       ;
@@ -751,8 +756,7 @@
          p->X      = p->x[h - 1];
+       }
 -      if ( Insert_Y_Turn( RAS_VARS bottom ) ||
 -           Insert_Y_Turn( RAS_VARS top )    )
 +      if ( Insert_Y_Turns( RAS_VARS bottom, top ) )
          return FAILURE;
        if ( !ras.gProfile )
@@ -1820,7 +1824,7 @@
      ras.cProfile = NULL;
      ras.top      = ras.buff;
 -    ras.maxBuff  = ras.sizeBuff;
 +    ras.maxBuff  = ras.sizeBuff - 1;  /* top reserve */
      ras.numTurns  = 0;
      ras.num_Profs = 0;

From:	Alexei Podtelezhnikov (@apodtele)
Subject:	[Git][freetype/freetype][master] [raster] Keep only bottom y-turns.
Date:	Thu, 16 Nov 2023 04:44:19 +0000