[raster] Rearrange dropout control.
This reduces the code duplication. * src/raster/ftraster.c (Function_Sweep_Span): Change signature. (Vertical_Sweep_Drop, Horizontal_Sweep_Drop): Focus on pixel setting and move duplicated the dropout control logic to... (Draw_Sweep): ... this function and refactor. (Vertical_Sweep_Span, Horizontal_Sweep_Span): Minor.
This commit is contained in:
Alexei Podtelezhnikov
parent
d7c72ff919
commit
da8e428977
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@ -401,9 +401,7 @@
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typedef void
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Function_Sweep_Span( RAS_ARGS Int y,
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FT_F26Dot6 x1,
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FT_F26Dot6 x2,
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PProfile left,
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PProfile right );
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FT_F26Dot6 x2 );
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typedef void
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Function_Sweep_Step( RAS_ARG );
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@ -1989,15 +1987,11 @@
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static void
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Vertical_Sweep_Span( RAS_ARGS Int y,
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FT_F26Dot6 x1,
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FT_F26Dot6 x2,
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PProfile left,
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PProfile right )
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FT_F26Dot6 x2 )
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{
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Int e1, e2;
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FT_UNUSED( y );
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FT_UNUSED( left );
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FT_UNUSED( right );
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FT_TRACE7(( " y=%d x=[% .*f;% .*f]",
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@ -2054,137 +2048,38 @@
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static void
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Vertical_Sweep_Drop( RAS_ARGS Int y,
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FT_F26Dot6 x1,
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FT_F26Dot6 x2,
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PProfile left,
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PProfile right )
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FT_F26Dot6 x2 )
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{
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Long e1, e2, pxl;
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Int c1, f1;
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Int e1 = (Int)TRUNC( x1 );
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Int e2 = (Int)TRUNC( x2 );
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Int c1, f1;
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FT_UNUSED( y );
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FT_TRACE7(( " y=%d x=[% .*f;% .*f]",
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y,
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ras.precision_bits, (double)x1 / (double)ras.precision,
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ras.precision_bits, (double)x2 / (double)ras.precision ));
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/* undocumented but confirmed: If the drop-out would result in a */
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/* pixel outside of the bounding box, use the pixel inside of the */
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/* bounding box instead */
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if ( e1 < 0 || e1 > ras.bRight )
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e1 = e2;
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/* Drop-out control */
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/* e2 x2 x1 e1 */
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/* */
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/* ^ | */
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/* | | */
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/* +-------------+---------------------+------------+ */
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/* | | */
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/* | v */
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/* */
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/* pixel contour contour pixel */
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/* center center */
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/* drop-out mode scan conversion rules (OpenType specs) */
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/* ------------------------------------------------------- */
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/* bit 0 exclude stubs if set */
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/* bit 1 ignore drop-outs if set */
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/* bit 2 smart rounding if set */
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e1 = CEILING( x1 );
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e2 = FLOOR ( x2 );
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pxl = e1;
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if ( e1 > e2 )
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/* otherwise check that the other pixel isn't set */
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else if ( e2 >=0 && e2 <= ras.bRight )
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{
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Int dropOutControl = left->flags & 7;
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c1 = (Int)( e2 >> 3 );
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f1 = (Int)( e2 & 7 );
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if ( e1 == e2 + ras.precision )
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{
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/* Drop-out Control Rules #4 and #6 */
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/* The specification neither provides an exact definition */
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/* of a `stub' nor gives exact rules to exclude them. */
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/* */
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/* Here the constraints we use to recognize a stub. */
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/* */
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/* upper stub: */
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/* */
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/* - P_Left and P_Right are in the same contour */
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/* - P_Right is the successor of P_Left in that contour */
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/* - y is the top of P_Left and P_Right */
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/* */
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/* lower stub: */
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/* */
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/* - P_Left and P_Right are in the same contour */
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/* - P_Left is the successor of P_Right in that contour */
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/* - y is the bottom of P_Left */
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/* */
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/* We draw a stub if the following constraints are met. */
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/* */
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/* - for an upper or lower stub, there is top or bottom */
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/* overshoot, respectively */
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/* - the covered interval is greater or equal to a half */
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/* pixel */
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if ( dropOutControl & 1 )
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{
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/* rightmost stub test */
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if ( left->next == right &&
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left->height == 1 &&
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!( left->flags & Overshoot_Top &&
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x2 - x1 >= ras.precision_half ) )
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goto Exit;
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/* leftmost stub test */
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if ( right->next == left &&
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left->offset == 0 &&
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!( left->flags & Overshoot_Bottom &&
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x2 - x1 >= ras.precision_half ) )
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goto Exit;
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}
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if ( dropOutControl & 4 )
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pxl = SMART( x1, x2 );
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else
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pxl = e2;
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/* undocumented but confirmed: If the drop-out would result in a */
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/* pixel outside of the bounding box, use the pixel inside of the */
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/* bounding box instead */
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if ( pxl < 0 )
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pxl = e1;
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else if ( TRUNC( pxl ) > ras.bRight )
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pxl = e2;
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/* check that the other pixel isn't set */
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e1 = ( pxl == e1 ) ? e2 : e1;
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e1 = TRUNC( e1 );
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c1 = (Int)( e1 >> 3 );
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f1 = (Int)( e1 & 7 );
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if ( e1 >= 0 && e1 <= ras.bRight &&
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ras.bLine[c1] & ( 0x80 >> f1 ) )
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goto Exit;
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}
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else
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goto Exit;
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if ( ras.bLine[c1] & ( 0x80 >> f1 ) )
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return;
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}
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e1 = TRUNC( pxl );
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if ( e1 >= 0 && e1 <= ras.bRight )
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{
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FT_TRACE7(( " -> x=%ld", e1 ));
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c1 = (Int)( e1 >> 3 );
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f1 = (Int)( e1 & 7 );
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ras.bLine[c1] |= 0x80 >> f1;
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}
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Exit:
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FT_TRACE7(( " dropout=%d\n", left->flags & 7 ));
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}
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@ -2218,15 +2113,10 @@
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static void
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Horizontal_Sweep_Span( RAS_ARGS Int y,
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FT_F26Dot6 x1,
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FT_F26Dot6 x2,
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PProfile left,
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PProfile right )
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FT_F26Dot6 x2 )
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{
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Long e1, e2;
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FT_UNUSED( left );
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FT_UNUSED( right );
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FT_TRACE7(( " x=%d y=[% .*f;% .*f]",
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y,
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@ -2290,103 +2180,37 @@
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static void
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Horizontal_Sweep_Drop( RAS_ARGS Int y,
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FT_F26Dot6 x1,
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FT_F26Dot6 x2,
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PProfile left,
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PProfile right )
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FT_F26Dot6 x2 )
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{
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Long e1, e2, pxl;
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Int e1 = (Int)TRUNC( x1 );
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Int e2 = (Int)TRUNC( x2 );
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PByte bits;
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Int f1;
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FT_TRACE7(( " x=%d y=[% .*f;% .*f]",
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y,
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ras.precision_bits, (double)x1 / (double)ras.precision,
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ras.precision_bits, (double)x2 / (double)ras.precision ));
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/* undocumented but confirmed: If the drop-out would result in a */
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/* pixel outside of the bounding box, use the pixel inside of the */
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/* bounding box instead */
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if ( e1 < 0 || e1 > ras.bTop )
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e1 = e2;
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/* During the horizontal sweep, we only take care of drop-outs */
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/* e1 + <-- pixel center */
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/* | */
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/* x1 ---+--> <-- contour */
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/* | */
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/* | */
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/* x2 <--+--- <-- contour */
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/* | */
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/* | */
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/* e2 + <-- pixel center */
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e1 = CEILING( x1 );
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e2 = FLOOR ( x2 );
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pxl = e1;
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if ( e1 > e2 )
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/* otherwise check that the other pixel isn't set */
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else if ( e2 >=0 && e2 <= ras.bTop )
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{
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Int dropOutControl = left->flags & 7;
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bits = ras.bOrigin + ( y >> 3 ) - e2 * ras.bPitch;
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f1 = 0x80 >> ( y & 7 );
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if ( e1 == e2 + ras.precision )
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{
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if ( dropOutControl & 1 )
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{
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/* rightmost stub test */
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if ( left->next == right &&
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left->height == 1 &&
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!( left->flags & Overshoot_Top &&
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x2 - x1 >= ras.precision_half ) )
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goto Exit;
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/* leftmost stub test */
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if ( right->next == left &&
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left->offset == 0 &&
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!( left->flags & Overshoot_Bottom &&
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x2 - x1 >= ras.precision_half ) )
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goto Exit;
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}
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if ( dropOutControl & 4 )
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pxl = SMART( x1, x2 );
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else
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pxl = e2;
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/* undocumented but confirmed: If the drop-out would result in a */
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/* pixel outside of the bounding box, use the pixel inside of the */
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/* bounding box instead */
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if ( pxl < 0 )
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pxl = e1;
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else if ( TRUNC( pxl ) > ras.bTop )
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pxl = e2;
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/* check that the other pixel isn't set */
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e1 = ( pxl == e1 ) ? e2 : e1;
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e1 = TRUNC( e1 );
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bits = ras.bOrigin + ( y >> 3 ) - e1 * ras.bPitch;
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f1 = 0x80 >> ( y & 7 );
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if ( e1 >= 0 && e1 <= ras.bTop &&
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*bits & f1 )
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goto Exit;
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}
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else
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goto Exit;
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if ( *bits & f1 )
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return;
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}
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e1 = TRUNC( pxl );
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if ( e1 >= 0 && e1 <= ras.bTop )
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{
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FT_TRACE7(( " -> y=%ld", e1 ));
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bits = ras.bOrigin + ( y >> 3 ) - e1 * ras.bPitch;
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f1 = 0x80 >> ( y & 7 );
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bits[0] |= f1;
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*bits |= f1;
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}
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Exit:
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FT_TRACE7(( " dropout=%d\n", left->flags & 7 ));
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}
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@ -2477,37 +2301,120 @@
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x2 = xs;
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}
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/* if bottom ceiling exceeds top floor, it is a drop-out */
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if ( CEILING( x1 ) > FLOOR( x2 ) )
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if ( CEILING( x1 ) <= FLOOR( x2 ) )
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ras.Proc_Sweep_Span( RAS_VARS y, x1, x2 );
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/* otherwise, bottom ceiling > top floor, it is a drop-out */
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else
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{
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Int dropOutControl = P_Left->flags & 7;
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/* Drop-out control */
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/* e2 x2 x1 e1 */
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/* */
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/* ^ | */
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/* | | */
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/* +-------------+---------------------+------------+ */
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/* | | */
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/* | v */
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/* */
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/* pixel contour contour pixel */
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/* center center */
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/* drop-out mode scan conversion rules (OpenType specs) */
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/* ------------------------------------------------------- */
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/* bit 0 exclude stubs if set */
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/* bit 1 ignore drop-outs if set */
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/* bit 2 smart rounding if set */
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if ( dropOutControl & 2 )
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goto Next_Pair;
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P_Left ->X = x1;
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P_Right->X = x2;
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/* The specification neither provides an exact definition */
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/* of a `stub' nor gives exact rules to exclude them. */
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/* */
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/* Here the constraints we use to recognize a stub. */
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/* */
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/* upper stub: */
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/* */
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/* - P_Left and P_Right are in the same contour */
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/* - P_Right is the successor of P_Left in that contour */
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/* - y is the top of P_Left and P_Right */
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/* */
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/* lower stub: */
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/* */
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/* - P_Left and P_Right are in the same contour */
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/* - P_Left is the successor of P_Right in that contour */
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/* - y is the bottom of P_Left */
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/* */
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/* We draw a stub if the following constraints are met. */
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/* */
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/* - for an upper or lower stub, there is top or bottom */
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/* overshoot, respectively */
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/* - the covered interval is greater or equal to a half */
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/* pixel */
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if ( dropOutControl & 1 )
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{
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/* rightmost stub test */
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if ( P_Left->next == P_Right &&
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P_Left->height == 1 &&
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!( P_Left->flags & Overshoot_Top &&
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x2 - x1 >= ras.precision_half ) )
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goto Next_Pair;
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/* leftmost stub test */
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if ( P_Right->next == P_Left &&
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P_Left->offset == 0 &&
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!( P_Left->flags & Overshoot_Bottom &&
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x2 - x1 >= ras.precision_half ) )
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goto Next_Pair;
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}
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/* select the pixel to set and the other pixel */
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if ( dropOutControl & 4 )
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{
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x2 = SMART( x1, x2 );
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x1 = x1 > x2 ? x2 + ras.precision : x2 - ras.precision;
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}
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else
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{
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x2 = FLOOR ( x2 );
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x1 = CEILING( x1 );
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}
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P_Left ->X = x2;
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P_Right->X = x1;
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/* mark profile for drop-out processing */
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P_Left->flags |= Dropout;
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dropouts++;
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}
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else
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ras.Proc_Sweep_Span( RAS_VARS y, x1, x2, P_Left, P_Right );
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Next_Pair:
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P_Left = P_Left->link;
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P_Right = P_Right->link;
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}
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/* handle drop-outs _after_ the span drawing -- */
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/* drop-out processing has been moved out of the loop */
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/* for performance tuning */
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if ( dropouts > 0 )
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goto Scan_DropOuts;
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/* handle drop-outs _after_ the span drawing */
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P_Left = draw_left;
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P_Right = draw_right;
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Next_Line:
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while ( dropouts && P_Left && P_Right )
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{
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if ( P_Left->flags & Dropout )
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{
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ras.Proc_Sweep_Drop( RAS_VARS y, P_Left->X, P_Right->X );
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P_Left->flags &= ~Dropout;
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dropouts--;
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}
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P_Left = P_Left->link;
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P_Right = P_Right->link;
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}
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ras.Proc_Sweep_Step( RAS_VAR );
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@ -2518,32 +2425,6 @@
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}
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return SUCCESS;
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Scan_DropOuts:
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P_Left = draw_left;
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P_Right = draw_right;
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while ( P_Left && P_Right )
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{
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if ( P_Left->flags & Dropout )
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{
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P_Left->flags &= ~Dropout;
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#if 0
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dropouts--; /* -- this is useful when debugging only */
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#endif
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ras.Proc_Sweep_Drop( RAS_VARS y,
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P_Left->X,
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P_Right->X,
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P_Left,
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P_Right );
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}
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P_Left = P_Left->link;
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P_Right = P_Right->link;
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}
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goto Next_Line;
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}
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