[Git][freetype/freetype-demos][ftmulti-misc] 3 commits: [ftmulti] Enable overlap flag testing.

[Alexei Podtelezhnikov (@apodtele)]

Alexei Podtelezhnikov pushed to branch ftmulti-misc at FreeType / FreeType Demo Programs

Commits:

• 46b5ae2d
  by Alexei Podtelezhnikov at 2023-02-11T18:30:39-05:00

  [ftmulti] Enable overlap flag testing.
  
  Variation fonts often relay on overlapping contours, which require
  oversampling to render properly. FreeType relies on FT_OUTLINE_OVERLAP
  to trigger the expensive mitigation algorithm. This commit enables
  tinkering with the overlap flags and, therefore, the oversampling.
  Normally, the flags should be set by the font designers sparingly.
  
  The bitmap strike toggle is no longer available, which has never
  been important for the variation font testing.
  
  * src/ftmulti.c (Process_Event): Reassign F4 to overlap toggle.
  (Render_Glyph): Tinker with the overlap flags before rendering.
  

• 1833b1d1
  by Alexei Podtelezhnikov at 2023-02-11T20:06:16-05:00

  * src/ftmulti.c (Render_All, Render_Text, main): Layout tweaks.
  

• c2ab3814
  by Alexei Podtelezhnikov at 2023-02-11T20:23:10-05:00

  * src/ftmulti.c (Process_Event): Miscellaneous tweaks.
  
  Set default step at 1/40 which covers most preferable coordinates.
  Adjust the step by doubling or halving it. Round all large-range
  coordinates, not just MM. Wrap the coordinates around.
  

1 changed file:

• src/ftmulti.c

Changes:

src/ftmulti.c

---

...	...	@@ -94,7 +94,7 @@
94	94	static int hinted = 1; /* is glyph hinting active? */
95	95	static int grouping = 1; /* is axis grouping active? */
96	96	static int antialias = 1; /* is anti-aliasing active? */
97		- static int use_sbits = 1; /* do we use embedded bitmaps? */
	97	+ static int overlaps = 0x0; /* flip overlap flags or not? */
98	98	static int Num; /* current first glyph index */
99	99
100	100	static int res = 72;
...	...	@@ -103,8 +103,6 @@
103	103
104	104	static int Fail;
105	105
106		- static int graph_init = 0;
107		-
108	106	static int render_mode = 1;
109	107
110	108	static FT_MM_Var *multimaster = NULL;
...	...	@@ -112,7 +110,7 @@
112	110	static FT_Fixed requested_pos[MAX_MM_AXES];
113	111	static unsigned int requested_cnt = 0;
114	112	static unsigned int used_num_axis = 0;
115		- static int increment = 20; /* for axes */
	113	+ static double increment = 0.025; /* for axes */
116	114
117	115	/*
118	116	* We use the following arrays to support both the display of all axes and
...	...	@@ -305,8 +303,6 @@
305	303	bit = (grBitmap*)surface;
306	304
307	305	fore_color = grFindColor( bit, 255, 255, 255, 255 ); /* white */
308		-
309		- graph_init = 1;
310	306	}
311	307
312	308
...	...	@@ -322,6 +318,10 @@
322	318	/* first, render the glyph image into a bitmap */
323	319	if ( glyph->format != FT_GLYPH_FORMAT_BITMAP )
324	320	{
	321	+ /* overlap flags mitigate AA rendering artifacts in overlaps */
	322	+ /* by oversampling, toggle the flag to test the effect */
	323	+ glyph->outline.flags ^= overlaps;
	324	+
325	325	error = FT_Render_Glyph( glyph, antialias ? FT_RENDER_MODE_NORMAL
326	326	: FT_RENDER_MODE_MONO );
327	327	if ( error )
...	...	@@ -373,14 +373,11 @@
373	373	int flags;
374	374
375	375
376		- flags = FT_LOAD_DEFAULT;
	376	+ flags = FT_LOAD_NO_BITMAP;
377	377
378	378	if ( !hint )
379	379	flags |= FT_LOAD_NO_HINTING;
380	380
381		- if ( !use_sbits )
382		- flags |= FT_LOAD_NO_BITMAP;
383		-
384	381	return FT_Load_Glyph( face, idx, flags );
385	382	}
386	383
...	...	@@ -394,9 +391,8 @@
394	391
395	392
396	393	start_x = 20 * 8;
397		- start_y = pt_size + HEADER_HEIGHT * 3;
398		-
399		- step_y = size->metrics.y_ppem + 10;
	394	+ start_y = size->metrics.y_ppem * 4 / 5 + HEADER_HEIGHT * 3;
	395	+ step_y = size->metrics.y_ppem + 10;
400	396
401	397	x = start_x;
402	398	y = start_y;
...	...	@@ -430,7 +426,7 @@
430	426	x = start_x;
431	427	y += step_y;
432	428
433		- if ( y >= bit->rows )
	429	+ if ( y >= bit->rows - size->metrics.y_ppem / 5 )
434	430	return FT_Err_Ok;
435	431	}
436	432
...	...	@@ -458,9 +454,8 @@
458	454
459	455
460	456	start_x = 20 * 8;
461		- start_y = pt_size + HEADER_HEIGHT * 3;
462		-
463		- step_y = size->metrics.y_ppem + 10;
	457	+ start_y = size->metrics.y_ppem * 4 / 5 + HEADER_HEIGHT * 3;
	458	+ step_y = size->metrics.y_ppem + 10;
464	459
465	460	x = start_x;
466	461	y = start_y;
...	...	@@ -501,7 +496,7 @@
501	496	x = start_x;
502	497	y += step_y;
503	498
504		- if ( y >= bit->rows )
	499	+ if ( y >= bit->rows - size->metrics.y_ppem / 5 )
505	500	return FT_Err_Ok;
506	501	}
507	502	}
...	...	@@ -558,7 +553,7 @@
558	553	grWriteln( "q, ESC quit ftmulti" );
559	554	grWriteln( "F2 toggle axis grouping" );
560	555	grWriteln( "F3 toggle outline hinting" );
561		- grWriteln( "F4 toggle embedded bitmaps" );
	556	+ grWriteln( "F4 toggle overlap flags" );
562	557	grWriteln( "F5 toggle anti-aliasing" );
563	558	grWriteln( "F6 cycle through hinting engines (if available)" );
564	559	grLn();
...	...	@@ -608,7 +603,7 @@
608	603	Process_Event( void )
609	604	{
610	605	grEvent event;
611		- int i;
	606	+ double i;
612	607	unsigned int axis;
613	608
614	609
...	...	@@ -645,10 +640,10 @@
645	640	break;
646	641
647	642	case grKeyF4:
648		- use_sbits = !use_sbits;
649		- new_header = use_sbits
650		- ? "embedded bitmaps are now used if available"
651		- : "embedded bitmaps are now ignored";
	643	+ overlaps ^= FT_OUTLINE_OVERLAP;
	644	+ new_header = overlaps
	645	+ ? "overlap flags are flipped"
	646	+ : "overlap flags are unchanged";
652	647	break;
653	648
654	649	case grKEY( ',' ):
...	...	@@ -687,14 +682,13 @@
687	682	/* MM-related keys */
688	683
689	684	case grKEY( '+' ):
690		- /* value 100 is arbitrary */
691		- if ( increment < 100 )
692		- increment += 1;
	685	+ if ( increment < 0.1 )
	686	+ increment *= 2.0;
693	687	break;
694	688
695	689	case grKEY( '-' ):
696		- if ( increment > 1 )
697		- increment -= 1;
	690	+ if ( increment > 0.01 )
	691	+ increment *= 0.5;
698	692	break;
699	693
700	694	case grKEY( 'a' ):
...	...	@@ -798,7 +792,7 @@
798	792	if ( axis < num_shown_axes )
799	793	{
800	794	FT_Var_Axis* a;
801		- FT_Fixed pos;
	795	+ FT_Fixed pos, rng;
802	796	unsigned int n;
803	797
804	798
...	...	@@ -806,6 +800,7 @@
806	800	axis = (unsigned int)shown_axes[axis];
807	801
808	802	a = multimaster->axis + axis;
	803	+ rng = a->maximum - a->minimum;
809	804	pos = design_pos[axis];
810	805
811	806	/*
...	...	@@ -814,15 +809,15 @@
814	809	* for mac fonts, which have a range of ~3. And it's rather extreme
815	810	* for optical size even in PS.
816	811	*/
817		- pos += FT_MulDiv( i, a->maximum - a->minimum, 1000 );
	812	+ pos += (FT_Fixed)( i * rng );
818	813	if ( pos < a->minimum )
819		- pos = a->minimum;
820		- if ( pos > a->maximum )
821	814	pos = a->maximum;
	815	+ if ( pos > a->maximum )
	816	+ pos = a->minimum;
822	817
823		- /* for MM fonts, round the design coordinates to integers, */
	818	+ /* for MM fonts or large ranges, round the design coordinates */
824	819	/* otherwise round to two decimal digits to make the PS name short */
825		- if ( !FT_IS_SFNT( face ) )
	820	+ if ( !FT_IS_SFNT( face ) || rng > 0x200000 )
826	821	pos = FT_RoundFix( pos );
827	822	else
828	823	{
...	...	@@ -1178,20 +1173,23 @@
1178	1173	grWriteCellString( bit, 0, 2 * HEADER_HEIGHT, Header, fore_color );
1179	1174
1180	1175	strbuf_reset( header );
1181		- strbuf_add( header, "axes:" );
1182		- grWriteCellString( bit, 0, 3 * HEADER_HEIGHT, Header, fore_color );
	1176	+ strbuf_format( header, "axes (\361 %.1f%%):", 100.0 * increment );
	1177	+ grWriteCellString( bit, 0, 4 * HEADER_HEIGHT, Header, fore_color );
1183	1178	for ( n = 0; n < num_shown_axes; n++ )
1184	1179	{
1185	1180	int axis = shown_axes[n];
1186	1181
1187	1182
1188	1183	strbuf_reset( header );
1189		- strbuf_format( header, "%c %.50s%s: %.02f",
	1184	+ strbuf_format( header, "%c %.50s%s:",
1190	1185	n + 'A',
1191	1186	multimaster->axis[axis].name,
1192		- hidden[axis] ? "*" : "",
1193		- design_pos[axis] / 65536.0 );
1194		- grWriteCellString( bit, 0, (int)( n + 4 ) * HEADER_HEIGHT,
	1187	+ hidden[axis] ? "*" : "" );
	1188	+ if ( design_pos[axis] & 0xFFFF )
	1189	+ strbuf_format( header, "% .2f", design_pos[axis] / 65536.0 );
	1190	+ else
	1191	+ strbuf_format( header, "% d", design_pos[axis] / 65536 );
	1192	+ grWriteCellString( bit, 0, (int)( n + 5 ) * HEADER_HEIGHT,
1195	1193	Header, fore_color );
1196	1194	}
1197	1195
...	...	@@ -1224,11 +1222,10 @@
1224	1222	strbuf_reset( header );
1225	1223	strbuf_format(
1226	1224	header,
1227		- "size: %dpt, first glyph: %d, format: %s, axis incr.: %.1f%%",
	1225	+ "size: %dpt, first glyph: %d, format: %s",
1228	1226	ptsize,
1229	1227	Num,
1230		- format_str,
1231		- increment / 10.0 );
	1228	+ format_str );
1232	1229	}
1233	1230	}
1234	1231	else

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