[Git][freetype/freetype][hdmx-advances] 5 commits: [truetype] Relocate subpixel flag setting.

[Alexei Podtelezhnikov (@apodtele)]

Alexei Podtelezhnikov pushed to branch hdmx-advances at FreeType / FreeType

Commits:

• 34fc55de
  by Alexei Podtelezhnikov at 2021-12-10T21:55:08-05:00

  [truetype] Relocate subpixel flag setting.
  
  Eventually, we will use these flags to assess the `hdmx` usability
  prior to the glyph parsing.
  
  * src/truetype/ttinterp.c (TT_RunIns): Move the flag setting to...
  * src/truetype/ttgload.c (tt_loader_init): ...here where it belongs
  and which is executed before each glyph is loaded.
  

• 2e3455b1
  by Alexei Podtelezhnikov at 2021-12-10T22:05:51-05:00

  [truetype] Limit INSTCTRL appication within specs.
  
  * src/truetype/ttinterp.c (Ins_INSTCTRL): Limit its global effects
  to the CVT program and local effects to the glyph program.
  

• fa353701
  by Alexei Podtelezhnikov at 2021-12-10T22:23:56-05:00

  [truetype] Initialize the loader with `hdmx` data.
  
  * include/freetype/internal/tttypes.h (TT_LoaderRec): Add field.
  * src/truetype/ttgload.c (compute_glyph_metrics): Relocate the `hdmx`
  code from here...
  (tt_loader_init): ... to here, before the glyph is loaded.
  

• eaa10b99
  by Alexei Podtelezhnikov at 2021-12-10T22:29:21-05:00

  [truetype] Honor FT_LOAD_ADVANCE_ONLY if `hdmx` is usable.
  
  This simply shortcuts the glyph loading if FT_LOAD_ADVANCE_ONLY
  is specified and the `hdmx` data are located.
  
  * src/truetype/ttgload.c (TT_Load_Glyph): Insert the shortcut.
  

• 0dc811b5
  by Alexei Podtelezhnikov at 2021-12-10T22:32:05-05:00

  [truetype] Binary search through `hdmx` records.
  
  The `hdmx` table is supposed to be sorted by ppem size, which
  enables binary search.  We also drop the check for the sufficient
  length of the record because it is now enforced when the table
  is loaded.
  
  * include/freetype/internal/tttypes.h (TT_FaceRec): Store the `hdmx`
  record pointers sorted by ppem instead of ppem's themselves.
  * src/truetype/ttpload.c (tt_face_load_hdmx): Prudently sort records.
  (tt_face_get_device_metrics): Implement binary search to retrieve
  advances.
  

4 changed files:

• include/freetype/internal/tttypes.h
• src/truetype/ttgload.c
• src/truetype/ttinterp.c
• src/truetype/ttpload.c

Changes:

include/freetype/internal/tttypes.h

---

...	...	@@ -1390,8 +1390,8 @@ FT_BEGIN_HEADER
1390	1390	* hdmx_record_size ::
1391	1391	* The size of a single hdmx record.
1392	1392	*
1393		- * hdmx_record_sizes ::
1394		- * An array holding the ppem sizes available in the 'hdmx' table.
	1393	+ * hdmx_records ::
	1394	+ * A array of pointers to the 'hdmx' table records sorted by ppem.
1395	1395	*
1396	1396	* sbit_table ::
1397	1397	* A pointer to the font's embedded bitmap location table.
...	...	@@ -1605,7 +1605,7 @@ FT_BEGIN_HEADER
1605	1605	FT_ULong hdmx_table_size;
1606	1606	FT_UInt hdmx_record_count;
1607	1607	FT_ULong hdmx_record_size;
1608		- FT_Byte* hdmx_record_sizes;
	1608	+ FT_Byte** hdmx_records;
1609	1609
1610	1610	FT_Byte* sbit_table;
1611	1611	FT_ULong sbit_table_size;
...	...	@@ -1769,6 +1769,9 @@ FT_BEGIN_HEADER
1769	1769	/* since version 2.6.2 */
1770	1770	FT_ListRec composites;
1771	1771
	1772	+ /* since version 2.11.2 */
	1773	+ FT_Byte* widthp;
	1774	+
1772	1775	} TT_LoaderRec;
1773	1776
1774	1777

src/truetype/ttgload.c

---

...	...	@@ -2230,10 +2230,6 @@
2230	2230	FT_UInt glyph_index )
2231	2231	{
2232	2232	TT_Face face = loader->face;
2233		-#if defined TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY || \
2234		- defined TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
2235		- TT_Driver driver = (TT_Driver)FT_FACE_DRIVER( face );
2236		-#endif
2237	2233
2238	2234	FT_BBox bbox;
2239	2235	FT_Fixed y_scale;
...	...	@@ -2256,37 +2252,10 @@
2256	2252
2257	2253	glyph->metrics.horiBearingX = bbox.xMin;
2258	2254	glyph->metrics.horiBearingY = bbox.yMax;
2259		- glyph->metrics.horiAdvance = SUB_LONG(loader->pp2.x, loader->pp1.x);
2260		-
2261		- /* Adjust advance width to the value contained in the hdmx table */
2262		- /* unless FT_LOAD_COMPUTE_METRICS is set or backward compatibility */
2263		- /* mode of the v40 interpreter is active. See `ttinterp.h' for */
2264		- /* details on backward compatibility mode. */
2265		- if ( IS_HINTED( loader->load_flags ) &&
2266		- !( loader->load_flags & FT_LOAD_COMPUTE_METRICS ) &&
2267		-#ifdef TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
2268		- !( driver->interpreter_version == TT_INTERPRETER_VERSION_40 &&
2269		- ( loader->exec && loader->exec->backward_compatibility ) ) &&
2270		-#endif
2271		-#ifdef TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY
2272		- !( driver->interpreter_version == TT_INTERPRETER_VERSION_38 &&
2273		- !SPH_OPTION_BITMAP_WIDTHS &&
2274		- FT_LOAD_TARGET_MODE( loader->load_flags ) !=
2275		- FT_RENDER_MODE_MONO &&
2276		- ( loader->exec && !loader->exec->compatible_widths ) ) &&
2277		-#endif
2278		- !face->postscript.isFixedPitch )
2279		- {
2280		- FT_Byte* widthp;
2281		-
2282		-
2283		- widthp = tt_face_get_device_metrics( face,
2284		- size->metrics->x_ppem,
2285		- glyph_index );
2286		-
2287		- if ( widthp )
2288		- glyph->metrics.horiAdvance = *widthp * 64;
2289		- }
	2255	+ if ( loader->widthp )
	2256	+ glyph->metrics.horiAdvance = loader->widthp[glyph_index] * 64;
	2257	+ else
	2258	+ glyph->metrics.horiAdvance = SUB_LONG(loader->pp2.x, loader->pp1.x);
2290	2259
2291	2260	/* set glyph dimensions */
2292	2261	glyph->metrics.width = SUB_LONG( bbox.xMax, bbox.xMin );
...	...	@@ -2720,11 +2689,64 @@
2720	2689	if ( driver->interpreter_version == TT_INTERPRETER_VERSION_38 &&
2721	2690	exec->GS.instruct_control & 4 )
2722	2691	exec->ignore_x_mode = 0;
2723		-#endif
	2692	+
	2693	+ exec->iup_called = FALSE;
	2694	+#endif /* TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY */
	2695	+
	2696	+#ifdef TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
	2697	+ /*
	2698	+ * Toggle backward compatibility according to what font wants, except
	2699	+ * when
	2700	+ *
	2701	+ * 1) we have a `tricky' font that heavily relies on the interpreter to
	2702	+ * render glyphs correctly, for example DFKai-SB, or
	2703	+ * 2) FT_RENDER_MODE_MONO (i.e, monochome rendering) is requested.
	2704	+ *
	2705	+ * In those cases, backward compatibility needs to be turned off to get
	2706	+ * correct rendering. The rendering is then completely up to the
	2707	+ * font's programming.
	2708	+ *
	2709	+ */
	2710	+ if ( driver->interpreter_version == TT_INTERPRETER_VERSION_38 &&
	2711	+ subpixel_hinting_lean &&
	2712	+ !FT_IS_TRICKY( glyph->face ) )
	2713	+ exec->backward_compatibility = !( exec->GS.instruct_control & 4 );
	2714	+ else
	2715	+ exec->backward_compatibility = FALSE;
	2716	+
	2717	+ exec->iupx_called = FALSE;
	2718	+ exec->iupy_called = FALSE;
	2719	+#endif /* TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL */
2724	2720
2725	2721	exec->pedantic_hinting = FT_BOOL( load_flags & FT_LOAD_PEDANTIC );
2726	2722	loader->exec = exec;
2727	2723	loader->instructions = exec->glyphIns;
	2724	+
	2725	+ /* Use the hdmx table if any unless FT_LOAD_COMPUTE_METRICS */
	2726	+ /* is set or backward compatibility mode of the v38 or v40 */
	2727	+ /* interpreters is active. See `ttinterp.h' for details on */
	2728	+ /* backward compatibility mode. */
	2729	+ if ( IS_HINTED( loader->load_flags ) &&
	2730	+ !( loader->load_flags & FT_LOAD_COMPUTE_METRICS ) &&
	2731	+#ifdef TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
	2732	+ !( driver->interpreter_version == TT_INTERPRETER_VERSION_40 &&
	2733	+ exec->backward_compatibility ) &&
	2734	+#endif
	2735	+#ifdef TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY
	2736	+ !( driver->interpreter_version == TT_INTERPRETER_VERSION_38 &&
	2737	+ !SPH_OPTION_BITMAP_WIDTHS &&
	2738	+ FT_LOAD_TARGET_MODE( loader->load_flags ) !=
	2739	+ FT_RENDER_MODE_MONO &&
	2740	+ exec->compatible_widths ) &&
	2741	+#endif
	2742	+ !face->postscript.isFixedPitch )
	2743	+ {
	2744	+ loader->widthp = tt_face_get_device_metrics( face,
	2745	+ size->metrics->x_ppem,
	2746	+ 0 );
	2747	+ }
	2748	+ else
	2749	+ loader->widthp = NULL;
2728	2750	}
2729	2751
2730	2752	#endif /* TT_USE_BYTECODE_INTERPRETER */
...	...	@@ -2923,6 +2945,15 @@
2923	2945	if ( error )
2924	2946	goto Exit;
2925	2947
	2948	+ /* done if we are only interested in the `hdmx` advance */
	2949	+ if ( load_flags & FT_LOAD_ADVANCE_ONLY &&
	2950	+ !( load_flags & FT_LOAD_VERTICAL_LAYOUT ) &&
	2951	+ loader.widthp )
	2952	+ {
	2953	+ glyph->metrics.horiAdvance = loader.widthp[glyph_index] * 64;
	2954	+ goto Done;
	2955	+ }
	2956	+
2926	2957	glyph->format = FT_GLYPH_FORMAT_OUTLINE;
2927	2958	glyph->num_subglyphs = 0;
2928	2959	glyph->outline.flags = 0;
...	...	@@ -3001,6 +3032,7 @@
3001	3032	glyph->outline.n_points,
3002	3033	glyph->outline.flags ));
3003	3034
	3035	+ Done:
3004	3036	tt_loader_done( &loader );
3005	3037
3006	3038	Exit:

src/truetype/ttinterp.c

---

...	...	@@ -5260,10 +5260,15 @@
5260	5260	}
5261	5261	}
5262	5262
5263		- exc->GS.instruct_control &= ~(FT_Byte)Kf;
5264		- exc->GS.instruct_control |= (FT_Byte)L;
	5263	+ /* INSTCTRL should only be used in the CVT program */
	5264	+ if ( exc->iniRange == tt_coderange_cvt )
	5265	+ {
	5266	+ exc->GS.instruct_control &= ~(FT_Byte)Kf;
	5267	+ exc->GS.instruct_control |= (FT_Byte)L;
	5268	+ }
5265	5269
5266		- if ( K == 3 )
	5270	+ /* except to change the subpixel flags temporarily */
	5271	+ else if ( exc->iniRange == tt_coderange_glyph && K == 3 )
5267	5272	{
5268	5273	#ifdef TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY
5269	5274	/* INSTCTRL modifying flag 3 also has an effect */
...	...	@@ -7755,35 +7760,6 @@
7755	7760	#endif /* TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY */
7756	7761
7757	7762
7758		-#ifdef TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY
7759		- exc->iup_called = FALSE;
7760		-#endif /* TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY */
7761		-
7762		-#ifdef TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
7763		- /*
7764		- * Toggle backward compatibility according to what font wants, except
7765		- * when
7766		- *
7767		- * 1) we have a `tricky' font that heavily relies on the interpreter to
7768		- * render glyphs correctly, for example DFKai-SB, or
7769		- * 2) FT_RENDER_MODE_MONO (i.e, monochome rendering) is requested.
7770		- *
7771		- * In those cases, backward compatibility needs to be turned off to get
7772		- * correct rendering. The rendering is then completely up to the
7773		- * font's programming.
7774		- *
7775		- */
7776		- if ( SUBPIXEL_HINTING_MINIMAL &&
7777		- exc->subpixel_hinting_lean &&
7778		- !FT_IS_TRICKY( &exc->face->root ) )
7779		- exc->backward_compatibility = !( exc->GS.instruct_control & 4 );
7780		- else
7781		- exc->backward_compatibility = FALSE;
7782		-
7783		- exc->iupx_called = FALSE;
7784		- exc->iupy_called = FALSE;
7785		-#endif
7786		-
7787	7763	/* We restrict the number of twilight points to a reasonable, */
7788	7764	/* heuristic value to avoid slow execution of malformed bytecode. */
7789	7765	num_twilight_points = FT_MAX( 30,

src/truetype/ttpload.c

---

...	...	@@ -498,6 +498,14 @@
498	498	}
499	499
500	500
	501	+ FT_COMPARE_DEF( int )
	502	+ compare_ppem( const void* a,
	503	+ const void* b )
	504	+ {
	505	+ return **(FT_Byte**)a - **(FT_Byte**)b;
	506	+ }
	507	+
	508	+
501	509	/**************************************************************************
502	510	*
503	511	* @Function:
...	...	@@ -574,20 +582,21 @@
574	582	goto Fail;
575	583	}
576	584
577		- if ( FT_QNEW_ARRAY( face->hdmx_record_sizes, num_records ) )
	585	+ if ( FT_QNEW_ARRAY( face->hdmx_records, num_records ) )
578	586	goto Fail;
579	587
580		- /* XXX: We do not check if the records are sorted by ppem */
581		- /* and cannot use binary search later. */
582	588	for ( nn = 0; nn < num_records; nn++ )
583	589	{
584	590	if ( p + record_size > limit )
585	591	break;
586		-
587		- face->hdmx_record_sizes[nn] = p[0];
588		- p += record_size;
	592	+ face->hdmx_records[nn] = p;
	593	+ p += record_size;
589	594	}
590	595
	596	+ /* The records must be already sorted by ppem but it does not */
	597	+ /* hurt to make sure so that the binary search works later. */
	598	+ ft_qsort( face->hdmx_records, nn, sizeof ( FT_Byte* ), compare_ppem );
	599	+
591	600	face->hdmx_record_count = nn;
592	601	face->hdmx_table_size = table_size;
593	602	face->hdmx_record_size = record_size;
...	...	@@ -611,7 +620,7 @@
611	620	FT_Memory memory = stream->memory;
612	621
613	622
614		- FT_FREE( face->hdmx_record_sizes );
	623	+ FT_FREE( face->hdmx_records );
615	624	FT_FRAME_RELEASE( face->hdmx_table );
616	625	}
617	626
...	...	@@ -619,27 +628,34 @@
619	628	/**************************************************************************
620	629	*
621	630	* Return the advance width table for a given pixel size if it is found
622		- * in the font's `hdmx' table (if any).
	631	+ * in the font's `hdmx' table (if any). The records must be sorted for
	632	+ * the binary search to work properly.
623	633	*/
624	634	FT_LOCAL_DEF( FT_Byte* )
625	635	tt_face_get_device_metrics( TT_Face face,
626	636	FT_UInt ppem,
627	637	FT_UInt gindex )
628	638	{
629		- FT_UInt nn;
630		- FT_Byte* result = NULL;
631		- FT_ULong record_size = face->hdmx_record_size;
632		- FT_Byte* record = FT_OFFSET( face->hdmx_table, 8 );
	639	+ FT_UInt min = 0;
	640	+ FT_UInt max = face->hdmx_record_count;
	641	+ FT_UInt mid;
	642	+ FT_Byte* result = NULL;
	643	+
633	644
	645	+ while ( min < max )
	646	+ {
	647	+ mid = ( min + max ) >> 1;
634	648
635		- for ( nn = 0; nn < face->hdmx_record_count; nn++ )
636		- if ( face->hdmx_record_sizes[nn] == ppem )
	649	+ if ( face->hdmx_records[mid][0] > ppem )
	650	+ max = mid;
	651	+ else if ( face->hdmx_records[mid][0] < ppem )
	652	+ min = mid + 1;
	653	+ else
637	654	{
638		- gindex += 2;
639		- if ( gindex < record_size )
640		- result = record + nn * record_size + gindex;
	655	+ result = face->hdmx_records[mid] + 2 + gindex;
641	656	break;
642	657	}
	658	+ }
643	659
644	660	return result;
645	661	}

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