Allow the user set which style to use for the kerning value.

This are freetype2 options:
 Unfitted - Scaled but un-grid-fitted kerning distances
 Default - Scaled and grid-fitted kerning distances

We always use Unfitted, but the "Default" style give better result here,
so please test and if nobody complain we can set this style as the default.

5 files changed, 37 insertions, 6 deletions

diff --git a/source/blender/blenfont/BLF_api.h b/source/blender/blenfont/BLF_api.h
index 53f108f87eb..99934a80143 100644
--- a/source/blender/blenfont/BLF_api.h
+++ b/source/blender/blenfont/BLF_api.h
@@ -137,6 +137,7 @@ void BLF_dir_free(char **dirs, int count);
 #define BLF_ROTATION (1<<0)
 #define BLF_CLIPPING (1<<1)
 #define BLF_SHADOW (1<<2)
+#define BLF_KERNING_DEFAULT (1<<3)
 
 /* font->mode. */
 #define BLF_MODE_TEXTURE 0
diff --git a/source/blender/blenfont/intern/blf_font.c b/source/blender/blenfont/intern/blf_font.c
index 989746ca501..affc35ea11e 100644
--- a/source/blender/blenfont/intern/blf_font.c
+++ b/source/blender/blenfont/intern/blf_font.c
@@ -102,7 +102,7 @@ void blf_font_draw(FontBLF *font, char *str)
 	FT_Vector delta;
 	FT_UInt glyph_index, g_prev_index;
 	int pen_x, pen_y;
-	int i, has_kerning;
+	int i, has_kerning, st;
 
 	if (!font->glyph_cache)
 		return;
@@ -143,9 +143,13 @@ void blf_font_draw(FontBLF *font, char *str)
 			delta.x= 0;
 			delta.y= 0;
 
-			if (FT_Get_Kerning(font->face, g_prev_index, glyph_index, FT_KERNING_UNFITTED, &delta) == 0) {
+			if (font->flags & BLF_KERNING_DEFAULT)
+				st= FT_Get_Kerning(font->face, g_prev_index, glyph_index, ft_kerning_default, &delta);
+			else
+				st= FT_Get_Kerning(font->face, g_prev_index, glyph_index, FT_KERNING_UNFITTED, &delta);
+
+			if (st == 0)
 				pen_x += delta.x >> 6;
-			}
 		}
 
 		/* do not return this loop if clipped, we want every character tested */
@@ -165,7 +169,7 @@ void blf_font_boundbox(FontBLF *font, char *str, rctf *box)
 	FT_UInt glyph_index, g_prev_index;
 	rctf gbox;
 	int pen_x, pen_y;
-	int i, has_kerning;
+	int i, has_kerning, st;
 
 	if (!font->glyph_cache)
 		return;
@@ -211,9 +215,13 @@ void blf_font_boundbox(FontBLF *font, char *str, rctf *box)
 			delta.x= 0;
 			delta.y= 0;
 
-			if (FT_Get_Kerning(font->face, g_prev_index, glyph_index, FT_KERNING_UNFITTED, &delta) == 0) {
+			if (font->flags & BLF_KERNING_DEFAULT)
+				st= FT_Get_Kerning(font->face, g_prev_index, glyph_index, ft_kerning_default, &delta);
+			else
+				st= FT_Get_Kerning(font->face, g_prev_index, glyph_index, FT_KERNING_UNFITTED, &delta);
+
+			if (st == 0)
 				pen_x += delta.x >> 6;
-			}
 		}
 
 		gbox.xmin= g->box.xmin + pen_x;
diff --git a/source/blender/editors/interface/interface_style.c b/source/blender/editors/interface/interface_style.c
index 83eb8a32701..57f35f71927 100644
--- a/source/blender/editors/interface/interface_style.c
+++ b/source/blender/editors/interface/interface_style.c
@@ -93,6 +93,7 @@ static uiStyle *ui_style_new(ListBase *styles, const char *name)
 
 	style->paneltitle.uifont_id= UIFONT_DEFAULT;
 	style->paneltitle.points= 13;
+	style->paneltitle.kerning= 0;
 	style->paneltitle.shadow= 5;
 	style->paneltitle.shadx= 2;
 	style->paneltitle.shady= -2;
@@ -101,6 +102,7 @@ static uiStyle *ui_style_new(ListBase *styles, const char *name)
 	
 	style->grouplabel.uifont_id= UIFONT_DEFAULT;
 	style->grouplabel.points= 12;
+	style->grouplabel.kerning= 0;
 	style->grouplabel.shadow= 3;
 	style->grouplabel.shadx= 1;
 	style->grouplabel.shady= -1;
@@ -108,6 +110,7 @@ static uiStyle *ui_style_new(ListBase *styles, const char *name)
 	
 	style->widgetlabel.uifont_id= UIFONT_DEFAULT;
 	style->widgetlabel.points= 11;
+	style->widgetlabel.kerning= 0;
 	style->widgetlabel.shadow= 3;
 	style->widgetlabel.shadx= 1;
 	style->widgetlabel.shady= -1;
@@ -116,6 +119,7 @@ static uiStyle *ui_style_new(ListBase *styles, const char *name)
 	
 	style->widget.uifont_id= UIFONT_DEFAULT;
 	style->widget.points= 11;
+	style->widget.kerning= 0;
 	style->widget.shadowalpha= 0.25f;
 
 	style->columnspace= 5;
@@ -169,10 +173,15 @@ void uiStyleFontDraw(uiFontStyle *fs, rcti *rect, char *str)
 		BLF_shadow_offset(fs->shadx, fs->shady);
 	}
 
+	if (fs->kerning == 1)
+		BLF_enable(BLF_KERNING_DEFAULT);
+
 	BLF_draw(str);
 	BLF_disable(BLF_CLIPPING);
 	if (fs->shadow)
 		BLF_disable(BLF_SHADOW);
+	if (fs->kerning == 1)
+		BLF_disable(BLF_KERNING_DEFAULT);
 }
 
 /* ************** helpers ************************ */
diff --git a/source/blender/makesdna/DNA_userdef_types.h b/source/blender/makesdna/DNA_userdef_types.h
index fcb10a33fda..0709d2d58b0 100644
--- a/source/blender/makesdna/DNA_userdef_types.h
+++ b/source/blender/makesdna/DNA_userdef_types.h
@@ -66,6 +66,8 @@ typedef struct uiFont {
 typedef struct uiFontStyle {
 	short uifont_id;		/* saved in file, 0 is default */
 	short points;			/* actual size depends on 'global' dpi */
+	short kerning;			/* unfitted or default kerning value. */
+	char pad[6];
 	short italic, bold;		/* style hint */
 	short shadow;			/* value is amount of pixels blur */
 	short shadx, shady;		/* shadow offset in pixels */
diff --git a/source/blender/makesrna/intern/rna_userdef.c b/source/blender/makesrna/intern/rna_userdef.c
index 03bd0c9cfe2..977c43e6b95 100644
--- a/source/blender/makesrna/intern/rna_userdef.c
+++ b/source/blender/makesrna/intern/rna_userdef.c
@@ -128,6 +128,11 @@ static void rna_def_userdef_theme_ui_font_style(BlenderRNA *brna)
 	StructRNA *srna;
 	PropertyRNA *prop;
 	
+	static EnumPropertyItem font_kerning_style[] = {
+		{0, "UNFITTED", 0, "Unfitted", "Use scaled but un-grid-fitted kerning distances."},
+		{1, "DEFAULT", 0, "Default", "Use scaled and grid-fitted kerning distances."},
+		{0, NULL, 0, NULL, NULL}};
+
 	srna= RNA_def_struct(brna, "ThemeFontStyle", NULL);
 	RNA_def_struct_sdna(srna, "uiFontStyle");
 	RNA_def_struct_ui_text(srna, "Font Style", "Theme settings for Font.");
@@ -137,6 +142,12 @@ static void rna_def_userdef_theme_ui_font_style(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "Points", "");
 	RNA_def_property_update(prop, NC_WINDOW, NULL);
 
+	prop= RNA_def_property(srna, "font_kerning_style", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_sdna(prop, NULL, "kerning");
+	RNA_def_property_enum_items(prop, font_kerning_style);
+	RNA_def_property_ui_text(prop, "Kerning Style", "Which style to use for font kerning.");
+	RNA_def_property_update(prop, NC_WINDOW, NULL);
+
 	prop= RNA_def_property(srna, "shadow", PROP_INT, PROP_NONE);
 	RNA_def_property_range(prop, 0, 5);
 	RNA_def_property_ui_text(prop, "Shadow Size", "Shadow size in pixels (0, 3 and 5 supported)");