Smal tweak to allow the user set a kerning value.

This commit add two option to the blenfont library:

1) BLF_FONT_KERNING

 This enable the kerning information that come with the
font, by default this option is disable and still don't
have a UI for change.

2) BLF USER_KERNING
 This allow the user set a kerning value to by apply for
every character, by default this option is enable but all
the font have a kerning value of zero.

Ton I add this option to the style with a default value of 1.

Access from:
 Outliner -> User Preferences -> Style -> FontStyle -> Kerning

5 files changed, 55 insertions, 8 deletions

diff --git a/source/blender/blenfont/BLF_api.h b/source/blender/blenfont/BLF_api.h
index b5a61f2727f..d1d802622ea 100644
--- a/source/blender/blenfont/BLF_api.h
+++ b/source/blender/blenfont/BLF_api.h
@@ -85,7 +85,7 @@ float BLF_height_default(char *str);
 void BLF_rotation(float angle);
 void BLF_clipping(float xmin, float ymin, float xmax, float ymax);
 void BLF_blur(int size);
-
+void BLF_kerning(int space);
 
 void BLF_enable(int option);
 void BLF_disable(int option);
@@ -117,6 +117,8 @@ void BLF_dir_free(char **dirs, int count);
 /* font->flags. */
 #define BLF_ROTATION (1<<0)
 #define BLF_CLIPPING (1<<1)
+#define BLF_FONT_KERNING (1<<2)
+#define BLF_USER_KERNING (1<<3)
 
 /* font->mode. */
 #define BLF_MODE_TEXTURE 0
diff --git a/source/blender/blenfont/intern/blf.c b/source/blender/blenfont/intern/blf.c
index 14bc6a33b72..ffb845f7888 100644
--- a/source/blender/blenfont/intern/blf.c
+++ b/source/blender/blenfont/intern/blf.c
@@ -491,3 +491,12 @@ void BLF_mode(int mode)
 	if (font)
 		font->mode= mode;
 }
+
+void BLF_kerning(int space)
+{
+	FontBLF *font;
+
+	font= global_font[global_font_cur];
+	if (font)
+		font->kerning= space;
+}
diff --git a/source/blender/blenfont/intern/blf_font.c b/source/blender/blenfont/intern/blf_font.c
index 1a96dbc13bc..df77aee70e8 100644
--- a/source/blender/blenfont/intern/blf_font.c
+++ b/source/blender/blenfont/intern/blf_font.c
@@ -100,7 +100,7 @@ void blf_font_draw(FontBLF *font, char *str)
 	GlyphBLF *g, *g_prev;
 	FT_Vector delta;
 	FT_UInt glyph_index, g_prev_index;
-	int pen_x, pen_y;
+	int pen_x, pen_y, old_pen_x;
 	int i, has_kerning;
 
 	if (!font->glyph_cache)
@@ -138,12 +138,24 @@ void blf_font_draw(FontBLF *font, char *str)
 		else if (font->mode == BLF_MODE_TEXTURE && (!g->tex_data))
 			g= blf_glyph_add(font, glyph_index, c);
 
-		if (has_kerning && g_prev) {
+		if ((font->flags & BLF_FONT_KERNING) && has_kerning && g_prev) {
+			old_pen_x= pen_x;
 			delta.x= 0;
 			delta.y= 0;
 
 			FT_Get_Kerning(font->face, g_prev_index, glyph_index, FT_KERNING_UNFITTED, &delta);
 			pen_x += delta.x >> 6;
+
+			if (pen_x < old_pen_x)
+				pen_x= old_pen_x;
+		}
+
+		if (font->flags & BLF_USER_KERNING) {
+			old_pen_x= pen_x;
+			pen_x += font->kerning;
+
+			if (pen_x < old_pen_x)
+				pen_x= old_pen_x;
 		}
 
 		/* do not return this loop if clipped, we want every character tested */
@@ -162,7 +174,7 @@ void blf_font_boundbox(FontBLF *font, char *str, rctf *box)
 	FT_Vector delta;
 	FT_UInt glyph_index, g_prev_index;
 	rctf gbox;
-	int pen_x, pen_y;
+	int pen_x, pen_y, old_pen_x;
 	int i, has_kerning;
 
 	if (!font->glyph_cache)
@@ -205,12 +217,24 @@ void blf_font_boundbox(FontBLF *font, char *str, rctf *box)
 		else if (font->mode == BLF_MODE_TEXTURE && (!g->tex_data))
 			g= blf_glyph_add(font, glyph_index, c);
 
-		if (has_kerning && g_prev) {
+		if ((font->flags & BLF_FONT_KERNING) && has_kerning && g_prev) {
+			old_pen_x= pen_x;
 			delta.x= 0;
 			delta.y= 0;
 
 			FT_Get_Kerning(font->face, g_prev_index, glyph_index, FT_KERNING_UNFITTED, &delta);
 			pen_x += delta.x >> 6;
+
+			if (pen_x < old_pen_x)
+				old_pen_x= pen_x;
+		}
+
+		if (font->flags & BLF_USER_KERNING) {
+			old_pen_x= pen_x;
+			pen_x += font->kerning;
+
+			if (pen_x < old_pen_x)
+				old_pen_x= pen_x;
 		}
 
 		gbox.xmin= g->box.xmin + pen_x;
@@ -294,9 +318,10 @@ void blf_font_fill(FontBLF *font)
 	font->clip_rec.xmax= 0.0f;
 	font->clip_rec.ymin= 0.0f;
 	font->clip_rec.ymax= 0.0f;
-	font->flags= 0;
+	font->flags= BLF_USER_KERNING;
 	font->dpi= 0;
 	font->size= 0;
+	font->kerning= 0;
 	font->cache.first= NULL;
 	font->cache.last= NULL;
 	font->glyph_cache= NULL;
diff --git a/source/blender/blenfont/intern/blf_glyph.c b/source/blender/blenfont/intern/blf_glyph.c
index 142d2145ab2..33a435cc5be 100644
--- a/source/blender/blenfont/intern/blf_glyph.c
+++ b/source/blender/blenfont/intern/blf_glyph.c
@@ -213,7 +213,11 @@ GlyphBLF *blf_glyph_texture_add(FontBLF *font, FT_UInt index, unsigned int c)
 	else
 		do_new= 1;
 
-	err= FT_Load_Glyph(font->face, index, FT_LOAD_NO_HINTING | FT_LOAD_NO_BITMAP);
+	if (font->flags & BLF_FONT_KERNING)
+		err= FT_Load_Glyph(font->face, index, FT_LOAD_NO_BITMAP);
+	else
+		err= FT_Load_Glyph(font->face, index, FT_LOAD_NO_HINTING | FT_LOAD_NO_BITMAP);
+
 	if (err)
 		return(NULL);
 
@@ -328,7 +332,11 @@ GlyphBLF *blf_glyph_bitmap_add(FontBLF *font, FT_UInt index, unsigned int c)
 	else
 		do_new= 1;
 
-	err= FT_Load_Glyph(font->face, index, FT_LOAD_NO_HINTING | FT_LOAD_NO_BITMAP);
+	if (font->flags & BLF_FONT_KERNING)
+		err= FT_Load_Glyph(font->face, index, FT_LOAD_NO_BITMAP);
+	else
+		err= FT_Load_Glyph(font->face, index, FT_LOAD_NO_HINTING | FT_LOAD_NO_BITMAP);
+
 	if (err)
 		return(NULL);
 
diff --git a/source/blender/blenfont/intern/blf_internal_types.h b/source/blender/blenfont/intern/blf_internal_types.h
index 1c55499b568..d200d910020 100644
--- a/source/blender/blenfont/intern/blf_internal_types.h
+++ b/source/blender/blenfont/intern/blf_internal_types.h
@@ -167,6 +167,9 @@ typedef struct FontBLF {
 	/* font size. */
 	int size;
 
+	/* kerning space, user setting. */
+	int kerning;
+
 	/* max texture size. */
 	int max_tex_size;