Add fallback font cache to font context.

3 files changed, 118 insertions, 65 deletions

diff --git a/source/fitz/font.c b/source/fitz/font.c
index 792e8d95..a7db05d4 100644
--- a/source/fitz/font.c
+++ b/source/fitz/font.c
@@ -178,12 +178,18 @@ fz_set_font_bbox(fz_context *ctx, fz_font *font, float xmin, float ymin, float x
  * Freetype hooks
  */
 
-struct fz_font_context_s {
+struct fz_font_context_s
+{
 	int ctx_refs;
 	FT_Library ftlib;
 	int ftlib_refs;
 	fz_load_system_font_func load_font;
 	fz_load_system_cjk_font_func load_cjk_font;
+
+	/* Cached fallback fonts */
+	struct { fz_font *serif, *sans; } fallback[256];
+	fz_font *symbol;
+	fz_font *emoji;
 };
 
 #undef __FTERRORS_H__
@@ -216,8 +222,19 @@ fz_keep_font_context(fz_context *ctx)
 
 void fz_drop_font_context(fz_context *ctx)
 {
+	int i;
+
 	if (!ctx)
 		return;
+
+	for (i = 0; i < nelem(ctx->font->fallback); ++i)
+	{
+		fz_drop_font(ctx, ctx->font->fallback[i].serif);
+		fz_drop_font(ctx, ctx->font->fallback[i].sans);
+	}
+	fz_drop_font(ctx, ctx->font->symbol);
+	fz_drop_font(ctx, ctx->font->emoji);
+
 	if (fz_drop_imp(ctx, ctx->font, &ctx->font->ctx_refs))
 		fz_free(ctx, ctx->font);
 }
@@ -266,6 +283,66 @@ fz_font *fz_load_system_cjk_font(fz_context *ctx, const char *name, int ros, int
 	return font;
 }
 
+fz_font *fz_load_fallback_font(fz_context *ctx, int script, int serif, int bold, int italic)
+{
+	unsigned char *data;
+	unsigned int size;
+
+	if (script < 0 || script > nelem(ctx->font->fallback))
+		return NULL;
+
+	/* TODO: bold and italic */
+
+	if (serif)
+	{
+		if (ctx->font->fallback[script].serif)
+			return ctx->font->fallback[script].serif;
+		data = fz_lookup_noto_font(ctx, script, 1, &size);
+		if (data)
+		{
+			ctx->font->fallback[script].serif = fz_new_font_from_memory(ctx, NULL, data, size, 0, 0);
+			return ctx->font->fallback[script].serif;
+		}
+	}
+
+	if (ctx->font->fallback[script].sans)
+		return ctx->font->fallback[script].sans;
+	data = fz_lookup_noto_font(ctx, script, 0, &size);
+	if (data)
+	{
+		ctx->font->fallback[script].sans = fz_new_font_from_memory(ctx, NULL, data, size, 0, 0);
+		return ctx->font->fallback[script].sans;
+	}
+
+	return NULL;
+}
+
+fz_font *fz_load_fallback_symbol_font(fz_context *ctx)
+{
+	unsigned char *data;
+	unsigned int size;
+	if (!ctx->font->symbol)
+	{
+		data = fz_lookup_noto_symbol_font(ctx, &size);
+		if (data)
+			ctx->font->symbol = fz_new_font_from_memory(ctx, NULL, data, size, 0, 0);
+	}
+	return ctx->font->symbol;
+}
+
+fz_font *fz_load_fallback_emoji_font(fz_context *ctx)
+{
+	unsigned char *data;
+	unsigned int size;
+	if (!ctx->font->emoji)
+	{
+		data = fz_lookup_noto_emoji_font(ctx, &size);
+		if (data)
+			ctx->font->emoji = fz_new_font_from_memory(ctx, NULL, data, size, 0, 0);
+	}
+	return ctx->font->emoji;
+}
+
 static const struct ft_error ft_errors[] =
 {
 #include FT_ERRORS_H
@@ -1366,31 +1443,45 @@ fz_encode_character(fz_context *ctx, fz_font *font, int ucs)
 }
 
 int
-fz_encode_character_with_fallback(fz_context *ctx, fz_font *first_font, int ucs, fz_font **out_font)
+fz_encode_character_with_fallback(fz_context *ctx, fz_font *user_font, int unicode, int script, fz_font **out_font)
 {
 	fz_font *font;
+	int gid;
+
+	gid = fz_encode_character(ctx, user_font, unicode);
+	if (gid > 0)
+		return *out_font = user_font, gid;
 
-	for (font = first_font; font; font = font->fallback)
+	if (script == 0)
+		script = ucdn_get_script(unicode);
+
+	font = fz_load_fallback_font(ctx, script, 0, 0, 0);
+	if (font)
 	{
-		int gid = fz_encode_character(ctx, font, ucs);
+		gid = fz_encode_character(ctx, font, unicode);
 		if (gid > 0)
-		{
-			*out_font = font;
-			return gid;
-		}
+			return *out_font = font, gid;
 	}
 
-	ucs = 0x25CF; /* bullet */
-	for (font = first_font; font; font = font->fallback)
+	font = fz_load_fallback_symbol_font(ctx);
+	if (font)
 	{
-		int gid = fz_encode_character(ctx, font, ucs);
+		gid = fz_encode_character(ctx, font, unicode);
 		if (gid > 0)
-		{
-			*out_font = font;
-			return gid;
-		}
+			return *out_font = font, gid;
 	}
 
-	*out_font = first_font;
-	return 0;
+	font = fz_load_fallback_emoji_font(ctx);
+	if (font)
+	{
+		gid = fz_encode_character(ctx, font, unicode);
+		if (gid > 0)
+			return *out_font = font, gid;
+	}
+
+	/* bullet */
+	if (unicode != 0x25CF)
+		return fz_encode_character_with_fallback(ctx, user_font, 0x25CF, UCDN_SCRIPT_LATIN, out_font);
+
+	return *out_font = user_font, 0;
 }
diff --git a/source/html/html-font.c b/source/html/html-font.c
index bca1625e..bb356d6c 100644
--- a/source/html/html-font.c
+++ b/source/html/html-font.c
@@ -8,41 +8,6 @@ static const char *font_names[16] =
 	"Courier", "Courier-Oblique", "Courier-Bold", "Courier-BoldOblique",
 };
 
-static fz_font *
-fz_load_html_fallback_font(fz_context *ctx, fz_html_font_set *set)
-{
-	fz_font *font;
-
-	/* TODO: Use set->fallback[script] instead of font->fallback chain */
-	if (!set->fallback)
-	{
-		unsigned char *data;
-		unsigned int size;
-		int script;
-
-		data = fz_lookup_noto_symbol_font(ctx, &size);
-		if (data)
-		{
-			font = fz_new_font_from_memory(ctx, NULL, data, size, 0, 0);
-			font->fallback = set->fallback;
-			set->fallback = font;
-		}
-
-		for (script = UCDN_SCRIPT_LATIN; script < UCDN_SCRIPT_SIGNWRITING; ++script)
-		{
-			data = fz_lookup_noto_font(ctx, script, 1, &size);
-			if (data)
-			{
-				font = fz_new_font_from_memory(ctx, NULL, data, size, 0, 0);
-				font->fallback = set->fallback;
-				set->fallback = font;
-			}
-		}
-	}
-
-	return set->fallback;
-}
-
 fz_font *
 fz_load_html_builtin_font(fz_context *ctx, fz_html_font_set *set, const char *family, int is_bold, int is_italic)
 {
@@ -58,7 +23,6 @@ fz_load_html_builtin_font(fz_context *ctx, fz_html_font_set *set, const char *fa
 		if (!data)
 			fz_throw(ctx, FZ_ERROR_GENERIC, "cannot load html font: %s", font_names[idx]);
 		set->fonts[idx] = fz_new_font_from_memory(ctx, font_names[idx], data, size, 0, 1);
-		set->fonts[idx]->fallback = fz_load_html_fallback_font(ctx, set);
 	}
 	return set->fonts[idx];
 }
@@ -101,8 +65,6 @@ fz_add_html_font_face(fz_context *ctx, fz_html_font_set *set,
 	custom->is_italic = is_italic;
 	custom->next = set->custom;
 	set->custom = custom;
-
-	font->fallback = fz_load_html_builtin_font(ctx, set, family, is_bold, is_italic);
 }
 
 fz_html_font_set *fz_new_html_font_set(fz_context *ctx)
@@ -128,7 +90,6 @@ void fz_drop_html_font_set(fz_context *ctx, fz_html_font_set *set)
 
 	for (i = 0; i < nelem(set->fonts); ++i)
 		fz_drop_font(ctx, set->fonts[i]);
-	fz_drop_font(ctx, set->fallback);
 
 	fz_free(ctx, set);
 }
diff --git a/source/html/html-layout.c b/source/html/html-layout.c
index 24edc567..3f6fe919 100644
--- a/source/html/html-layout.c
+++ b/source/html/html-layout.c
@@ -553,7 +553,7 @@ static void measure_word(fz_context *ctx, fz_html_flow *node, float em)
 	while (*s)
 	{
 		s += fz_chartorune(&c, s);
-		g = fz_encode_character_with_fallback(ctx, node->style->font, c, &font);
+		g = fz_encode_character_with_fallback(ctx, node->style->font, c, 0, &font);
 		w += fz_advance_glyph(ctx, font, g) * em;
 	}
 	node->w = w;
@@ -931,6 +931,7 @@ static void draw_flow_box(fz_context *ctx, fz_html *box, float page_top, float p
 			/* TODO: reuse text object if color is unchanged */
 			text = fz_new_text(ctx);
 
+
 			trm.e = node->x;
 			trm.f = node->y;
 			s = node->content.text;
@@ -944,7 +945,7 @@ static void draw_flow_box(fz_context *ctx, fz_html *box, float page_top, float p
 					t += fz_chartorune(&c, t);
 					if (node->mirror)
 						c = ucdn_mirror(c);
-					g = fz_encode_character_with_fallback(ctx, node->style->font, c, &font);
+					g = fz_encode_character_with_fallback(ctx, node->style->font, c, 0, &font);
 					w += fz_advance_glyph(ctx, font, g) * node->em;
 				}
 
@@ -954,7 +955,7 @@ static void draw_flow_box(fz_context *ctx, fz_html *box, float page_top, float p
 					s += fz_chartorune(&c, s);
 					if (node->mirror)
 						c = ucdn_mirror(c);
-					g = fz_encode_character_with_fallback(ctx, node->style->font, c, &font);
+					g = fz_encode_character_with_fallback(ctx, node->style->font, c, 0, &font);
 					trm.e -= fz_advance_glyph(ctx, font, g) * node->em;
 					if (node->style->visibility == V_VISIBLE)
 						fz_add_text(ctx, text, font, 0, &trm, g, c);
@@ -966,7 +967,7 @@ static void draw_flow_box(fz_context *ctx, fz_html *box, float page_top, float p
 				while (*s)
 				{
 					s += fz_chartorune(&c, s);
-					g = fz_encode_character_with_fallback(ctx, node->style->font, c, &font);
+					g = fz_encode_character_with_fallback(ctx, node->style->font, c, 0, &font);
 					if (node->style->visibility == V_VISIBLE)
 						fz_add_text(ctx, text, font, 0, &trm, g, c);
 					trm.e += fz_advance_glyph(ctx, font, g) * node->em;
@@ -1154,8 +1155,8 @@ static void draw_list_mark(fz_context *ctx, fz_html *box, float page_top, float
 	while (*s)
 	{
 		s += fz_chartorune(&c, s);
-		g = fz_encode_character_with_fallback(ctx, box->style.font, c, &font);
-		w += fz_advance_glyph(ctx, box->style.font, g) * box->em;
+		g = fz_encode_character_with_fallback(ctx, box->style.font, c, UCDN_SCRIPT_LATIN, &font);
+		w += fz_advance_glyph(ctx, font, g) * box->em;
 	}
 
 	s = buf;
@@ -1164,9 +1165,9 @@ static void draw_list_mark(fz_context *ctx, fz_html *box, float page_top, float
 	while (*s)
 	{
 		s += fz_chartorune(&c, s);
-		g = fz_encode_character(ctx, box->style.font, c);
-		fz_add_text(ctx, text, box->style.font, 0, &trm, g, c);
-		trm.e += fz_advance_glyph(ctx, box->style.font, g) * box->em;
+		g = fz_encode_character_with_fallback(ctx, box->style.font, c, UCDN_SCRIPT_LATIN, &font);
+		fz_add_text(ctx, text, font, 0, &trm, g, c);
+		trm.e += fz_advance_glyph(ctx, font, g) * box->em;
 	}
 
 	color[0] = box->style.color.r / 255.0f;