font fallbacks

5 files changed, 113 insertions, 54 deletions

diff --git a/buffer.c b/buffer.c
index 3ca57f9..5cf1820 100644
--- a/buffer.c
+++ b/buffer.c
@@ -956,8 +956,14 @@ bool buffer_pixels_to_pos(TextBuffer *buffer, vec2 pixel_coords, BufferPos *pos)
 	x -= buffer->x1;
 	y -= buffer->y1;
 	
-	x = clampd(x, 0, buffer->x2 - buffer->x1);
-	y = clampd(y, 0, buffer->y2 - buffer->y1);
+	double buffer_width = buffer->x2 - buffer->x1;
+	double buffer_height = buffer->y2 - buffer->y1;
+	
+	if (x < 0 || y < 0 || x >= buffer_width || y >= buffer_height)
+		ret = false;
+	
+	x = clampd(x, 0, buffer_width);
+	y = clampd(y, 0, buffer_height);
 	
 	double xoff = x + buffer->scroll_x * text_font_char_width(font, ' ');
 	
diff --git a/session.c b/session.c
index 8860cd1..af55eba 100644
--- a/session.c
+++ b/session.c
@@ -116,7 +116,7 @@ static char read_char(FILE *fp) {
 }
 
 static bool read_bool(FILE *fp) {
-	return (bool)getc(fp);
+	return getc(fp) != 0;
 }
 
 static void write_cstr(FILE *fp, const char *cstr) {
@@ -244,6 +244,12 @@ static void session_read_buffer(Ted *ted, FILE *fp) {
 		buffer->selection = read_bool(fp);
 		if (buffer->selection)
 			buffer->selection_pos = buffer_pos_read(buffer, fp);
+		buffer_pos_validate(buffer, &buffer->cursor_pos);
+		buffer_pos_validate(buffer, &buffer->selection_pos);
+		if (buffer->selection && buffer_pos_eq(buffer->cursor_pos, buffer->selection_pos)) {
+			// this could happen if the file was changed on disk
+			buffer->selection = false;
+		}
 	}
 }
 
diff --git a/ted.c b/ted.c
index 19d360c..1eec19c 100644
--- a/ted.c
+++ b/ted.c
@@ -313,7 +313,8 @@ static Font *ted_load_single_font(Ted *ted, const char *filename) {
 
 static Font *ted_load_multifont(Ted *ted, const char *filenames) {
 	char filename[TED_PATH_MAX];
-	Font *font = NULL;
+	Font *first_font = NULL;
+	Font *curr_font = NULL;
 	
 	while (*filenames) {
 		while (*filenames == ',') ++filenames;
@@ -321,12 +322,17 @@ static Font *ted_load_multifont(Ted *ted, const char *filenames) {
 		strn_cpy(filename, sizeof filename, filenames, len);
 		str_trim(filename);
 		if (*filename) {
-			font = ted_load_single_font(ted, filename);
+			Font *font = ted_load_single_font(ted, filename);
+			if (!first_font)
+				first_font = font;
+			if (curr_font)
+				text_font_set_fallback(curr_font, font);
+			curr_font = font;
 		}
 		filenames += len;
 	}
 	
-	return font;
+	return first_font;
 }
 
 void ted_load_fonts(Ted *ted) {
diff --git a/text.c b/text.c
index 9d161c4..29d1831 100644
--- a/text.c
+++ b/text.c
@@ -26,9 +26,9 @@ typedef struct {
 
 typedef struct {
 	char32_t c;
+	bool defined;
 	u32 texture;
 	stbtt_packedchar data;
-	bool defined; // whether this character is actually defined in the font file
 } CharInfo;
 
 // characters are split into this many "buckets" according to
@@ -56,6 +56,7 @@ struct Font {
 	CharInfo *char_info[CHAR_BUCKET_COUNT]; // each entry is a dynamic array of char info
 	// TTF data (i.e. the contents of the TTF file)
 	u8 *ttf_data;
+	Font *fallback;
 };
 
 const TextRenderState text_render_state_default = {
@@ -90,6 +91,10 @@ static void text_set_err(const char *fmt, ...) {
 	}
 }
 
+void text_font_set_fallback(Font *font, Font *fallback) {
+	font->fallback = fallback;
+}
+
 static GLuint text_program;
 static GLuint text_vbo, text_vao;
 static GLuint text_v_pos, text_v_color, text_v_tex_coord;
@@ -137,7 +142,6 @@ static u32 char_bucket_index(char32_t c) {
 
 
 static FontTexture *font_new_texture(Font *font) {
-	debug_println("Create new texture for font %p", (void *)font);
 	PROFILE_TIME(start);
 	unsigned char *pixels = calloc(FONT_TEXTURE_WIDTH, FONT_TEXTURE_HEIGHT);
 	if (!pixels) {
@@ -183,7 +187,9 @@ static void font_texture_free(FontTexture *texture) {
 	memset(texture, 0, sizeof *texture);
 }
 
-// on success, *info is filled out
+// on success, *info is filled out.
+// success includes cases where c is not defined by the font so a substitute character is used.
+// failure only indicates something very bad.
 static Status text_load_char(Font *font, char32_t c, CharInfo *info) {
 	u32 bucket = char_bucket_index(c);
 	arr_foreach_ptr(font->char_info[bucket], CharInfo, i) {
@@ -195,51 +201,57 @@ static Status text_load_char(Font *font, char32_t c, CharInfo *info) {
 	}
 	
 	glGetError(); // clear error
+	memset(info, 0, sizeof *info);
 	
 	if (c != UNICODE_BOX_CHARACTER && stbtt_FindGlyphIndex(&font->stb_info, (int)c) == 0) {
-		// this code point is not defined by the font — use the box character
-		printf("Using box character for U+%04X\n",c);
+		// this code point is not defined by the font
+		
+		// use the box character
 		if (!text_load_char(font, UNICODE_BOX_CHARACTER, info))
 			return false;
 		info->c = c;
 		info->defined = false;
-	} else {
-		info->defined = true;
-		if (!font->textures) {
-			if (!font_new_texture(font))
-				return false;
-		}
-		
-		int success = 0;
-		FontTexture *texture = arr_lastp(font->textures);
-		for (int i = 0; i < 2; i++) {
-			info->c = c;
-			info->texture = arr_len(font->textures) - 1;
-			success = stbtt_PackFontRange(&texture->pack_context, font->ttf_data, 0, font->char_height,
-				(int)c, 1, &info->data);
-			if (success) break;
-			// texture is full; create a new one
-			stbtt_PackEnd(&texture->pack_context);
-			font_texture_update_if_needed(texture);
-			free(texture->pixels);
-			texture->pixels = NULL;
-			texture = font_new_texture(font);
-			if (!texture)
-				return false;
-		}
-		
-		if (!success) {
-			// a brand new texture couldn't fit the character.
-			// something has gone horribly wrong.
-			font_texture_free(texture);
-			arr_remove_last(font->textures);
-			text_set_err("Error rasterizing character %lc", (wchar_t)c);
+		arr_add(font->char_info[bucket], *info);
+		return true;
+	}
+
+	info->defined = true;
+
+	if (!font->textures) {
+		if (!font_new_texture(font))
 			return false;
-		}
-		
-		texture->needs_update = true;
 	}
 	
+	int success = 0;
+	FontTexture *texture = arr_lastp(font->textures);
+	for (int i = 0; i < 2; i++) {
+		info->c = c;
+		info->texture = arr_len(font->textures) - 1;
+		success = stbtt_PackFontRange(&texture->pack_context, font->ttf_data, 0, font->char_height,
+			(int)c, 1, &info->data);
+		if (success) break;
+		// texture is full; create a new one
+		stbtt_PackEnd(&texture->pack_context);
+		font_texture_update_if_needed(texture);
+		free(texture->pixels);
+		texture->pixels = NULL;
+		debug_println("Create new texture for font %p (triggered by U+%04X)", (void *)font, c);
+		texture = font_new_texture(font);
+		if (!texture)
+			return false;
+	}
+	
+	if (!success) {
+		// a brand new texture couldn't fit the character.
+		// something has gone horribly wrong.
+		font_texture_free(texture);
+		arr_remove_last(font->textures);
+		text_set_err("Error rasterizing character %lc", (wchar_t)c);
+		return false;
+	}
+	
+	texture->needs_update = true;
+	
 	arr_add(font->char_info[bucket], *info);
 	return true;
 }
@@ -306,10 +318,13 @@ float text_font_char_height(Font *font) {
 
 float text_font_char_width(Font *font, char32_t c) {
 	CharInfo info = {0};
-	if (text_load_char(font, c, &info))
+	if (text_load_char(font, c, &info)) {
+		if (!info.defined && font->fallback)
+			return text_font_char_width(font->fallback, c);
 		return info.data.xadvance;
-	else
+	} else {
 		return 0;
+	}
 }
 
 void text_render(Font *font) {
@@ -336,6 +351,10 @@ void text_render(Font *font) {
 		glDrawArrays(GL_TRIANGLES, 0, (GLsizei)(3 * ntriangles));
 		arr_clear(texture->triangles);
 	}
+	
+	if (font->fallback) {
+		text_render(font->fallback);
+	}
 }
 
 void text_char_with_state(Font *font, TextRenderState *state, char32_t c) {
@@ -352,6 +371,13 @@ top:
 
 	if (!text_load_char(font, c, &info))
 		return;
+	
+	if (!info.defined && font->fallback) {
+		text_char_with_state(font->fallback, state, c);
+		return;
+	}
+	
+	
 	const float char_height = font->char_height;
 	
 	stbtt_aligned_quad q = {0};
@@ -513,12 +539,6 @@ void text_get_size32(Font *font, const char32_t *text, u64 len, float *width, fl
 	if (height) *height = (float)render_state.y + font->char_height * (2/3.0f);
 }
 
-static void font_free_textures(Font *font) {
-	arr_foreach_ptr(font->textures, FontTexture, texture) {
-		font_texture_free(texture);
-	}
-	arr_clear(font->textures);
-}
 
 static void font_free_char_info(Font *font) {
 	for (u32 i = 0; i < CHAR_BUCKET_COUNT; i++) {
@@ -526,10 +546,19 @@ static void font_free_char_info(Font *font) {
 	}
 }
 
+static void font_free_textures(Font *font) {
+	arr_foreach_ptr(font->textures, FontTexture, texture) {
+		font_texture_free(texture);
+	}
+	arr_clear(font->textures);
+}
+
 void text_font_change_size(Font *font, float new_size) {
 	font_free_textures(font);
 	font_free_char_info(font);
 	font->char_height = new_size;
+	if (font->fallback)
+		text_font_change_size(font->fallback, new_size);
 }
 
 void text_font_free(Font *font) {
diff --git a/text.h b/text.h
index 79f99ad..8d317e8 100644
--- a/text.h
+++ b/text.h
@@ -68,7 +68,15 @@ const char *text_get_err(void);
 void text_clear_err(void);
 /// Load a TTF font found in ttf_filename with the given font size (character pixel height)
 Font *text_font_load(const char *ttf_filename, float font_size);
-/// Change size of font. Avoid calling this function too often, since all font textures are trashed.
+/// Set a fallback font to use if a character is not defined by `font`.
+///
+/// You can pass `NULL` to clear any previous fallback.
+/// Do not create a loop of fallback fonts.
+void text_font_set_fallback(Font *font, Font *fallback);
+/// Change size of font.
+///
+/// Avoid calling this function too often, since all font textures are trashed.
+/// Also changes size of fallback fonts.
 void text_font_change_size(Font *font, float new_size);
 /// Height of a character of this font in pixels.
 float text_font_char_height(Font *font);
@@ -91,8 +99,12 @@ void text_char_with_state(Font *font, TextRenderState *state, char32_t c);
 /// Draw some UTF-8 text with a \ref TextRenderState.
 void text_utf8_with_state(Font *font, TextRenderState *state, const char *str);
 /// Free memory used by font.
+///
+/// Does NOT free the font's fallback.
 void text_font_free(Font *font);
 /// Render all text drawn with \ref text_utf8, etc.
+///
+/// This will render the fallback font and its fallback, and so on.
 void text_render(Font *font);
 /// The "default" text rendering state - everything you need to just render text normally.
 /// This lets you do stuff like: