Patch [#34373] Use i18n monospace font in Text editor and Python console

This patch allows Blender to display i18n monospace font in the text
editor and the Python interactive console. Wide characters that occupy
multiple columns such as CJK characters can be displayed correctly.
Furthermore, wrapping, selection, suggestion, cursor drawing, and
syntax highlighting should work.

Also fixes a bug [#34543]: In Text Editor false color in comment on cyrillic

To estimate how many columns each character occupies, this patch uses
wcwidth.c written by Markus Kuhn and distributed under MIT-style license:

  http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c

wcwidth.c is stored in extern/wcwidth and used as a static library.

This patch adds new API to blenfont, blenlib and blenkernel:

BLF_get_unifont_mono()
BLF_free_unifont_mono()
BLF_draw_mono()
BLI_wcwidth()
BLI_wcswidth()
BLI_str_utf8_char_width()
BLI_str_utf8_char_width_safe()
txt_utf8_offset_to_column()
txt_utf8_column_to_offset()

2 files changed, 177 insertions, 123 deletions

diff --git a/source/blender/editors/space_text/text_draw.c b/source/blender/editors/space_text/text_draw.c
index a146fec3dac..95fd7fce878 100644
--- a/source/blender/editors/space_text/text_draw.c
+++ b/source/blender/editors/space_text/text_draw.c
@@ -67,12 +67,14 @@ static void text_font_end(SpaceText *UNUSED(st))
 {
 }
 
-static int text_font_draw(SpaceText *UNUSED(st), int x, int y, const char *str)
+static int text_font_draw(SpaceText *st, int x, int y, const char *str)
 {
+	int columns;
+
 	BLF_position(mono, x, y, 0);
-	BLF_draw(mono, str, BLF_DRAW_STR_DUMMY_MAX);
+	columns = BLF_draw_mono(mono, str, BLF_DRAW_STR_DUMMY_MAX, st->cwidth);
 
-	return BLF_width(mono, str);
+	return st->cwidth * columns;
 }
 
 static int text_font_draw_character(SpaceText *st, int x, int y, char c)
@@ -85,10 +87,13 @@ static int text_font_draw_character(SpaceText *st, int x, int y, char c)
 
 static int text_font_draw_character_utf8(SpaceText *st, int x, int y, const char *c)
 {
+	int columns;
+
 	const size_t len = BLI_str_utf8_size_safe(c);
 	BLF_position(mono, x, y, 0);
-	BLF_draw(mono, c, len);
-	return st->cwidth;
+	columns = BLF_draw_mono(mono, c, len, st->cwidth);
+
+	return st->cwidth * columns;
 }
 
 #if 0
@@ -216,7 +221,7 @@ void wrap_offset(SpaceText *st, ARegion *ar, TextLine *linein, int cursin, int *
 	}
 
 	max = wrap_width(st, ar);
-	cursin = txt_utf8_offset_to_index(linein->line, cursin);
+	cursin = txt_utf8_offset_to_column(linein->line, cursin);
 
 	while (linep) {
 		start = 0;
@@ -225,6 +230,7 @@ void wrap_offset(SpaceText *st, ARegion *ar, TextLine *linein, int cursin, int *
 		*offc = 0;
 		for (i = 0, j = 0; linep->line[j]; j += BLI_str_utf8_size_safe(linep->line + j)) {
 			int chars;
+			int columns = BLI_str_utf8_char_width_safe(linep->line + j); /* = 1 for tab */
 
 			/* Mimic replacement of tabs */
 			ch = linep->line[j];
@@ -238,7 +244,9 @@ void wrap_offset(SpaceText *st, ARegion *ar, TextLine *linein, int cursin, int *
 			}
 
 			while (chars--) {
-				if (i - start >= max) {
+				if (i + columns - start > max) {
+					end = MIN2(end, i);
+
 					if (chop && linep == linein && i >= cursin) {
 						if (i == cursin) {
 							(*offl)++;
@@ -261,7 +269,7 @@ void wrap_offset(SpaceText *st, ARegion *ar, TextLine *linein, int cursin, int *
 					if (linep == linein && i >= cursin)
 						return;
 				}
-				i++;
+				i += columns;
 			}
 		}
 		if (linep == linein) break;
@@ -286,9 +294,10 @@ void wrap_offset_in_line(SpaceText *st, ARegion *ar, TextLine *linein, int cursi
 	end = max;
 	chop = 1;
 	*offc = 0;
-	cursin = txt_utf8_offset_to_index(linein->line, cursin);
+	cursin = txt_utf8_offset_to_column(linein->line, cursin);
 
 	for (i = 0, j = 0; linein->line[j]; j += BLI_str_utf8_size_safe(linein->line + j)) {
+		int columns = BLI_str_utf8_char_width_safe(linein->line + j); /* = 1 for tab */
 
 		/* Mimic replacement of tabs */
 		ch = linein->line[j];
@@ -301,7 +310,9 @@ void wrap_offset_in_line(SpaceText *st, ARegion *ar, TextLine *linein, int cursi
 			chars = 1;
 
 		while (chars--) {
-			if (i - start >= max) {
+			if (i + columns - start > max) {
+				end = MIN2(end, i);
+
 				if (chop && i >= cursin) {
 					if (i == cursin) {
 						(*offl)++;
@@ -324,7 +335,7 @@ void wrap_offset_in_line(SpaceText *st, ARegion *ar, TextLine *linein, int cursi
 				if (i >= cursin)
 					return;
 			}
-			i++;
+			i += columns;
 		}
 	}
 }
@@ -337,24 +348,35 @@ int text_get_char_pos(SpaceText *st, const char *line, int cur)
 		if (line[i] == '\t')
 			a += st->tabnumber - a % st->tabnumber;
 		else
-			a++;
+			a += BLI_str_utf8_char_width_safe(line + i);
 	}
 	return a;
 }
 
-static const char *txt_utf8_get_nth(const char *str, int n)
+static const char *txt_utf8_forward_columns(const char *str, int columns, int *padding)
 {
-	int pos = 0;
-	while (str[pos] && n--) {
-		pos += BLI_str_utf8_size_safe(str + pos);
+	int col;
+	const char *p = str;
+	while (*p) {
+		col = BLI_str_utf8_char_width(p);
+		if (columns - col < 0)
+			break;
+		columns -= col;
+		p += BLI_str_utf8_size_safe(p);
+		if (columns == 0)
+			break;
 	}
-	return str + pos;
+	if (padding)
+		*padding = *p ? columns : 0;
+	return p;
 }
 
 static int text_draw_wrapped(SpaceText *st, const char *str, int x, int y, int w, const char *format, int skip)
 {
 	FlattenString fs;
-	int basex, i, a, start, end, max, lines; /* view */
+	int basex, lines;
+	int i, wrap, end, max, columns, padding; /* column */
+	int a, fstart, fpos;                     /* utf8 chars */
 	int mi, ma, mstart, mend;                /* mem */
 	char fmt_prev = 0xff;
 	
@@ -365,41 +387,46 @@ static int text_draw_wrapped(SpaceText *st, const char *str, int x, int y, int w
 	basex = x;
 	lines = 1;
 	
-	start = 0; mstart = 0;
-	end = max; mend = txt_utf8_get_nth(str, max) - str;
+	fpos = fstart = 0; mstart = 0;
+	mend = txt_utf8_forward_columns(str, max, &padding) - str;
+	end = wrap = max - padding;
 	
-	for (i = 0, mi = 0; str[mi]; i++, mi += BLI_str_utf8_size_safe(str + mi)) {
-		if (i - start >= max) {
+	for (i = 0, mi = 0; str[mi]; i += columns, mi += BLI_str_utf8_size_safe(str + mi)) {
+		columns = BLI_str_utf8_char_width_safe(str + mi);
+		if (i + columns > end) {
 			/* skip hidden part of line */
 			if (skip) {
 				skip--;
-				start = end; mstart = mend;
-				end += max; mend = txt_utf8_get_nth(str + mend, max) - str;
+				fstart = fpos; mstart = mend;
+				mend = txt_utf8_forward_columns(str + mend, max, &padding) - str;
+				end = (wrap += max - padding);
 				continue;
 			}
 
 			/* Draw the visible portion of text on the overshot line */
-			for (a = start, ma = mstart; a < end; a++, ma += BLI_str_utf8_size_safe(str + ma)) {
+			for (a = fstart, ma = mstart; ma < mend; a++, ma += BLI_str_utf8_size_safe(str + ma)) {
 				if (st->showsyntax && format) {
 					if (fmt_prev != format[a]) format_draw_color(fmt_prev = format[a]);
 				}
 				x += text_font_draw_character_utf8(st, x, y, str + ma);
+				fpos++;
 			}
 			y -= st->lheight_dpi + TXT_LINE_SPACING;
 			x = basex;
 			lines++;
-			start = end; mstart = mend;
-			end += max; mend = txt_utf8_get_nth(str + mend, max) - str;
+			fstart = fpos; mstart = mend;
+			mend = txt_utf8_forward_columns(str + mend, max, &padding) - str;
+			end = (wrap += max - padding);
 
 			if (y <= 0) break;
 		}
 		else if (str[mi] == ' ' || str[mi] == '-') {
-			end = i + 1; mend = mi + 1;
+			wrap = i + 1; mend = mi + 1;
 		}
 	}
 
 	/* Draw the remaining text */
-	for (a = start, ma = mstart; str[ma] && y > 0; a++, ma += BLI_str_utf8_size_safe(str + ma)) {
+	for (a = fstart, ma = mstart; str[ma] && y > 0; a++, ma += BLI_str_utf8_size_safe(str + ma)) {
 		if (st->showsyntax && format) {
 			if (fmt_prev != format[a]) format_draw_color(fmt_prev = format[a]);
 		}
@@ -412,53 +439,55 @@ static int text_draw_wrapped(SpaceText *st, const char *str, int x, int y, int w
 	return lines;
 }
 
-static int text_draw(SpaceText *st, char *str, int cshift, int maxwidth, int draw, int x, int y, const char *format)
+static void text_draw(SpaceText *st, char *str, int cshift, int maxwidth, int x, int y, const char *format)
 {
 	FlattenString fs;
-	int *acc, r = 0;
-	const char *in;
+	int columns, size, n, w = 0, padding, amount = 0;
+	const char *in = NULL;
 
-	int w = flatten_string(st, &fs, str);
-	if (w < cshift) {
-		flatten_string_free(&fs);
-		return 0; /* String is shorter than shift */
-	}
-	
-	in = txt_utf8_get_nth(fs.buf, cshift);
-	acc = fs.accum + cshift;
-	w = w - cshift;
+	for (n = flatten_string(st, &fs, str), str = fs.buf; n > 0; n--) {
+		columns = BLI_str_utf8_char_width_safe(str);
+		size = BLI_str_utf8_size_safe(str);
 
-	if (draw) {
-		int amount = maxwidth ? MIN2(w, maxwidth) : w;
-		
-		if (st->showsyntax && format) {
-			int a, str_shift = 0;
-			char fmt_prev = 0xff;
-			format = format + cshift;
-
-			for (a = 0; a < amount; a++) {
-				if (format[a] != fmt_prev) format_draw_color(fmt_prev = format[a]);
-				x += text_font_draw_character_utf8(st, x, y, in + str_shift);
-				str_shift += BLI_str_utf8_size_safe(in + str_shift);
+		if (!in) {
+			if (w >= cshift) {
+				padding = w - cshift;
+				in = str;
 			}
+			else if (format)
+				format++;
 		}
-		else {
-			text_font_draw(st, x, y, in);
+		if (in) {
+			if (maxwidth && w + columns > cshift + maxwidth)
+				break;
+			amount++;
+		}
+
+		w += columns;
+		str += size;
+	}
+	if (!in) {
+		flatten_string_free(&fs);
+		return; /* String is shorter than shift or ends with a padding */
+	}
+
+	x += st->cwidth * padding;
+
+	if (st->showsyntax && format) {
+		int a, str_shift = 0;
+		char fmt_prev = 0xff;
+
+		for (a = 0; a < amount; a++) {
+			if (format[a] != fmt_prev) format_draw_color(fmt_prev = format[a]);
+			x += text_font_draw_character_utf8(st, x, y, in + str_shift);
+			str_shift += BLI_str_utf8_size_safe(in + str_shift);
 		}
 	}
 	else {
-		while (w-- && *acc++ < maxwidth)
-			r += st->cwidth;
+		text_font_draw(st, x, y, in);
 	}
 
 	flatten_string_free(&fs);
-
-	if (cshift && r == 0)
-		return 0;
-	else if (st->showlinenrs)
-		return r + TXT_OFFSET + TEXTXLOC;
-	else
-		return r + TXT_OFFSET;
 }
 
 /************************ cache utilities *****************************/
@@ -672,6 +701,8 @@ int text_get_visible_lines(SpaceText *st, ARegion *ar, const char *str)
 	start = 0;
 	end = max;
 	for (i = 0, j = 0; str[j]; j += BLI_str_utf8_size_safe(str + j)) {
+		int columns = BLI_str_utf8_char_width_safe(str + j); /* = 1 for tab */
+
 		/* Mimic replacement of tabs */
 		ch = str[j];
 		if (ch == '\t') {
@@ -683,16 +714,16 @@ int text_get_visible_lines(SpaceText *st, ARegion *ar, const char *str)
 		}
 
 		while (chars--) {
-			if (i - start >= max) {
+			if (i + columns - start > max) {
 				lines++;
-				start = end;
+				start = MIN2(end, i);
 				end += max;
 			}
 			else if (ch == ' ' || ch == '-') {
 				end = i + 1;
 			}
 
-			i++;
+			i += columns;
 		}
 	}
 
@@ -931,7 +962,7 @@ static void draw_documentation(SpaceText *st, ARegion *ar)
 			buf[i] = '\0';
 			if (lines >= 0) {
 				y -= st->lheight_dpi;
-				text_draw(st, buf, 0, 0, 1, x + 4, y - 3, NULL);
+				text_draw(st, buf, 0, 0, x + 4, y - 3, NULL);
 			}
 			i = 0; br = DOC_WIDTH; lines++;
 		}
@@ -940,7 +971,7 @@ static void draw_documentation(SpaceText *st, ARegion *ar)
 			buf[br] = '\0';
 			if (lines >= 0) {
 				y -= st->lheight_dpi;
-				text_draw(st, buf, 0, 0, 1, x + 4, y - 3, NULL);
+				text_draw(st, buf, 0, 0, x + 4, y - 3, NULL);
 			}
 			p -= i - br - 1; /* Rewind pointer to last break */
 			i = 0; br = DOC_WIDTH; lines++;
@@ -959,9 +990,9 @@ static void draw_documentation(SpaceText *st, ARegion *ar)
 static void draw_suggestion_list(SpaceText *st, ARegion *ar)
 {
 	SuggItem *item, *first, *last, *sel;
-	TextLine *tmp;
-	char str[SUGG_LIST_WIDTH + 1];
-	int w, boxw = 0, boxh, i, l, x, y, *top;
+	char str[SUGG_LIST_WIDTH * BLI_UTF8_MAX + 1];
+	int offl, offc, vcurl, vcurc;
+	int w, boxw = 0, boxh, i, x, y, *top;
 	const int lheight = st->lheight_dpi + TXT_LINE_SPACING;
 	const int margin_x = 2;
 	
@@ -977,24 +1008,24 @@ static void draw_suggestion_list(SpaceText *st, ARegion *ar)
 	sel = texttool_suggest_selected();
 	top = texttool_suggest_top();
 
-	/* Count the visible lines to the cursor */
-	for (tmp = st->text->curl, l = -st->top; tmp; tmp = tmp->prev, l++) ;
-	if (l < 0) return;
-	
-	if (st->showlinenrs) {
-		x = st->cwidth * (st->text->curc - st->left) + TXT_OFFSET + TEXTXLOC - 4;
-	}
-	else {
-		x = st->cwidth * (st->text->curc - st->left) + TXT_OFFSET - 4;
-	}
+	wrap_offset(st, ar, st->text->curl, st->text->curc, &offl, &offc);
+	vcurl = txt_get_span(st->text->lines.first, st->text->curl) - st->top + offl;
+	vcurc = text_get_char_pos(st, st->text->curl->line, st->text->curc) - st->left + offc;
+
+	x = st->showlinenrs ? TXT_OFFSET + TEXTXLOC : TXT_OFFSET;
+	x += vcurc * st->cwidth - 4;
+	y = ar->winy - (vcurl + 1) * lheight - 2;
+
 	/* offset back so the start of the text lines up with the suggestions,
 	 * not essential but makes suggestions easier to follow */
 	x -= st->cwidth * (st->text->curc - text_find_identifier_start(st->text->curl->line, st->text->curc));
-	y = ar->winy - lheight * l - 2;
 
 	boxw = SUGG_LIST_WIDTH * st->cwidth + 20;
 	boxh = SUGG_LIST_SIZE * lheight + 8;
 	
+	if (x + boxw > ar->winx)
+		x = MAX2(0, ar->winx - boxw);
+
 	/* not needed but stands out nicer */
 	uiDrawBoxShadow(220, x, y - boxh, x + boxw, y);
 
@@ -1007,12 +1038,13 @@ static void draw_suggestion_list(SpaceText *st, ARegion *ar)
 	for (i = 0, item = first; i < *top && item->next; i++, item = item->next) ;
 
 	for (i = 0; i < SUGG_LIST_SIZE && item; i++, item = item->next) {
+		int len = txt_utf8_forward_columns(item->name, SUGG_LIST_WIDTH, NULL) - item->name;
 
 		y -= lheight;
 
-		BLI_strncpy(str, item->name, SUGG_LIST_WIDTH);
+		BLI_strncpy(str, item->name, len + 1);
 
-		w = BLF_width(mono, str);
+		w = st->cwidth * text_get_char_pos(st, str, len);
 		
 		if (item == sel) {
 			UI_ThemeColor(TH_SHADE2);
@@ -1020,7 +1052,7 @@ static void draw_suggestion_list(SpaceText *st, ARegion *ar)
 		}
 
 		format_draw_color(item->type);
-		text_draw(st, str, 0, 0, 1, x + margin_x, y - 1, NULL);
+		text_draw(st, str, 0, 0, x + margin_x, y - 1, NULL);
 
 		if (item == last) break;
 	}
@@ -1382,7 +1414,7 @@ void draw_text_main(SpaceText *st, ARegion *ar)
 		}
 		else {
 			/* draw unwrapped text */
-			text_draw(st, tmp->line, st->left, ar->winx / st->cwidth, 1, x, y, tmp->format);
+			text_draw(st, tmp->line, st->left, ar->winx / st->cwidth, x, y, tmp->format);
 			y -= st->lheight_dpi + TXT_LINE_SPACING;
 		}
 		
@@ -1439,8 +1471,6 @@ void text_scroll_to_cursor(SpaceText *st, ScrArea *sa)
 			winx = ar->winx;
 			break;
 		}
-	
-	winx -= TXT_SCROLL_WIDTH;
 
 	text_update_character_width(st);
 
@@ -1458,10 +1488,11 @@ void text_scroll_to_cursor(SpaceText *st, ScrArea *sa)
 		st->left = 0;
 	}
 	else {
-		x = text_draw(st, text->sell->line, st->left, text->selc, 0, 0, 0, NULL);
+		x = st->cwidth * (text_get_char_pos(st, text->sell->line, text->selc) - st->left);
+		winx -= TXT_OFFSET + (st->showlinenrs ? TEXTXLOC : 0) + TXT_SCROLL_WIDTH;
 
-		if (x == 0 || x > winx)
-			st->left = text->curc - 0.5 * winx / st->cwidth;
+		if (x <= 0 || x > winx)
+			st->left += (x - winx / 2) / st->cwidth;
 	}
 
 	if (st->top < 0) st->top = 0;
diff --git a/source/blender/editors/space_text/text_ops.c b/source/blender/editors/space_text/text_ops.c
index e6f95c39baf..3a7070e1a7a 100644
--- a/source/blender/editors/space_text/text_ops.c
+++ b/source/blender/editors/space_text/text_ops.c
@@ -72,7 +72,7 @@
 /************************ poll ***************************/
 
 
-BLI_INLINE int text_pixel_x_to_index(SpaceText *st, const int x)
+BLI_INLINE int text_pixel_x_to_column(SpaceText *st, const int x)
 {
 	/* add half the char width so mouse cursor selection is inbetween letters */
 	return (x + (st->cwidth / 2)) / st->cwidth;
@@ -1407,6 +1407,8 @@ static int text_get_cursor_rel(SpaceText *st, ARegion *ar, TextLine *linein, int
 
 	for (i = 0, j = 0; loop; j += BLI_str_utf8_size_safe(linein->line + j)) {
 		int chars;
+		int columns = BLI_str_utf8_char_width_safe(linein->line + j); /* = 1 for tab */
+
 		/* Mimic replacement of tabs */
 		ch = linein->line[j];
 		if (ch == '\t') {
@@ -1418,16 +1420,18 @@ static int text_get_cursor_rel(SpaceText *st, ARegion *ar, TextLine *linein, int
 		}
 
 		while (chars--) {
-			if (rell == 0 && i - start == relc) {
+			if (rell == 0 && i - start <= relc && i + columns - start > relc) {
 				/* current position could be wrapped to next line */
 				/* this should be checked when end of current line would be reached */
 				selc = j;
 				found = 1;
 			}
-			else if (i - end == relc) {
+			else if (i - end <= relc && i + columns - end > relc) {
 				curs = j;
 			}
-			if (i - start >= max) {
+			if (i + columns - start > max) {
+				end = MIN2(end, i);
+
 				if (found) {
 					/* exact cursor position was found, check if it's */
 					/* still on needed line (hasn't been wrapped) */
@@ -1443,7 +1447,7 @@ static int text_get_cursor_rel(SpaceText *st, ARegion *ar, TextLine *linein, int
 				chop = 1;
 				rell--;
 
-				if (rell == 0 && i - start >= relc) {
+				if (rell == 0 && i + columns - start > relc) {
 					selc = curs;
 					loop = 0;
 					break;
@@ -1460,7 +1464,7 @@ static int text_get_cursor_rel(SpaceText *st, ARegion *ar, TextLine *linein, int
 					break;
 				}
 
-				if (rell == 0 && i - start >= relc) {
+				if (rell == 0 && i + columns - start > relc) {
 					selc = curs;
 					loop = 0;
 					break;
@@ -1469,7 +1473,7 @@ static int text_get_cursor_rel(SpaceText *st, ARegion *ar, TextLine *linein, int
 				endj = j;
 				chop = 0;
 			}
-			i++;
+			i += columns;
 		}
 	}
 
@@ -1587,6 +1591,8 @@ static void txt_wrap_move_bol(SpaceText *st, ARegion *ar, short sel)
 
 	for (i = 0, j = 0; loop; j += BLI_str_utf8_size_safe((*linep)->line + j)) {
 		int chars;
+		int columns = BLI_str_utf8_char_width_safe((*linep)->line + j); /* = 1 for tab */
+
 		/* Mimic replacement of tabs */
 		ch = (*linep)->line[j];
 		if (ch == '\t') {
@@ -1598,11 +1604,13 @@ static void txt_wrap_move_bol(SpaceText *st, ARegion *ar, short sel)
 		}
 
 		while (chars--) {
-			if (i - start >= max) {
+			if (i + columns - start > max) {
+				end = MIN2(end, i);
+
 				*charp = endj;
 
 				if (j >= oldc) {
-					if (ch == '\0') *charp = txt_utf8_index_to_offset((*linep)->line, start);
+					if (ch == '\0') *charp = txt_utf8_column_to_offset((*linep)->line, start);
 					loop = 0;
 					break;
 				}
@@ -1615,7 +1623,7 @@ static void txt_wrap_move_bol(SpaceText *st, ARegion *ar, short sel)
 			}
 			else if (ch == ' ' || ch == '-' || ch == '\0') {
 				if (j >= oldc) {
-					*charp = txt_utf8_index_to_offset((*linep)->line, start);
+					*charp = txt_utf8_column_to_offset((*linep)->line, start);
 					loop = 0;
 					break;
 				}
@@ -1624,7 +1632,7 @@ static void txt_wrap_move_bol(SpaceText *st, ARegion *ar, short sel)
 				endj = j + 1;
 				chop = 0;
 			}
-			i++;
+			i += columns;
 		}
 	}
 
@@ -1655,6 +1663,8 @@ static void txt_wrap_move_eol(SpaceText *st, ARegion *ar, short sel)
 
 	for (i = 0, j = 0; loop; j += BLI_str_utf8_size_safe((*linep)->line + j)) {
 		int chars;
+		int columns = BLI_str_utf8_char_width_safe((*linep)->line + j); /* = 1 for tab */
+
 		/* Mimic replacement of tabs */
 		ch = (*linep)->line[j];
 		if (ch == '\t') {
@@ -1666,7 +1676,9 @@ static void txt_wrap_move_eol(SpaceText *st, ARegion *ar, short sel)
 		}
 
 		while (chars--) {
-			if (i - start >= max) {
+			if (i + columns - start > max) {
+				end = MIN2(end, i);
+
 				if (chop) endj = BLI_str_prev_char_utf8((*linep)->line + j) - (*linep)->line;
 
 				if (endj >= oldc) {
@@ -1690,7 +1702,7 @@ static void txt_wrap_move_eol(SpaceText *st, ARegion *ar, short sel)
 				endj = j;
 				chop = 0;
 			}
-			i++;
+			i += columns;
 		}
 	}
 
@@ -2352,7 +2364,7 @@ typedef struct SetSelection {
 	short old[2];
 } SetSelection;
 
-static int flatten_len(SpaceText *st, const char *str)
+static int flatten_width(SpaceText *st, const char *str)
 {
 	int i, total = 0;
 
@@ -2361,21 +2373,29 @@ static int flatten_len(SpaceText *st, const char *str)
 			total += st->tabnumber - total % st->tabnumber;
 		}
 		else {
-			total++;
+			total += BLI_str_utf8_char_width_safe(str + i);
 		}
 	}
 	
 	return total;
 }
 
-static int flatten_index_to_offset(SpaceText *st, const char *str, int index)
+static int flatten_column_to_offset(SpaceText *st, const char *str, int index)
 {
-	int i, j;
-	for (i = 0, j = 0; i < index; j += BLI_str_utf8_size_safe(str + j))
+	int i = 0, j = 0, col;
+
+	while (*(str + j)) {
 		if (str[j] == '\t')
-			i += st->tabnumber - i % st->tabnumber;
+			col = st->tabnumber - i % st->tabnumber;
 		else
-			i++;
+			col = BLI_str_utf8_char_width_safe(str + j);
+		
+		if (i + col > index)
+			break;
+		
+		i += col;
+		j += BLI_str_utf8_size_safe(str + j);
+	}
 	
 	return j;
 }
@@ -2402,7 +2422,7 @@ static TextLine *get_first_visible_line(SpaceText *st, ARegion *ar, int *y)
 static void text_cursor_set_to_pos_wrapped(SpaceText *st, ARegion *ar, int x, int y, int sel)
 {
 	Text *text = st->text;
-	int max = wrap_width(st, ar); /* view */
+	int max = wrap_width(st, ar); /* column */
 	int charp = -1;               /* mem */
 	int loop = 1, found = 0;      /* flags */
 	char ch;
@@ -2411,12 +2431,13 @@ static void text_cursor_set_to_pos_wrapped(SpaceText *st, ARegion *ar, int x, in
 	TextLine *linep = get_first_visible_line(st, ar, &y);
 	
 	while (loop && linep) {
-		int i = 0, start = 0, end = max; /* view */
+		int i = 0, start = 0, end = max; /* column */
 		int j = 0, curs = 0, endj = 0;   /* mem */
 		int chop = 1;                    /* flags */
 		
 		for (; loop; j += BLI_str_utf8_size_safe(linep->line + j)) {
 			int chars;
+			int columns = BLI_str_utf8_char_width_safe(linep->line + j); /* = 1 for tab */
 			
 			/* Mimic replacement of tabs */
 			ch = linep->line[j];
@@ -2436,17 +2457,19 @@ static void text_cursor_set_to_pos_wrapped(SpaceText *st, ARegion *ar, int x, in
 					break;
 					/* Exactly at the cursor */
 				}
-				else if (y == 0 && i - start == x) {
+				else if (y == 0 && i - start <= x && i + columns - start > x) {
 					/* current position could be wrapped to next line */
 					/* this should be checked when end of current line would be reached */
 					charp = curs = j;
 					found = 1;
 					/* Prepare curs for next wrap */
 				}
-				else if (i - end == x) {
+				else if (i - end <= x && i + columns - end > x) {
 					curs = j;
 				}
-				if (i - start >= max) {
+				if (i + columns - start > max) {
+					end = MIN2(end, i);
+					
 					if (found) {
 						/* exact cursor position was found, check if it's */
 						/* still on needed line (hasn't been wrapped) */
@@ -2463,7 +2486,7 @@ static void text_cursor_set_to_pos_wrapped(SpaceText *st, ARegion *ar, int x, in
 						y--;
 					
 					chop = 1;
-					if (y == 0 && i - start >= x) {
+					if (y == 0 && i + columns - start > x) {
 						charp = curs;
 						loop = 0;
 						break;
@@ -2475,7 +2498,7 @@ static void text_cursor_set_to_pos_wrapped(SpaceText *st, ARegion *ar, int x, in
 						break;
 					}
 					
-					if (y == 0 && i - start >= x) {
+					if (y == 0 && i + columns - start > x) {
 						charp = curs;
 						loop = 0;
 						break;
@@ -2484,7 +2507,7 @@ static void text_cursor_set_to_pos_wrapped(SpaceText *st, ARegion *ar, int x, in
 					endj = j;
 					chop = 0;
 				}
-				i++;
+				i += columns;
 			}
 			
 			if (ch == '\0') break;
@@ -2523,7 +2546,7 @@ static void text_cursor_set_to_pos(SpaceText *st, ARegion *ar, int x, int y, int
 	else x -= TXT_OFFSET;
 
 	if (x < 0) x = 0;
-	x = text_pixel_x_to_index(st, x) + st->left;
+	x = text_pixel_x_to_column(st, x) + st->left;
 	
 	if (st->wordwrap) {
 		text_cursor_set_to_pos_wrapped(st, ar, x, y, sel);
@@ -2546,8 +2569,8 @@ static void text_cursor_set_to_pos(SpaceText *st, ARegion *ar, int x, int y, int
 		}
 
 		
-		w = flatten_len(st, (*linep)->line);
-		if (x < w) *charp = flatten_index_to_offset(st, (*linep)->line, x);
+		w = flatten_width(st, (*linep)->line);
+		if (x < w) *charp = flatten_column_to_offset(st, (*linep)->line, x);
 		else *charp = (*linep)->len;
 	}
 	if (!sel) txt_pop_sel(text);