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()

1 files changed, 54 insertions, 31 deletions

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);