ui: refactor style handling

The old style handling had a lot edge cases where one of the
colours or the attribute wouldn't get applied correctly. This
commit adds a new style_set() method to the Ui which should be
called instead of manually touching a cell's style. This also
means that the Cell struct can be made opaque since all the
handling is now done inside the ui-terminal files.

With this it is now viable to combine the light and dark 16 colour
themes into a single base-16 theme. This theme works very well
with the Linux virtual console and will now be the default theme
regardless of if the terminal supports 256 colours or not.  This
should address the common complaints about vis not respecting the
users default terminal colours.

fixes #1151: Theming is sometimes partially applied or ignored
see #1103: terminal no longer has transparency/opacity
see #1040: Transparent background and setting options by default

lua/themes/dark-16.lua → lua/themes/base-16.lua

@@ -1,8 +1,7 @@
 -- Eight-color scheme
 local lexers = vis.lexers
--- dark
-lexers.STYLE_DEFAULT ='back:black,fore:white'
-lexers.STYLE_NOTHING = 'back:black'
+lexers.STYLE_DEFAULT =''
+lexers.STYLE_NOTHING = ''
 lexers.STYLE_CLASS = 'fore:yellow,bold'
 lexers.STYLE_COMMENT = 'fore:blue,bold'
 lexers.STYLE_CONSTANT = 'fore:cyan,bold'
@@ -21,17 +20,17 @@ lexers.STYLE_TYPE = 'fore:green,bold'
 lexers.STYLE_VARIABLE = 'fore:blue,bold'
 lexers.STYLE_WHITESPACE = ''
 lexers.STYLE_EMBEDDED = 'back:blue,bold'
-lexers.STYLE_IDENTIFIER = 'fore:white'
+lexers.STYLE_IDENTIFIER = ''
 
-lexers.STYLE_LINENUMBER = 'fore:white'
+lexers.STYLE_LINENUMBER = ''
 lexers.STYLE_LINENUMBER_CURSOR = lexers.STYLE_LINENUMBER
-lexers.STYLE_CURSOR = 'reverse'
+lexers.STYLE_CURSOR = 'back:white'
 lexers.STYLE_CURSOR_PRIMARY = lexers.STYLE_CURSOR..',fore:yellow'
 lexers.STYLE_CURSOR_LINE = 'underlined'
 lexers.STYLE_COLOR_COLUMN = 'back:red'
-lexers.STYLE_SELECTION = 'back:white'
+lexers.STYLE_SELECTION = 'back:white,bold'
 lexers.STYLE_STATUS = 'reverse'
 lexers.STYLE_STATUS_FOCUSED = 'reverse,bold'
 lexers.STYLE_SEPARATOR = lexers.STYLE_DEFAULT
-lexers.STYLE_INFO = 'fore:default,back:default,bold'
+lexers.STYLE_INFO = 'bold'
 lexers.STYLE_EOF = ''

lua/themes/default.lua

@@ -0,0 +1 @@
+base-16.lua

lua/vis-std.lua

@@ -2,9 +2,9 @@
 
 vis.events.subscribe(vis.events.INIT, function()
 	if os.getenv("TERM_PROGRAM") == "Apple_Terminal" then
-		vis:command("set change-256colors false");
+		vis:command("set change-256colors false")
 	end
-	vis:command("set theme ".. (vis.ui.colors <= 16 and "default-16" or "default-256"))
+	vis:command("set theme default")
 end)
 
 vis:option_register("theme", "string", function(name)

ui-terminal-curses.c

@@ -50,9 +50,13 @@
 
 #define MAX_COLOR_CLOBBER 240
 
-static short color_clobber_idx = 0;
-static uint32_t clobbering_colors[MAX_COLOR_CLOBBER];
 static int change_colors = -1;
+static short default_fg = -1;
+static short default_bg = -1;
+
+static inline bool cell_color_equal(CellColor c1, CellColor c2) {
+	return c1 == c2;
+}
 
 /* Calculate r,g,b components of one of the standard upper 240 colors */
 static void get_6cube_rgb(unsigned int n, int *r, int *g, int *b)
@@ -82,10 +86,13 @@ static void undo_palette(void)
 /* Work out the nearest color from the 256 color set, or perhaps exactly. */
 static CellColor color_rgb(UiTerm *ui, uint8_t r, uint8_t g, uint8_t b)
 {
+	static short color_clobber_idx = 0;
+	static uint32_t clobbering_colors[MAX_COLOR_CLOBBER];
+
 	if (change_colors == -1)
 		change_colors = ui->vis->change_colors && can_change_color() && COLORS >= 256;
 	if (change_colors) {
-		uint32_t hexrep = ((r << 16) | (g << 8) | b) + 1;
+		uint32_t hexrep = (r << 16) | (g << 8) | b;
 		for (short i = 0; i < MAX_COLOR_CLOBBER; ++i) {
 			if (clobbering_colors[i] == hexrep)
 				return i + 16;
@@ -169,7 +176,7 @@ static inline unsigned int color_pair_hash(short fg, short bg) {
 
 static short color_pair_get(short fg, short bg) {
 	static bool has_default_colors;
-	static short *color2palette, default_fg, default_bg;
+	static short *color2palette;
 	static short color_pairs_max, color_pair_current;
 
 	if (!color2palette) {
@@ -299,3 +306,15 @@ static void ui_curses_free(UiTerm *term) {
 bool is_default_color(CellColor c) {
 	return c == CELL_COLOR_DEFAULT;
 }
+
+static bool is_default_bg(CellColor c) {
+	if (change_colors == 1)
+		return c == default_bg;
+	return is_default_color(c);
+}
+
+static bool is_default_fg(CellColor c) {
+	if (change_colors == 1)
+		return c == default_fg;
+	return is_default_color(c);
+}

ui-terminal-vt100.c

@@ -75,6 +75,12 @@ typedef struct {
 	Buffer buf;
 } UiVt100;
 
+static inline bool cell_color_equal(CellColor c1, CellColor c2) {
+	if (c1.index != (uint8_t)-1 || c2.index != (uint8_t)-1)
+		return c1.index == c2.index;
+	return c1.r == c2.r && c1.g == c2.g && c1.b == c2.b;
+}
+
 static CellColor color_rgb(UiTerm *ui, uint8_t r, uint8_t g, uint8_t b) {
 	return (CellColor){ .r = r, .g = g, .b = b, .index = (uint8_t)-1 };
 }
@@ -217,6 +223,14 @@ static void ui_vt100_free(UiTerm *tui) {
 	buffer_release(&vtui->buf);
 }
 
-bool is_default_color(CellColor c) {
+static bool is_default_color(CellColor c) {
 	return c.index == ((CellColor) CELL_COLOR_DEFAULT).index;
 }
+
+static bool is_default_fg(CellColor c) {
+	return is_default_color(c);
+}
+
+static bool is_default_bg(CellColor c) {
+	return is_default_color(c);
+}

ui-terminal.c

@@ -282,10 +282,21 @@ static void ui_window_draw(UiWin *w) {
 	}
 }
 
-static CellStyle ui_window_style_get(UiWin *w, enum UiStyle style) {
+static void ui_window_style_set(UiWin *w, Cell *cell, enum UiStyle id) {
 	UiTermWin *win = (UiTermWin*)w;
 	UiTerm *tui = win->ui;
-	return tui->styles[win->id * UI_STYLE_MAX + style];
+	CellStyle set, style = tui->styles[win->id * UI_STYLE_MAX + id];
+
+	if (id == UI_STYLE_DEFAULT) {
+		memcpy(&cell->style, &style, sizeof(CellStyle));
+		return;
+	}
+
+	set.fg = is_default_fg(style.fg)? cell->style.fg : style.fg;
+	set.bg = is_default_bg(style.bg)? cell->style.bg : style.bg;
+	set.attr = cell->style.attr | style.attr;
+
+	memcpy(&cell->style, &set, sizeof(CellStyle));
 }
 
 static void ui_window_status(UiWin *w, const char *status) {
@@ -516,7 +527,7 @@ static UiWin *ui_window_new(Ui *ui, Win *w, enum UiOption options) {
 		return NULL;
 
 	win->uiwin = (UiWin) {
-		.style_get = ui_window_style_get,
+		.style_set = ui_window_style_set,
 		.status = ui_window_status,
 		.options_set = ui_window_options_set,
 		.options_get = ui_window_options_get,

ui.h

@@ -54,23 +54,12 @@ enum UiStyle {
 #if CONFIG_CURSES
 typedef uint64_t CellAttr;
 typedef short CellColor;
-
-static inline bool cell_color_equal(CellColor c1, CellColor c2) {
-	return c1 == c2;
-}
 #else
 typedef uint8_t CellAttr;
 typedef struct {
 	uint8_t r, g, b;
 	uint8_t index;
 } CellColor;
-
-static inline bool cell_color_equal(CellColor c1, CellColor c2) {
-	if (c1.index != (uint8_t)-1 || c2.index != (uint8_t)-1)
-		return c1.index == c2.index;
-	return c1.r == c2.r && c1.g == c2.g && c1.b == c2.b;
-}
-
 #endif
 
 typedef struct {
@@ -107,7 +96,7 @@ struct Ui {
 };
 
 struct UiWin {
-	CellStyle (*style_get)(UiWin*, enum UiStyle);
+	void (*style_set)(UiWin*, Cell*, enum UiStyle);
 	void (*status)(UiWin*, const char *txt);
 	void (*options_set)(UiWin*, enum UiOption);
 	enum UiOption (*options_get)(UiWin*);
@@ -116,7 +105,6 @@ struct UiWin {
 	int (*window_height)(UiWin*);
 };
 
-bool is_default_color(CellColor c);
 enum UiLayout ui_layout_get(Ui *ui);
 
 #endif

view.c

@@ -170,7 +170,7 @@ static void view_clear(View *view) {
 	view->wrapcol = 0;
 	view->prevch_breakat = false;
 	if (view->ui)
-		view->cell_blank.style = view->ui->style_get(view->ui, UI_STYLE_DEFAULT);
+		view->ui->style_set(view->ui, &view->cell_blank, UI_STYLE_DEFAULT);
 }
 
 Filerange view_viewport_get(View *view) {
@@ -1405,11 +1405,10 @@ bool view_style_define(View *view, enum UiStyle id, const char *style) {
 	return view->ui->style_define(view->ui, id, style);
 }
 
-void view_style(View *view, enum UiStyle style_id, size_t start, size_t end) {
+void view_style(View *view, enum UiStyle style, size_t start, size_t end) {
 	if (end < view->start || start > view->end)
 		return;
 
-	CellStyle style = view->ui->style_get(view->ui, style_id);
 	size_t pos = view->start;
 	Line *line = view->topline;
 
@@ -1435,7 +1434,7 @@ void view_style(View *view, enum UiStyle style_id, size_t start, size_t end) {
 	do {
 		while (pos <= end && col < width) {
 			pos += line->cells[col].len;
-			line->cells[col++].style = style;
+			view->ui->style_set(view->ui, &line->cells[col++], style);
 		}
 		col = 0;
 	} while (pos <= end && (line = line->next));

view.h

@@ -6,6 +6,7 @@
 
 typedef struct View View;
 typedef struct Selection Selection;
+typedef struct Cell Cell;
 
 #include "text.h"
 #include "ui.h"
@@ -16,7 +17,7 @@ typedef struct {
 	Mark cursor;
 } SelectionRegion;
 
-typedef struct {
+struct Cell {
 	char data[16];      /* utf8 encoded character displayed in this cell (might be more than
 	                       one Unicode codepoint. might also not be the same as in the
 	                       underlying text, for example tabs get expanded */
@@ -26,7 +27,7 @@ typedef struct {
 	                       occupied by the same character have a length of 0. */
 	int width;          /* display width i.e. number of columns occupied by this character */
 	CellStyle style;    /* colors and attributes used to display this cell */
-} Cell;
+};
 
 typedef struct Line Line;
 struct Line {               /* a line on the screen, *not* in the file */