Restructure display code

Use pull instead of push based model for display code. Previously view.c
was calling into the ui frontend code, with the new scheme this switches
around: the necessary data is fetched by the ui as necessary.

The UI independent display code is moved out of view.c/ui-curses.c into
vis.c. The cell styles are now directly embedded into the Cell struct.

New UI styles are introduced for:

 - status bar (focused / non-focused)
 - info message
 - window separator
 - EOF symbol

You will have to update your color themes.

The terminal output code is further abstracted into a generic ui-terminal.c
part which keeps track of the whole in-memory cell matrix and #includes
ui-terminal-curses.c for the actual terminal output. This architecture
currently assumes that there are no overlapping windows. It will also
allow non-curses based terminal user interfaces.

1 files changed, 286 insertions, 0 deletions

diff --git a/ui-terminal-curses.c b/ui-terminal-curses.c
new file mode 100644
index 0000000..5f0319b
--- /dev/null
+++ b/ui-terminal-curses.c
@@ -0,0 +1,286 @@
+/* This file is included from ui-terminal.c */
+#include <stdio.h>
+#include <curses.h>
+
+#define ui_term_backend_init ui_curses_init
+#define ui_term_backend_blit ui_curses_blit
+#define ui_term_backend_clear ui_curses_clear
+#define ui_term_backend_colors ui_curses_colors
+#define ui_term_backend_resize ui_curses_resize
+#define ui_term_backend_restore ui_curses_restore
+#define ui_term_backend_save ui_curses_save
+#define ui_term_backend_new ui_curses_new
+#define ui_term_backend_resume ui_curses_resume
+#define ui_term_backend_suspend ui_curses_suspend
+#define ui_term_backend_free ui_curses_suspend
+
+#define CELL_COLOR_BLACK   COLOR_BLACK
+#define CELL_COLOR_RED     COLOR_RED
+#define CELL_COLOR_GREEN   COLOR_GREEN
+#define CELL_COLOR_YELLOW  COLOR_YELLOW
+#define CELL_COLOR_BLUE    COLOR_BLUE
+#define CELL_COLOR_MAGENTA COLOR_MAGENTA
+#define CELL_COLOR_CYAN    COLOR_CYAN
+#define CELL_COLOR_WHITE   COLOR_WHITE
+#define CELL_COLOR_DEFAULT (-1)
+
+#ifndef A_ITALIC
+#define A_ITALIC A_NORMAL
+#endif
+#define CELL_ATTR_NORMAL    A_NORMAL
+#define CELL_ATTR_UNDERLINE A_UNDERLINE
+#define CELL_ATTR_REVERSE   A_REVERSE
+#define CELL_ATTR_BLINK     A_BLINK
+#define CELL_ATTR_BOLD      A_BOLD
+#define CELL_ATTR_ITALIC    A_ITALIC
+
+#ifdef NCURSES_VERSION
+# ifndef NCURSES_EXT_COLORS
+#  define NCURSES_EXT_COLORS 0
+# endif
+# if !NCURSES_EXT_COLORS
+#  define MAX_COLOR_PAIRS 256
+# endif
+#endif
+#ifndef MAX_COLOR_PAIRS
+# define MAX_COLOR_PAIRS COLOR_PAIRS
+#endif
+
+#define MAX_COLOR_CLOBBER 240
+
+static short color_clobber_idx = 0;
+static uint32_t clobbering_colors[MAX_COLOR_CLOBBER];
+static int change_colors = -1;
+
+/* 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)
+{
+	if (n < 16) {
+		return;
+	} else if (n < 232) {
+		n -= 16;
+		*r = (n / 36) ? (n / 36) * 40 + 55 : 0;
+		*g = ((n / 6) % 6) ? ((n / 6) % 6) * 40 + 55 : 0;
+		*b = (n % 6) ? (n % 6) * 40 + 55 : 0;
+	} else if (n < 256) {
+		n -= 232;
+		*r = n * 10 + 8;
+		*g = n * 10 + 8;
+		*b = n * 10 + 8;
+	}
+}
+
+/* Reset color palette to default values using OSC 104 */
+static void undo_palette(void)
+{
+	fputs("\033]104;\a", stderr);
+	fflush(stderr);
+}
+
+/* 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)
+{
+	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;
+		for (short i = 0; i < MAX_COLOR_CLOBBER; ++i) {
+			if (clobbering_colors[i] == hexrep)
+				return i + 16;
+			else if (!clobbering_colors[i])
+				break;
+		}
+
+		short i = color_clobber_idx;
+		clobbering_colors[i] = hexrep;
+		init_color(i + 16, (r * 1000) / 0xff, (g * 1000) / 0xff,
+		           (b * 1000) / 0xff);
+
+		/* in the unlikely case a user requests this many colors, reuse old slots */
+		if (++color_clobber_idx >= MAX_COLOR_CLOBBER)
+			color_clobber_idx = 0;
+
+		return i + 16;
+	}
+
+	static const unsigned char color_256_to_16[256] = {
+		 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15,
+		 0,  4,  4,  4, 12, 12,  2,  6,  4,  4, 12, 12,  2,  2,  6,  4,
+		12, 12,  2,  2,  2,  6, 12, 12, 10, 10, 10, 10, 14, 12, 10, 10,
+		10, 10, 10, 14,  1,  5,  4,  4, 12, 12,  3,  8,  4,  4, 12, 12,
+		 2,  2,  6,  4, 12, 12,  2,  2,  2,  6, 12, 12, 10, 10, 10, 10,
+		14, 12, 10, 10, 10, 10, 10, 14,  1,  1,  5,  4, 12, 12,  1,  1,
+		 5,  4, 12, 12,  3,  3,  8,  4, 12, 12,  2,  2,  2,  6, 12, 12,
+		10, 10, 10, 10, 14, 12, 10, 10, 10, 10, 10, 14,  1,  1,  1,  5,
+		12, 12,  1,  1,  1,  5, 12, 12,  1,  1,  1,  5, 12, 12,  3,  3,
+		 3,  7, 12, 12, 10, 10, 10, 10, 14, 12, 10, 10, 10, 10, 10, 14,
+		 9,  9,  9,  9, 13, 12,  9,  9,  9,  9, 13, 12,  9,  9,  9,  9,
+		13, 12,  9,  9,  9,  9, 13, 12, 11, 11, 11, 11,  7, 12, 10, 10,
+		10, 10, 10, 14,  9,  9,  9,  9,  9, 13,  9,  9,  9,  9,  9, 13,
+		 9,  9,  9,  9,  9, 13,  9,  9,  9,  9,  9, 13,  9,  9,  9,  9,
+		 9, 13, 11, 11, 11, 11, 11, 15,  0,  0,  0,  0,  0,  0,  8,  8,
+		 8,  8,  8,  8,  7,  7,  7,  7,  7,  7, 15, 15, 15, 15, 15, 15
+	};
+
+	int i = 0;
+	if ((!r || (r - 55) % 40 == 0) &&
+	    (!g || (g - 55) % 40 == 0) &&
+	    (!b || (b - 55) % 40 == 0)) {
+		i = 16;
+		i += r ? ((r - 55) / 40) * 36 : 0;
+		i += g ? ((g - 55) / 40) * 6 : 0;
+		i += g ? ((b - 55) / 40) : 0;
+	} else if (r == g && g == b && (r - 8) % 10 == 0 && r < 239) {
+		i = 232 + ((r - 8) / 10);
+	} else {
+		unsigned lowest = UINT_MAX;
+		for (int j = 16; j < 256; ++j) {
+			int jr = 0, jg = 0, jb = 0;
+			get_6cube_rgb(j, &jr, &jg, &jb);
+			int dr = jr - r;
+			int dg = jg - g;
+			int db = jb - b;
+			unsigned int distance = dr * dr + dg * dg + db * db;
+			if (distance < lowest) {
+				lowest = distance;
+				i = j;
+			}
+		}
+	}
+
+	if (COLORS <= 16)
+		return color_256_to_16[i];
+	return i;
+}
+
+static CellColor color_terminal(UiTerm *ui, uint8_t index) {
+	return index;
+}
+
+static inline unsigned int color_pair_hash(short fg, short bg) {
+	if (fg == -1)
+		fg = COLORS;
+	if (bg == -1)
+		bg = COLORS + 1;
+	return fg * (COLORS + 2) + bg;
+}
+
+static short color_pair_get(short fg, short bg) {
+	static bool has_default_colors;
+	static short *color2palette, default_fg, default_bg;
+	static short color_pairs_max, color_pair_current;
+
+	if (!color2palette) {
+		pair_content(0, &default_fg, &default_bg);
+		if (default_fg == -1)
+			default_fg = CELL_COLOR_WHITE;
+		if (default_bg == -1)
+			default_bg = CELL_COLOR_BLACK;
+		has_default_colors = (use_default_colors() == OK);
+		color_pairs_max = MIN(COLOR_PAIRS, MAX_COLOR_PAIRS);
+		if (COLORS)
+			color2palette = calloc((COLORS + 2) * (COLORS + 2), sizeof(short));
+	}
+
+	if (fg >= COLORS)
+		fg = default_fg;
+	if (bg >= COLORS)
+		bg = default_bg;
+
+	if (!has_default_colors) {
+		if (fg == -1)
+			fg = default_fg;
+		if (bg == -1)
+			bg = default_bg;
+	}
+
+	if (!color2palette || (fg == -1 && bg == -1))
+		return 0;
+
+	unsigned int index = color_pair_hash(fg, bg);
+	if (color2palette[index] == 0) {
+		short oldfg, oldbg;
+		if (++color_pair_current >= color_pairs_max)
+			color_pair_current = 1;
+		pair_content(color_pair_current, &oldfg, &oldbg);
+		unsigned int old_index = color_pair_hash(oldfg, oldbg);
+		if (init_pair(color_pair_current, fg, bg) == OK) {
+			color2palette[old_index] = 0;
+			color2palette[index] = color_pair_current;
+		}
+	}
+
+	return color2palette[index];
+}
+
+static inline attr_t style_to_attr(CellStyle *style) {
+	return style->attr | COLOR_PAIR(color_pair_get(style->fg, style->bg));
+}
+
+static void ui_curses_blit(UiTerm *tui) {
+	int w = tui->width, h = tui->height;
+	Cell *cell = tui->cells;
+	for (int y = 0; y < h; y++) {
+		for (int x = 0; x < w; x++) {
+			attrset(style_to_attr(&cell->style));
+			mvaddstr(y, x, cell->data);
+			cell++;
+		}
+	}
+	wnoutrefresh(stdscr);
+	doupdate();
+}
+
+static void ui_curses_clear(UiTerm *tui) {
+	clear();
+}
+
+static void ui_curses_resize(UiTerm *tui, int width, int height) {
+	resizeterm(height, width);
+	wresize(stdscr, height, width);
+}
+
+static void ui_curses_save(UiTerm *tui) {
+	curs_set(1);
+	reset_shell_mode();
+}
+
+static void ui_curses_restore(UiTerm *tui) {
+	reset_prog_mode();
+	wclear(stdscr);
+	curs_set(0);
+}
+
+static int ui_curses_colors(Ui *ui) {
+	return COLORS;
+}
+
+static bool ui_curses_init(UiTerm *tui, const char *term) {
+	if (!newterm(term, stderr, stdin)) {
+		snprintf(tui->info, sizeof(tui->info), "Warning: unknown term `%s'", term);
+		if (!newterm(strstr(term, "-256color") ? "xterm-256color" : "xterm", stderr, stdin))
+			return false;
+	}
+	start_color();
+	use_default_colors();
+	raw();
+	noecho();
+	nonl();
+	keypad(stdscr, TRUE);
+	meta(stdscr, TRUE);
+	curs_set(0);
+	return true;
+}
+
+static UiTerm *ui_curses_new(void) {
+	return calloc(1, sizeof(UiTerm));
+}
+
+static void ui_curses_resume(UiTerm *term) { }
+
+static void ui_curses_suspend(UiTerm *term) {
+	if (change_colors == 1)
+		undo_palette();
+	endwin();
+}
+