vis: try to reduce number of redraws

This is a not yet successful attempt to reduce terminal flickering
when resizing windows as is for example the case when entering
command mode.

UI related debug output can be enabled with:

 $ make CFLAGS=-DDEBUG_UI=1
 $ ./vis > log

5 files changed, 34 insertions, 23 deletions

diff --git a/ui-curses.c b/ui-curses.c
index fe3a966..1b01166 100644
--- a/ui-curses.c
+++ b/ui-curses.c
@@ -44,6 +44,16 @@ int ESCDELAY;
 
 #define CONTROL(k) ((k)&0x1F)
 
+#ifndef DEBUG_UI
+#define DEBUG_UI 0
+#endif
+
+#if DEBUG_UI
+#define debug(...) do { printf(__VA_ARGS__); fflush(stdout); } while (0)
+#else
+#define debug(...) do { } while (0)
+#endif
+
 #if 0
 #define wresize(win, y, x) do { \
 	if (wresize(win, y, x) == ERR) { \
@@ -572,6 +582,7 @@ static bool ui_window_syntax_style(UiWin *w, int id, const char *style) {
 }
 
 static void ui_window_resize(UiCursesWin *win, int width, int height) {
+	debug("ui-win-resize[%s]: %dx%d\n", win->file->name ? win->file->name : "noname", width, height);
 	win->width = width;
 	win->height = height;
 	if (win->winstatus)
@@ -580,10 +591,10 @@ static void ui_window_resize(UiCursesWin *win, int width, int height) {
 	if (win->winside)
 		wresize(win->winside, height-1, win->sidebar_width);
 	view_resize(win->view, width - win->sidebar_width, win->winstatus ? height - 1 : height);
-	view_update(win->view);
 }
 
 static void ui_window_move(UiCursesWin *win, int x, int y) {
+	debug("ui-win-move[%s]: (%d, %d)\n", win->file->name ? win->file->name : "noname", x, y);
 	win->x = x;
 	win->y = y;
 	mvwin(win->win, y, x + win->sidebar_width);
@@ -648,6 +659,7 @@ static void ui_window_draw(UiWin *w) {
 	if (!ui_window_draw_sidebar(win))
 		return;
 
+	debug("ui-win-draw[%s]\n", win->file->name ? win->file->name : "noname");
 	wbkgd(win->win, style_to_attr(&win->styles[UI_STYLE_DEFAULT]));
 	wmove(win->win, 0, 0);
 	int width = view_width_get(win->view);
@@ -718,6 +730,7 @@ static void ui_window_reload(UiWin *w, File *file) {
 }
 
 static void ui_window_update(UiCursesWin *win) {
+	debug("ui-win-update[%s]\n", win->file->name ? win->file->name : "noname");
 	if (win->winstatus)
 		wnoutrefresh(win->winstatus);
 	if (win->winside)
@@ -726,6 +739,7 @@ static void ui_window_update(UiCursesWin *win) {
 }
 
 static void ui_arrange(Ui *ui, enum UiLayout layout) {
+	debug("ui-arrange\n");
 	UiCurses *uic = (UiCurses*)ui;
 	uic->layout = layout;
 	int n = 0, m = !!uic->info[0], x = 0, y = 0;
@@ -769,6 +783,7 @@ static void ui_arrange(Ui *ui, enum UiLayout layout) {
 }
 
 static void ui_draw(Ui *ui) {
+	debug("ui-draw\n");
 	UiCurses *uic = (UiCurses*)ui;
 	erase();
 	ui_arrange(ui, uic->layout);
@@ -815,16 +830,14 @@ static void ui_resize(Ui *ui) {
 static void ui_update(Ui *ui) {
 	UiCurses *uic = (UiCurses*)ui;
 	if (need_resize) {
-		ui_resize(ui);
 		need_resize = false;
+		ui_resize(ui);
+		vis_update(uic->vis);
+		return;
 	}
-	for (UiCursesWin *win = uic->windows; win; win = win->next) {
-		if (win != uic->selwin)
-			ui_window_update(win);
-	}
-
-	if (uic->selwin)
-		ui_window_update(uic->selwin);
+	for (UiCursesWin *win = uic->windows; win; win = win->next)
+		ui_window_update(win);
+	debug("ui-doupdate\n");
 	doupdate();
 }
 
diff --git a/view.c b/view.c
index 4b06d3a..33e73cd 100644
--- a/view.c
+++ b/view.c
@@ -513,6 +513,8 @@ bool view_resize(View *view, int width, int height) {
 		width = 1;
 	if (height <= 0)
 		height = 1;
+	if (view->width == width && view->height == height)
+		return true;
 	size_t lines_size = height*(sizeof(Line) + width*sizeof(Cell));
 	if (lines_size > view->lines_size) {
 		Line *lines = realloc(view->lines, lines_size);
@@ -525,6 +527,8 @@ bool view_resize(View *view, int width, int height) {
 	view->height = height;
 	memset(view->lines, 0, view->lines_size);
 	view_draw(view);
+	if (view->ui)
+		view_update(view);
 	return true;
 }
 
diff --git a/vis-core.h b/vis-core.h
index 51c9447..9e3c4f1 100644
--- a/vis-core.h
+++ b/vis-core.h
@@ -197,7 +197,7 @@ void action_reset(Action*);
 void mode_set(Vis *vis, Mode *new_mode);
 
 void window_selection_save(Win *win);
-Win *window_new_file(Vis *vis, File *file);
+Win *window_new_file(Vis*, File*, enum UiOption);
 
 const char *file_name_get(File*);
 void file_name_set(File*, const char *name);
diff --git a/vis-prompt.c b/vis-prompt.c
index 8f7e1a9..ffe3ea2 100644
--- a/vis-prompt.c
+++ b/vis-prompt.c
@@ -152,17 +152,16 @@ static const KeyBinding prompt_backspace_binding = {
 
 void vis_prompt_show(Vis *vis, const char *title) {
 	Win *active = vis->win;
-	Win *prompt = window_new_file(vis, title[0] == ':' ? vis->command_file : vis->search_file);
+	Win *prompt = window_new_file(vis, title[0] == ':' ? vis->command_file : vis->search_file,
+		UI_OPTION_ONELINE);
 	if (!prompt)
 		return;
 	if (vis->mode->visual)
 		window_selection_save(active);
-	view_options_set(prompt->view, UI_OPTION_ONELINE);
 	Text *txt = prompt->file->text;
 	text_insert(txt, text_size(txt), title, strlen(title));
 	Cursor *cursor = view_cursors_primary_get(prompt->view);
 	view_cursors_scroll_to(cursor, text_size(txt));
-	view_draw(prompt->view);
 	prompt->parent = active;
 	prompt->parent_mode = vis->mode;
 	vis_window_mode_map(prompt, VIS_MODE_NORMAL, true, "<Enter>", &prompt_enter_binding);
@@ -172,7 +171,6 @@ void vis_prompt_show(Vis *vis, const char *title) {
 	vis_window_mode_map(prompt, VIS_MODE_INSERT, true, "<Up>", &prompt_up_binding);
 	vis_window_mode_map(prompt, VIS_MODE_INSERT, true, "<Backspace>", &prompt_backspace_binding);
 	vis_mode_switch(vis, VIS_MODE_INSERT);
-	vis_draw(vis);
 }
 
 void vis_info_show(Vis *vis, const char *msg, ...) {
@@ -190,7 +188,7 @@ void vis_message_show(Vis *vis, const char *msg) {
 	if (!msg)
 		return;
 	if (!vis->message_window)
-		vis->message_window = window_new_file(vis, vis->error_file);
+		vis->message_window = window_new_file(vis, vis->error_file, UI_OPTION_STATUSBAR);
 	Win *win = vis->message_window;
 	if (!win)
 		return;
diff --git a/vis.c b/vis.c
index 3b5e0d0..cdc3057 100644
--- a/vis.c
+++ b/vis.c
@@ -217,7 +217,7 @@ static void window_draw(void *ctx) {
 	}
 }
 
-Win *window_new_file(Vis *vis, File *file) {
+Win *window_new_file(Vis *vis, File *file, enum UiOption options) {
 	Win *win = calloc(1, sizeof(Win));
 	if (!win)
 		return NULL;
@@ -228,7 +228,7 @@ Win *window_new_file(Vis *vis, File *file) {
 	win->event.draw = window_draw;
 	win->horizon = 1 << 15;
 	win->view = view_new(file->text, &win->event);
-	win->ui = vis->ui->window_new(vis->ui, win->view, file, UI_OPTION_STATUSBAR);
+	win->ui = vis->ui->window_new(vis->ui, win->view, file, options);
 	if (!win->jumplist || !win->view || !win->ui) {
 		window_free(win);
 		return NULL;
@@ -267,7 +267,7 @@ bool vis_window_reload(Win *win) {
 }
 
 bool vis_window_split(Win *original) {
-	Win *win = window_new_file(original->vis, original->file);
+	Win *win = window_new_file(original->vis, original->file, UI_OPTION_STATUSBAR);
 	if (!win)
 		return false;
 	for (size_t i = 0; i < LENGTH(win->modes); i++) {
@@ -281,7 +281,6 @@ bool vis_window_split(Win *original) {
 	vis_window_syntax_set(win, vis_window_syntax_get(original));
 	view_options_set(win->view, view_options_get(original->view));
 	view_cursor_to(win->view, view_cursor_get(original->view));
-	vis_draw(win->vis);
 	return true;
 }
 
@@ -344,7 +343,6 @@ void vis_redraw(Vis *vis) {
 void vis_update(Vis *vis) {
 	for (Win *win = vis->windows; win; win = win->next)
 		view_update(win->view);
-	view_update(vis->win->view);
 	vis->ui->update(vis->ui);
 }
 
@@ -356,14 +354,12 @@ bool vis_window_new(Vis *vis, const char *filename) {
 	File *file = file_new(vis, filename);
 	if (!file)
 		return false;
-	Win *win = window_new_file(vis, file);
+	Win *win = window_new_file(vis, file, UI_OPTION_STATUSBAR);
 	if (!win) {
 		file_free(vis, file);
 		return false;
 	}
 
-	vis_draw(vis);
-
 	return true;
 }