From a6908296b6ac83ab3eb5474ad6b4a509c8f5099c Mon Sep 17 00:00:00 2001
From: P. J. McDermott <pj@pehjota.net>
Date: Thu, 27 Jan 2022 04:59:39 -0500
Subject: tk: Blink text cursor

---
(limited to 'src/tk')

diff --git a/src/tk/style.h b/src/tk/style.h
index be4c2bb..95bbf00 100644
--- a/src/tk/style.h
+++ b/src/tk/style.h
@@ -45,4 +45,6 @@
 #define MFTK_COLOR_CHKM_B 0x00
 #define MFTK_COLOR_CHKM_A 0xFF
 
+#define MFTK_CURSOR_BLINK_MS 500  /* Milliseconds between cursor blinks */
+
 #endif  /* MFTK_STYLE_H_ */
diff --git a/src/tk/text.c b/src/tk/text.c
index 9ba9faa..76bb27a 100644
--- a/src/tk/text.c
+++ b/src/tk/text.c
@@ -41,6 +41,8 @@ struct mftk_text {
 	int                  ascent;
 	SDL_Texture         *texture;
 	int                  editable;
+	int                  blink_state;
+	Uint32               blink_timer;
 	int                (*action)(void *, const char *);
 	int                (*submit)(void *);
 	void                *user_data;
@@ -60,7 +62,12 @@ _mftk_text_layout(struct mftk_widget *w __attribute__((__unused__)))
 static void
 _mftk_text_focus(struct mftk_widget *w __attribute__((__unused__)))
 {
+	struct mftk_text *t = (struct mftk_text *) w;
+
 	SDL_StartTextInput();
+
+	t->blink_state = SDL_TRUE;
+	t->blink_timer = SDL_GetTicks();
 }
 
 static void
@@ -78,6 +85,9 @@ _mftk_text_key_event(struct mftk_widget *w, SDL_Event *e)
 	int               newlen;
 	int               j;
 
+	t->blink_state = SDL_TRUE;
+	t->blink_timer = SDL_GetTicks();
+
 	switch (e->type) {
 		case SDL_KEYDOWN:
 			switch (e->key.keysym.sym) {
@@ -249,6 +259,7 @@ _mftk_text_render(struct mftk_widget *w, SDL_Renderer *renderer, int x, int y)
 	struct mftk_text *t = (struct mftk_text *) w;
 	SDL_Rect          rect;
 	int               cur_x;
+	Uint32            timer;
 
 	if (t->val[0] != '\0' && t->texture == NULL &&
 			_mftk_text_render_val(t, renderer) < 0) {
@@ -282,7 +293,17 @@ _mftk_text_render(struct mftk_widget *w, SDL_Renderer *renderer, int x, int y)
 				SDL_GetError());
 		return -1;
 	}
-	if (w->focused == SDL_TRUE && SDL_RenderDrawLine(renderer,
+	timer = SDL_GetTicks();
+	if (timer - t->blink_timer >= MFTK_CURSOR_BLINK_MS) {
+		if (t->blink_state == SDL_TRUE) {
+			t->blink_state = SDL_FALSE;
+		} else if (t->blink_state == SDL_FALSE) {
+			t->blink_state = SDL_TRUE;
+		}
+		t->blink_timer = timer;
+	}
+	if (w->focused == SDL_TRUE && t->blink_state == SDL_TRUE &&
+			SDL_RenderDrawLine(renderer,
 				x + cur_x, y + t->y, x + cur_x, y + t->h) < 0) {
 		SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
 				"Couldn't render widget: %s",
@@ -327,6 +348,8 @@ mftk_text_new(const char *allowed_chars, int len, const char *val,
 	t->ascent        = TTF_FontAscent  (font);
 	t->texture       = NULL;
 	t->editable      = editable;
+	t->blink_state   = SDL_TRUE;
+	t->blink_timer   = 0;
 	t->action        = action;
 	t->submit        = submit;
 	t->user_data     = user_data;
--
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