From 9def1258a0a33360780f4f6cec16aadec960ebb7 Mon Sep 17 00:00:00 2001
From: TOKITA Hiroshi <tokita.hiroshi@fujitsu.com>
Date: Fri, 12 May 2023 07:46:27 +0900
Subject: [PATCH] fb: cfb: Add cfb_draw_point() API

Add cfb_draw_point() API for rendering dot.

Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@fujitsu.com>
---
 include/zephyr/display/cfb.h | 15 +++++++++++++++
 subsys/fb/cfb.c              | 30 ++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)

diff --git a/include/zephyr/display/cfb.h b/include/zephyr/display/cfb.h
index 0d0da059d25..e7dc53b3f9c 100644
--- a/include/zephyr/display/cfb.h
+++ b/include/zephyr/display/cfb.h
@@ -57,6 +57,11 @@ struct cfb_font {
 	uint8_t last_char;
 };
 
+struct cfb_position {
+	uint16_t x;
+	uint16_t y;
+};
+
 /**
  * @brief Macro for creating a font entry.
  *
@@ -104,6 +109,16 @@ int cfb_print(const struct device *dev, const char *const str, uint16_t x, uint1
  */
 int cfb_draw_text(const struct device *dev, const char *const str, int16_t x, int16_t y);
 
+/**
+ * @brief Draw a point.
+ *
+ * @param dev Pointer to device structure for driver instance
+ * @param pos position of the point
+ *
+ * @return 0 on success, negative value otherwise
+ */
+int cfb_draw_point(const struct device *dev, const struct cfb_position *pos);
+
 /**
  * @brief Clear framebuffer.
  *
diff --git a/subsys/fb/cfb.c b/subsys/fb/cfb.c
index f26fc45fd9e..010151ab8d7 100644
--- a/subsys/fb/cfb.c
+++ b/subsys/fb/cfb.c
@@ -183,6 +183,27 @@ static uint8_t draw_char_vtmono(const struct char_framebuffer *fb,
 	return fptr->width;
 }
 
+static inline void draw_point(struct char_framebuffer *fb, int16_t x, int16_t y)
+{
+	const bool need_reverse = ((fb->screen_info & SCREEN_INFO_MONO_MSB_FIRST) != 0);
+	const size_t index = ((y / 8) * fb->x_res);
+	uint8_t m = BIT(y % 8);
+
+	if (x < 0 || x >= fb->x_res) {
+		return;
+	}
+
+	if (y < 0 || y >= fb->y_res) {
+		return;
+	}
+
+	if (need_reverse) {
+		m = byte_reverse(m);
+	}
+
+	fb->buf[index + x] |= m;
+}
+
 static int draw_text(const struct device *dev, const char *const str, int16_t x, int16_t y,
 		     bool wrap)
 {
@@ -215,6 +236,15 @@ static int draw_text(const struct device *dev, const char *const str, int16_t x,
 	return -EINVAL;
 }
 
+int cfb_draw_point(const struct device *dev, const struct cfb_position *pos)
+{
+	struct char_framebuffer *fb = &char_fb;
+
+	draw_point(fb, pos->x, pos->y);
+
+	return 0;
+}
+
 int cfb_draw_text(const struct device *dev, const char *const str, int16_t x, int16_t y)
 {
 	return draw_text(dev, str, x, y, false);