From b6528469df637d4b47a026b2d4761a1776272747 Mon Sep 17 00:00:00 2001
From: Diego Sueiro <diego.sueiro@gmail.com>
Date: Sun, 4 Nov 2018 09:01:02 +0000
Subject: [PATCH] subsys/fb/cfb: Introduce cfb_framebuffer_invert function

Adds the cfb_framebuffer_invert function to invert Pixels in the
Character Framebuffer

Signed-off-by: Diego Sueiro <diego.sueiro@gmail.com>
---
 include/display/cfb.h |  9 +++++++++
 subsys/fb/cfb.c       | 14 ++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/include/display/cfb.h b/include/display/cfb.h
index 2ce79e9b652..6de9bdc5f0a 100644
--- a/include/display/cfb.h
+++ b/include/display/cfb.h
@@ -100,6 +100,15 @@ int cfb_print(struct device *dev, char *str, u16_t x, u16_t y);
  */
 int cfb_framebuffer_clear(struct device *dev, bool clear_display);
 
+/**
+ * @brief Invert Pixels.
+ *
+ * @param dev Pointer to device structure for driver instance
+ *
+ * @return 0 on success, negative value otherwise
+ */
+int cfb_framebuffer_invert(struct device *dev);
+
 /**
  * @brief Finalize framebuffer and write it to display RAM,
  * invert or reorder pixels if necessary.
diff --git a/subsys/fb/cfb.c b/subsys/fb/cfb.c
index d0ef674bd22..9e86e528f0f 100644
--- a/subsys/fb/cfb.c
+++ b/subsys/fb/cfb.c
@@ -185,6 +185,20 @@ int cfb_framebuffer_clear(struct device *dev, bool clear_display)
 	return 0;
 }
 
+
+int cfb_framebuffer_invert(struct device *dev)
+{
+	struct char_framebuffer *fb = &char_fb;
+
+	if (!fb || !fb->buf) {
+		return -1;
+	}
+
+	fb->inverted = !fb->inverted;
+
+	return 0;
+}
+
 int cfb_framebuffer_finalize(struct device *dev)
 {
 	const struct display_driver_api *api = dev->driver_api;