From 42ccc3ac28dcf0cd36d373452d2182caabafff00 Mon Sep 17 00:00:00 2001
From: Federico Amedeo Izzo <federico.izzo42@gmail.com>
Date: Sun, 29 Nov 2020 08:43:58 +0100
Subject: [PATCH] GFX: Add gfx_clearRows() implementation

---
 openrtx/include/interfaces/graphics.h  | 13 ++++++++++++-
 openrtx/src/graphics/graphics_rgb565.c | 10 ++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/openrtx/include/interfaces/graphics.h b/openrtx/include/interfaces/graphics.h
index 9e8f47a5..a64e032b 100644
--- a/openrtx/include/interfaces/graphics.h
+++ b/openrtx/include/interfaces/graphics.h
@@ -147,7 +147,18 @@ void gfx_render();
 bool gfx_renderingInProgress();
 
 /**
- * Makes the screen black.
+ * Clears a portion of the screen content
+ * This results in a black screen on color displays
+ * And a white screen on B/W displays
+ * @param startRow: first row of the framebuffer section to be cleared
+ * @param endRow: last row of the framebuffer section to be cleared
+ */
+void gfx_clearRows(uint8_t startRow, uint8_t endRow);
+
+/**
+ * Clears the content of the screen
+ * This results in a black screen on color displays
+ * And a white screen on B/W displays
  */
 void gfx_clearScreen();
 
diff --git a/openrtx/src/graphics/graphics_rgb565.c b/openrtx/src/graphics/graphics_rgb565.c
index bcb7487d..d627d06b 100644
--- a/openrtx/src/graphics/graphics_rgb565.c
+++ b/openrtx/src/graphics/graphics_rgb565.c
@@ -85,6 +85,16 @@ rgb565_t _true2highColor(color_t true_color)
     return high_color;
 }
 
+void gfx_clearRows(uint8_t startRow, uint8_t endRow)
+{
+    if(!initialized) return;
+    if(endRow < startRow) return;
+    uint16_t start = startRow * SCREEN_WIDTH * sizeof(rgb565_t);
+    uint16_t height = endRow - startRow * SCREEN_WIDTH * sizeof(rgb565_t);
+    // Set the specified rows to 0x00 = make the screen black
+    memset(buf + start, 0x00, height);
+}
+
 void gfx_clearScreen()
 {
     if(!initialized) return;