From fede96edc958de9c79a761e5dd5dd2f3f9f557f3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Franti=C5=A1ek=20Boh=C3=A1=C4=8Dek?=
 <fandabohacek@gmail.com>
Date: Wed, 16 Jun 2021 10:17:55 +0200
Subject: [PATCH] refactor: add option to clear display without render

---
 image-viewer/include/display_utils.h |  3 ++-
 image-viewer/src/display_utils.c     | 14 ++++++++------
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/image-viewer/include/display_utils.h b/image-viewer/include/display_utils.h
index a8d8c88..4f1484d 100644
--- a/image-viewer/include/display_utils.h
+++ b/image-viewer/include/display_utils.h
@@ -2,6 +2,7 @@
 #define __DISPLAY_UTILS_H__
 
 #include <stdint.h>
+#include <stdbool.h>
 
 #define DISPLAY_MAX_RED 31u
 #define DISPLAY_MAX_GREEN 63u
@@ -53,7 +54,7 @@ display_t display_init(display_data_t data);
 void display_deinit(display_t *display);
 
 void display_render(display_t *display);
-void display_clear(display_t *display);
+void display_clear(display_t *display, bool render);
 
 display_pixel_t display_get_pixel(display_t *display, uint16_t x, uint16_t y);
 void display_set_pixel(display_t *display, uint16_t x, uint16_t y,
diff --git a/image-viewer/src/display_utils.c b/image-viewer/src/display_utils.c
index 321704b..ff4e74e 100644
--- a/image-viewer/src/display_utils.c
+++ b/image-viewer/src/display_utils.c
@@ -5,6 +5,7 @@
 #ifdef COMPUTER
 #include "xwin_sdl.h"
 #endif
+
 const display_pixel_t BLACK_PIXEL = {.bits = 0};
 const display_pixel_t WHITE_PIXEL = {.bits = 0xFFFF};
 
@@ -50,12 +51,13 @@ display_t display_init(display_data_t data) {
 
   if (data.base_address != NULL) {
     parlcd_hx8357_init(data.base_address);
-    display_clear(&display);
+    display_clear(&display, true);
   }
 
   #ifdef COMPUTER
   xwin_init(DISPLAY_WIDTH, DISPLAY_HEIGHT);
   #endif
+
   return display;
 }
 void display_deinit(display_t *display) {
@@ -84,19 +86,19 @@ void display_render(display_t *display) {
   for (int i = 0; i < count; i++) {
     parlcd_write_data(display->data.base_address, display->pixels[i].bits);
   }
+  #endif
 }
 
-void display_clear(display_t *display) {
-  if (display->data.base_address == NULL) {
-    return;
-  }
+void display_clear(display_t *display, bool render) {
 
   int count = DISPLAY_HEIGHT * DISPLAY_WIDTH;
   for (int i = 0; i < count; i++) {
     display->pixels[i] = BLACK_PIXEL;
   }
 
-  display_render(display);
+  if (render) {
+    display_render(display);
+  }
 }
 
 display_pixel_t display_get_pixel(display_t *display, uint16_t x, uint16_t y) {
-- 
2.48.1