From 588b14f02925ea432a0425dfce0064a9db628c28 Mon Sep 17 00:00:00 2001
From: martinberlin <martin@luckycloud.de>
Date: Sun, 13 Jun 2021 15:18:48 +0200
Subject: [PATCH] Leave buf_copy_to_framebuffer as the default method and Gabor
 method as secondary

---
 lvgl_tft/epdiy_epaper.cpp | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/lvgl_tft/epdiy_epaper.cpp b/lvgl_tft/epdiy_epaper.cpp
index 569781c..898889b 100644
--- a/lvgl_tft/epdiy_epaper.cpp
+++ b/lvgl_tft/epdiy_epaper.cpp
@@ -12,8 +12,8 @@ uint8_t temperature = 25;
 bool init = true;
 // MODE_DU: Fast monochrome | MODE_GC16 slow with 16 grayscales
 enum EpdDrawMode updateMode = MODE_DU;
-
-#define BUF_MAX 111600
+// Ideally this BUF should be width/2*height = 259200. Now set to 111600
+#define BUF_MAX 110400
 
 /* Display initialization routine */
 void epdiy_init(void)
@@ -26,6 +26,18 @@ void epdiy_init(void)
     epd_fullclear(&hl, temperature);
 }
 
+/* Suggested by @kisvegabor https://forum.lvgl.io/t/lvgl-port-to-be-used-with-epaper-displays/5630/26 */
+void buf_area_to_framebuffer(const lv_area_t *area, const uint8_t *image_data) {
+  assert(framebuffer != NULL);
+  uint8_t *fb_ptr = &framebuffer[area->y1 * EPD_WIDTH / 2 + area->x1 / 2];
+  lv_coord_t img_w = lv_area_get_width(area);
+  for(uint32_t y = area->y1; y < area->y2; y++) {
+      memcpy(fb_ptr, image_data, img_w / 2);
+      fb_ptr += EPD_WIDTH / 2;
+      image_data += img_w / 2;
+  }
+}
+
 /* A copy from epd_copy_to_framebuffer with temporary lenght prediction */
 void buf_copy_to_framebuffer(EpdRect image_area, const uint8_t *image_data) {
   assert(framebuffer != NULL);
@@ -34,10 +46,10 @@ void buf_copy_to_framebuffer(EpdRect image_area, const uint8_t *image_data) {
     // Get out if we get the end of the buffer. Question: How to detect the end without a lenght?
     // Zero terminator check gets out before: (image_data[value_index / 2]== '\0')  
     // 111684 seems to be the last element in image_data
-    if (i / 2 > BUF_MAX) {
+    /* if (i / 2 > BUF_MAX) {
         printf("FOUND END incr:%d Aw:%d Ah:%d\n", i, image_area.width, image_area.height);
         break;
-    } 
+    }  */
     uint8_t val = (i % 2) ? (image_data[i / 2] & 0xF0) >> 4
                                     : image_data[i / 2] & 0x0F;
     int xx = image_area.x + i % image_area.width;
@@ -81,6 +93,9 @@ void epdiy_flush(lv_disp_drv_t *drv, const lv_area_t *area, lv_color_t *color_ma
     // Does not work for full screen update yet (Should check large of buf)
     buf_copy_to_framebuffer(update_area, buf);
 
+    //Faster mode suggested in LVGL forum (Leaves ghosting)
+    //buf_area_to_framebuffer(area, buf);
+
     epd_hl_update_area(&hl, updateMode, temperature, update_area); //update_area
 
     printf("epdiy_flush %d x:%d y:%d w:%d h:%d\n", flushcalls,(uint16_t)area->x1,(uint16_t)area->y1,w,h);
@@ -89,8 +104,7 @@ void epdiy_flush(lv_disp_drv_t *drv, const lv_area_t *area, lv_color_t *color_ma
 }
 
 /* 
- * Called for each pixel. Designed with the idea to fill the buffer directly, not to set each pixel, see:
- * https://forum.lvgl.io/t/lvgl-port-to-be-used-with-epaper-displays/5630/3
+ * Called for each pixel. Designed with the idea to fill the buffer directly, not to set each pixel, see LVGL Forum (buf_area_to_framebuffer)
 */
 void epdiy_set_px_cb(lv_disp_drv_t * disp_drv, uint8_t* buf,
     lv_coord_t buf_w, lv_coord_t x, lv_coord_t y,