From 7def9a9bb21a85cff27bffeec36dde56c0bdf9a7 Mon Sep 17 00:00:00 2001
From: Gabor Kiss-Vamosi <kisvegabor@gmail.com>
Date: Mon, 21 Sep 2020 11:57:37 +0200
Subject: [PATCH] add Arduino example

---
 examples/LVGL_Arduino.ino  | 119 +++++++++++++++++++++++++++++++++++++
 src/lv_widgets/lv_slider.c |   3 +-
 2 files changed, 120 insertions(+), 2 deletions(-)
 create mode 100644 examples/LVGL_Arduino.ino

diff --git a/examples/LVGL_Arduino.ino b/examples/LVGL_Arduino.ino
new file mode 100644
index 000000000..4e777c19e
--- /dev/null
+++ b/examples/LVGL_Arduino.ino
@@ -0,0 +1,119 @@
+#include <lvgl.h>
+#include <TFT_eSPI.h>
+
+TFT_eSPI tft = TFT_eSPI(); /* TFT instance */
+static lv_disp_buf_t disp_buf;
+static lv_color_t buf[LV_HOR_RES_MAX * 10];
+
+#if USE_LV_LOG != 0
+/* Serial debugging */
+void my_print(lv_log_level_t level, const char * file, uint32_t line, const char * dsc)
+{
+
+    Serial.printf("%s@%d->%s\r\n", file, line, dsc);
+    Serial.flush();
+}
+#endif
+
+/* Display flushing */
+void my_disp_flush(lv_disp_drv_t *disp, const lv_area_t *area, lv_color_t *color_p)
+{
+    uint32_t w = (area->x2 - area->x1 + 1);
+    uint32_t h = (area->y2 - area->y1 + 1);
+
+    tft.startWrite();
+    tft.setAddrWindow(area->x1, area->y1, w, h);
+    tft.pushColors(&color_p->full, w * h, true);
+    tft.endWrite();
+
+    lv_disp_flush_ready(disp);
+}
+
+/*Read the touchpad*/
+bool my_touchpad_read(lv_indev_drv_t * indev_driver, lv_indev_data_t * data)
+{
+    uint16_t touchX, touchY;
+
+    bool touched = tft.getTouch(&touchX, &touchY, 600);
+
+    if(!touched)
+    {
+      data->state = LV_INDEV_STATE_REL;
+      return false;
+    }
+    else
+    {
+      data->state = LV_INDEV_STATE_PR;
+    }
+
+    if(touchX>screenWidth || touchY > screenHeight)
+    {
+      Serial.println("Y or y outside of expected parameters..");
+      Serial.print("y:");
+      Serial.print(touchX);
+      Serial.print(" x:");
+      Serial.print(touchY);
+    }
+    else
+    {
+      /*Set the coordinates*/
+      data->point.x = touchX;
+      data->point.y = touchY;
+  
+      Serial.print("Data x");
+      Serial.println(touchX);
+      
+      Serial.print("Data y");
+      Serial.println(touchY);
+
+    }
+
+    return false; /*Return `false` because we are not buffering and no more data to read*/
+}
+
+void setup()
+{
+    Serial.begin(115200); /* prepare for possible serial debug */
+
+    lv_init();
+
+#if USE_LV_LOG != 0
+    lv_log_register_print_cb(my_print); /* register print function for debugging */
+#endif
+
+    tft.begin(); /* TFT init */
+    tft.setRotation(1); /* Landscape orientation */
+
+    uint16_t calData[5] = { 275, 3620, 264, 3532, 1 };
+    tft.setTouch(calData);
+  
+    lv_disp_buf_init(&disp_buf, buf, NULL, LV_HOR_RES_MAX * 10);
+
+    /*Initialize the display*/
+    lv_disp_drv_t disp_drv;
+    lv_disp_drv_init(&disp_drv);
+    disp_drv.hor_res = 320;
+    disp_drv.ver_res = 240;
+    disp_drv.flush_cb = my_disp_flush;
+    disp_drv.buffer = &disp_buf;
+    lv_disp_drv_register(&disp_drv);
+
+    /*Initialize the (dummy) input device driver*/
+    lv_indev_drv_t indev_drv;
+    lv_indev_drv_init(&indev_drv);
+    indev_drv.type = LV_INDEV_TYPE_POINTER;
+    indev_drv.read_cb = my_touchpad_read;
+    lv_indev_drv_register(&indev_drv);
+
+		/* Try an example from the lv_examples repository
+		 * https://github.com/lvgl/lv_examples*/
+		lv_ex_btn_1();
+}
+
+
+void loop()
+{
+
+    lv_task_handler(); /* let the GUI do its work */
+    delay(5);
+}
diff --git a/src/lv_widgets/lv_slider.c b/src/lv_widgets/lv_slider.c
index 7e658226d..7cc949244 100644
--- a/src/lv_widgets/lv_slider.c
+++ b/src/lv_widgets/lv_slider.c
@@ -165,8 +165,7 @@ static lv_design_res_t lv_slider_design(lv_obj_t * slider, const lv_area_t * cli
     }
     /*Draw the object*/
     else if(mode == LV_DESIGN_DRAW_MAIN) {
-
-        /*The ancestor design function will draw the background and the indicator.
+        /* The ancestor design function will draw the background and the indicator.
          * It also sets ext->bar.indic_area*/
         ancestor_design_f(slider, clip_area, mode);