From 7522f4e2f0b066f6f98939d05e80cdb1ce0e52c1 Mon Sep 17 00:00:00 2001
From: Gabor Kiss-Vamosi <kisvegabor@gmail.com>
Date: Mon, 24 May 2021 15:11:07 +0200
Subject: [PATCH] feat(chart) add scatter chart example

---
 examples/widgets/chart/lv_example_chart_7.c | 59 +++++++++++++++++++++
 examples/widgets/lv_example_widgets.h       |  1 +
 2 files changed, 60 insertions(+)
 create mode 100644 examples/widgets/chart/lv_example_chart_7.c

diff --git a/examples/widgets/chart/lv_example_chart_7.c b/examples/widgets/chart/lv_example_chart_7.c
new file mode 100644
index 000000000..8f4a9a660
--- /dev/null
+++ b/examples/widgets/chart/lv_example_chart_7.c
@@ -0,0 +1,59 @@
+#include "../../lv_examples.h"
+#if LV_USE_CHART && LV_BUILD_EXAMPLES
+
+static void draw_event_cb(lv_event_t * e)
+{
+    lv_obj_draw_part_dsc_t * dsc = lv_event_get_draw_part_dsc(e);
+    if(dsc->part == LV_PART_ITEMS) {
+        lv_obj_t * obj = lv_event_get_target(e);
+        uint32_t cnt = lv_chart_get_point_count(obj);
+        /*Make older value more transparent*/
+        dsc->rect_dsc->bg_opa = (LV_OPA_COVER *  dsc->id) / (cnt - 1);
+
+        /*Make smaller values blue, higher values red*/
+        dsc->rect_dsc->bg_color = lv_color_mix(lv_palette_main(LV_PALETTE_RED),
+                                                lv_palette_main(LV_PALETTE_BLUE),
+                                               (dsc->value * LV_OPA_COVER) / 1000);
+    }
+}
+
+static void add_data(lv_timer_t * timer)
+{
+    LV_UNUSED(timer);
+    static uint32_t cnt = 0;
+    lv_obj_t * chart = timer->user_data;
+    lv_chart_set_next_value2(chart, lv_chart_get_series_next(chart, NULL), lv_rand(-100,100), lv_rand(0,1000));
+}
+
+/**
+ * A scatter chart
+ */
+void lv_example_chart_7(void)
+{
+    lv_obj_t * chart = lv_chart_create(lv_scr_act());
+    lv_obj_set_size(chart, 200, 150);
+    lv_obj_align(chart, LV_ALIGN_CENTER, 0, -0);
+    lv_obj_add_event_cb(chart, draw_event_cb, LV_EVENT_DRAW_PART_BEGIN, NULL);
+    lv_obj_set_style_line_width(chart, 0, LV_PART_ITEMS);
+
+    lv_chart_set_type(chart, LV_CHART_TYPE_SCATTER);
+
+    lv_chart_set_axis_tick(chart, LV_CHART_AXIS_PRIMARY_X, 10, 5, 10, 1, true, 30);
+    lv_chart_set_axis_tick(chart, LV_CHART_AXIS_PRIMARY_Y, 10, 5, 6, 5, true, 50);
+
+    lv_chart_set_range(chart, LV_CHART_AXIS_PRIMARY_X, -100, 100);
+    lv_chart_set_range(chart, LV_CHART_AXIS_PRIMARY_Y, 0, 1000);
+
+
+    lv_chart_set_point_count(chart, 50);
+
+    lv_chart_series_t * ser = lv_chart_add_series(chart, lv_palette_main(LV_PALETTE_RED), LV_CHART_AXIS_PRIMARY_Y);
+    uint32_t i;
+    for(i = 0; i < 50; i++) {
+        lv_chart_set_next_value2(chart, ser, lv_rand(-100,100), lv_rand(0,1000));
+    }
+
+    lv_timer_create(add_data, 100, chart);
+}
+
+#endif
diff --git a/examples/widgets/lv_example_widgets.h b/examples/widgets/lv_example_widgets.h
index 526a23bbf..5faa99b11 100644
--- a/examples/widgets/lv_example_widgets.h
+++ b/examples/widgets/lv_example_widgets.h
@@ -56,6 +56,7 @@ void lv_example_chart_3(void);
 void lv_example_chart_4(void);
 void lv_example_chart_5(void);
 void lv_example_chart_6(void);
+void lv_example_chart_7(void);
 
 void lv_example_checkbox_1(void);