adding micropython examples (#2286)

* adding micropython examples

* adding micropython examples

examples/scroll/lv_example_scroll_1.py

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+#
+# Demonstrate how scrolling appears automatically
+#
+# Create an object with the new style
+panel = lv.obj(lv.scr_act())
+panel.set_size(200, 200)
+panel.center()
+
+child = lv.obj(panel)
+child.set_pos(0, 0)
+label = lv.label(child)
+label.set_text("Zero")
+label.center()
+
+child = lv.obj(panel)
+child.set_pos(-40, 100)
+label = lv.label(child)
+label.set_text("Left")
+label.center()
+
+child = lv.obj(panel)
+child.set_pos(90, -30)
+label = lv.label(child)
+label.set_text("Top")
+label.center()
+
+child = lv.obj(panel)
+child.set_pos(150, 80)
+label = lv.label(child)
+label.set_text("Right")
+label.center()
+
+child = lv.obj(panel)
+child.set_pos(60, 170)
+label = lv.label(child)
+label.set_text("Bottom")
+label.center()
+

examples/scroll/lv_example_scroll_2.py

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+def sw_event_cb(e,panel):
+
+    code = e.get_code()
+    sw = e.get_target()
+
+    if code == lv.EVENT.VALUE_CHANGED:
+
+        if sw.has_state(lv.STATE.CHECKED):
+            panel.add_flag(lv.obj.FLAG.SCROLL_ONE)
+        else:
+            panel.clear_flag(lv.obj.FLAG.SCROLL_ONE)
+
+
+#
+# Show an example to scroll snap
+#
+
+panel = lv.obj(lv.scr_act())
+panel.set_size(280, 150)
+panel.set_scroll_snap_x(lv.SCROLL_SNAP.CENTER)
+panel.set_flex_flow(lv.FLEX_FLOW.ROW)
+panel.center()
+
+for i in range(10): 
+    btn = lv.btn(panel)
+    btn.set_size(150, 100)
+
+    label = lv.label(btn)
+    if i == 3:
+        label.set_text("Panel {:d}\nno snap".format(i))
+        btn.clear_flag(lv.obj.FLAG.SNAPABLE)
+    else:
+        label.set_text("Panel {:d}".format(i))
+    label.center()
+
+panel.update_snap(lv.ANIM.ON)
+
+
+# Switch between "One scroll" and "Normal scroll" mode
+sw = lv.switch(lv.scr_act());
+sw.align(lv.ALIGN.TOP_RIGHT, -20, 10)
+sw.add_event_cb(lambda evt:  sw_event_cb(evt,panel), lv.EVENT.ALL, None)
+label = lv.label(lv.scr_act())
+label.set_text("One scroll")
+label.align_to(sw, lv.ALIGN.OUT_BOTTOM_MID, 0, 5)
+
+

examples/scroll/lv_example_scroll_3.py

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+class ScrollExample_3():
+    def __init__(self):
+        self.btn_cnt = 1
+        #
+        # Create a list a with a floating button
+        #
+
+        list = lv.list(lv.scr_act())
+        list.set_size(280, 220)
+        list.center()
+
+        for btn_cnt in range(2):
+            list.add_btn(lv.SYMBOL.AUDIO,"Track {:d}".format(btn_cnt))
+
+            float_btn = lv.btn(list)
+            float_btn.set_size(50, 50)
+            float_btn.add_flag(lv.obj.FLAG.FLOATING)
+            float_btn.align(lv.ALIGN.BOTTOM_RIGHT, 0, -list.get_style_pad_right(lv.PART.MAIN))
+            float_btn.add_event_cb(lambda evt: self.float_btn_event_cb(evt,list), lv.EVENT.ALL, None)
+            float_btn.set_style_radius(lv.RADIUS.CIRCLE, 0)
+            float_btn.set_style_bg_img_src(lv.SYMBOL.PLUS, 0)
+            float_btn.set_style_text_font(lv.theme_get_font_large(float_btn), 0)
+            
+    def float_btn_event_cb(self,e,list):
+        code = e.get_code()
+        float_btn = e.get_target()
+
+        if code == lv.EVENT.CLICKED:
+            list_btn = list.add_btn(lv.SYMBOL.AUDIO, "Track {:d}".format(self.btn_cnt))
+            self.btn_cnt += 1
+
+            float_btn.move_foreground()
+
+            list_btn.scroll_to_view(lv.ANIM.ON)
+            
+scroll_example_3 = ScrollExample_3()
+
+

examples/scroll/lv_example_scroll_4.py

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+#
+# Styling the scrollbars
+#
+obj = lv.obj(lv.scr_act())
+obj.set_size(200, 100)
+obj.center()
+
+label = lv.label(obj)
+label.set_text(
+"""
+Lorem ipsum dolor sit amet, consectetur adipiscing elit.
+Etiam dictum, tortor vestibulum lacinia laoreet, mi neque consectetur neque, vel mattis odio dolor egestas ligula.
+Sed vestibulum sapien nulla, id convallis ex porttitor nec.
+Duis et massa eu libero accumsan faucibus a in arcu.
+Ut pulvinar odio lorem, vel tempus turpis condimentum quis. Nam consectetur condimentum sem in auctor.
+Sed nisl augue, venenatis in blandit et, gravida ac tortor.
+Etiam dapibus elementum suscipit.
+Proin mollis sollicitudin convallis.
+Integer dapibus tempus arcu nec viverra.
+Donec molestie nulla enim, eu interdum velit placerat quis.
+Donec id efficitur risus, at molestie turpis.
+Suspendisse vestibulum consectetur nunc ut commodo.
+Fusce molestie rhoncus nisi sit amet tincidunt.
+Suspendisse a nunc ut magna ornare volutpat.
+""")
+
+
+# Remove the style of scrollbar to have clean start
+obj.remove_style(None, lv.PART.SCROLLBAR | lv.STATE.ANY)
+
+# Create a transition the animate the some properties on state change
+props = [lv.STYLE.BG_OPA, lv.STYLE.WIDTH, 0]
+trans = lv.style_transition_dsc_t()
+trans.init(props, lv.anim_t.path_linear, 200, 0, None)
+
+# Create a style for the scrollbars
+style = lv.style_t()
+style.init()
+style.set_width(4)               # Width of the scrollbar
+style.set_pad_right(5)           # Space from the parallel side
+style.set_pad_top(5)             # Space from the perpendicular side
+
+style.set_radius(2)
+style.set_bg_opa(lv.OPA._70)
+style.set_bg_color(lv.palette_main(lv.PALETTE.BLUE))
+style.set_border_color(lv.palette_darken(lv.PALETTE.BLUE, 3))
+style.set_border_width(2)
+style.set_shadow_width(8)
+style.set_shadow_spread(2)
+style.set_shadow_color(lv.palette_darken(lv.PALETTE.BLUE, 1))
+
+style.set_transition(trans)
+
+# Make the scrollbars wider and use 100% opacity when scrolled
+style_scrolled =  lv.style_t()
+style_scrolled.init()
+style_scrolled.set_width(8)
+style_scrolled.set_bg_opa(lv.OPA.COVER)
+
+obj.add_style(style, lv.PART.SCROLLBAR)
+obj.add_style(style_scrolled, lv.PART.SCROLLBAR | lv.STATE.SCROLLED)
+

examples/scroll/lv_example_scroll_5.py

@@ -0,0 +1,13 @@
+#
+# Scrolling with Right To Left base direction
+#
+obj = lv.obj(lv.scr_act())
+obj.set_style_base_dir(lv.BASE_DIR.RTL, 0)
+obj.set_size(200, 100)
+obj.center()
+
+label = lv.label(obj)
+label.set_text("میکروکُنترولر (به انگلیسی: Microcontroller) گونه‌ای ریزپردازنده است که دارای حافظهٔ دسترسی تصادفی (RAM) و حافظهٔ فقط‌خواندنی (ROM)، تایمر، پورت‌های ورودی و خروجی (I/O) و درگاه ترتیبی (Serial Port پورت سریال)، درون خود تراشه است، و می‌تواند به تنهایی ابزارهای دیگر را کنترل کند. به عبارت دیگر یک میکروکنترلر، مدار مجتمع کوچکی است که از یک CPU کوچک و اجزای دیگری مانند تایمر، درگاه‌های ورودی و خروجی آنالوگ و دیجیتال و حافظه تشکیل شده‌است.")
+label.set_width(400)
+label.set_style_text_font(lv.font_dejavu_16_persian_hebrew, 0)
+

examples/scroll/lv_example_scroll_6.py

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+def scroll_event_cb(e):
+
+    cont = e.get_target()
+
+    cont_a = lv.area_t()
+    cont.get_coords(cont_a)
+    cont_y_center = cont_a.y1 + cont_a.get_height() // 2
+
+    r = cont.get_height() * 7 // 10
+    
+    child_cnt = cont.get_child_cnt()
+    for i in range(child_cnt):
+        child = cont.get_child(i)
+        child_a = lv.area_t()
+        child.get_coords(child_a)
+
+        child_y_center = child_a.y1 + child_a.get_height() // 2
+
+        diff_y = child_y_center - cont_y_center;
+        diff_y = abs(diff_y)
+
+        # Get the x of diff_y on a circle.
+        
+        # If diff_y is out of the circle use the last point of the circle (the radius)
+        if diff_y >= r:
+            x = r
+        else:
+            # Use Pythagoras theorem to get x from radius and y
+            x_sqr = r * r - diff_y * diff_y;
+            res = lv.sqrt_res_t()
+            lv.sqrt(x_sqr, res, 0x8000)   # Use lvgl's built in sqrt root function
+            x = r - res.i
+
+        # Translate the item by the calculated X coordinate
+        child.set_style_translate_x(x, 0)
+
+        # Use some opacity with larger translations
+        opa = lv.map(x, 0, r, lv.OPA.TRANSP, lv.OPA.COVER)
+        child.set_style_opa(lv.OPA.COVER - opa, 0)
+
+#
+# Translate the object as they scroll
+#
+
+cont = lv.obj(lv.scr_act())
+cont.set_size(200, 200)
+cont.center()
+cont.set_flex_flow(lv.FLEX_FLOW.COLUMN)
+cont.add_event_cb(scroll_event_cb, lv.EVENT.SCROLL, None)
+cont.set_style_radius(lv.RADIUS.CIRCLE, 0)
+cont.set_style_clip_corner(True, 0)
+cont.set_scroll_dir(lv.DIR.VER)
+cont.set_scroll_snap_y(lv.SCROLL_SNAP.CENTER)
+cont.set_scrollbar_mode(lv.SCROLLBAR_MODE.OFF)
+
+for i in range(20):
+    btn = lv.btn(cont)
+    btn.set_width(lv.pct(100))
+    
+    label = lv.label(btn)
+    label.set_text("Button " + str(i))
+
+    # Update the buttons position manually for first*
+    lv.event_send(cont, lv.EVENT.SCROLL, None)
+
+    # Be sure the fist button is in the middle
+    #lv.obj.scroll_to_view(cont.get_child(0), lv.ANIM.OFF)
+    cont.get_child(0).scroll_to_view(lv.ANIM.OFF)