adding micropython examples (#2286)

* adding micropython examples

* adding micropython examples

examples/widgets/img/lv_example_img_3.py

@@ -0,0 +1,61 @@
+#!/opt/bin/lv_micropython -i
+import sys
+import lvgl as lv
+import display_driver
+from imagetools import get_png_info, open_png
+
+# Register PNG image decoder
+decoder = lv.img.decoder_create()
+decoder.info_cb = get_png_info
+decoder.open_cb = open_png
+
+# Create an image from the png file
+try:
+    with open('../../assets/img_cogwheel_argb.png','rb') as f:
+        png_data = f.read()
+except:
+    print("Could not find img_cogwheel_argb.png")
+    sys.exit()
+    
+img_cogwheel_argb = lv.img_dsc_t({
+  'data_size': len(png_data),
+  'data': png_data 
+})
+
+def set_angle(img, v):
+    img.set_angle(v)
+
+def set_zoom(img, v):
+    img.set_zoom(v)
+
+
+#
+# Show transformations (zoom and rotation) using a pivot point.
+#
+
+# Now create the actual image
+img = lv.img(lv.scr_act())
+img.set_src(img_cogwheel_argb)
+img.align(lv.ALIGN.CENTER, 50, 50)
+img.set_pivot(0, 0)               # Rotate around the top left corner
+
+a1 = lv.anim_t()
+a1.init()
+a1.set_var(img)
+a1.set_custom_exec_cb(lambda a,val: set_angle(img,val))
+a1.set_values(0, 3600)
+a1.set_time(5000)
+a1.set_repeat_count(lv.ANIM_REPEAT.INFINITE)
+lv.anim_t.start(a1)
+
+a2 = lv.anim_t()
+a2.init()
+a2.set_var(img)
+a2.set_custom_exec_cb(lambda a,val: set_zoom(img,val))
+a2.set_values(128, 256)
+a2.set_time(5000)
+a2.set_playback_time(3000)
+a2.set_repeat_count(LV_ANIM_REPEAT_INFINITE)
+lv.anim_t.start(a2)
+
+