adding micropython examples (#2286)

* adding micropython examples

* adding micropython examples

examples/widgets/img/lv_example_img_2.py

@@ -0,0 +1,70 @@
+#!/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 create_slider(color):
+    slider = lv.slider(lv.scr_act())
+    slider.set_range(0, 255)
+    slider.set_size(10, 200);
+    slider.set_style_bg_color(color, lv.PART.KNOB);
+    slider.set_style_bg_color(color.color_darken(lv.OPA._40), lv.PART.INDICATOR)
+    slider.add_event_cb(slider_event_cb, lv.EVENT.VALUE_CHANGED, None)
+    return slider
+
+def slider_event_cb(e):
+    # Recolor the image based on the sliders' values
+    color  = lv.color_make(red_slider.get_value(), green_slider.get_value(), blue_slider.get_value())
+    intense = intense_slider.get_value()
+    img1.set_style_img_recolor_opa(intense, 0)
+    img1.set_style_img_recolor(color, 0)
+    
+#
+# Demonstrate runtime image re-coloring
+#
+# Create 4 sliders to adjust RGB color and re-color intensity
+red_slider = create_slider(lv.palette_main(lv.PALETTE.RED))
+green_slider = create_slider(lv.palette_main(lv.PALETTE.GREEN))
+blue_slider = create_slider(lv.palette_main(lv.PALETTE.BLUE))
+intense_slider = create_slider(lv.palette_main(lv.PALETTE.GREY))
+
+red_slider.set_value(lv.OPA._20, lv.ANIM.OFF)
+green_slider.set_value(lv.OPA._90, lv.ANIM.OFF)
+blue_slider.set_value(lv.OPA._60, lv.ANIM.OFF)
+intense_slider.set_value(lv.OPA._50, lv.ANIM.OFF)
+
+red_slider.align(lv.ALIGN.LEFT_MID, 25, 0)
+green_slider.align_to(red_slider, lv.ALIGN.OUT_RIGHT_MID, 25, 0)
+blue_slider.align_to(green_slider, lv.ALIGN.OUT_RIGHT_MID, 25, 0)
+intense_slider.align_to(blue_slider, lv.ALIGN.OUT_RIGHT_MID, 25, 0)
+
+# Now create the actual image
+img1 = lv.img(lv.scr_act())
+img1.set_src(img_cogwheel_argb)
+img1.align(lv.ALIGN.RIGHT_MID, -20, 0)
+
+lv.event_send(intense_slider, lv.EVENT.VALUE_CHANGED, None)
+
+
+
+
+