example(canvas): add MicroPython draw examples (#3823)

examples/widgets/canvas/lv_example_canvas_5.py

@@ -0,0 +1,32 @@
+#!/opt/bin/lv_micropython -i
+# Initialize 
+
+import lvgl as lv
+import display_driver
+import fs_driver
+
+CANVAS_WIDTH  = 50
+CANVAS_HEIGHT = 50
+
+LV_COLOR_SIZE = 32
+
+#
+# Draw an arc to the canvas
+#
+
+# Create a buffer for the canvas
+cbuf = bytearray((LV_COLOR_SIZE // 8) * CANVAS_WIDTH * CANVAS_HEIGHT)
+
+# Create a canvas and initialize its palette
+canvas = lv.canvas(lv.scr_act())
+canvas.set_buffer(cbuf, CANVAS_WIDTH, CANVAS_HEIGHT, lv.img.CF.TRUE_COLOR)
+canvas.fill_bg(lv.color_hex3(0xccc), lv.OPA.COVER)
+canvas.center()
+
+dsc = lv.draw_arc_dsc_t()
+dsc.init()
+dsc.color = lv.palette_main(lv.PALETTE.RED)
+dsc.width = 5
+
+canvas.draw_arc(25, 25, 15, 0, 220, dsc)
+