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

examples/widgets/canvas/lv_example_canvas_4.py

@@ -0,0 +1,44 @@
+import fs_driver
+
+CANVAS_WIDTH  = 50
+CANVAS_HEIGHT = 50
+
+LV_COLOR_SIZE = 32
+
+#
+# Draw a text 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_label_dsc_t()
+dsc.init()
+
+dsc.color = lv.palette_main(lv.PALETTE.RED)
+
+try:
+    dsc.font = lv_font_montserrat_18
+except:
+    # needed for dynamic font loading
+    fs_drv = lv.fs_drv_t()
+    fs_driver.fs_register(fs_drv, 'S')
+
+    print("Loading font montserrat_18")
+    font_montserrat_18 = lv.font_load("S:../../assets/font/montserrat-18.fnt")
+    if not font_montserrat_18:
+        print("Font loading failed")
+    else:
+        dsc.font = font_montserrat_18
+
+dsc.decor = lv.TEXT_DECOR.UNDERLINE
+print('Printing "Hello"')
+canvas.draw_text(10, 10, 30, dsc, "Hello")
+
+