first commit

libraries/lvgl/examples/others/snapshot/lv_example_snapshot_1.py

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+import gc
+import lvgl as lv
+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
+
+# Measure memory usage
+gc.enable()
+gc.collect()
+mem_free = gc.mem_free()
+
+label = lv.label(lv.scr_act())
+label.align(lv.ALIGN.BOTTOM_MID, 0, -10)
+label.set_text(" memory free:" + str(mem_free/1024) + " kB")
+
+# Create an image from the png file
+try:
+    with open('../../assets/img_star.png','rb') as f:
+        png_data = f.read()
+except:
+    print("Could not find star.png")
+    sys.exit()
+
+img_star = lv.img_dsc_t({
+  'data_size': len(png_data),
+  'data': png_data
+})
+
+def event_cb(e, snapshot_obj):
+    img = e.get_target()
+
+    if snapshot_obj:
+        # no need to free the old source for snapshot_obj, gc will free it for us.
+
+        # take a new snapshot, overwrite the old one
+        dsc = lv.snapshot_take(img.get_parent(), lv.img.CF.TRUE_COLOR_ALPHA)
+        snapshot_obj.set_src(dsc)
+
+    gc.collect()
+    mem_used = mem_free - gc.mem_free()
+    label.set_text("memory used:" + str(mem_used/1024) + " kB")
+
+root = lv.scr_act()
+root.set_style_bg_color(lv.palette_main(lv.PALETTE.LIGHT_BLUE), 0)
+
+# Create an image object to show snapshot
+snapshot_obj = lv.img(root)
+snapshot_obj.set_style_bg_color(lv.palette_main(lv.PALETTE.PURPLE), 0)
+snapshot_obj.set_style_bg_opa(lv.OPA.COVER, 0)
+snapshot_obj.set_zoom(128)
+
+# Create the container and its children
+container = lv.obj(root)
+container.align(lv.ALIGN.CENTER, 0, 0)
+container.set_size(180, 180)
+container.set_flex_flow(lv.FLEX_FLOW.ROW_WRAP)
+container.set_flex_align(lv.FLEX_ALIGN.SPACE_EVENLY, lv.FLEX_ALIGN.CENTER, lv.FLEX_ALIGN.CENTER)
+container.set_style_radius(50, 0)
+
+for i in range(4):
+    img = lv.img(container)
+    img.set_src(img_star)
+    img.set_style_bg_color(lv.palette_main(lv.PALETTE.GREY), 0)
+    img.set_style_bg_opa(lv.OPA.COVER, 0)
+    img.set_style_transform_zoom(400, lv.STATE.PRESSED)
+    img.add_flag(img.FLAG.CLICKABLE)
+    img.add_event_cb(lambda e: event_cb(e, snapshot_obj), lv.EVENT.PRESSED, None)
+    img.add_event_cb(lambda e: event_cb(e, snapshot_obj), lv.EVENT.RELEASED, None)