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ndg/lib/lvgl/examples/others/snapshot/lv_example_snapshot_1.py

72 lines
2.1 KiB
Python

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)