ui/loader: shrink before deactivating

src/trezor/ui/loader.py

@@ -1,52 +1,65 @@
 import utime
 from micropython import const
-from trezor import loop
-from trezor import ui
-from trezor import res
+from trezor import loop, res, ui
+
+_TARGET_MS = const(1000)
+_SHRINK_BY = const(2)
 
 
 class Loader(ui.Widget):
 
-    def __init__(self, target_ms=1000, style=ui.LDR_DEFAULT):
-        self.target_ms = target_ms
-        self.start_ticks_ms = None
+    def __init__(self, style=ui.LDR_DEFAULT):
+        self.target_ms = _TARGET_MS
         self.normal_style = style['normal'] or ui.LDR_DEFAULT['normal']
         self.active_style = style['active'] or ui.LDR_DEFAULT['active']
+        self.start_ms = None
+        self.stop_ms = None
 
     def start(self):
-        self.start_ticks_ms = utime.ticks_ms()
-        ui.display.bar(0, 32, 240, 240 - 80, ui.BG)
+        self.start_ms = utime.ticks_ms()
+        self.stop_ms = None
 
     def stop(self):
-        ui.display.bar(0, 32, 240, 240 - 80, ui.BG)
-        if self.start_ticks_ms is not None:
-            ticks_diff = utime.ticks_ms() - self.start_ticks_ms
+        if self.start_ms is not None and self.stop_ms is None:
+            diff_ms = utime.ticks_ms() - self.start_ms
         else:
-            ticks_diff = 0
-        self.start_ticks_ms = None
-        return ticks_diff >= self.target_ms
+            diff_ms = 0
+        self.stop_ms = utime.ticks_ms()
+        return diff_ms >= self.target_ms
 
     def is_active(self):
-        return self.start_ticks_ms is not None
+        return self.start_ms is not None
 
     def render(self):
-        progress = min(utime.ticks_ms() - self.start_ticks_ms, self.target_ms)
-        if progress == self.target_ms:
+        target = self.target_ms
+        start = self.start_ms
+        stop = self.stop_ms
+        now = utime.ticks_ms()
+        if stop is None:
+            r = min(now - start, target)
+        else:
+            r = max(stop - start + (stop - now) * _SHRINK_BY, 0)
+            if r == 0:
+                self.start_ms = None
+                self.stop_ms = None
+        if r == target:
             s = self.active_style
         else:
             s = self.normal_style
         if s['icon'] is None:
             ui.display.loader(
-                progress, -24, s['fg-color'], s['bg-color'])
+                r, -24, s['fg-color'], s['bg-color'])
         elif s['icon-fg-color'] is None:
             ui.display.loader(
-                progress, -24, s['fg-color'], s['bg-color'], res.load(s['icon']))
+                r, -24, s['fg-color'], s['bg-color'], res.load(s['icon']))
         else:
             ui.display.loader(
-                progress, -24, s['fg-color'], s['bg-color'], res.load(s['icon']), s['icon-fg-color'])
+                r, -24, s['fg-color'], s['bg-color'], res.load(s['icon']), s['icon-fg-color'])
 
     def __iter__(self):
-        sleep = loop.sleep(1000000 // 60)  # 60 fps
+        sleep = loop.sleep(1000000 // 30)  # 30 fps
+        ui.display.bar(0, 32, 240, 240 - 80, ui.BG)  # clear
         while self.is_active():
             self.render()
             yield sleep
+        ui.display.bar(0, 32, 240, 240 - 80, ui.BG)  # clear