ReaderDictionary: tweak timings if interrupted quickly

Rework b66d0be3 and 6205f260 by making that simpler
to comprehend:
- If interruption or search result window is shown in
less than 3 secondes: no specific tweak, a tap outside
will dismiss everything instantaneously.
- If done after 3 seconds: show the interruption or result
window, and discard input for a few 100ms.
- UIManager:discardEvents(): increase a bit default delays.

frontend/apps/reader/modules/readerdictionary.lua

@@ -101,6 +101,13 @@ function ReaderDictionary:init()
         os.getenv("STARDICT_DATA_DIR") or
         DataStorage:getDataDir() .. "/data/dict"
 
+    -- Show the "Seaching..." InfoMessage after this delay
+    self.lookup_msg_delay = 0.5
+    -- Allow quick interruption or dismiss of search result window
+    -- with tap if done before this delay. After this delay, the
+    -- result window is shown and dismiss prevented for a few 100ms
+    self.quick_dismiss_before_delay = 3
+
     -- Gather info about available dictionaries
     if not available_ifos then
         available_ifos = {}
@@ -797,12 +804,17 @@ function ReaderDictionary:startSdcv(word, dict_names, fuzzy_search)
             {
                 dict = "",
                 word = word,
-                definition = lookup_cancelled and _("Dictionary lookup canceled.") or _("No definition found."),
+                definition = lookup_cancelled and _("Dictionary lookup interrupted.") or _("No definition found."),
                 no_result = true,
                 lookup_cancelled = lookup_cancelled,
             }
         }
     end
+    if lookup_cancelled then
+        -- Also put this as a k/v into the results array: when using dict_ext,
+        -- we may get results from the 1st lookup, and have interrupted the 2nd.
+        final_results.lookup_cancelled = true
+    end
 
     return final_results
 end
@@ -839,11 +851,11 @@ function ReaderDictionary:stardictLookup(word, dict_names, fuzzy_search, box, li
         return
     end
 
-    self:showLookupInfo(word, 0.5)
+    self:showLookupInfo(word, self.lookup_msg_delay)
 
-    local lookup_start_ts = ffiUtil.getTimestamp()
+    self._lookup_start_ts = ffiUtil.getTimestamp()
     local results = self:startSdcv(word, dict_names, fuzzy_search)
-    if results and results[1] and results[1].lookup_cancelled and ffiUtil.getDuration(lookup_start_ts) < 1.5 then
+    if results and results.lookup_cancelled and ffiUtil.getDuration(self._lookup_start_ts) <= self.quick_dismiss_before_delay then
         -- If interrupted quickly just after launch, don't display anything
         -- (this might help avoiding refreshes and the need to dismiss
         -- after accidental long-press when holding a device).
@@ -902,10 +914,11 @@ function ReaderDictionary:showDict(word, results, box, link)
     self:dismissLookupInfo()
     if results and results[1] then
         UIManager:show(self.dict_window)
-        if not results[1].lookup_cancelled then
-            -- Discard queued and coming up events to avoid accidental
-            -- dismissal (but not if lookup interrupted, so 2 quick
-            -- taps can discard everything)
+        if not results.lookup_cancelled and ffiUtil.getDuration(self._lookup_start_ts) > self.quick_dismiss_before_delay then
+            -- If the search took more than a few seconds to be done, discard
+            -- queued and coming up events to avoid a voluntary dismissal
+            -- (because the user felt the result would not come) to kill the
+            -- result that finally came and is about to be displayed
             UIManager:discardEvents(true)
         end
     end

frontend/ui/uimanager.lua

@@ -811,11 +811,13 @@ function UIManager:discardEvents(set_or_seconds)
         -- is really painted on screen) are discarded.
         if Device:hasEinkScreen() then
             -- A screen refresh can take a few 100ms,
-            -- sometimes > 500ms on some devices/temperatures
-            usecs = 600000
+            -- sometimes > 500ms on some devices/temperatures.
+            -- So, block for 400ms (to have it displayed) + 400ms
+            -- for user reaction to it
+            usecs = 800000
         else
-            -- On non-eInk screen, it's usually instantaneous
-            usecs = 300000
+            -- On non-eInk screen, display is usually instantaneous
+            usecs = 400000
         end
     else -- we expect a number
         usecs = set_or_seconds * MILLION