Frontlight - Add checkbox use system settings (#5307)

See: https://github.com/koreader/koreader/issues/5205#issuecomment-526935357

Devices with `hasLightLevelFallback = true` (for now Android) has extra checkbutton `Use system settings`. Default unchecked.

frontend/apps/reader/modules/readerfrontlight.lua

@@ -179,7 +179,9 @@ end
 
 function ReaderFrontLight:onShowFlDialog()
     local FrontLightWidget = require("ui/widget/frontlightwidget")
-    UIManager:show(FrontLightWidget:new{})
+    UIManager:show(FrontLightWidget:new{
+        use_system_fl = Device:hasLightLevelFallback()
+    })
 end
 
 function ReaderFrontLight:close()

frontend/apps/reader/modules/readergesture.lua

@@ -8,6 +8,7 @@ local InfoMessage = require("ui/widget/infomessage")
 local InputContainer = require("ui/widget/container/inputcontainer")
 local InputDialog = require("ui/widget/inputdialog")
 local LuaData = require("luadata")
+local Notification = require("ui/widget/notification")
 local Screen = require("device").screen
 local UIManager = require("ui/uimanager")
 local T = require("ffi/util").template
@@ -1196,6 +1197,10 @@ function ReaderGesture:registerGesture(ges, action, ges_type, zone, overrides, d
     })
 end
 
+local function lightFrontlight()
+    return Device:hasLightLevelFallback() and G_reader_settings:nilOrTrue("light_fallback")
+end
+
 function ReaderGesture:gestureAction(action, ges)
     if action == "ignore" then
         return
@@ -1302,6 +1307,14 @@ function ReaderGesture:gestureAction(action, ges)
             self.ui:handleEvent(Event:new("ShowFlDialog"))
         end
     elseif action == "increase_frontlight" then
+        -- when using frontlight system settings
+        if lightFrontlight() then
+            UIManager:show(Notification:new{
+                text = _("Frontlight controlled by system settings."),
+                timeout = 2.5,
+            })
+            return true
+        end
         if self.ges_mode == "gesture_fm" then
             local ReaderFrontLight = require("apps/reader/modules/readerfrontlight")
             ReaderFrontLight:onChangeFlIntensity(ges, 1)
@@ -1309,6 +1322,14 @@ function ReaderGesture:gestureAction(action, ges)
             self.ui:handleEvent(Event:new("ChangeFlIntensity", ges, 1))
         end
     elseif action == "decrease_frontlight" then
+        -- when using frontlight system settings
+        if lightFrontlight() then
+            UIManager:show(Notification:new{
+                text = _("Frontlight controlled by system settings."),
+                timeout = 2.5,
+            })
+            return true
+        end
         if self.ges_mode == "gesture_fm" then
             local ReaderFrontLight = require("apps/reader/modules/readerfrontlight")
             ReaderFrontLight:onChangeFlIntensity(ges, -1)
@@ -1332,6 +1353,14 @@ function ReaderGesture:gestureAction(action, ges)
     elseif action == "toggle_bookmark" then
         self.ui:handleEvent(Event:new("ToggleBookmark"))
     elseif action == "toggle_frontlight" then
+        -- when using frontlight system settings
+        if lightFrontlight() then
+            UIManager:show(Notification:new{
+                text = _("Frontlight controlled by system settings."),
+                timeout = 2.5,
+            })
+            return true
+        end
         Device:getPowerDevice():toggleFrontlight()
         self:onShowFLOnOff()
     elseif action == "toggle_gsensor" then
@@ -1490,7 +1519,6 @@ function ReaderGesture:pageUpdate(page)
 end
 
 function ReaderGesture:onShowFLOnOff()
-    local Notification = require("ui/widget/notification")
     local powerd = Device:getPowerDevice()
     local new_text
     if powerd.is_fl_on then
@@ -1506,7 +1534,6 @@ function ReaderGesture:onShowFLOnOff()
 end
 
 function ReaderGesture:onGSensorToggle()
-    local Notification = require("ui/widget/notification")
     local new_text
     if G_reader_settings:isTrue("input_ignore_gsensor") then
         new_text = _("Accelerometer rotation events will now be ignored.")

frontend/device/android/device.lua

@@ -66,6 +66,7 @@ local Device = Generic:new{
     hasEinkScreen = function() return android.isEink() end,
     hasColorScreen = function() return not android.isEink() end,
     hasFrontlight = yes,
+    hasLightLevelFallback = yes,
     canRestart = no,
     firmware_rev = android.app.activity.sdkVersion,
     display_dpi = android.lib.AConfiguration_getDensity(android.app.config),
@@ -194,6 +195,12 @@ function Device:init()
         android.setVolumeKeysIgnored(true);
     end
 
+    -- check if we enable a custom light level for this activity
+    local last_value = G_reader_settings:readSetting("fl_last_level")
+    if type(last_value) == "number" and last_value >= 0 then
+        Device:setScreenBrightness(last_value)
+    end
+
     Generic.init(self)
 end
 
@@ -233,6 +240,10 @@ function Device:setViewport(x,y,w,h)
     self.screen:setViewport(viewport)
 end
 
+function Device:setScreenBrightness(level)
+    android.setScreenBrightness(level)
+end
+
 function Device:toggleFullscreen()
     local api = android.app.activity.sdkVersion
     if api >= 19 then

frontend/device/generic/device.lua

@@ -27,6 +27,7 @@ local Device = {
     hasWifiManager = no,
     isTouchDevice = no,
     hasFrontlight = no,
+    hasLightLevelFallback = no,
     hasNaturalLight = no, -- FL warmth implementation specific to NTX boards (Kobo, Cervantes)
     hasNaturalLightMixer = no, -- Same, but only found on newer boards
     needsTouchScreenProbe = no,
@@ -292,6 +293,9 @@ function Device:saveSettings() end
 -- Device specific method for toggling the GSensor
 function Device:toggleGSensor(toggle) end
 
+-- Device specific method for set custom light levels
+function Device:setScreenBrightness(level) end
+
 --[[
 prepare for application shutdown
 --]]

frontend/ui/widget/frontlightwidget.lua

@@ -31,9 +31,11 @@ local FrontLightWidget = InputContainer:new{
     height = nil,
     -- This should stay active during natural light configuration
     is_always_active = true,
+    use_system_fl = false,
 }
 
 function FrontLightWidget:init()
+    self.light_fallback = self.use_system_fl and G_reader_settings:nilOrTrue("light_fallback")
     self.medium_font_face = Font:getFace("ffont")
     self.larger_font_face = Font:getFace("cfont")
     self.light_bar = {}
@@ -76,7 +78,7 @@ function FrontLightWidget:init()
         margin = button_margin,
         padding = button_padding,
         bordersize = button_bordersize,
-        enabled = true,
+        enabled = not self.light_fallback,
         width = self.button_width,
         show_parent = self,
     }
@@ -117,6 +119,7 @@ function FrontLightWidget:setProgress(num, step, num_warmth)
     local button_group_up = HorizontalGroup:new{ align = "center" }
     local fl_group = HorizontalGroup:new{ align = "center" }
     local vertical_group = VerticalGroup:new{ align = "center" }
+    self.fl_prog_button.enabled = not self.light_fallback
     local set_fl
     local enable_button_plus = true
     local enable_button_minus = true
@@ -136,6 +139,14 @@ function FrontLightWidget:setProgress(num, step, num_warmth)
             else
                 self.powerd:setIntensity(set_fl)
             end
+
+            if not self.light_fallback and self.fl_cur >= 0 then
+                G_reader_settings:saveSetting("fl_last_level", self.fl_cur * 10)
+            elseif self.light_fallback then
+                G_reader_settings:saveSetting("fl_last_level", nil)
+                Device:setScreenBrightness(-1)
+            end
+
             -- get back the real level (different from set_fl if untoggle)
             self.fl_cur = self.powerd:frontlightIntensity()
             -- and update our step_num with it for accurate progress bar
@@ -176,7 +187,7 @@ function FrontLightWidget:setProgress(num, step, num_warmth)
         text = "-1",
         margin = Size.margin.small,
         radius = 0,
-        enabled = enable_button_minus,
+        enabled = enable_button_minus and not self.light_fallback,
         width = self.screen_width * 0.20,
         show_parent = self,
         callback = function()  self:setProgress(self.fl_cur - 1, step) end,
@@ -185,7 +196,7 @@ function FrontLightWidget:setProgress(num, step, num_warmth)
         text = "+1",
         margin = Size.margin.small,
         radius = 0,
-        enabled = enable_button_plus,
+        enabled = enable_button_plus and not self.light_fallback,
         width = self.screen_width * 0.20,
         show_parent = self,
         callback = function() self:setProgress(self.fl_cur + 1, step) end,
@@ -200,7 +211,7 @@ function FrontLightWidget:setProgress(num, step, num_warmth)
         text = _("Min"),
         margin = Size.margin.small,
         radius = 0,
-        enabled = true,
+        enabled = not self.light_fallback,
         width = self.screen_width * 0.20,
         show_parent = self,
         callback = function() self:setProgress(self.fl_min+1, step) end, -- min is 1 (use toggle for 0)
@@ -209,7 +220,7 @@ function FrontLightWidget:setProgress(num, step, num_warmth)
         text = _("Max"),
         margin = Size.margin.small,
         radius = 0,
-        enabled = true,
+        enabled = not self.light_fallback,
         width = self.screen_width * 0.20,
         show_parent = self,
         callback = function() self:setProgress(self.fl_max, step) end,
@@ -218,7 +229,7 @@ function FrontLightWidget:setProgress(num, step, num_warmth)
         text = _("Toggle"),
         margin = Size.margin.small,
         radius = 0,
-        enabled = true,
+        enabled = not self.light_fallback,
         width = self.screen_width * 0.20,
         show_parent = self,
         callback = function()
@@ -247,6 +258,20 @@ function FrontLightWidget:setProgress(num, step, num_warmth)
         -- widgets below.
         table.insert(vertical_group, text_br)
     end
+    local system_level_checkbutton
+    system_level_checkbutton = CheckButton:new{
+        text = _("Use system settings"),
+        checked = self.light_fallback,
+        callback = function()
+            if system_level_checkbutton.checked then
+                self.light_fallback = false
+            else
+                self.light_fallback = true
+            end
+            G_reader_settings:saveSetting("light_fallback", self.light_fallback)
+            self:setProgress(self.fl_cur, step)
+        end,
+    }
     table.insert(button_group_up, button_table_up)
     table.insert(button_group_down, button_table_down)
     table.insert(vertical_group, padding_span)
@@ -256,6 +281,10 @@ function FrontLightWidget:setProgress(num, step, num_warmth)
     table.insert(vertical_group, padding_span)
     table.insert(vertical_group, button_group_down)
     table.insert(vertical_group, padding_span)
+    if self.use_system_fl then
+        table.insert(vertical_group, system_level_checkbutton)
+        table.insert(vertical_group, padding_span)
+    end
     if self.natural_light then
         -- If the device supports natural light, add the widgets for 'warmth',
         -- as well as a 'Configure' button for devices *without* a mixer

platform/android/luajit-launcher

@@ -1 +1 @@
-Subproject commit 4c8319700f0b5dae5685df7c561edaa627f19189
+Subproject commit 3750551c6607aa5fa53c77a7095e1dba0b11237b