Update ImageWidget to support more stretch settings, and enable screensaver on kobo

defaults.lua

@@ -178,7 +178,7 @@ KOBO_LIGHT_ON_START = -2           -- -1, -2 or 0-100. -1 leaves light as it
                                    -- sets light on start/wake up
 KOBO_SYNC_BRIGHTNESS_WITH_NICKEL = true  -- Save brightness set in KOreader
                                          -- with nickel's 'Kobo eReader.conf'
-KOBO_SCREEN_SAVER = ""             -- image or directory with pictures or "-"
+KOBO_SCREEN_SAVER = ""             -- image or directory with pictures or empty
 KOBO_SCREEN_SAVER_LAST_BOOK = true -- get screensaver from last book if possible
 
 -- Network proxy settings

frontend/ui/screensaver.lua

@@ -25,26 +25,6 @@ function Screensaver:getCoverImage(file)
         local data = DocSettings:open(lastfile)
         local proportional_cover = data:readSetting("proportional_screensaver")
         if image then
-            if proportional_cover then
-                image_height = image:getHeight()
-                image_width = image:getWidth()
-                local image_ratio = image_width / image_height
-                if image_ratio < 1 then
-                    image_height = screen_height
-                    image_width = image_height * image_ratio
-                else
-                    image_width = screen_width
-                    image_height = image_width / image_ratio
-                end
-            else
-                image_height = screen_height
-                image_width = screen_width
-            end
-            local image_widget = ImageWidget:new{
-                image = image,
-                width = image_width,
-                height = image_height,
-            }
             return AlphaContainer:new{
                 alpha = 1,
                 height = screen_height,
@@ -56,7 +36,12 @@ function Screensaver:getCoverImage(file)
                         padding = 0,
                         height = screen_height,
                         width = screen_width,
-                        image_widget
+                        ImageWidget:new{
+                            image = image,
+                            height = screen_height,
+                            width = screen_width,
+                            overflow = proportional_cover,
+                        }
                     }
                 }
             }
@@ -64,8 +49,23 @@ function Screensaver:getCoverImage(file)
     end
 end
 
-function Screensaver:getRandomImage(dir)
-    local ImageWidget = require("ui/widget/imagewidget")
+local function createWidget(file)
+    if lfs.attributes(file, "mode") == "file" then
+        local ImageWidget = require("ui/widget/imagewidget")
+        return ImageWidget:new{
+            file = file,
+            width = Screen:getWidth(),
+            height = Screen:getHeight(),
+            overflow = true,
+            centering = true,
+        }
+    end
+end
+
+local function getRandomImage(dir)
+    if string.sub(dir, string.len(dir)) ~= "/" then
+       dir = dir .. "/"
+    end
     local pics = {}
     local i = 0
     math.randomseed(os.time())
@@ -80,14 +80,7 @@ function Screensaver:getRandomImage(dir)
     end
     local image = pics[math.random(i)]
     if image then
-        image = dir .. image
-        if lfs.attributes(image, "mode") == "file" then
-            return ImageWidget:new{
-                file = image,
-                width = Screen:getWidth(),
-                height = Screen:getHeight(),
-            }
-        end
+        return createWidget(dir .. image)
     end
 end
 
@@ -110,17 +103,9 @@ function Screensaver:show()
         if type(KOBO_SCREEN_SAVER) == "string" then
             local file = KOBO_SCREEN_SAVER
             if lfs.attributes(file, "mode") == "directory" then
-                if string.sub(file,string.len(file)) ~= "/" then
-                   file = file .. "/"
-                end
-                self.suspend_msg = self:getRandomImage(file)
-            elseif lfs.attributes(file, "mode") == "file" then
-                local ImageWidget = require("ui/widget/imagewidget")
-                self.suspend_msg = ImageWidget:new{
-                    file = file,
-                    width = Screen:getWidth(),
-                    height = Screen:getHeight(),
-                }
+                self.suspend_msg = getRandomImage(file)
+            else
+                self.suspend_msg = createWidget(file)
             end
         end
     end

frontend/ui/widget/imagewidget.lua

@@ -39,6 +39,21 @@ local ImageWidget = Widget:new{
     autoscale = false,
     -- when alpha is set to true, alpha values from the image will be honored
     alpha = false,
+    -- when autostretch is set to true, image will be stretched to best fit the
+    -- widget size. i.e. either fit the width or fit the height according to the
+    -- original image size.
+    autostretch = false,
+    -- when overflow is set to true, image will be stretched to fit the widget
+    -- size vertically and horizontally, without impact original aspect ratio.
+    -- But overflow part will be ignored.
+    overflow = false,
+    -- when nostretch is set to true, image won't be stretched.
+    nostretch = false,
+    -- when centering is set to true, image will be placed in the middle of the
+    -- widget. This setting takes effect only with overflow, autostretch and
+    -- nostretch. i.e. only when the image size is not consistent with widget
+    -- size.
+    centering = false,
     _bb = nil
 }
 
@@ -79,15 +94,35 @@ function ImageWidget:_render()
         error("cannot render image")
     end
     local native_w, native_h = self._bb:getWidth(), self._bb:getHeight()
-    local scaled_w, scaled_h = self.width, self.height
+    local w, h
     if self.autoscale then
         local dpi_scale = Screen:getDPI() / 167
         -- rounding off to power of 2 to avoid alias with pow(2, floor(log(x)/log(2))
         local scale = math.pow(2, math.max(0, math.floor(math.log(dpi_scale)/0.69)))
-        scaled_w, scaled_h = scale * native_w, scale * native_h
+        w, h = scale * native_w, scale * native_h
+    elseif self.autostretch then
+        local ratio = native_w / self.width / native_h * self.height
+        if ratio < 1 then
+            h = self.height
+            w = self.width * ratio
+        else
+            h = self.height * ratio
+            w = self.width
+        end
+    elseif self.nostretch then
+        w, h = native_w, native_h
+    elseif self.overflow then
+        local ratio = native_w / self.width / native_h * self.height
+        if ratio < 1 then
+            h = self.height / ratio
+            w = self.width
+        else
+            h = self.height
+            w = self.width / ratio
+        end
     end
-    if (scaled_w and scaled_w ~= native_w) or (scaled_h and scaled_h ~= native_h) then
-        self._bb = self._bb:scale(scaled_w or native_w, scaled_h or native_h)
+    if (w and w ~= native_w) or (h and h ~= native_h) then
+        self._bb = self._bb:scale(w or native_w, h or native_h)
     end
 end
 
@@ -110,6 +145,10 @@ function ImageWidget:paintTo(bb, x, y)
         w = size.w,
         h = size.h
     }
+    if self.centering then
+        x = x - (size.w - self.width) / 2
+        y = y - (size.h - self.height) / 2
+    end
     if self.alpha == true then
         bb:alphablitFrom(self._bb, x, y, 0, 0, size.w, size.h)
     else

reader.lua

@@ -97,7 +97,12 @@ local UIManager = require("ui/uimanager")
 local Device = require("device")
 local Font = require("ui/font")
 
--- read some global reader setting here:
+-- change some global default values according to the device types
+if Device:isKobo() then
+    KOBO_SCREEN_SAVER = "/mnt/onboard/screensaver"
+end
+
+-- read some global reader settings here:
 -- font
 local fontmap = G_reader_settings:readSetting("fontmap")
 if fontmap ~= nil then