Change default zoom mode & add warning message for fit page + scroll (#5170)

* [UX] Change default zoom mode to page width

Fixes #5166.

* Warning popup for weird scroll mode combinations

frontend/apps/reader/modules/readerview.lua

@@ -9,6 +9,7 @@ local Device = require("device")
 local Geom = require("ui/geometry")
 local Event = require("ui/event")
 local ImageWidget = require("ui/widget/imagewidget")
+local InfoMessage = require("ui/widget/infomessage")
 local OverlapGroup = require("ui/widget/overlapgroup")
 local ReaderDogear = require("apps/reader/modules/readerdogear")
 local ReaderFlipping = require("apps/reader/modules/readerflipping")
@@ -736,6 +737,16 @@ function ReaderView:onSetFullScreen(full_screen)
 end
 
 function ReaderView:onSetScrollMode(page_scroll)
+    if self.ui.document.info.has_pages and page_scroll and self.ui.zooming.paged_modes[self.zoom_mode] then
+        UIManager:show(InfoMessage:new{
+            text = _([[
+Continuous view (scroll mode) works best with zoom to page width or zoom to content width.
+
+In combination with zoom to fit page, page height, content height or content, continuous view can cause unexpected shifts when turning pages.]]),
+            timeout = 5,
+        })
+    end
+
     self.page_scroll = page_scroll
     self:recalculate()
     self.ui:handleEvent(Event:new("InitScrollPageStates"))

frontend/apps/reader/modules/readerzooming.lua

@@ -1,24 +1,31 @@
 local Cache = require("cache")
-local InputContainer = require("ui/widget/container/inputcontainer")
 local ConfirmBox = require("ui/widget/confirmbox")
-local GestureRange = require("ui/gesturerange")
-local UIManager = require("ui/uimanager")
 local Device = require("device")
-local Input = require("device").input
-local Screen = require("device").screen
-local Geom = require("ui/geometry")
 local Event = require("ui/event")
+local Geom = require("ui/geometry")
+local GestureRange = require("ui/gesturerange")
+local InfoMessage = require("ui/widget/infomessage")
+local InputContainer = require("ui/widget/container/inputcontainer")
+local UIManager = require("ui/uimanager")
 local logger = require("logger")
-local T = require("ffi/util").template
 local _ = require("gettext")
+local Input = Device.input
+local Screen = Device.screen
+local T = require("ffi/util").template
 
 local ReaderZooming = InputContainer:new{
     zoom = 1.0,
     -- default to nil so we can trigger ZoomModeUpdate events on start up
     zoom_mode = nil,
-    DEFAULT_ZOOM_MODE = "page",
+    DEFAULT_ZOOM_MODE = "pagewidth",
     current_page = 1,
-    rotation = 0
+    rotation = 0,
+    paged_modes = {
+        page = _("Zoom to fit page works best with page view."),
+        pageheight = _("Zoom to fit page height works best with page view."),
+        contentheight = _("Zoom to fit content height works best with page view."),
+        content = _("Zoom to fit content works best with page view."),
+    },
 }
 
 function ReaderZooming:init()
@@ -333,6 +340,16 @@ function ReaderZooming:genSetZoomModeCallBack(mode)
 end
 
 function ReaderZooming:setZoomMode(mode)
+    if self.ui.view.page_scroll and self.paged_modes[mode] then
+        UIManager:show(InfoMessage:new{
+            text = T(_([[
+%1
+
+In combination with continuous view (scroll mode), this can cause unexpected vertical shifts when turning pages.]]), self.paged_modes[mode]),
+            timeout = 5,
+        })
+    end
+
     self.ui:handleEvent(Event:new("SetZoomMode", mode))
     self.ui:handleEvent(Event:new("InitScrollPageStates"))
 end

spec/unit/readerlink_spec.lua

@@ -28,6 +28,7 @@ describe("ReaderLink module", function()
             document = DocumentRegistry:openDocument(sample_pdf),
         }
         readerui:handleEvent(Event:new("SetScrollMode", false))
+        readerui:handleEvent(Event:new("SetZoomMode", "page"))
         readerui.paging:onGotoPage(1)
         readerui.link:onTap(nil, {pos = {x = 363, y = 585}})
         UIManager:run()
@@ -40,6 +41,7 @@ describe("ReaderLink module", function()
             document = DocumentRegistry:openDocument(sample_pdf),
         }
         readerui:handleEvent(Event:new("SetScrollMode", true))
+        readerui:handleEvent(Event:new("SetZoomMode", "page"))
         readerui.paging:onGotoPage(1)
         assert.is.same(1, readerui.paging.current_page)
         readerui.link:onTap(nil, {pos = {x = 250, y = 534}})
@@ -67,6 +69,7 @@ describe("ReaderLink module", function()
             document = DocumentRegistry:openDocument(sample_pdf),
         }
         readerui:handleEvent(Event:new("SetScrollMode", false))
+        readerui:handleEvent(Event:new("SetZoomMode", "page"))
         readerui.paging:onGotoPage(1)
         readerui.link:onTap(nil, {pos = {x = 363, y = 585}})
         UIManager:run()
@@ -81,6 +84,7 @@ describe("ReaderLink module", function()
             document = DocumentRegistry:openDocument(sample_pdf),
         }
         readerui:handleEvent(Event:new("SetScrollMode", true))
+        readerui:handleEvent(Event:new("SetZoomMode", "page"))
         readerui.paging:onGotoPage(1)
         assert.is.same(1, readerui.paging.current_page)
         readerui.link:onTap(nil, {pos = {x = 250, y = 534}})
@@ -131,6 +135,7 @@ describe("ReaderLink module", function()
         local readerui = ReaderUI:new{
             document = DocumentRegistry:openDocument(sample_pdf),
         }
+        readerui:handleEvent(Event:new("SetZoomMode", "page"))
         assert.is.falsy(readerui.view.footer_visible)
         readerui.paging:onGotoPage(1)
         assert.is.same(1, readerui.paging.current_page)

spec/unit/readerview_spec.lua

@@ -106,6 +106,7 @@ describe("Readerview module", function()
             document = DocumentRegistry:openDocument(sample_pdf),
         }
         readerui:handleEvent(Event:new("SetScrollMode", true))
+        readerui:handleEvent(Event:new("SetZoomMode", "page"))
         readerui.zooming:setZoomMode("page")
         local view = readerui.view
         local ctx = view:getViewContext()