[fix] PDF footer margins (#5620)

closes #5612 

the change in `ReaderView:recalculate()` causes the viewable page size to be calculated by not including the footer, causing the text not to get cut off.

since the page area was not drawing under the footer `ReaderView:drawPageSurround()` had to be fixed to draw the margin under the footer so when tapping the footer off the area should be dran the background color.

frontend/apps/reader/modules/readerpaging.lua

@@ -766,11 +766,6 @@ function ReaderPaging:onScrollPanRel(diff)
     return true
 end
 
-function ReaderPaging:calculateOverlap()
-    local footer_height = (self.view.footer_visible and 1 or 0) * self.view.footer.height
-    return self.overlap + footer_height
-end
-
 function ReaderPaging:onScrollPageRel(page_diff)
     if page_diff == 0 then return true end
     if page_diff > 0 then
@@ -786,7 +781,7 @@ function ReaderPaging:onScrollPageRel(page_diff)
 
         local blank_area = Geom:new{}
         blank_area:setSizeTo(self.view.dimen)
-        local overlap = self:calculateOverlap()
+        local overlap = self.overlap
         local offset = Geom:new{
             x = 0,
             y = last_visible_area.h - overlap
@@ -796,7 +791,7 @@ function ReaderPaging:onScrollPageRel(page_diff)
         -- page up, first page should be moved to bottom
         local blank_area = Geom:new{}
         blank_area:setSizeTo(self.view.dimen)
-        local overlap = self:calculateOverlap()
+        local overlap = self.overlap
         local first_page_state = table.remove(self.view.page_states, 1)
         local offset = Geom:new{
             x = 0,
@@ -912,7 +907,7 @@ function ReaderPaging:onGotoPageRel(diff)
     else
         -- not end of page yet, goto next view
         -- adjust panning step according to overlap
-        local overlap = self:calculateOverlap()
+        local overlap = self.overlap
         if x_pan_off > overlap then
             -- moving to next view, move view
             x_pan_off = x_pan_off - overlap

frontend/apps/reader/modules/readerview.lua

@@ -304,8 +304,9 @@ end
 function ReaderView:drawPageSurround(bb, x, y)
     if self.dimen.h > self.visible_area.h then
         bb:paintRect(x, y, self.dimen.w, self.state.offset.y, self.outer_page_color)
-        bb:paintRect(x, y + self.dimen.h - self.state.offset.y - 1,
+        local bottom_margin = y + self.visible_area.h + self.state.offset.y
-            self.dimen.w, self.state.offset.y + 1, self.outer_page_color)
+        bb:paintRect(x, bottom_margin, self.dimen.w, self.state.offset.y +
+            self.ui.view.footer:getHeight(), self.outer_page_color)
     end
     if self.dimen.w > self.visible_area.w then
         bb:paintRect(x, y, self.state.offset.x, self.dimen.h, self.outer_page_color)
@@ -573,6 +574,9 @@ function ReaderView:recalculate()
             self.state.rotation)
         -- reset our size
         self.visible_area:setSizeTo(self.dimen)
+        if self.ui.view.footer_visible then
+            self.visible_area.h = self.visible_area.h - self.ui.view.footer:getHeight()
+        end
         if self.ui.document.configurable.writing_direction == 0 then
             -- starts from left top of page_area
             self.visible_area.x = self.page_area.x
@@ -594,8 +598,12 @@ function ReaderView:recalculate()
     end
     self.state.offset = Geom:new{x = 0, y = 0}
     if self.dimen.h > self.visible_area.h then
+        if self.ui.view.footer_visible then
+            self.state.offset.y = (self.dimen.h - (self.visible_area.h + self.ui.view.footer:getHeight())) / 2
+        else
             self.state.offset.y = (self.dimen.h - self.visible_area.h) / 2
         end
+    end
     if self.dimen.w > self.visible_area.w then
         self.state.offset.x = (self.dimen.w - self.visible_area.w) / 2
     end

spec/unit/readerlink_spec.lua

@@ -30,7 +30,7 @@ describe("ReaderLink module", function()
         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}})
+        readerui.link:onTap(nil, {pos = {x = 363, y = 565}})
         UIManager:run()
         assert.is.same(22, readerui.paging.current_page)
     end)
@@ -71,7 +71,7 @@ describe("ReaderLink module", function()
         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}})
+        readerui.link:onTap(nil, {pos = {x = 363, y = 565}})
         UIManager:run()
         assert.is.same(22, readerui.paging.current_page)
         readerui.link:onGoBackLink()