Adds CreDocument:getScreenPositionFromXPointer()

Factorize same code used by ReaderLink and ReaderRolling into
CreDocument:getScreenPositionFromXPointer().

frontend/apps/reader/modules/readerlink.lua

@@ -289,16 +289,7 @@ end
 --- Check if a xpointer to <a> node really points to itself
 function ReaderLink:isXpointerCoherent(a_xpointer)
     -- Get screen coordinates of xpointer
-    local doc_margins = self.ui.document:getPageMargins()
-    local header_height = self.ui.document:getHeaderHeight() -- top full status bar (0 when bottom mini bar used)
-    local doc_y, doc_x = self.ui.document:getPosFromXPointer(a_xpointer)
-    local top_y = self.ui.document:getCurrentPos()
-    -- (strange, but using doc_margins.top is accurate even in scroll mode)
-    local screen_y = doc_y - top_y
-    if self.view.view_mode == "page" then
-        screen_y = screen_y + doc_margins["top"] + header_height
-    end
-    local screen_x = doc_x + doc_margins["left"]
+    local screen_y, screen_x = self.ui.document:getScreenPositionFromXPointer(a_xpointer)
     -- Get again link and a_xpointer from this position
     local re_link_xpointer, re_a_xpointer = self.ui.document:getLinkFromPosition({x = screen_x, y = screen_y}) -- luacheck: no unused
     -- We should get the same a_xpointer. If not, crengine has messed up

frontend/apps/reader/modules/readerrolling.lua

@@ -508,14 +508,8 @@ function ReaderRolling:onGotoXPointer(xp, marker_xp)
     if marker_xp and marker_setting then
         -- Show a mark on left side of screen to give a visual feedback of
         -- where xpointer target is (and remove if after 1s)
-        local doc_y = self.ui.document:getPosFromXPointer(marker_xp)
-        local top_y = self.ui.document:getCurrentPos()
-        local screen_y = doc_y - top_y
+        local screen_y = self.ui.document:getScreenPositionFromXPointer(marker_xp)
         local doc_margins = self.ui.document:getPageMargins()
-        local header_height = self.ui.document:getHeaderHeight() -- top full status bar (0 when bottom mini bar used)
-        if self.view.view_mode == "page" then
-            screen_y = screen_y + doc_margins["top"] + header_height
-        end
         local marker_h = Screen:scaleBySize(self.ui.font.font_size * 1.1 * self.ui.font.line_space_percent/100.0)
         -- Make it 4/5 of left margin wide (and bigger when huge margin)
         local marker_w = math.floor(math.max(doc_margins["left"] - Screen:scaleBySize(5), doc_margins["left"] * 4/5))

frontend/document/credocument.lua

@@ -21,6 +21,7 @@ local CreDocument = Document:new{
 
     _document = false,
     _loaded = false,
+    _view_mode = nil,
 
     line_space_percent = 100,
     default_font = "Noto Serif",
@@ -114,12 +115,11 @@ function CreDocument:init()
         self.default_css = "./data/fb2.css"
     end
 
-    -- @TODO check the default view_mode to a global user configurable
-    -- variable  22.12 2012 (houqp)
+    -- This mode must be the same as the default one set as ReaderView.view_mode
+    self._view_mode = DCREREADER_VIEW_MODE == "scroll" and self.SCROLL_VIEW_MODE or self.PAGE_VIEW_MODE
+
     local ok
-    ok, self._document = pcall(cre.newDocView, Screen:getWidth(), Screen:getHeight(),
-        DCREREADER_VIEW_MODE == "scroll" and self.SCROLL_VIEW_MODE or self.PAGE_VIEW_MODE
-    ) -- this mode must be the same as the default one set as ReaderView.view_mode
+    ok, self._document = pcall(cre.newDocView, Screen:getWidth(), Screen:getHeight(), self._view_mode)
     if not ok then
         error(self._document)  -- will contain error message
     end
@@ -375,6 +375,22 @@ function CreDocument:getPageFromXPointer(xp)
     return self._document:getPageFromXPointer(xp)
 end
 
+function CreDocument:getScreenPositionFromXPointer(xp)
+    -- We do not ensure xp is in the current page: we may return
+    -- a negative screen_y, which could be useful in some contexts
+    local doc_margins = self:getPageMargins()
+    local doc_y, doc_x = self:getPosFromXPointer(xp)
+    local top_y = self:getCurrentPos()
+    local screen_y = doc_y - top_y
+    if self._view_mode == self.PAGE_VIEW_MODE then
+        screen_y = screen_y + doc_margins["top"] + self:getHeaderHeight()
+    end
+    local screen_x = doc_x + doc_margins["left"]
+    -- Just as getPosFromXPointer() does, we return y first and x second,
+    -- as callers most often just need the y
+    return screen_y, screen_x
+end
+
 function CreDocument:getFontFace()
     return self._document:getFontFace()
 end
@@ -554,10 +570,11 @@ function CreDocument:setViewMode(new_mode)
     if new_mode then
         logger.dbg("CreDocument: set view mode", new_mode)
         if new_mode == "scroll" then
-            self._document:setViewMode(self.SCROLL_VIEW_MODE)
+            self._view_mode = self.SCROLL_VIEW_MODE
         else
-            self._document:setViewMode(self.PAGE_VIEW_MODE)
+            self._view_mode = self.PAGE_VIEW_MODE
         end
+        self._document:setViewMode(self._view_mode)
     end
 end