show a box indicator when tapping on a link

only for PDF/DJVU docs for now since there is no easy way
to get link box from crengine

frontend/apps/reader/modules/readerlink.lua

@@ -1,5 +1,7 @@
 local InputContainer = require("ui/widget/container/inputcontainer")
 local GestureRange = require("ui/gesturerange")
+local LinkBox = require("ui/widget/linkbox")
+local UIManager = require("ui/uimanager")
 local Geom = require("ui/geometry")
 local Screen = require("ui/screen")
 local Device = require("ui/device")
@@ -59,9 +61,18 @@ function ReaderLink:onTap(arg, ges)
     if self.ui.document.info.has_pages then
         local pos = self.view:screenToPageTransform(ges.pos)
         if pos then
-            local link = self.ui.document:getLinkFromPosition(pos.page, pos)
-            if link then
-                return self:onGotoLink(link)
+            local link, lbox = self.ui.document:getLinkFromPosition(pos.page, pos)
+            if link and lbox then
+                -- screen box that holds the link
+                local sbox = self.view:pageToScreenTransform(pos.page, lbox)
+                if sbox then
+                    UIManager:show(LinkBox:new{
+                        box = sbox,
+                        timeout = 0.5,
+                        callback = function() self:onGotoLink(link) end
+                    })
+                    return true
+                end
             end
         end
     else

frontend/apps/reader/modules/readerview.lua

@@ -167,6 +167,7 @@ Given rectangle in original page return rectangle on the screen
 ]]--
 function ReaderView:pageToScreenTransform(page, rect)
     if self.ui.document.info.has_pages then
+        rect = self.ui.document:nativeToPageRectTransform(page, rect)
         if self.page_scroll then
             return self:getScrollPageRect(page, rect)
         else

frontend/document/djvudocument.lua

@@ -72,6 +72,10 @@ function DjvuDocument:getPageBoxesFromPositions(pageno, ppos0, ppos1)
     return self.koptinterface:getPageBoxesFromPositions(self, pageno, ppos0, ppos1)
 end
 
+function DjvuDocument:nativeToPageRectTransform(pageno, rect)
+    return self.koptinterface:nativeToPageRectTransform(self, pageno, rect)
+end
+
 function DjvuDocument:getOCRWord(pageno, wbox)
     return self.koptinterface:getOCRWord(self, pageno, wbox)
 end

frontend/document/koptinterface.lua

@@ -843,13 +843,13 @@ function KoptInterface:getLinkFromPosition(doc, pageno, pos)
             local link = page_links[i]
             -- enlarge tappable link box
             local lbox = Geom:new{
-                x = link.x0 - Screen:scaleByDPI(15),
-                y = link.y0 - Screen:scaleByDPI(15),
-                w = link.x1 - link.x0 + Screen:scaleByDPI(30),
-                h = link.y1 - link.y0 + Screen:scaleByDPI(30)
+                x = link.x0 - Screen:scaleByDPI(5),
+                y = link.y0 - Screen:scaleByDPI(5),
+                w = link.x1 - link.x0 + Screen:scaleByDPI(10),
+                h = link.y1 - link.y0 + Screen:scaleByDPI(10)
             }
             if inside_box(pos, lbox) and link.page then
-                return link
+                return link, lbox
             end
         end
     end
@@ -972,6 +972,32 @@ function KoptInterface:getPageBoxesFromPositions(doc, pageno, ppos0, ppos1)
     end
 end
 
+--[[
+get page rect from native rect
+--]]
+function KoptInterface:nativeToPageRectTransform(doc, pageno, rect)
+    if doc.configurable.text_wrap == 1 then
+        local pos0 = {
+            x = rect.x + 5, y = rect.y + 5
+        }
+        local pos1 = {
+            x = rect.x + rect.w - 5,
+            y = rect.y + rect.h - 5
+        }
+        local boxes = self:getPageBoxesFromPositions(doc, pageno, pos0, pos1)
+        res_rect = nil
+        if #boxes > 0 then
+            res_rect = boxes[1]
+            for _, box in pairs(boxes) do
+                res_rect = res_rect:combine(box)
+            end
+        end
+        return res_rect
+    else
+        return rect
+    end
+end
+
 --[[
 helper functions
 --]]

frontend/document/pdfdocument.lua

@@ -97,6 +97,10 @@ function PdfDocument:getPageBoxesFromPositions(pageno, ppos0, ppos1)
     return self.koptinterface:getPageBoxesFromPositions(self, pageno, ppos0, ppos1)
 end
 
+function PdfDocument:nativeToPageRectTransform(pageno, rect)
+    return self.koptinterface:nativeToPageRectTransform(self, pageno, rect)
+end
+
 function PdfDocument:getOCRWord(pageno, wbox)
     return self.koptinterface:getOCRWord(self, pageno, wbox)
 end

frontend/ui/widget/linkbox.lua

@@ -0,0 +1,52 @@
+local InputContainer = require("ui/widget/container/inputcontainer")
+local GestureRange = require("ui/gesturerange")
+local UIManager = require("ui/uimanager")
+local Screen = require("ui/screen")
+local Geom = require("ui/geometry")
+local Device = require("ui/device")
+
+local LinkBox = InputContainer:new{
+    box = nil,
+    color = 8,
+    radius = 0,
+    bordersize = 2,
+}
+
+function LinkBox:init()
+    if Device:isTouchDevice() then
+        self.ges_events.TapClose = {
+            GestureRange:new{
+                ges = "tap",
+                range = Geom:new{
+                    x = 0, y = 0,
+                    w = Screen:getWidth(),
+                    h = Screen:getHeight(),
+                }
+            }
+        }
+    end
+end
+
+function LinkBox:paintTo(bb)
+    bb:paintBorder(self.box.x, self.box.y, self.box.w, self.box.h,
+            self.bordersize, self.color, self.radius)
+end
+
+function LinkBox:onShow()
+    if self.timeout then
+        UIManager:scheduleIn(self.timeout, function()
+            UIManager:close(self)
+            if self.callback then self.callback() end
+        end)
+    end
+    return true
+end
+
+function LinkBox:onTapClose()
+    UIManager:close(self)
+    self.callback = nil
+    return true
+end
+
+return LinkBox
+