fix looking up wrong word in reflowed page

that has a text layer underneath.

For multi-column page reflowing usually fits individual column to
page width and no finner word boxes are available to map reflowed
word box onto native word box. Now the relative position of a reflowed
word center is calculated as portion of the width and height of a larger
block it belongs. This relative position is also considered in
reflow-to-native position transform so that dictionary lookup now works
on multi-column pages in reflowing mode.

This should fix #376.

frontend/document/koptinterface.lua

@@ -665,20 +665,40 @@ function KoptInterface:getWordFromPosition(doc, pos)
 	end
 end
 
+local function getBoxRelativePosition(s_box, l_box)
+	local pos_rel = {}
+	local s_box_center = s_box:center()
+	pos_rel.x = (s_box_center.x - l_box.x)/l_box.w
+	pos_rel.y = (s_box_center.y - l_box.y)/l_box.h
+	return pos_rel
+end
+
 --[[
 get word and word box from position in reflowed page
 ]]--
 function KoptInterface:getWordFromReflowPosition(doc, boxes, pos)
 	local pageno = pos.page
-	local reflowed_page_boxes = self:getReflowedTextBoxesFromScratch(doc, pageno)
+	
+	local scratch_reflowed_page_boxes = self:getReflowedTextBoxesFromScratch(doc, pageno)
+	local scratch_reflowed_word_box = self:getWordFromBoxes(scratch_reflowed_page_boxes, pos)
+	--DEBUG("word box from scratch", scratch_reflowed_word_box)
+	
+	local reflowed_page_boxes = self:getReflowedTextBoxes(doc, pageno)
 	local reflowed_word_box = self:getWordFromBoxes(reflowed_page_boxes, pos)
-	local reflowed_pos = reflowed_word_box.box:center()
-	local native_pos = self:reflowToNativePosTransform(doc, pageno, reflowed_pos)
+	--DEBUG("word box from reflow", reflowed_word_box)
+	
+	local reflowed_pos_abs = scratch_reflowed_word_box.box:center()
+	local reflowed_pos_rel = getBoxRelativePosition(scratch_reflowed_word_box.box, reflowed_word_box.box)
+	--DEBUG("word box absolote center", reflowed_pos_abs)
+	--DEBUG("word box relative center", reflowed_pos_rel)
+	
+	local native_pos = self:reflowToNativePosTransform(doc, pageno, reflowed_pos_abs, reflowed_pos_rel)
 	local native_word_box = self:getWordFromBoxes(boxes, native_pos)
+	
 	local word_box = {
 		word = native_word_box.word,
 		pbox = native_word_box.box,   -- box on page
-		sbox = reflowed_word_box.box, -- box on screen
+		sbox = scratch_reflowed_word_box.box, -- box on screen
 		pos = native_pos,
 	}
 	return word_box
@@ -716,7 +736,7 @@ end
 --[[
 transform position in reflowed page to native page
 ]]--
-function KoptInterface:reflowToNativePosTransform(doc, pageno, pos)
+function KoptInterface:reflowToNativePosTransform(doc, pageno, abs_pos, rel_pos)
 	local bbox = doc:getPageBBox(pageno)
 	local context_hash = self:getContextHash(doc, pageno, bbox)
 	local kctx_hash = "kctx|"..context_hash
@@ -725,7 +745,7 @@ function KoptInterface:reflowToNativePosTransform(doc, pageno, pos)
 	--kc:setDebug()
 	--DEBUG("transform reflowed pos", pos)
 	local npos = {}
-	npos.x, npos.y = kc:reflowToNativePosTransform(pos.x, pos.y)
+	npos.x, npos.y = kc:reflowToNativePosTransform(abs_pos.x, abs_pos.y, rel_pos.x, rel_pos.y)
 	--DEBUG("transformed native pos", npos)
 	return npos
 end
@@ -749,14 +769,22 @@ get text and text boxes from screen positions for reflowed page
 ]]--
 function KoptInterface:getTextFromReflowPositions(doc, native_boxes, pos0, pos1)
 	local pageno = pos0.page
-	local reflowed_page_boxes = self:getReflowedTextBoxesFromScratch(doc, pageno)
-	local reflowed_box0 = self:getWordFromBoxes(reflowed_page_boxes, pos0)
-	local reflowed_pos0 = reflowed_box0.box:center()
-	local native_pos0 = self:reflowToNativePosTransform(doc, pageno, reflowed_pos0)
 	
-	local reflowed_box1 = self:getWordFromBoxes(reflowed_page_boxes, pos1)
-	local reflowed_pos1 = reflowed_box1.box:center()
-	local native_pos1 = self:reflowToNativePosTransform(doc, pageno, reflowed_pos1)
+	local scratch_reflowed_page_boxes = self:getReflowedTextBoxesFromScratch(doc, pageno)
+	local reflowed_page_boxes = self:getReflowedTextBoxes(doc, pageno)
+	
+	local scratch_reflowed_word_box0 = self:getWordFromBoxes(scratch_reflowed_page_boxes, pos0)
+	local reflowed_word_box0 = self:getWordFromBoxes(reflowed_page_boxes, pos0)
+	local scratch_reflowed_word_box1 = self:getWordFromBoxes(scratch_reflowed_page_boxes, pos1)
+	local reflowed_word_box1 = self:getWordFromBoxes(reflowed_page_boxes, pos1)
+	
+	local reflowed_pos_abs0 = scratch_reflowed_word_box0.box:center()
+	local reflowed_pos_rel0 = getBoxRelativePosition(scratch_reflowed_word_box0.box, reflowed_word_box0.box)
+	local reflowed_pos_abs1 = scratch_reflowed_word_box1.box:center()
+	local reflowed_pos_rel1 = getBoxRelativePosition(scratch_reflowed_word_box1.box, reflowed_word_box1.box)
+	
+	local native_pos0 = self:reflowToNativePosTransform(doc, pageno, reflowed_pos_abs0, reflowed_pos_rel0)
+	local native_pos1 = self:reflowToNativePosTransform(doc, pageno, reflowed_pos_abs1, reflowed_pos_rel1)
 	
 	local reflowed_text_boxes = self:getTextFromBoxes(reflowed_page_boxes, pos0, pos1)
 	local native_text_boxes = self:getTextFromBoxes(native_boxes, pos0, pos1)

koreader-base

@@ -1 +1 @@
-Subproject commit 2ec1e66a21ce6b32435845f9f4f8e5184af2e0a4
+Subproject commit 730c130930e758b3d838687ad03ba9607731d655