add advanced option forced_ocr to force ocring text

frontend/document/koptinterface.lua

@@ -402,7 +402,7 @@ returned boxes are in native page coordinates zoomed at 1.0
 --]]
 function KoptInterface:getTextBoxes(doc, pageno)
     local text = doc:getPageTextBoxes(pageno)
-    if text and #text > 1 then
+    if text and #text > 1 and doc.configurable.forced_ocr == 0 then
         return text
     -- if we have no text in original page then we will reuse native word boxes
     -- in reflow mode and find text boxes from scratch in non-reflow mode

frontend/ui/data/koptoptions.lua

@@ -201,6 +201,14 @@ local KoptOptions = {
                 values={0.5, 1.0, 1.5},
                 default_value = DKOPTREADER_CONFIG_RENDER_QUALITY,
             },
+            {
+                name = "forced_ocr",
+                name_text = S.FORCED_OCR,
+                toggle = {S.ON, S.OFF},
+                values = {1, 0},
+                default_value = 0,
+                advanced = true,
+            },
             {
                 name = "defect_size",
                 name_text = S.DEFECT_SIZE,

frontend/ui/data/strings.lua

@@ -27,6 +27,7 @@ S.VIEW_MODE = _("View Mode")
 S.EMBEDDED_STYLE = _("Embedded Style")
 S.WRITING_DIR = _("Writing Direction")
 S.PROGRESS_BAR = _("Progress Bar")
+S.FORCED_OCR = _("Forced OCR")
 
 S.ON = _("on")
 S.OFF = _("off")