From 9b9734ffd11b9601d1b17e1e9c4b191dc5b395c9 Mon Sep 17 00:00:00 2001
From: Jakub Melka <Jakub.Melka@seznam.cz>
Date: Sun, 13 Dec 2020 16:19:59 +0100
Subject: [PATCH] Bugfix: Text selection

---
 PdfForQtLib/sources/pdftextlayout.cpp | 38 +++++++++++++++++++++++++--
 1 file changed, 36 insertions(+), 2 deletions(-)

diff --git a/PdfForQtLib/sources/pdftextlayout.cpp b/PdfForQtLib/sources/pdftextlayout.cpp
index 0ae3d80..3dd5aa2 100644
--- a/PdfForQtLib/sources/pdftextlayout.cpp
+++ b/PdfForQtLib/sources/pdftextlayout.cpp
@@ -338,12 +338,16 @@ PDFTextSelection PDFTextLayout::createTextSelection(PDFInteger pageIndex, const
         QRectF rect(xMin, yMin, xMax - xMin, yMax - yMin);
         QPainterPath rectPath;
         rectPath.addRect(rect);
-        QPainterPath intersectionPath = block.getBoundingBox().intersected(rectPath);
+        const QPainterPath& boundingBoxPath = block.getBoundingBox();
+        QPainterPath intersectionPath = boundingBoxPath.intersected(rectPath);
         if (!intersectionPath.isEmpty())
         {
             QRectF intersectionRect = intersectionPath.boundingRect();
             Q_ASSERT(intersectionRect.isValid());
 
+            bool isTopPointAboveText = false;
+            bool isBottomPointBelowText = false;
+
             const PDFTextLines& lines = block.getLines();
             auto itLineA = std::find_if(lines.cbegin(), lines.cend(), [pointA](const PDFTextLine& line) { return line.getBoundingBox().contains(pointA); });
             auto itLineB = std::find_if(lines.cbegin(), lines.cend(), [pointB](const PDFTextLine& line) { return line.getBoundingBox().contains(pointB); });
@@ -361,10 +365,24 @@ PDFTextSelection PDFTextLayout::createTextSelection(PDFInteger pageIndex, const
             {
                 // Otherwise points are not in the same line. Then start point will be
                 // point top of the second point. Bottom point will mark end of selection.
-                if (pointA.y() > pointB.y())
+                if (pointA.y() < pointB.y())
                 {
                     std::swap(pointA, pointB);
                 }
+
+                QRectF rect = boundingBoxPath.controlPointRect();
+
+                // If start point is above the text block, move start point to the left.
+                if (rect.bottom() < pointA.y())
+                {
+                    pointA.setX(rect.left());
+                    isTopPointAboveText = true;
+                }
+                if (rect.top() > pointB.y())
+                {
+                    pointB.setX(rect.right());
+                    isBottomPointBelowText = true;
+                }
             }
 
             // Now, we have pointA as start point and pointB as end point. We must found
@@ -409,6 +427,22 @@ PDFTextSelection PDFTextLayout::createTextSelection(PDFInteger pageIndex, const
                 }
             }
 
+            if (isTopPointAboveText && !lines.empty())
+            {
+                ptrA.pageIndex = pageIndex;
+                ptrA.blockIndex = blockId;
+                ptrA.lineIndex = 0;
+                ptrA.characterIndex = 0;
+            }
+
+            if (isBottomPointBelowText && !lines.empty())
+            {
+                ptrB.pageIndex = pageIndex;
+                ptrB.blockIndex = blockId;
+                ptrB.lineIndex = lines.size() - 1;
+                ptrB.characterIndex = lines.back().getCharacters().size() - 1;
+            }
+
             // If we have filled the pointers, add them to the selection
             if (ptrA.isValid() && ptrB.isValid())
             {