TextDocumentLayout: Added TextOffsetAt()

It iterates over the ParagraphLayoutInfos and finds
the one which must contain the location. Untestet.

src/apps/haiku-depot/textview/TextDocumentLayout.cpp

@@ -144,6 +144,29 @@ TextDocumentLayout::GetTextBounds(int32 textOffset, float& x1, float& y1,
 }
 
 
+int32
+TextDocumentLayout::TextOffsetAt(float x, float y, bool& rightOfCenter)
+{
+	_ValidateLayout();
+
+	int32 textOffset = 0;
+	rightOfCenter = false;
+
+	int32 paragraphs = fParagraphLayouts.CountItems();
+	for (int32 i = 0; i < paragraphs; i++) {
+		const ParagraphLayoutInfo& info = fParagraphLayouts.ItemAtFast(i);
+		if (y > info.y + info.layout->Height()) {
+			textOffset += info.layout->CountGlyphs();
+			continue;
+		}
+
+		textOffset += info.layout->TextOffsetAt(x, y - info.y, rightOfCenter);
+		break;
+	}
+	
+	return textOffset;
+}
+
 // #pragma mark - private
 
 

src/apps/haiku-depot/textview/TextDocumentLayout.h

@@ -92,6 +92,9 @@ public:
 									float& x1, float& y1,
 									float& x2, float& y2);
 
+			int32				TextOffsetAt(float x, float y,
+									bool& rightOfCenter);
+
 private:
 			void				_Init();
 			void				_ValidateLayout();