C# MatrixTransform.TryTransform方法代码示例

        /// <summary> 
        /// Transforms point to content's coordinate system.
        /// </summary>
        /// <param name="point">Point to which transform is applied.</param>
        private void TransformFromContent(ref Point point) 
        {
            Point newPoint; 
 
            // DocumentPage.Visual for printing scenarions needs to be always returned
            // in LeftToRight FlowDirection. Hence, if the document is RightToLeft, 
            // mirroring transform need to be applied to the content of DocumentPage.Visual.
            FlowDirection flowDirection = (FlowDirection)_owner.StructuralCache.PropertyOwner.GetValue(FlowDocument.FlowDirectionProperty);
            if (flowDirection == FlowDirection.RightToLeft)
            { 
                MatrixTransform transform = new MatrixTransform(-1.0, 0.0, 0.0, 1.0, _owner.Size.Width, 0.0);
                transform.TryTransform(point, out newPoint); 
                point = newPoint; 
            }
        } 

        /// <summary> 
        /// Returns the ContentPosition for the given page.
        /// </summary> 
        /// <param name="page">Document page.</param>
        /// <returns>Returns the ContentPosition for the given page.</returns>
        /// <exception cref="ArgumentException">
        /// Throws ArgumentException if the page is not valid. 
        /// </exception>
        public override ContentPosition GetPagePosition(DocumentPage page) 
        { 
            FlowDocumentPage flowDocumentPage;
            ITextView textView; 
            ITextPointer position;
            Point point, newPoint;
            MatrixTransform transform;
 
            // Ensure usage from just one Dispatcher object.
            // FlowDocumentPaginator runs its own layout, hence there is a need 
            // to protect it from random access from other threads. 
            _dispatcherObject.VerifyAccess();
 
            // ContentPosition cannot be null.
            if (page == null)
            {
                throw new ArgumentNullException("page"); 
            }
            // DocumentPage must be of appropriate type. 
            flowDocumentPage = page as FlowDocumentPage; 
            if (flowDocumentPage == null || flowDocumentPage.IsDisposed)
            { 
                return ContentPosition.Missing;
            }

            // DocumentPage.Visual for printing scenarions needs to be always returned 
            // in LeftToRight FlowDirection. Hence, if the document is RightToLeft,
            // mirroring transform need to be applied to the content of DocumentPage.Visual. 
            point = new Point(0, 0); 
            if (_document.FlowDirection == FlowDirection.RightToLeft)
            { 
                transform = new MatrixTransform(-1.0, 0.0, 0.0, 1.0, flowDocumentPage.Size.Width, 0.0);
                transform.TryTransform(point, out newPoint);
                point = newPoint;
            } 

            // Get TextView for DocumentPage. Position of the page is calculated through hittesting 
            // the top-left of the page. If position cannot be found, the start position of 
            // the first range for TextView is treated as ContentPosition for the page.
            textView = (ITextView)((IServiceProvider)flowDocumentPage).GetService(typeof(ITextView)); 
            Invariant.Assert(textView != null, "Cannot access ITextView for FlowDocumentPage.");
            Invariant.Assert(textView.TextSegments.Count > 0, "Page cannot be empty.");
            position = textView.GetTextPositionFromPoint(point, true);
            if (position == null) 
            {
                position = textView.TextSegments[0].Start; 
            } 
            return (position is TextPointer) ? (ContentPosition)position : ContentPosition.Missing;
        }