400 lines
14 KiB
C#
400 lines
14 KiB
C#
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#region PDFsharp - A .NET library for processing PDF
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//
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// Authors:
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// Stefan Lange
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//
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// Copyright (c) 2005-2017 empira Software GmbH, Cologne Area (Germany)
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//
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// http://www.pdfsharp.com
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// http://sourceforge.net/projects/pdfsharp
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//
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// Permission is hereby granted, free of charge, to any person obtaining a
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// copy of this software and associated documentation files (the "Software"),
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// to deal in the Software without restriction, including without limitation
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// the rights to use, copy, modify, merge, publish, distribute, sublicense,
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// and/or sell copies of the Software, and to permit persons to whom the
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// Software is furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included
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// in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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// DEALINGS IN THE SOFTWARE.
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#endregion
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using System;
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using System.Collections.Generic;
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using PdfSharp.Pdf.IO;
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namespace PdfSharp.Drawing.Layout
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{
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/// <summary>
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/// Represents a very simple text formatter.
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/// If this class does not satisfy your needs on formatting paragraphs I recommend to take a look
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/// at MigraDoc Foundation. Alternatively you should copy this class in your own source code and modify it.
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/// </summary>
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public class XTextFormatter
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{
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/// <summary>
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/// Initializes a new instance of the <see cref="XTextFormatter"/> class.
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/// </summary>
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public XTextFormatter(XGraphics gfx)
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{
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if (gfx == null)
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throw new ArgumentNullException("gfx");
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_gfx = gfx;
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}
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readonly XGraphics _gfx;
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/// <summary>
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/// Gets or sets the text.
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/// </summary>
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/// <value>The text.</value>
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public string Text
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{
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get { return _text; }
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set { _text = value; }
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}
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string _text;
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/// <summary>
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/// Gets or sets the font.
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/// </summary>
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public XFont Font
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{
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get { return _font; }
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set
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{
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if (value == null)
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throw new ArgumentNullException("Font");
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_font = value;
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_lineSpace = _font.GetHeight(); // old: _font.GetHeight(_gfx);
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_cyAscent = _lineSpace * _font.CellAscent / _font.CellSpace;
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_cyDescent = _lineSpace * _font.CellDescent / _font.CellSpace;
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// HACK in XTextFormatter
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_spaceWidth = _gfx.MeasureString("x<>x", value).Width;
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_spaceWidth -= _gfx.MeasureString("xx", value).Width;
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}
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}
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XFont _font;
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double _lineSpace;
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double _cyAscent;
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double _cyDescent;
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double _spaceWidth;
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/// <summary>
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/// Gets or sets the bounding box of the layout.
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/// </summary>
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public XRect LayoutRectangle
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{
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get { return _layoutRectangle; }
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set { _layoutRectangle = value; }
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}
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XRect _layoutRectangle;
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/// <summary>
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/// Gets or sets the alignment of the text.
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/// </summary>
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public XParagraphAlignment Alignment
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{
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get { return _alignment; }
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set { _alignment = value; }
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}
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XParagraphAlignment _alignment = XParagraphAlignment.Left;
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/// <summary>
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/// Draws the text.
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/// </summary>
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/// <param name="text">The text to be drawn.</param>
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/// <param name="font">The font.</param>
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/// <param name="brush">The text brush.</param>
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/// <param name="layoutRectangle">The layout rectangle.</param>
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public void DrawString(string text, XFont font, XBrush brush, XRect layoutRectangle)
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{
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DrawString(text, font, brush, layoutRectangle, XStringFormats.TopLeft);
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}
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/// <summary>
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/// Draws the text.
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/// </summary>
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/// <param name="text">The text to be drawn.</param>
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/// <param name="font">The font.</param>
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/// <param name="brush">The text brush.</param>
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/// <param name="layoutRectangle">The layout rectangle.</param>
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/// <param name="format">The format. Must be <c>XStringFormat.TopLeft</c></param>
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public void DrawString(string text, XFont font, XBrush brush, XRect layoutRectangle, XStringFormat format)
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{
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if (text == null)
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throw new ArgumentNullException("text");
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if (font == null)
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throw new ArgumentNullException("font");
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if (brush == null)
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throw new ArgumentNullException("brush");
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if (format.Alignment != XStringAlignment.Near || format.LineAlignment != XLineAlignment.Near)
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throw new ArgumentException("Only TopLeft alignment is currently implemented.");
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Text = text;
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Font = font;
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LayoutRectangle = layoutRectangle;
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if (text.Length == 0)
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return;
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CreateBlocks();
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CreateLayout();
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double dx = layoutRectangle.Location.X;
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double dy = layoutRectangle.Location.Y + _cyAscent;
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int count = _blocks.Count;
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for (int idx = 0; idx < count; idx++)
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{
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Block block = _blocks[idx];
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if (block.Stop)
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break;
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if (block.Type == BlockType.LineBreak)
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continue;
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_gfx.DrawString(block.Text, font, brush, dx + block.Location.X, dy + block.Location.Y);
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}
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}
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void CreateBlocks()
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{
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_blocks.Clear();
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int length = _text.Length;
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bool inNonWhiteSpace = false;
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int startIndex = 0, blockLength = 0;
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for (int idx = 0; idx < length; idx++)
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{
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char ch = _text[idx];
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// Treat CR and CRLF as LF
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if (ch == Chars.CR)
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{
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if (idx < length - 1 && _text[idx + 1] == Chars.LF)
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idx++;
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ch = Chars.LF;
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}
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if (ch == Chars.LF)
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{
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if (blockLength != 0)
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{
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string token = _text.Substring(startIndex, blockLength);
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_blocks.Add(new Block(token, BlockType.Text,
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_gfx.MeasureString(token, _font).Width));
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}
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startIndex = idx + 1;
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blockLength = 0;
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_blocks.Add(new Block(BlockType.LineBreak));
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}
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// The non-breaking space is whitespace, so we treat it like non-whitespace.
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else if (ch != Chars.NonBreakableSpace && char.IsWhiteSpace(ch))
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{
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if (inNonWhiteSpace)
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{
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string token = _text.Substring(startIndex, blockLength);
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_blocks.Add(new Block(token, BlockType.Text,
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_gfx.MeasureString(token, _font).Width));
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startIndex = idx + 1;
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blockLength = 0;
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}
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else
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{
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blockLength++;
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}
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}
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else
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{
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inNonWhiteSpace = true;
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blockLength++;
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}
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}
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if (blockLength != 0)
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{
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string token = _text.Substring(startIndex, blockLength);
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_blocks.Add(new Block(token, BlockType.Text,
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_gfx.MeasureString(token, _font).Width));
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}
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}
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void CreateLayout()
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{
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double rectWidth = _layoutRectangle.Width;
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double rectHeight = _layoutRectangle.Height - _cyAscent - _cyDescent;
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int firstIndex = 0;
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double x = 0, y = 0;
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int count = _blocks.Count;
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for (int idx = 0; idx < count; idx++)
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{
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Block block = _blocks[idx];
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if (block.Type == BlockType.LineBreak)
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{
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if (Alignment == XParagraphAlignment.Justify)
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_blocks[firstIndex].Alignment = XParagraphAlignment.Left;
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AlignLine(firstIndex, idx - 1, rectWidth);
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firstIndex = idx + 1;
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x = 0;
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y += _lineSpace;
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if (y > rectHeight)
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{
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block.Stop = true;
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break;
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}
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}
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else
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{
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double width = block.Width;
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if ((x + width <= rectWidth || x == 0) && block.Type != BlockType.LineBreak)
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{
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block.Location = new XPoint(x, y);
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x += width + _spaceWidth;
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}
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else
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{
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AlignLine(firstIndex, idx - 1, rectWidth);
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firstIndex = idx;
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y += _lineSpace;
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if (y > rectHeight)
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{
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block.Stop = true;
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break;
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}
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block.Location = new XPoint(0, y);
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x = width + _spaceWidth;
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}
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}
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}
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if (firstIndex < count && Alignment != XParagraphAlignment.Justify)
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AlignLine(firstIndex, count - 1, rectWidth);
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}
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/// <summary>
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/// Align center, right, or justify.
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/// </summary>
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void AlignLine(int firstIndex, int lastIndex, double layoutWidth)
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{
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XParagraphAlignment blockAlignment = _blocks[firstIndex].Alignment;
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if (_alignment == XParagraphAlignment.Left || blockAlignment == XParagraphAlignment.Left)
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return;
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int count = lastIndex - firstIndex + 1;
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if (count == 0)
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return;
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double totalWidth = -_spaceWidth;
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for (int idx = firstIndex; idx <= lastIndex; idx++)
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totalWidth += _blocks[idx].Width + _spaceWidth;
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double dx = Math.Max(layoutWidth - totalWidth, 0);
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//Debug.Assert(dx >= 0);
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if (_alignment != XParagraphAlignment.Justify)
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{
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if (_alignment == XParagraphAlignment.Center)
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dx /= 2;
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for (int idx = firstIndex; idx <= lastIndex; idx++)
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{
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Block block = _blocks[idx];
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block.Location += new XSize(dx, 0);
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}
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}
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else if (count > 1) // case: justify
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{
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dx /= count - 1;
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for (int idx = firstIndex + 1, i = 1; idx <= lastIndex; idx++, i++)
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{
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Block block = _blocks[idx];
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block.Location += new XSize(dx * i, 0);
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}
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}
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}
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readonly List<Block> _blocks = new List<Block>();
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enum BlockType
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{
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Text, Space, Hyphen, LineBreak,
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}
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/// <summary>
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/// Represents a single word.
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/// </summary>
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class Block
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{
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/// <summary>
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/// Initializes a new instance of the <see cref="Block"/> class.
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/// </summary>
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/// <param name="text">The text of the block.</param>
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/// <param name="type">The type of the block.</param>
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/// <param name="width">The width of the text.</param>
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public Block(string text, BlockType type, double width)
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{
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Text = text;
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Type = type;
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Width = width;
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}
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/// <summary>
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/// Initializes a new instance of the <see cref="Block"/> class.
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/// </summary>
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/// <param name="type">The type.</param>
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public Block(BlockType type)
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{
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Type = type;
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}
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/// <summary>
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/// The text represented by this block.
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/// </summary>
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public readonly string Text;
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/// <summary>
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/// The type of the block.
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/// </summary>
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public readonly BlockType Type;
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/// <summary>
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/// The width of the text.
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/// </summary>
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public readonly double Width;
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/// <summary>
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/// The location relative to the upper left corner of the layout rectangle.
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/// </summary>
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public XPoint Location;
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/// <summary>
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/// The alignment of this line.
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/// </summary>
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public XParagraphAlignment Alignment;
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/// <summary>
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/// A flag indicating that this is the last block that fits in the layout rectangle.
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/// </summary>
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public bool Stop;
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}
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// TODO:
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// - more XStringFormat variations
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// - calculate bounding box
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// - left and right indent
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// - first line indent
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// - margins and paddings
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// - background color
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// - text background color
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// - border style
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// - hyphens, soft hyphens, hyphenation
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// - kerning
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// - change font, size, text color etc.
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// - line spacing
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// - underline and strike-out variation
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// - super- and sub-script
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// - ...
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}
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}
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