Question

我按照ItextSharp示例获取图形结构，使用代码获取矩形坐标：

class VectorGraphicsListener : IExtRenderListener
{
public void ModifyPath(PathConstructionRenderInfo renderInfo)
{
    if (renderInfo.Operation == PathConstructionRenderInfo.RECT)
    {
        float x = renderInfo.SegmentData[0];
        float y = renderInfo.SegmentData[1];
        float w = renderInfo.SegmentData[2];
        float h = renderInfo.SegmentData[3];  
...

我尝试了renderInfo.GetFillColor（）; 但是没有这样的方法。

我想获得额外的矩形属性：
像矩形填充颜色，（有些类似于DIV样式=＆＃34;背景：蓝色;边框：黑色;＆＃34;标签在html中）我是怎么得到的？

Answer 1

TextRenderInfo您正在寻找的方法PathConstructionRenderInfo没有。

你从哪里得到这个例子？您可能使用的版本与使用的版本文档版本不同。

本文解释了您需要做什么，但它提供的Java源代码应该很容易移植到C＃：http://techqa.info/programming/question/41728853/how-to-extract-the-color-of-a-rectangle-in-a-pdf,-with-itext

为了总结相关部分，它使用GraphicsState来获取填充颜色。要实现这一点，您需要使用PdfReaderContentParser将ExtRenderListener传递给processContent方法解析所有PDF内容，如下所示（取自上面的Java代码）：

PdfReader pdfReader = new PdfReader(resource);
ExtRenderListener extRenderListener = new ExtRenderListener();
for (int page = 1; page <= pdfReader.getNumberOfPages(); page++)
{
    PdfReaderContentParser parser = new PdfReaderContentParser(pdfReader);
    parser.processContent(page, extRenderListener);

}

ExtRenderListener将需要覆盖renderPath：

public override Path renderPath(PathPaintingRenderInfo renderInfo)
{
    Field gsField = PathPaintingRenderInfo.class.getDeclaredField("gs");
    gsField.setAccessible(true);
    GraphicsState graphicsState = (GraphicsState) gsField.get(renderInfo);
    if ((renderInfo.getOperation() & PathPaintingRenderInfo.FILL) != 0)
    {
        var fillColor = graphicsState.getFillColor();
        bool filledRect= false;
        for (PathConstructionRenderInfo pathConstructionRenderInfo in pathInfos) 
        {
            if(pathConstructionRenderInfo.getOperation()==PathConstructionRenderInfo.RECT)
            {
                filledRect=true;
                break;
            }
            if (filledRect && fillColor!=null)
                Console.WriteLine("{0},{1},{2}",
                fillColor.getRed(), fillColor.getGreen(), fillColor.getBlue());
        }
    }
}

Answer 2

page Alexander in his answer posted a link to是earlier answer by me here on stack overflow的副本。

因此，我只是将该答案（使用iText / Java）的代码移植到iTextSharp / C＃：

自定义`IExtRenderListener`实施

class ExtRenderListener : IExtRenderListener
{
    public void BeginTextBlock() { }
    public void RenderText(TextRenderInfo renderInfo) { }
    public void EndTextBlock() { }
    public void RenderImage(ImageRenderInfo renderInfo) { }

    public void ModifyPath(PathConstructionRenderInfo renderInfo)
    {
        pathInfos.Add(renderInfo);
    }

    public iTextSharp.text.pdf.parser.Path RenderPath(PathPaintingRenderInfo renderInfo)
    {
        GraphicsState graphicsState = getGraphicsState(renderInfo);
        Matrix ctm = graphicsState.GetCtm();

        if ((renderInfo.Operation & PathPaintingRenderInfo.FILL) != 0)
        {
            Console.Write("FILL ({0}) ", toString(graphicsState.FillColor));
            if ((renderInfo.Operation & PathPaintingRenderInfo.STROKE) != 0)
                Console.Write("and ");
        }
        if ((renderInfo.Operation & PathPaintingRenderInfo.STROKE) != 0)
        {
            Console.Write("STROKE ({0}) ", toString(graphicsState.StrokeColor));
        }

        Console.Write("the path ");

        foreach (PathConstructionRenderInfo pathConstructionRenderInfo in pathInfos)
        {
            switch (pathConstructionRenderInfo.Operation)
            {
                case PathConstructionRenderInfo.MOVETO:
                    Console.Write("move to {0} ", toString(transform(ctm, pathConstructionRenderInfo.SegmentData)));
                    break;
                case PathConstructionRenderInfo.CLOSE:
                    Console.Write("close {0} ", toString(transform(ctm, pathConstructionRenderInfo.SegmentData)));
                    break;
                case PathConstructionRenderInfo.CURVE_123:
                    Console.Write("curve123 {0} ", toString(transform(ctm, pathConstructionRenderInfo.SegmentData)));
                    break;
                case PathConstructionRenderInfo.CURVE_13:
                    Console.Write("curve13 {0} ", toString(transform(ctm, pathConstructionRenderInfo.SegmentData)));
                    break;
                case PathConstructionRenderInfo.CURVE_23:
                    Console.Write("curve23 {0} ", toString(transform(ctm, pathConstructionRenderInfo.SegmentData)));
                    break;
                case PathConstructionRenderInfo.LINETO:
                    Console.Write("line to {0} ", toString(transform(ctm, pathConstructionRenderInfo.SegmentData)));
                    break;
                case PathConstructionRenderInfo.RECT:
                    Console.Write("rectangle {0} ", toString(transform(ctm, expandRectangleCoordinates(pathConstructionRenderInfo.SegmentData))));
                    break;
            }
        }
        Console.WriteLine();

        pathInfos.Clear();
        return null;
    }

    String toString(IList<float> coordinates)
    {
        StringBuilder result = new StringBuilder();
        result.Append("[ ");
        for (int i = 0; i < coordinates.Count; i++)
        {
            result.Append(coordinates[i]);
            result.Append(' ');
        }
        result.Append(']');
        return result.ToString();
    }

    List<float> transform(Matrix ctm, IList<float> coordinates)
    {
        List<float> result = new List<float>();
        for (int i = 0; i + 1 < coordinates.Count; i += 2)
        {
            Vector vector = new Vector(coordinates[i], coordinates[i + 1], 1);
            vector = vector.Cross(ctm);
            result.Add(vector[Vector.I1]);
            result.Add(vector[Vector.I2]);
        }
        return result;
    }

    List<float> expandRectangleCoordinates(IList<float> rectangle)
    {
        if (rectangle.Count < 4)
            return new List<float>();
        return new List<float>
        {
                rectangle[0], rectangle[1],
                rectangle[0] + rectangle[2], rectangle[1],
                rectangle[0] + rectangle[2], rectangle[1] + rectangle[3],
                rectangle[0], rectangle[1] + rectangle[3]
        };
    }

    String toString(BaseColor baseColor)
    {
        if (baseColor == null)
            return "DEFAULT";
        return String.Format("{0},{1},{2}", baseColor.R, baseColor.G, baseColor.B);
    }

    GraphicsState getGraphicsState(PathPaintingRenderInfo renderInfo)
    {
        System.Reflection.FieldInfo gsField = typeof(PathPaintingRenderInfo).GetField("gs", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance);
        return (GraphicsState) gsField.GetValue(renderInfo);
    }

    public void ClipPath(int rule)
    {
    }

    List<PathConstructionRenderInfo> pathInfos = new List<PathConstructionRenderInfo>();
}

检索GraphicsState所需的反映发生在方法getGraphicsState中。

使用`ExtRenderListener`类

using (var pdfReader = new PdfReader([FILE TO PARSE]))
{
    IExtRenderListener extRenderListener = new ExtRenderListener();
    // Loop through each page of the document
    for (var page = 1; page <= pdfReader.NumberOfPages; page++)
    {
        Console.Write("\nPage {0}\n====\n", page);
        PdfReaderContentParser parser = new PdfReaderContentParser(pdfReader);
        parser.ProcessContent(page, extRenderListener);
    }
}

输出

对于前一个问题的PDF，此代码返回

Page 1
====
STROKE (0,0,0) the path rectangle [ 88,3 693,69 227,77 693,69 227,77 788 88,3 788 ] 
STROKE (0,0,0) the path rectangle [ 227,77 693,69 367,24 693,69 367,24 788 227,77 788 ] 
STROKE (0,0,0) the path rectangle [ 367,23 693,69 506,7 693,69 506,7 788 367,23 788 ] 
FILL (255,0,0) the path rectangle [ 229,77 695,69 365,37 695,69 365,37 786,09 229,77 786,09 ] 
STROKE (DEFAULT) the path move to [ 228 810 ] line to [ 338 810 ]

（正如您在坐标输出中所观察到的，我当前的语言环境使用逗号作为小数分隔符...）

itextsharp：如何找到矩形的填充颜色

2 个答案:

自定义`IExtRenderListener`实施

使用`ExtRenderListener`类

输出

itextsharp：如何找到矩形的填充颜色

2 个答案:

自定义IExtRenderListener实施

使用ExtRenderListener类

输出

自定义`IExtRenderListener`实施

使用`ExtRenderListener`类