O2S.Components.PDFRender4NET.dll 图片空白BUG问题

 1 /// <summary>
 2         /// 将PDF文档转换为图片的方法
 3         /// </summary>
 4         /// <param name="pdfInputPath">PDF文件路径</param>
 5         /// <param name="imageOutputPath">图片输出完整路径(包括文件名)</param>
 6         /// <param name="startPageNum">从PDF文档的第几页开始转换</param>
 7         /// <param name="endPageNum">从PDF文档的第几页开始停止转换</param>
 8         /// <param name="imageFormat">设置所需图片格式</param>
 9         /// <param name="definition">设置图片的清晰度，数字越大越清晰</param>
10         private static void ConvertPdf2Image(string pdfInputPath, string imageOutputPath,
11              int startPageNum, int endPageNum, ImageFormat imageFormat, int definition)
12         {
13             
14             PDFFile pdfFile = PDFFile.Open(pdfInputPath);
15             
16             if (startPageNum <= 0)
17             {
18                 startPageNum = 1;
19             }
20 
21             if (endPageNum > pdfFile.PageCount)
22             {
23                 endPageNum = pdfFile.PageCount;
24             }
25 
26             if (startPageNum > endPageNum)
27             {
28                 int tempPageNum = startPageNum;
29                 startPageNum = endPageNum;
30                 endPageNum = startPageNum;
31             }
32 
33             var bitMap = new Bitmap[endPageNum];
34 
35             for (int i = startPageNum; i <= endPageNum; i++)
36             {
37                 Bitmap pageImage = pdfFile.GetPageImage(i - 1, 56 * definition);

38                 Bitmap newPageImage = new Bitmap(pageImage.Width/4 , pageImage.Height/4);
39 
40                 Graphics g = Graphics.FromImage(newPageImage);
41                 g.InterpolationMode = InterpolationMode.HighQualityBicubic;
　　　　　　　　　　　//重新画图的时候Y轴减去130，高度也减去130  这样水印就看不到了
42                 g.DrawImage(pageImage, new Rectangle(0, 0, pageImage.Width/4 , pageImage.Height/4),
43                     new Rectangle(0, 130, pageImage.Width, pageImage.Height-130), GraphicsUnit.Pixel);
44 
45                 bitMap[i - 1] = newPageImage;
46 　　　　　　　　　g.Dispose();
47             }
48 
49             //合并图片
50             var mergerImg = MergerImg(bitMap);
51             //保存图片
52             mergerImg.Save(imageOutputPath, imageFormat);
53             pdfFile.Dispose();
54         }
55 
56         /// <summary>
57         /// 合并图片
58         /// </summary>
59         /// <param name="maps"></param>
60         /// <returns></returns>
61         private static Bitmap MergerImg(params Bitmap[] maps)
62         {
63             int i = maps.Length;
64             
65             if (i == 0)
66                 throw new Exception("图片数不能够为0");
67             else if (i == 1)
68                 return maps[0];
69 
70             //创建要显示的图片对象,根据参数的个数设置宽度
71             Bitmap backgroudImg = new Bitmap(maps[0].Width, i * maps[0].Height);
72             Graphics g = Graphics.FromImage(backgroudImg);
73             //清除画布,背景设置为白色
74             g.Clear(System.Drawing.Color.White);
75             for (int j = 0; j < i; j++)
76             {
77                 g.DrawImage(maps[j], 0, j * maps[j].Height, maps[j].Width, maps[j].Height);
78             }
79             g.Dispose();
80             return backgroudImg;
81         }