PdfiumViewer组件扩展(Pdfium.Net.Free)--PDF操作
项目地址：
Pdfium.Net：https://github.com/1000374/Pdfium.Net.Free
PdfiumViewer：https://github.com/1000374/PdfiumViewer
Pdfium.Net.Free 支持
-
.NETFramework 4.0
-
.NETFramework 4.5
-
.NETStandard 2.0
- .Net8.0
可以和PdfiumViewer.Free共同使用预览、编辑pdf，也可以直接引用Pdfium.Net.Free 操作pdf，Pdfium.Net.Free封装了现有Pdfium的函数，实现了部分操作pdf的功能，部分功能等待后续~~
Pdfium.Net支持对PDF操作：
- 转成图片
- 拆分
- 合并
- 插入
- 替换
- 删除
- 旋转
- 导出缩略图
- 多页合并成一页
1.转成图片
1.基于GDI+下：
/// <summary>
/// Renders a page of the PDF document to the provided graphics instance. <see cref="Platforms.Windows"/>
/// </summary>
/// <param name="graphics">Graphics instance to render the page on.</param>
/// <param name="dpiX">Horizontal DPI.</param>
/// <param name="dpiY">Vertical DPI.</param>
/// <param name="bounds">Bounds to render the page in.</param>
/// <param name="rotation"><see cref="FpdfRotation"/></param>
/// <param name="flags">Flags used to influence the rendering.</param>
public void Render(Graphics graphics, float dpiX, float dpiY, Rectangle bounds, FpdfRotation rotation, RenderFlags flags)
示例代码：
var pathPdf = "./Pdfium.NetTests/resources/annotation_highlight_long_content.pdf";
using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
{
var page0 = doc.Pages[0];
Image image = new Bitmap((int)page0.Width, (int)page0.Height);
var g = Graphics.FromImage(image);
page0.Render(g, g.DpiX, g.DpiY, new Rectangle(
AdjustDpi(g.DpiX, 0),
AdjustDpi(g.DpiY, 0),
AdjustDpi(g.DpiX, image.Width),
AdjustDpi(g.DpiY, image.Height)),FpdfRotation.Rotate0,RenderFlags.None);
image.Save("./Pdfium.NetTests/Render.png");
}
2.不基于GDI+
/// <summary>
/// Renders a page of the PDF document to an image.
/// </summary>
/// <param name="width">Width of the rendered image.</param>
/// <param name="height">Height of the rendered image.</param>
/// <param name="dpiX">Horizontal DPI.</param>
/// <param name="dpiY">Vertical DPI.</param>
/// <param name="rotate">Rotation.</param>
/// <param name="flags">Flags used to influence the rendering.</param>
/// <returns>The rendered image.</returns>
public Image Render(int width, int height, float dpiX, float dpiY, FpdfRotation rotate, RenderFlags flags)
示例代码：
var pathPdf = "./Pdfium.NetTests/resources/annotation_highlight_long_content.pdf";
using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
for (int i = 0; i < doc.PageCount; i++)
{
using (var image = doc.Pages[i].Render((int)doc.Pages[i].Width * 4 / 3, (int)doc.Pages[i].Height * 4 / 3, 96, 96, FpdfRotation.Rotate0, RenderFlags.Annotations | RenderFlags.CorrectFromDpi))
{
}
}
3.不基于GDI+ 获取指定区域
区域坐标可通过框选获取，详情查看此
Pdfium.Net.Free 一个免费的Pdfium的 .net包装器--PDF预览器框选
/// <summary>
/// Renders the page.
/// </summary>
/// <param name="width">
/// The full width of the rendered image in px.
/// If 0, width will be calculated from height using the correct apsect ratio.
/// Height and width can not be both set to zero.
/// </param>
/// <param name="height">
/// The full wiheightth of the rendered image in px.
/// If 0, height will be calculated from height using the correct apsect ratio.
/// Height and width can not be both set to zero.
/// </param>
/// <param name="clipX">X value of the start point of the clipping area</param>
/// <param name="clipY">Y value of the start point of the clipping area</param>
/// <param name="clipWidth">Width of the clip area</param>
/// <param name="clipHeight">Height of the clip area</param>
/// <param name="dpiX">DPI to render page. If set, width and height will accept percentage.</param>
/// <param name="dpiY">DPI to render page. If set, width and height will accept percentage.</param>
/// <param name="rotate">Specify rotation.</param>
/// <param name="flags">Specify flags.</param>
/// <returns>Image from the page.</returns>
public Image Render(int width, int height, int clipX, int clipY, int clipWidth, int clipHeight, float dpiX, float dpiY, FpdfRotation rotate, RenderFlags flags)
示例代码：
var pathPdf = "./Pdfium.NetTests/resources/annotation_highlight_long_content.pdf";
using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
for (int i = 0; i < doc.PageCount; i++)
{
using (var image = doc.Pages[i].Render(
(int)doc.Pages[i].Width,
(int)doc.Pages[i].Height,
16, // x of the top/left of clipping rectangle
283, // y of the top/left point of clipping rectangle
555, // width of clipping reactangle
316, // height of clipping reactangle
0,//DPIx
0,//DPIy
FpdfRotation.Rotate0, // no rotation
RenderFlags.None // no render flags
))
{
Assert.AreEqual(555, image.Width);
}
}
2.拆分
可使用封装好的函数直接获取每一页后保存
var pathPdf = "./Pdfium.NetTests/resources/viewer_ref.pdf";
using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
{
for (int i = 0; i < doc.PageCount; i++)
{
var doci = doc.GetPDFPage(i);
}
}
也可直接使用doc对象保存
var pathPdf = "./Pdfium.NetTests/resources/viewer_ref.pdf";
using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
{
for (int i = 0; i < doc.PageCount; i++)
{
var newDocument = PdfDocument.CreateNew();
if (newDocument.Pages.Add(doc, i))
{
newDocument.Save($"./Pdfium.NetTests/AddTest{i}.pdf");
}
}
}
3.合并
var pathPdf = "./Pdfium.NetTests/resources/viewer_ref.pdf";
using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
using (var doc1 = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
{
doc.MergePDF(doc1);
}
4.插入
var pathPdf = "./Pdfium.NetTests/resources/viewer_ref.pdf";
var pathPdf1 = "./Pdfium.NetTests/resources/zero_length_stream.pdf";
using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
using (var doc1 = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf1))))
{
doc.ImportPage(doc1, 1);
}
5.替换
var pathPdf = "./Pdfium.NetTests/resources/viewer_ref.pdf";
var pathPdf1 = "./Pdfium.NetTests/resources/zero_length_stream.pdf";
using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
using (var doc1 = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf1))))
{
doc.DeletePage(1);
doc.ImportPage(doc1, 1);
}
6.删除
var pathPdf = "./Pdfium.NetTests/resources/viewer_ref.pdf";
using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
{
doc.DeletePage(0);
}
也可通过以下删除
var pathPdf = "./Pdfium.NetTests/resources/viewer_ref.pdf";
using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
{
doc.Pages.RemoveAt(0);
}
7.旋转
pdf可进行360度旋转 具体看枚举值FpdfRotation
/// <summary>
/// Specifies the rotation of pages shown in the PDF renderer.
/// </summary>
public enum FpdfRotation
{
/// <summary>
/// Rotates the output 0 degrees.
/// </summary>
Rotate0,
/// <summary>
/// Rotates the output 90 degrees.
/// </summary>
Rotate90,
/// <summary>
/// Rotates the output 180 degrees.
/// </summary>
Rotate180,
/// <summary>
/// Rotates the output 270 degrees.
/// </summary>
Rotate270
}
示例：
var pathPdf = "./Pdfium.NetTests/resources/viewer_ref.pdf";
using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
{
doc.RotatePage(0,FpdfRotation.Rotate90);
}
8.导出缩略图
var pathPdf = "./Pdfium.NetTests/resources/simple_thumbnail.pdf";
using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
for (int i = 0; i < doc.PageCount; i++)
{
var image = doc.Pages[i].RenderThumbnail();
}
9.多页合并成一页
函数声明：
-
num_pages_on_x_axis ：横向几页合并成一页默认2
-
num_pages_on_y_axis ：纵向几页合并成一页默认1
/// <summary> /// Create a new document from |src_doc|. The pages of |src_doc| will be combined to provide |num_pages_on_x_axis x num_pages_on_y_axis| pages per |output_doc| page. /// number of pages per page = num_pages_on_x_axis * num_pages_on_y_axis /// </summary> /// <param name="output_width">The output page width in PDF "user space" units.</param> /// <param name="output_height">The output page height in PDF "user space" units.</param> /// <param name="num_pages_on_x_axis">The number of pages on X Axis.</param> /// <param name="num_pages_on_y_axis">The number of pages on Y Axis.</param> /// <returns>A handle to the created document, or NULL on failure.</returns> public PdfDocument ImportNPagesToOne(float output_width, float output_height, uint num_pages_on_x_axis = 2, uint num_pages_on_y_axis = 1)
var pathPdf = "./Pdfium.NetTests/resources/rectangles_multi_pages.pdf";
using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
{
using (var doc1 = doc.ImportNPagesToOne(612 * 2, 792))
{}
}
