Output File Names

DynamicPDF Rasterizer allows outputting image files using either a default naming strategy or using user-defined names. The default naming strategy makes generating a file easier while manually controlling an output file name provides developers greater flexibility.

Default Output File Names

When using the PdfRasterizer class's Draw method to convert the PDF document to an image file, one image file is created for each PDF page specified. These output files use the value specified in the Draw method's fileName parameter.

The naming strategy for multi-page rasterization is as follows. When rasterizing more than one page, each page names the output image as the specified file name (minus the extension), the page number, and then appends the image file's extension.

<file name> + <page-number>.<file-type-extension>

Example

The following code illustrates the default output file naming and creating multiple files from a PDF.

PdfRasterizer rasterizer = new PdfRasterizer("DocumentA.pdf");
rasterizer.Draw(@"png-output-example.png"), ImageFormat.Png, ImageSize.Dpi72);    

Dim rasterizer As New PdfRasterizer("DocumentA.pdf")
rasterizer.Draw("png-output-example.png"), ImageFormat.Png, ImageSize.Dpi72)

The DocumentA.pdf file contains four pages which when rasterized produces the following four images:

• png-output-example.png,
• png-output-example2.png,
• png-output-example3.png, and
• png-output-example4.png.

Manual Control of Output File Names

Developers also have control of file names by iterating over a collection of Pages in a PdfRasterizer object and then calling the Draw method individually for each page. Each page within the loop outputs the current image from the PDF document and allows naming each page uniquely.

Example

The following code illustrates manual output file naming when creating a PNG from a PDF.

PdfRasterizer rasterizer = new PdfRasterizer(@"DocumentA.pdf");
for (int i = 0; i < rasterizer.Pages.Count; i++) {
    rasterizer.Pages[i].Draw("manual-output" + i + ".png", ImageFormat.Png, ImageSize.Dpi72);
}

Dim rasterizer As New PdfRasterizer(Program.GetResourcePath("DocumentA.pdf"))

For i As Integer = 0 To rasterizer.Pages.Count - 1
  rasterizer.Pages(i).Draw("manual-output" & i & ".png"), ImageFormat.Png, ImageSize.Dpi72)
Next

The DocumentA.pdf file contains four pages which when rasterized produces the following four images:

• manualOutput0.png,
• manualOutput1.png,
• manualOutput2.png, and
• manualOutput3.png.