PDFDrawSetDPI Method

public void SetDPI(
	double dpi
)

Public Sub SetDPI ( 
	dpi As Double
)

public:
virtual void SetDPI(
	[InAttribute] double dpi
) sealed

function SetDPI(dpi);

Parameters

dpi

Type: SystemDouble
The output image resolution.

DPI stands for Dots Per Inch. This parameter is used to specify the output image size and quality. A typical screen resolution for monitors these days is 92 DPI, but printers could use 200 DPI or more.

The size of resulting image is a function of DPI and the dimensions of the source PDF page. For example, is DPI is 92 and page is 8 inches wide, the output bitmap will have 92*8 = 736 pixels per line. If you know the dimensions of the destination bitmap, but don't care about DPI of the image you can use pdfdraw.SetImageSize() instead.

if you would like to rasterize extremely large bitmaps (e.g. with resolutions of 2000 DPI or more) it is not practical to use PDFDraw directly because of the memory required to store the entire image. In this case, you can use PDFRasterizer directly to generate the rasterized image in stripes or tiles.

Reference