PeachPDF
PeachPDF.PdfGenerateConfig
PdfGenerateConfig.MaxRasterPixels Property
The largest number of pixels a single rasterized region may have (see RasterizationDpi). A region that would exceed it is rendered at a lower resolution just large enough to fit. Defaults to 64 million pixels (about 256 MB of working memory for one region).
public long MaxRasterPixels { get; set; }