用的是破解版的 O2S.Components.PDFRender4NET.dll 插件, 简单引用即可
public static class PdfToImage
{
public static MemoryStream GetPdfImagePageStream(string pdfInputPath, int pageIndex, ImageFormat format, int width = , int height = , int quality = )
{
try
{
//pdf处理插件
PDFFile pdfFile = PDFFile.Open(pdfInputPath);
int total = pdfFile.PageCount; #region 防止异常参数
if (pageIndex < )
{
pageIndex = ;
}
if (pageIndex > total)
{
pageIndex = total - ;
}
if (quality < )
{
quality = ;
}
if (quality > )
{
quality = ;
}
if (width <= )
{
width = ;
} if (height <= )
{
height = ;
}
#endregion //pdf转换图片
SizeF pageSize = pdfFile.GetPageSize(pageIndex); Bitmap pageImage = pdfFile.GetPageImage(pageIndex, * quality); MemoryStream ms = new MemoryStream(); pageImage.Save(ms, format); //原图
Image img = Image.FromStream(ms, true); double ratio = (double)width / (double)height; double oRatio = (double)img.Width / (double)img.Height; int sbWidth = ; int sbHeight = ; int outX = ;
int outY = ; if (oRatio < ratio)
{
sbWidth = (int)(img.Width * ((double)height / (double)(img.Height)));
sbHeight = height; outX = (width - sbWidth) / ;
}
else
{
sbHeight = (int)(img.Height * ((double)width / (double)(img.Width)));
sbWidth = width; outY = (height - sbHeight) / ;
} //缩放
Image sbImg = new Bitmap(sbWidth, sbHeight);
Graphics sbGra = Graphics.FromImage(sbImg);
sbGra.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
sbGra.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
sbGra.Clear(Color.White);
sbGra.DrawImage(img, new System.Drawing.Rectangle(, , sbWidth, sbHeight), new System.Drawing.Rectangle(, , img.Width, img.Height), System.Drawing.GraphicsUnit.Pixel); //补白
Image outImg = new System.Drawing.Bitmap(width, height);
Graphics outGra = System.Drawing.Graphics.FromImage(outImg);
outGra.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
outGra.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
outGra.Clear(Color.White);
outGra.DrawImage(sbImg, new System.Drawing.Rectangle(outX, outY, sbWidth, sbHeight), new System.Drawing.Rectangle(, , sbWidth, sbHeight), System.Drawing.GraphicsUnit.Pixel); MemoryStream outMs = new MemoryStream(); outImg.Save(outMs, format); sbImg.Dispose();
outImg.Dispose();
img.Dispose(); return outMs; }
catch (Exception ex)
{ } return new MemoryStream();
} public static MemoryStream GetPdfImagePageStream(Stream stream, int pageIndex, ImageFormat format, int width = , int height = , int quality = )
{
try
{
//pdf处理插件
PDFFile pdfFile = PDFFile.Open(stream);
int total = pdfFile.PageCount; #region 防止异常参数
if (pageIndex < )
{
pageIndex = ;
}
if (pageIndex > total)
{
pageIndex = total - ;
}
if (quality < )
{
quality = ;
}
if (quality > )
{
quality = ;
}
if (width <= )
{
width = ;
} if (height <= )
{
height = ;
}
#endregion //pdf转换图片
SizeF pageSize = pdfFile.GetPageSize(pageIndex); Bitmap pageImage = pdfFile.GetPageImage(pageIndex, * quality); MemoryStream ms = new MemoryStream(); pageImage.Save(ms, format); //原图
Image img = Image.FromStream(ms, true); double ratio = (double)width / (double)height; double oRatio = (double)img.Width / (double)img.Height; int sbWidth = ; int sbHeight = ; int outX = ;
int outY = ; if (oRatio < ratio)
{
sbWidth = (int)(img.Width * ((double)height / (double)(img.Height)));
sbHeight = height; outX = (width - sbWidth) / ;
}
else
{
sbHeight = (int)(img.Height * ((double)width / (double)(img.Width)));
sbWidth = width; outY = (height - sbHeight) / ;
} //缩放
Image sbImg = new Bitmap(sbWidth, sbHeight);
Graphics sbGra = Graphics.FromImage(sbImg);
sbGra.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
sbGra.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
sbGra.Clear(Color.White);
sbGra.DrawImage(img, new System.Drawing.Rectangle(, , sbWidth, sbHeight), new System.Drawing.Rectangle(, , img.Width, img.Height), System.Drawing.GraphicsUnit.Pixel); //补白
Image outImg = new System.Drawing.Bitmap(width, height);
Graphics outGra = System.Drawing.Graphics.FromImage(outImg);
outGra.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
outGra.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
outGra.Clear(Color.White);
outGra.DrawImage(sbImg, new System.Drawing.Rectangle(outX, outY, sbWidth, sbHeight), new System.Drawing.Rectangle(, , sbWidth, sbHeight), System.Drawing.GraphicsUnit.Pixel); MemoryStream outMs = new MemoryStream(); outImg.Save(outMs, format); sbImg.Dispose();
outImg.Dispose();
img.Dispose(); return outMs; }
catch (Exception ex)
{ } return new MemoryStream();
}
}
