public static void Thumbnail (int int_Width, int int_Height, string input_ImgFile, string out_ImgFile)
{
System.Drawing.Image oldimage = System.Drawing.Image.FromFile(input_ImgFile);
float New_Width; // 新的宽度
float New_Height; // 新的高度
float Old_Width,Old_Height; //原始高宽
int flat = 0;//标记图片是不是等比
int xPoint = 0;//若果要补白边的话，原图像所在的x，y坐标。
int yPoint=0;
//判断图片
Old_Width = (float)oldimage.Width;
Old_Height = (float)oldimage.Height;
if ((Old_Width / Old_Height) > ((float)int_Width / (float)int_Height)) //当图片太宽的时候
{
New_Height = Old_Height * ((float)int_Width / (float)Old_Width);
New_Width = (float)int_Width;
//此时x坐标不用修改
yPoint = (int)(((float)int_Height - New_Height) / 2);
flat = 1;
}
else if ((oldimage.Width / oldimage.Height) == ((float)int_Width / (float)int_Height))
{
New_Width = int_Width;
New_Height = int_Height;
}
else
{
New_Width = (int)oldimage.Width * ((float)int_Height / (float)oldimage.Height); //太高的时候
New_Height = int_Height;
//此时y坐标不用修改
xPoint = (int)(((float)int_Width - New_Width) / 2);
flat = 1;
}
// ＝＝＝缩小图片＝＝＝
System.Drawing.Image thumbnailImage = oldimage.GetThumbnailImage((int)New_Width, (int)New_Height, new System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback), IntPtr.Zero);
Bitmap bm = new Bitmap(thumbnailImage);
if (flat != 0)
{
Bitmap bmOutput = new Bitmap(int_Width,int_Height);
Graphics gc = Graphics.FromImage(bmOutput);
SolidBrush tbBg = new SolidBrush(Color.White);
gc.FillRectangle(tbBg,0, 0, int_Width, int_Height); //填充为白色
gc.DrawImage(bm,xPoint, yPoint, (int)New_Width, (int)New_Height);
bmOutput.Save(out_ImgFile);
}
else
{
bm.Save(out_ImgFile);
}
}

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