public static ImageSource ChangeSize(string imgSourcePath, double ratio,AdjustMode mode)
{
var originalImage = GetImage(imgSourcePath);
int towidth =(int)(originalImage.Width*ratio);
int toheight = (int)(originalImage.Height * ratio);
return ChangeSize(originalImage, towidth, toheight,mode);
}
public static ImageSource ChangeSize(Image originalImage, int width, int height, AdjustMode mode)
{
int towidth = width;
int toheight = height;
int x = 0;
int y = 0;
int ow = originalImage.Width;
int oh = originalImage.Height;
switch (mode)
{
case AdjustMode.HW://指定高宽缩放（可能变形）
break;
case AdjustMode.H://指定宽，高按比例
toheight = originalImage.Height * width / originalImage.Width;
break;
case AdjustMode.W://指定高，宽按比例
towidth = originalImage.Width * height / originalImage.Height;
break;
case AdjustMode.Cut://指定高宽裁减（不变形）
if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
{
oh = originalImage.Height;
ow = originalImage.Height * towidth / toheight;
y = 0;
x = (originalImage.Width - ow) / 2;
}
else
{
ow = originalImage.Width;
oh = originalImage.Width * height / towidth;
x = 0;
y = (originalImage.Height - oh) / 2;
}
break;
default:
break;
}
//新建一个bmp图片
Bitmap bitmap = new Bitmap(towidth, toheight);
//新建一个画板
Graphics g = Graphics.FromImage(bitmap);
//设置高质量插值法
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
//设置高质量,低速度呈现平滑程度
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
//清空画布并以透明背景色填充
g.Clear(System.Drawing.Color.Transparent);
//在指定位置并且按指定大小绘制原图片的指定部分
g.DrawImage(originalImage, new Rectangle(0, 0, towidth, toheight), new Rectangle(x, y, ow, oh), GraphicsUnit.Pixel);
try
{
IntPtr ip = bitmap.GetHbitmap();
BitmapSource bitmapSource = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(ip, IntPtr.Zero, Int32Rect.Empty,
BitmapSizeOptions.FromEmptyOptions());
DeleteObject(ip);
return bitmapSource;
//保存缩略图
// bitmap.Save(thumbnailPath, imgtype);
}
catch (Exception e)
{
throw e;
}
finally
{
originalImage.Dispose();
bitmap.Dispose();
g.Dispose();
}
}
public static ImageSource ChangeSize(string imgSourcePath, int width, int height, AdjustMode mode)
{
var originalImage = GetImage(imgSourcePath);
return ChangeSize(originalImage, width, height, mode);
}