/// <summary>
/// 生成缩略图
/// </summary>
/// <param name="image"></param>
/// <param name="proportion"></param>
/// <param name="width"></param>
/// <param name="height"></param>
/// <returns></returns>
public static Image CreateThumb(Image image, ThumbnailProportion proportion, int width, int height)
{
if (image == null)
{
throw new ArgumentNullException("图片为空image");
}
int x = 0, y = 0, ow = image.Width, oh = image.Height, towidth = width, toheight = height;
switch (proportion)
{
case ThumbnailProportion.WIDTH_HEIHT:
break;
case ThumbnailProportion.WIDTH:
toheight = image.Height * width / image.Width;
break;
case ThumbnailProportion.HEIHT:
towidth = image.Width * height / image.Height;
break;
case ThumbnailProportion.CUT:
//剪切图片高比宽长
if ((double)image.Width / (double)image.Height > (double)towidth / (double)toheight)
{
oh = image.Height;
ow = image.Height * towidth / toheight;
y = 0;
x = (image.Width - ow) / 2;
}
else
{
ow = image.Width;
oh = image.Width * height / towidth;
x = 0;
y = (image.Height - oh) / 2;
}
break;
}
//指定位图大小
Bitmap bmp = new Bitmap(towidth, toheight);
//创建画布
using (Graphics gs = Graphics.FromImage(bmp))
{
gs.SmoothingMode = SmoothingMode.HighQuality;
gs.CompositingQuality = CompositingQuality.HighQuality;
gs.InterpolationMode = InterpolationMode.HighQualityBicubic;
//清空画布并以透明背景色填充
gs.Clear(Color.Transparent);
//在指定位置并且按指定大小绘制原图片的指定部分
gs.DrawImage(image, new Rectangle(0, 0, towidth, toheight),
new Rectangle(x, y, ow, oh),
GraphicsUnit.Pixel);
return(bmp);
}
}
/// <summary>
/// 剪裁图片
/// </summary>
/// <param name="abPath"></param>
/// <param name="cut"></param>
/// <param name="resize"></param>
/// <returns></returns>
private Image CutImage(string abPath, string cut, string resize)
{
Image image = Image.FromFile(abPath);
if (resize.StartsWith("w_") && resize.StartsWith("h_"))
{
return(image);
}
ThumbnailProportion pro = ThumbnailProportion.WIDTH;
int width = 0, height = 0;
string w, h;
if (resize.IndexOf('x') > -1)
{
var arr = resize.Split("x");
for (int i = 0; i < arr.Length; i++)
{
if (arr[i].StartsWith("w_"))
{
w = arr[i].Replace("w_", "");
int.TryParse(w, out width);
}
else
{
h = arr[i].Replace("h_", "");
int.TryParse(h, out height);
}
}
}
else if (resize.StartsWith("h_"))
{
h = resize.Replace("h_", "");
int.TryParse(h, out height);
}
else if (resize.StartsWith("w_"))
{
w = resize.Replace("w_", "");
int.TryParse(w, out width);
}
switch (cut)
{
case "m_fill":
pro = ThumbnailProportion.CUT;
if (width <= 0 || height <= 0)
{
return(image);
}
break;
case "m_fixed":
pro = ThumbnailProportion.WIDTH_HEIHT;
if (width <= 0 || height <= 0)
{
return(image);
}
break;
case "m_h":
pro = ThumbnailProportion.HEIHT;
if (height <= 0)
{
return(image);
}
break;
case "m_w":
pro = ThumbnailProportion.WIDTH;
if (width <= 0)
{
return(image);
}
break;
default:
return(image);
}
var thumb = ImageHelper.CreateThumb(image, pro, width, height);
image.Dispose();
return(thumb);
}
