/// <summary>
/// 生成缩略图
/// </summary>
/// <param name="originalImagePath"></param>
/// <param name="width"></param>
/// <param name="height"></param>
/// <param name="mode"></param>
/// <returns></returns>
public static bool MakeThumbnail(string originalImagePath, int width, int height, ThumbnailMod mode)
{
string thumbnailPath = originalImagePath.Substring(0, originalImagePath.LastIndexOf('.')) + "s.jpg";
Image originalImage = Image.FromFile(originalImagePath);
int towidth = width;
int toheight = height;
int x = 0;
int y = 0;
int ow = originalImage.Width;
int oh = originalImage.Height;
switch (mode)
{
case ThumbnailMod.HW: //指定高宽缩放（可能变形）
break;
case ThumbnailMod.W: //指定宽，高按比例
toheight = originalImage.Height * width / originalImage.Width;
break;
case ThumbnailMod.H: //指定高，宽按比例
towidth = originalImage.Width * height / originalImage.Height;
break;
case ThumbnailMod.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
Image 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);
bool isok = false;
try
{
//以jpg格式保存缩略图
bitmap.Save(thumbnailPath, ImageFormat.Jpeg);
isok = true;
}
catch (Exception)
{
thumbnailPath = originalImagePath;
}
finally
{
originalImage.Dispose();
bitmap.Dispose();
g.Dispose();
}
return(isok);
}
/// <summary>
/// 生成缩略图
/// </summary>
/// <param name="originalImagePath"></param>
/// <param name="width"></param>
/// <param name="height"></param>
/// <param name="mode"></param>
/// <returns></returns>
public static bool MakeThumbnail(string originalImagePath, int width, int height, ThumbnailMod mode)
{
string thumbnailPath = originalImagePath.Substring(0, originalImagePath.LastIndexOf('.')) + "s.jpg";
Image originalImage = Image.FromFile(originalImagePath);
int towidth = width;
int toheight = height;
int x = 0;
int y = 0;
int ow = originalImage.Width;
int oh = originalImage.Height;
switch (mode)
{
case ThumbnailMod.HW://指定高宽缩放（可能变形）
break;
case ThumbnailMod.W://指定宽，高按比例
toheight = originalImage.Height * width / originalImage.Width;
break;
case ThumbnailMod.H://指定高，宽按比例
towidth = originalImage.Width * height / originalImage.Height;
break;
case ThumbnailMod.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
Image 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);
bool isok = false;
try
{
//以jpg格式保存缩略图
bitmap.Save(thumbnailPath, ImageFormat.Jpeg);
isok = true;
}
catch (Exception)
{
thumbnailPath = originalImagePath;
}
finally
{
originalImage.Dispose();
bitmap.Dispose();
g.Dispose();
}
return isok;
}
public static Image MakeThumbnail(Image originalImage, int width, int height, ThumbnailMod mode)
{
int towidth = width;
int toheight = height;
int x = 0;
int y = 0;
int ow = originalImage.Width;
int oh = originalImage.Height;
switch (mode)
{
case ThumbnailMod.HW: //指定高宽缩放（可能变形）
break;
case ThumbnailMod.W: //指定宽，高按比例
toheight = originalImage.Height * width / originalImage.Width;
break;
case ThumbnailMod.H: //指定高，宽按比例
towidth = originalImage.Width * height / originalImage.Height;
break;
case ThumbnailMod.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
Image 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 = InterpolationMode.High;
//设置高质量,低速度呈现平滑程度
g.SmoothingMode = SmoothingMode.HighQuality;
//清空画布并以透明背景色填充
g.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
g.DrawImage(originalImage, new Rectangle(0, 0, towidth, toheight), new Rectangle(x, y, ow, oh), GraphicsUnit.Pixel);
g.Dispose();
return(bitmap);
}
