/// <summary>
/// 生成缩略图
/// </summary>
/// <param name="originalImage">源图Image信息</param>
/// <param name="thumbnailWidth">缩略图宽度</param>
/// <param name="thumbnailHeight">缩略图高度</param>
/// <param name="thumbCutMode"></param>
/// <returns></returns>
public static Stream MakeThumbnail(Image originalImage, int thumbnailWidth, int thumbnailHeight, ThumbnailCutModes thumbCutMode)
{
Stream newImageStream = null;
if (originalImage != null)
{
bool isNeedCut = true;
//约束的宽高
int cw = thumbnailWidth;
int ch = thumbnailHeight;
//原图的宽高
int ow = originalImage.Width;
int oh = originalImage.Height;
//新图的宽高
int dw = thumbnailWidth;
int dh = thumbnailHeight;
switch (thumbCutMode)
{
case ThumbnailCutModes.HW: //指定高宽缩放（可能变形）
if (cw > ow && ch > oh)
{
isNeedCut = false;
}
else
{
dw = cw;
dh = ch;
}
break;
case ThumbnailCutModes.W: //指定宽，高按比例
if (cw > ow)
{
isNeedCut = false;
}
else
{
dw = thumbnailWidth;
dh = originalImage.Height * thumbnailWidth / originalImage.Width;
}
break;
case ThumbnailCutModes.H: //指定高，宽按比例
if (ch > oh)
{
isNeedCut = false;
}
else
{
dh = thumbnailHeight;
dw = originalImage.Width * thumbnailHeight / originalImage.Height;
}
break;
case ThumbnailCutModes.Auto: //指定高宽裁减（不变形）
default:
if (ch > oh && cw > ow)
{
isNeedCut = false;
}
else
{
double or = (double)ow / (double)oh;
double cr = (double)cw / (double)ch;
if (or > cr)
{
dw = cw;
dh = oh * dw / ow;
}
else
{
dh = ch;
dw = ow * dh / oh;
}
}
break;
}
if (isNeedCut == false)
{
dw = ow;
dh = oh;
}
//新建一个bmp图片
Image bitmap = new Bitmap(dw, dh);
//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, dw, dh), new Rectangle(0, 0, ow, oh), GraphicsUnit.Pixel);
try
{
newImageStream = new MemoryStream();
//以jpg格式保存缩略图
bitmap.Save(newImageStream, System.Drawing.Imaging.ImageFormat.Jpeg);
}
catch (System.Exception e)
{
throw e;
}
finally
{
originalImage.Dispose();
bitmap.Dispose();
g.Dispose();
}
}
return(newImageStream);
}
/// <summary>
/// 生成缩略图
/// </summary>
/// <param name="originalImageStream">源图的数据流</param>
/// <param name="thumbnailFullName">缩略图路径（物理路径）</param>
/// <param name="thumbnailWidth">缩略图宽度</param>
/// <param name="thumbnailHeight">缩略图高度</param>
/// <param name="mode">生成缩略图的方式</param>
public static Stream MakeThumbnail(Stream originalImageStream, int thumbnailWidth, int thumbnailHeight, ThumbnailCutModes thumbCutMode)
{
Image originalImage = Image.FromStream(originalImageStream);
return(MakeThumbnail(originalImage, thumbnailWidth, thumbnailHeight, thumbCutMode));
}
/// <summary>
/// 生成缩略图
/// </summary>
/// <param name="originalImageFullName">源图路径（物理路径）</param>
/// <param name="thumbnailFullName">缩略图路径（物理路径）</param>
/// <param name="thumbnailWidth">缩略图宽度</param>
/// <param name="thumbnailHeight">缩略图高度</param>
/// <param name="mode">生成缩略图的方式</param>
public static Stream MakeThumbnail(string originalImageFullName, int thumbnailWidth, int thumbnailHeight, ThumbnailCutModes thumbCutMode)
{
Image originalImage = Image.FromFile(originalImageFullName);
return(MakeThumbnail(originalImage, thumbnailWidth, thumbnailHeight, thumbCutMode));
}
/// <summary>
/// 生成缩略图
/// </summary>
/// <param name="originalImage">源图Image信息</param>
/// <param name="thumbnailWidth">缩略图宽度</param>
/// <param name="thumbnailHeight">缩略图高度</param>
/// <param name="thumbCutMode"></param>
/// <returns></returns>
public static Stream MakeThumbnail(Image originalImage, int thumbnailWidth, int thumbnailHeight, ThumbnailCutModes thumbCutMode)
{
Stream newImageStream = null;
if (originalImage != null)
{
bool isNeedCut = true;
//约束的宽高
int cw = thumbnailWidth;
int ch = thumbnailHeight;
//原图的宽高
int ow = originalImage.Width;
int oh = originalImage.Height;
//新图的宽高
int dw = thumbnailWidth;
int dh = thumbnailHeight;
switch (thumbCutMode)
{
case ThumbnailCutModes.HW://指定高宽缩放（可能变形）
if (cw > ow && ch > oh)
{
isNeedCut = false;
}
else
{
dw = cw;
dh = ch;
}
break;
case ThumbnailCutModes.W://指定宽，高按比例
if (cw > ow)
{
isNeedCut = false;
}
else
{
dw = thumbnailWidth;
dh = originalImage.Height * thumbnailWidth / originalImage.Width;
}
break;
case ThumbnailCutModes.H://指定高，宽按比例
if (ch > oh)
{
isNeedCut = false;
}
else
{
dh = thumbnailHeight;
dw = originalImage.Width * thumbnailHeight / originalImage.Height;
}
break;
case ThumbnailCutModes.Auto://指定高宽裁减（不变形）
default:
if (ch > oh && cw > ow)
{
isNeedCut = false;
}
else
{
double or = (double)ow / (double)oh;
double cr = (double)cw / (double)ch;
if (or > cr)
{
dw = cw;
dh = oh * dw / ow;
}
else
{
dh = ch;
dw = ow * dh / oh;
}
}
break;
}
if (isNeedCut == false)
{
dw = ow;
dh = oh;
}
//新建一个bmp图片
Image bitmap = new Bitmap(dw, dh);
//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, dw, dh), new Rectangle(0, 0, ow, oh), GraphicsUnit.Pixel);
try
{
newImageStream = new MemoryStream();
//以jpg格式保存缩略图
bitmap.Save(newImageStream, System.Drawing.Imaging.ImageFormat.Jpeg);
}
catch (System.Exception e)
{
throw e;
}
finally
{
originalImage.Dispose();
bitmap.Dispose();
g.Dispose();
}
}
return newImageStream;
}
/// <summary>
/// 生成缩略图
/// </summary>
/// <param name="originalImageStream">源图的数据流</param>
/// <param name="thumbnailFullName">缩略图路径（物理路径）</param>
/// <param name="thumbnailWidth">缩略图宽度</param>
/// <param name="thumbnailHeight">缩略图高度</param>
/// <param name="mode">生成缩略图的方式</param>
public static Stream MakeThumbnail(Stream originalImageStream, int thumbnailWidth, int thumbnailHeight, ThumbnailCutModes thumbCutMode)
{
Image originalImage = Image.FromStream(originalImageStream);
return MakeThumbnail(originalImage, thumbnailWidth, thumbnailHeight, thumbCutMode);
}
/// <summary>
/// 生成缩略图
/// </summary>
/// <param name="originalImageFullName">源图路径（物理路径）</param>
/// <param name="thumbnailFullName">缩略图路径（物理路径）</param>
/// <param name="thumbnailWidth">缩略图宽度</param>
/// <param name="thumbnailHeight">缩略图高度</param>
/// <param name="mode">生成缩略图的方式</param>
public static Stream MakeThumbnail(string originalImageFullName, int thumbnailWidth, int thumbnailHeight, ThumbnailCutModes thumbCutMode)
{
Image originalImage = Image.FromFile(originalImageFullName);
return MakeThumbnail(originalImage, thumbnailWidth, thumbnailHeight, thumbCutMode);
}
