/// <summary>
/// 生成缩略图
/// </summary>
/// <param name="originalImagePath">源图路径（物理路径）</param>
/// <param name="thumbnailPath">缩略图路径（物理路径）</param>
/// <param name="specifiedwidth">缩略图宽度</param>
/// <param name="specifiedheight">缩略图高度</param>
/// <param name="mode">生成缩略图的方式</param>
/// <param name="isaddwatermark">是否添加水印</param>
/// <param name="quality">图片品质</param>
/// <param name="imagePosition">水印位置</param>
/// <param name="waterImagePath">水印图片路径（物理路径）</param>
public static OperatedResult <string> BuilderThumbnails(string originalImagePath, string thumbnailPath, int specifiedwidth, int specifiedheight, ThumbnailImageCutMode mode, bool isaddwatermark, WatermarkImagesPosition imagePosition, string waterImagePath, int quality)
{
CheckResult _checkedThumbnailsParamter = CheckedThumbnailsParamter(originalImagePath, thumbnailPath, isaddwatermark, waterImagePath);
if (!_checkedThumbnailsParamter.State)
{
return(OperatedResult <string> .Fail(_checkedThumbnailsParamter.Message));
}
Image _originalImage = Image.FromFile(originalImagePath);
int _cutedWidth = specifiedwidth;
int _cutedHeight = specifiedheight;
int x = 0;
int y = 0;
int _originalWidth = _originalImage.Width;
int _originalHeigh = _originalImage.Height;
switch (mode)
{
case ThumbnailImageCutMode.W: //指定宽，高按比例
_cutedHeight = _originalImage.Height * specifiedwidth / _originalImage.Width;
break;
case ThumbnailImageCutMode.H: //指定高，宽按比例
_cutedWidth = _originalImage.Width * specifiedheight / _originalImage.Height;
break;
case ThumbnailImageCutMode.Cut: //指定高宽裁减（不变形）
if (_originalImage.Width >= _cutedWidth && _originalImage.Height >= _cutedHeight)
{
if ((double)_originalImage.Width / (double)_originalImage.Height > (double)_cutedWidth / (double)_cutedHeight)
{
_originalHeigh = _originalImage.Height;
_originalWidth = _originalImage.Height * _cutedWidth / _cutedHeight;
y = 0;
x = (_originalImage.Width - _originalWidth) / 2;
}
else
{
_originalWidth = _originalImage.Width;
_originalHeigh = _originalImage.Width * specifiedheight / _cutedWidth;
x = 0;
y = (_originalImage.Height - _originalHeigh) / 2;
}
}
else
{
x = (_originalImage.Width - _cutedWidth) / 2;
y = (_originalImage.Height - _cutedHeight) / 2;
_originalWidth = _cutedWidth;
_originalHeigh = _cutedHeight;
}
break;
case ThumbnailImageCutMode.Fit: //不超出尺寸，比它小就不截了，不留白，大就缩小到最佳尺寸，主要为手机用
if (_originalImage.Width > _cutedWidth && _originalImage.Height > _cutedHeight)
{
if ((double)_originalImage.Width / (double)_originalImage.Height > (double)_cutedWidth / (double)_cutedHeight)
{
_cutedHeight = _originalImage.Height * specifiedwidth / _originalImage.Width;
}
else
{
_cutedWidth = _originalImage.Width * specifiedheight / _originalImage.Height;
}
}
else if (_originalImage.Width > _cutedWidth)
{
_cutedHeight = _originalImage.Height * specifiedwidth / _originalImage.Width;
}
else if (_originalImage.Height > _cutedHeight)
{
_cutedWidth = _originalImage.Width * specifiedheight / _originalImage.Height;
}
else
{
_cutedWidth = _originalImage.Width;
_cutedHeight = _originalImage.Height;
_originalWidth = _cutedWidth;
_originalHeigh = _cutedHeight;
}
break;
default:
break;
}
Image _thumbnailImage = new Bitmap(_cutedWidth, _cutedHeight);
Graphics _g = SetThumbnailGraphics(_originalImage, _thumbnailImage, _cutedWidth, _cutedHeight, _originalWidth, _originalHeigh, x, y);
try
{
SetThumbnailWaterImage(isaddwatermark, waterImagePath, imagePosition, _g, _cutedWidth, _cutedHeight);
EncoderParameters _encoderParams = null;
ImageCodecInfo _jpegICI = SetThumbnailImageQuality(quality, out _encoderParams);
SaveThumbnailImage(thumbnailPath, _thumbnailImage, _jpegICI, _encoderParams);
}
catch (Exception ex)
{
OperatedResult <string> .Fail(string.Format("生成缩略图失败，原因:{0}", ex.Message));
}
finally
{
_originalImage.Dispose();
_thumbnailImage.Dispose();
_g.Dispose();
}
return(OperatedResult <string> .Success(string.Format("生成{0}的缩略图成功", originalImagePath), thumbnailPath));
}
/// <summary>
/// 设置缩略图的水印
/// </summary>
private static void SetThumbnailWaterImage(bool isaddwatermark, string waterImagePath, WatermarkImagesPosition imagePosition, Graphics g, int cutedWidth, int cutedHeight)
{
if (isaddwatermark)
{
Image _waterImage = Image.FromFile(waterImagePath);
int _xPosOfWm;
int _yPosOfWm;
int _wmHeight = _waterImage.Height;
int _wmWidth = _waterImage.Width;
int _phHeight = cutedHeight;
int _phWidth = cutedWidth;
switch (imagePosition)
{
case WatermarkImagesPosition.LeftBottom:
_xPosOfWm = 70;
_yPosOfWm = _phHeight - _wmHeight - 70;
break;
case WatermarkImagesPosition.LeftTop:
_xPosOfWm = 70;
_yPosOfWm = 0 - 70;
break;
case WatermarkImagesPosition.RightTop:
_xPosOfWm = _phWidth - _wmWidth - 70;
_yPosOfWm = 0 - 70;
break;
case WatermarkImagesPosition.RigthBottom:
_xPosOfWm = _phWidth - _wmWidth - 70;
_yPosOfWm = _phHeight - _wmHeight - 70;
break;
default:
_xPosOfWm = 10;
_yPosOfWm = 0;
break;
}
g.DrawImage(_waterImage, new Rectangle(_xPosOfWm, _yPosOfWm, _waterImage.Width, _waterImage.Height), 0, 0, _waterImage.Width, _waterImage.Height, GraphicsUnit.Pixel);
}
}
