/// <summary>
/// 以填充模式缩略图片
/// </summary>
public virtual void ThumbByFill(Stream sourceStream, Stream ouputStream, int width, int height, bool highQuality)
{
Image source = Image.FromStream(sourceStream);
if (source.RawFormat.Guid != ImageFormat.Gif.Guid)
{
throw new IOException(string.Format("文件不是GIF格式的图片!"));
}
if (width == 0 || (width > 200 && width > source.Width))
{
width = source.Width; //做200的限制,实际文件超过200的，就以实际为大小
}
if (height == 0 || (height > 200 && height > source.Height))
{
height = source.Height; //做200的限制,实际文件超过200的，就以实际为大小
}
int x = 0, y = 0, tw, th;
//先等比缩放
if (source.Width > source.Height)
{
//宽大于高，以宽等比缩放
tw = source.Width > width ? width : source.Width;
th = (int)(source.Height * (double)tw / (double)source.Width);
if (th > height)//得到的结果比需要的高度高，则根据高度缩放
{
th = source.Height > height ? height : source.Height;
tw = (int)(source.Width * (double)th / (double)source.Height);
}
}
else
{
//高大于宽，以高等比缩放
th = source.Height > height ? height : source.Height;
tw = (int)(source.Width * (double)th / (double)source.Height);
if (tw > width)//得到的结果比需要的宽度宽，则根据宽度缩放
{
tw = source.Width > width ? width : source.Width;
th = (int)(source.Height * (double)tw / (double)source.Width);
}
}
if (tw < width)
{
x = (width - tw) / 2;
}
if (th < height)
{
y = (height - th) / 2;
}
sourceStream.Seek(0, SeekOrigin.Begin);
Bitmap ora_Img = new Bitmap(sourceStream);
List <Frame> frames = new List <Frame>();
foreach (Guid guid in ora_Img.FrameDimensionsList)
{
FrameDimension frameDimension = new FrameDimension(guid);
int frameCount = ora_Img.GetFrameCount(frameDimension);
byte[] buffer = ora_Img.GetPropertyItem(20736).Value;
for (int i = 0; i < frameCount; i++)
{
if (ora_Img.SelectActiveFrame(frameDimension, i) == 0)
{
int delay = BitConverter.ToInt32(buffer, i * 4);
System.IO.MemoryStream stream = new System.IO.MemoryStream();
source = Image.FromHbitmap(ora_Img.GetHbitmap()) as Bitmap;
Color backColor = Color.White;
Bitmap img = new Bitmap(width, height);
img.SetResolution(72f, 72f);
img.SetResolution(source.HorizontalResolution, source.VerticalResolution);
using (Graphics gdiobj = Graphics.FromImage(img))
{
SetQuality(gdiobj);
gdiobj.FillRectangle(new SolidBrush(Color.White), 0, 0, width, height);
Rectangle destrect = new Rectangle(x, y, tw, th);
gdiobj.DrawImage(source, destrect, 0, 0, source.Width,
source.Height, GraphicsUnit.Pixel);
}
Frame frame = new Frame(img, delay, backColor);
frames.Add(frame);
}
}
}
AnimatedGifEncoder gif = new AnimatedGifEncoder();
gif.Start(ouputStream);
gif.SetRepeat(0);
for (int i = 0; i < frames.Count; i++)
{
gif.SetDelay(frames[i].Delay);
gif.AddFrame(frames[i].Img);
}
gif.Finish();
}
/// <summary>
/// 保留全图的缩放（但会使图像变形）
/// </summary>
/// <param name="sourceStream"></param>
/// <param name="ouputStream"></param>
/// <param name="width"></param>
/// <param name="height"></param>
/// <param name="format"></param>
/// <param name="highQuality"></param>
public virtual void ThumbByFull(Stream sourceStream, Stream ouputStream, int width, int height, bool highQuality)
{
Image source = null;
try
{
source = System.Drawing.Image.FromStream(sourceStream);
ImageZip(source.Width, source.Height, ref width, ref height);
sourceStream.Seek(0, SeekOrigin.Begin);
Bitmap ora_Img = new Bitmap(sourceStream);
List <Frame> frames = new List <Frame>();
foreach (Guid guid in ora_Img.FrameDimensionsList)
{
FrameDimension frameDimension = new FrameDimension(guid);
int frameCount = ora_Img.GetFrameCount(frameDimension);
byte[] buffer = ora_Img.GetPropertyItem(20736).Value;
for (int i = 0; i < frameCount; i++)
{
if (ora_Img.SelectActiveFrame(frameDimension, i) == 0)
{
int delay = BitConverter.ToInt32(buffer, i * 4);
System.IO.MemoryStream stream = new System.IO.MemoryStream();
source = Image.FromHbitmap(ora_Img.GetHbitmap()) as Bitmap;
Color backColor = Color.White;
Bitmap img = new Bitmap(width, height);
//img.SetResolution(72f, 72f);
img.SetResolution(source.HorizontalResolution, source.VerticalResolution);
using (Graphics gdiobj = Graphics.FromImage(img))
{
SetQuality(gdiobj);
gdiobj.FillRectangle(new SolidBrush(Color.White), 0, 0, width, height);
Rectangle destrect = new Rectangle(0, 0, width, height);
gdiobj.DrawImage(source, destrect, 0, 0, source.Width,
source.Height, GraphicsUnit.Pixel);
}
Frame frame = new Frame(img, delay, backColor);
frames.Add(frame);
}
}
}
AnimatedGifEncoder gif = new AnimatedGifEncoder();
gif.Start(ouputStream);
gif.SetRepeat(0);
for (int i = 0; i < frames.Count; i++)
{
gif.SetDelay(frames[i].Delay);
gif.AddFrame(frames[i].Img);
}
gif.Finish();
}
catch (Exception ex)
{
throw ex;
}
finally
{
source.Dispose();
}
}
public virtual void ThumbByCut(Stream sourceStream, Stream ouputStream, int width, int height, bool highQuality)
{
Image source = null;
try
{
source = System.Drawing.Image.FromStream(sourceStream);
//先等比裁剪
int tw = width;
int th = height;
if (tw == 0 && th != 0)
{
tw = (int)(source.Width * (double)th / source.Height);
}
else if (th == 0 && tw != 0)
{
th = (int)(source.Height * (double)width / source.Width);
}
else if (th == 0 && tw == 0)
{
th = source.Height;
tw = source.Width;
}
int cutWidth = 0;
int cutHeight = 0;
int bywWidth = source.Width;
int bywHeight = (int)(source.Width * (double)th / tw);
if (bywHeight < 1)
{
bywHeight = 1;
}
int byhWidth = (int)(source.Height * (double)tw / th);
if (byhWidth < 1)
{
byhWidth = 1;
}
int byhHeight = source.Height;
if (bywHeight > source.Height)//如果根据宽度裁剪得到的高度超过原始高度
{
cutWidth = byhWidth;
cutHeight = byhHeight;
}
else if (byhWidth > source.Width) //如果根据高度裁剪得到的宽度高过原始宽度
{
cutWidth = bywWidth;
cutHeight = bywHeight;
}
else
{
//如果两个依据都符合，则根据面积的大小判断，面积越大，精确度越高
if ((bywWidth * bywHeight) > (byhWidth * byhHeight))
{
cutWidth = bywWidth;
cutHeight = bywHeight;
}
else
{
cutWidth = byhWidth;
cutHeight = byhHeight;
}
}
//根据中心点，得到裁剪的起始地址
int x = (int)((double)source.Width / 2 - (double)cutWidth / 2);
int y = (int)((double)source.Height / 2 - (double)cutHeight / 2);
if (x < 0)
{
x = 0;
}
if (y < 0)
{
y = 0;
}
sourceStream.Seek(0, SeekOrigin.Begin);
Bitmap ora_Img = new Bitmap(sourceStream);
List <Frame> frames = new List <Frame>();
foreach (Guid guid in ora_Img.FrameDimensionsList)
{
FrameDimension frameDimension = new FrameDimension(guid);
int frameCount = ora_Img.GetFrameCount(frameDimension);
byte[] buffer = ora_Img.GetPropertyItem(20736).Value;
for (int i = 0; i < frameCount; i++)
{
if (ora_Img.SelectActiveFrame(frameDimension, i) == 0)
{
int delay = BitConverter.ToInt32(buffer, i * 4);
System.IO.MemoryStream stream = new System.IO.MemoryStream();
source = Image.FromHbitmap(ora_Img.GetHbitmap()) as Bitmap;
Color backColor = Color.White;
Bitmap img = new Bitmap(cutWidth, cutHeight, PixelFormat.Format32bppArgb);
using (Graphics g = Graphics.FromImage(img))
{
Rectangle destRect = new Rectangle(0, 0, cutWidth, cutHeight);
g.DrawImage(source, destRect, x, y, cutWidth, cutHeight, GraphicsUnit.Pixel);
using (MemoryStream ms = new MemoryStream())
{
img.Save(ms, ImageFormat.Jpeg);
source.Dispose();
source = Image.FromStream(ms);
//再缩放
ImageZip(cutWidth, cutHeight, ref width, ref height);
img = new Bitmap(width, height);
//img.SetResolution(72f, 72f);
img.SetResolution(source.HorizontalResolution, source.VerticalResolution);
using (Graphics gdiobj = Graphics.FromImage(img))
{
SetQuality(gdiobj);
gdiobj.FillRectangle(new SolidBrush(Color.White), 0, 0, width, height);
Rectangle destrect = new Rectangle(0, 0, width, height);
gdiobj.DrawImage(source, destrect, 0, 0, source.Width,
source.Height, GraphicsUnit.Pixel);
}
}
}
Frame frame = new Frame(img, delay, backColor);
frames.Add(frame);
}
}
}
AnimatedGifEncoder gif = new AnimatedGifEncoder();
gif.Start(ouputStream);
gif.SetRepeat(0);
for (int i = 0; i < frames.Count; i++)
{
gif.SetDelay(frames[i].Delay);
gif.AddFrame(frames[i].Img);
}
gif.Finish();
}
catch (Exception ex)
{
throw ex;
}
finally
{
source.Dispose();
}
}