针对移动端网络图片加载缓慢，网上又缺少批量压缩图片的工具，于是自己开发了一个，分享出来，希望能给大家带来帮助。
工具：vs2017
创建项目 windowsform
文件压缩方法
/// <summary>
/// 获取缩略图
/// </summary>
/// <param name="bitmap"></param>
/// <param name="width"></param>
/// <returns></returns>
public static Image GetThumbnailImageByte(Image bitmap, int width)
{
System.Drawing.Image img = bitmap.Clone() as Image;
if (bitmap.RawFormat == System.Drawing.Imaging.ImageFormat.Gif)
{
#region gif动态图缩放
//不够100*100的不缩放
if (img.Width > width)
{
System.IO.MemoryStream stream = new System.IO.MemoryStream();
var height = (img.Height * width) / img.Width;
//新图第一帧
Image new_img = new Bitmap(width, height);
//新图其他帧
Image new_imgs = new Bitmap(width, height);
//新图第一帧GDI+绘图对象
Graphics g_new_img = Graphics.FromImage(new_img);
//新图其他帧GDI+绘图对象
Graphics g_new_imgs = Graphics.FromImage(new_imgs);
//配置新图第一帧GDI+绘图对象
g_new_img.CompositingMode = CompositingMode.SourceCopy;
g_new_img.InterpolationMode = InterpolationMode.HighQualityBicubic;
g_new_img.PixelOffsetMode = PixelOffsetMode.HighQuality;
g_new_img.SmoothingMode = SmoothingMode.HighQuality;
g_new_img.Clear(Color.FromKnownColor(KnownColor.Transparent));
//配置其他帧GDI+绘图对象
g_new_imgs.CompositingMode = CompositingMode.SourceCopy;
g_new_imgs.InterpolationMode = InterpolationMode.HighQualityBicubic;
g_new_imgs.PixelOffsetMode = PixelOffsetMode.HighQuality;
g_new_imgs.SmoothingMode = SmoothingMode.HighQuality;
g_new_imgs.Clear(Color.FromKnownColor(KnownColor.Transparent));
//遍历维数
foreach (Guid gid in img.FrameDimensionsList)
{
//因为是缩小GIF文件所以这里要设置为Time
//如果是TIFF这里要设置为PAGE
FrameDimension f = FrameDimension.Time;
//获取总帧数
int count = img.GetFrameCount(f);
//保存标示参数
System.Drawing.Imaging.Encoder encoder = System.Drawing.Imaging.Encoder.SaveFlag;
//
EncoderParameters ep = null;
//图片编码、解码器
ImageCodecInfo ici = null;
//图片编码、解码器集合
ImageCodecInfo[] icis = ImageCodecInfo.GetImageDecoders();
//为 图片编码、解码器 对象 赋值
foreach (ImageCodecInfo ic in icis)
{
if (ic.FormatID == ImageFormat.Gif.Guid)
{
ici = ic;
break;
}
}
//每一帧
for (int c = 0; c < count; c++)
{
//选择由维度和索引指定的帧
img.SelectActiveFrame(f, c);
//第一帧
if (c == 0)
{
//将原图第一帧画给新图第一帧
g_new_img.DrawImage(img, new Rectangle(0, 0, width, height), new Rectangle(0, 0, img.Width, img.Height), GraphicsUnit.Pixel);
//把振频和透明背景调色板等设置复制给新图第一帧
for (int i = 0; i < img.PropertyItems.Length; i++)
{
new_img.SetPropertyItem(img.PropertyItems[i]);
}
ep = new EncoderParameters(1);
//第一帧需要设置为MultiFrame
ep.Param[0] = new EncoderParameter(encoder, (long)EncoderValue.MultiFrame);
//保存第一帧
new_img.Save(stream, ici, ep);
}
//其他帧
else
{
//把原图的其他帧画给新图的其他帧
g_new_imgs.DrawImage(img, new Rectangle(0, 0, width, height), new Rectangle(0, 0, img.Width, img.Height), GraphicsUnit.Pixel);
//把振频和透明背景调色板等设置复制给新图第一帧
for (int i = 0; i < img.PropertyItems.Length; i++)
{
new_imgs.SetPropertyItem(img.PropertyItems[i]);
}
ep = new EncoderParameters(1);
//如果是GIF这里设置为FrameDimensionTime
//如果为TIFF则设置为FrameDimensionPage
ep.Param[0] = new EncoderParameter(encoder, (long)EncoderValue.FrameDimensionTime);
//向新图添加一帧
new_img.SaveAdd(new_imgs, ep);
}
}
ep = new EncoderParameters(1);
//关闭多帧文件流
ep.Param[0] = new EncoderParameter(encoder, (long)EncoderValue.Flush);
new_img.SaveAdd(ep);
}
byte[] byData = new Byte[stream.Length];
stream.Position = 0;
stream.Read(byData, 0, byData.Length);
stream.Close();
//释放文件
img.Dispose();
new_img.Dispose();
new_imgs.Dispose();
g_new_img.Dispose();
g_new_imgs.Dispose();
return BytesToBitmap(byData);
}
#endregion
}
else
{
#region 静态缩略图
if (img.Width > width)
{
Graphics g = null;
try
{
var height = (img.Height * width) / img.Width;
Bitmap bmpDest = new Bitmap(width, height);
g = Graphics.FromImage(bmpDest);
//g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.Default;
g.Clear(Color.White);
g.DrawImage(img, new Rectangle(0, 0, width, height), new Rectangle(0, 0, img.Size.Width, img.Size.Height), GraphicsUnit.Pixel);
g.Flush();
return bmpDest;
}
catch
{
return null;
}
finally
{
g.Dispose();
img.Dispose();
}
}
#endregion
}
return img;
}
工具下载地址：
链接：https://pan.baidu.com/s/19MTOQbssM7Dbzwwc5E1HLw
提取码：xw2x
源码下载地址：
链接：https://pan.baidu.com/s/1Txez9qzBFQXauiAIazlCpw
提取码：gyze