C# - 图片操作和Base64处理

旋转

/// <summary>
/// 根据角度旋转图标
/// </summary>
/// <param name="img"></param>
public Image RotateImg(Image img, float angle)
{
//通过Png图片设置图片透明，修改旋转图片变黑问题。
int width = img.Width;
int height = img.Height;
//角度
Matrix mtrx = new Matrix();
mtrx.RotateAt(angle, new PointF((width / 2), (height / 2)), MatrixOrder.Append);
//得到旋转后的矩形
GraphicsPath path = new GraphicsPath();
path.AddRectangle(new RectangleF(0f, 0f, width, height));
RectangleF rct = path.GetBounds(mtrx);
//生成目标位图
Bitmap devImage = new Bitmap((int)(rct.Width), (int)(rct.Height));
Graphics g = Graphics.FromImage(devImage);
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.Bilinear;
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
//计算偏移量
Point Offset = new Point((int)(rct.Width - width) / 2, (int)(rct.Height - height) / 2);
//构造图像显示区域：让图像的中心与窗口的中心点一致
Rectangle rect = new Rectangle(Offset.X, Offset.Y, (int)width, (int)height);
Point center = new Point((int)(rect.X + rect.Width / 2), (int)(rect.Y + rect.Height / 2));
g.TranslateTransform(center.X, center.Y);
g.RotateTransform(angle);
//恢复图像在水平和垂直方向的平移
g.TranslateTransform(-center.X, -center.Y);
g.DrawImage(img, rect);
//重至绘图的所有变换
g.ResetTransform();
g.Save();
g.Dispose();
path.Dispose();
return devImage;
}

/// <summary>
/// 第二种方法
/// </summary>
/// <param name="b"></param>
/// <param name="angle"></param>
/// <returns></returns>
public Image RotateImg2(Image b, float angle)
{
angle = angle % 360;            //弧度转换
double radian = angle * Math.PI / 180.0;
double cos = Math.Cos(radian);
double sin = Math.Sin(radian);
//原图的宽和高
int w = b.Width;
int h = b.Height;
int W = (int)(Math.Max(Math.Abs(w * cos - h * sin), Math.Abs(w * cos + h * sin)));
int H = (int)(Math.Max(Math.Abs(w * sin - h * cos), Math.Abs(w * sin + h * cos)));
//目标位图
Image dsImage = new Bitmap(W, H);
System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(dsImage);
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.Bilinear;
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
//计算偏移量
Point Offset = new Point((W - w) / 2, (H - h) / 2);
//构造图像显示区域：让图像的中心与窗口的中心点一致
Rectangle rect = new Rectangle(Offset.X, Offset.Y, w, h);
Point center = new Point(rect.X + rect.Width / 2, rect.Y + rect.Height / 2);
g.TranslateTransform(center.X, center.Y);
g.RotateTransform(360-angle);
//恢复图像在水平和垂直方向的平移
g.TranslateTransform(-center.X, -center.Y);
g.DrawImage(b, rect);
//重至绘图的所有变换
g.ResetTransform();
g.Save();
g.Dispose();
//dsImage.Save("yuancd.jpg", System.Drawing.Imaging.ImageFormat.Jpeg);
return dsImage;
}

/// <summary>
/// 旋转（利用已封装的方法）
/// </summary>
/// <param name="path">图片路径</param>
/// <param name="rotateFlipType">旋转方式</param>
/// <returns></returns>
public bool KiRotate(string path, RotateFlipType rotateFlipType)
{
try
{
using (Bitmap bitmap = new Bitmap(path))
{
// 顺时针旋转90度 RotateFlipType.Rotate90FlipNone
// 逆时针旋转90度 RotateFlipType.Rotate270FlipNone
// 水平翻转 RotateFlipType.Rotate180FlipY
// 垂直翻转 RotateFlipType.Rotate180FlipX
bitmap.RotateFlip(rotateFlipType);
bitmap.Save(path);
}
return true;
}
catch(Exception ex)
{
return false;
}
}

转换

// 程序集
System.Xaml.dll
System.Drawing.dll
WindowsBase.dll
PresentationCore.dll
// 命名空间
using System.Drawing;
using System.IO;
using System.Windows.Media.Imaging;
using System.Windows.Interop;
using System.Windows;

/// <summary>
/// 创建一个Bitmap对象
/// </summary>
/// <param name="_uri">"../Images/test.png"</param>
public Bitmap CreatBitmapObject(string _uri)
{
Bitmap bitmap = new Bitmap(_uri);
return bitmap;
}

/// <summary>
/// 创建一个BitmapImage对象
/// </summary>
/// <param name="_uri">"../Images/test.png"</param>
public BitmapImage CreatBitmapImageObject(string _uri)
{
BitmapImage bitmapImage = new BitmapImage(
new Uri(_uri, UriKind.Relative));
return bitmapImage;
}

/// <summary>
/// BitmapImage to Bitmap
/// </summary>
public Bitmap BitmapImage2Bitmap(BitmapImage bitmapImage)
{
using (MemoryStream outStream = new MemoryStream())
{
BitmapEncoder enc = new BmpBitmapEncoder();
enc.Frames.Add(BitmapFrame.Create(bitmapImage));
enc.Save(outStream);
Bitmap bitmap = new Bitmap(outStream);
return new Bitmap(bitmap);
}
}

/// <summary>
/// Bitmap to BitmapImage
/// </summary>
[System.Runtime.InteropServices.DllImport("gdi32.dll")]
public static extern bool DeleteObject(IntPtr hObject);
public BitmapImage Bitmap2BitmapImage(Bitmap bitmap)
{
IntPtr hBitmap = bitmap.GetHbitmap();
BitmapImage retval;

try
{
retval = (BitmapImage)Imaging.CreateBitmapSourceFromHBitmap(
hBitmap, IntPtr.Zero, Int32Rect.Empty,
BitmapSizeOptions.FromEmptyOptions());
}
finally
{
DeleteObject(hBitmap);
}

return retval;
}

/// <summary>
/// Bitmap to 字节数组
/// </summary>
public byte[] Bitmap2Bytes(Bitmap bitmap)
{
ImageFormat format = bitmap.RawFormat;
using (MemoryStream ms = new MemoryStream())
{
bitmap.Save(ms, format);
byte[] data = new byte[ms.Length];
//Save()会改变MemoryStream的Position，需要重新Seek到Begin也就是开始的0位置
ms.Seek(0, SeekOrigin.Begin);
ms.Read(data, 0, Convert.ToInt32(ms.Length));
return data;
}
}
/// <summary>
/// 字节数组 to Bitmap
/// </summary>
public Bitmap Bytes2Bitmap(byte[] data)
{
MemoryStream ms = null;
try
{
ms = new MemoryStream(data);
return new Bitmap((Image)new Bitmap(ms));
}
catch (Exception ex)
{
throw ex;
}
finally
{
ms.Close();
}
}

/// <summary>
/// BitmapImage to 字节数组
/// </summary>
public byte[] BitmapImage2Bytes(BitmapImage bitmapImage)
{
byte[] bytes = null;
try
{
Stream ms = bitmapImage.StreamSource;
if (ms != null && ms.Length > 0)
{
//很重要，因为Position经常位于stream的末尾，导致下面读取到的长度为0
ms.Position = 0;
using (BinaryReader br = new BinaryReader(ms))
{
bytes = br.ReadBytes((int)ms.Length);
}
}
}
catch(Exception ex)
{
bytes = null;
throw ex;
}
return bytes;
}
/// <summary>
/// 字节数组 to BitmapImage
/// </summary>
public BitmapImage Bytes2BitmapImage(byte[] data)
{
BitmapImage bitmapImage = null;
try
{
bitmapImage = new BitmapImage();
bitmapImage.BeginInit();
bitmapImage.StreamSource = new MemoryStream(data);
bitmapImage.EndInit();
}
catch(Exception ex)
{
bitmapImage = null;
throw ex;
}
return bitmapImage;
}

// Image抽象类，Bitmap密封类
public abstract class Image： xxx
public sealed class Bitmap : Image
// ImageSource和BitmapSource抽象类，BitmapImage密封类
public abstract class ImageSource： xxx
public abstract class BitmapSource : ImageSource
public sealed class BitmapImage : BitmapSource

压缩

/// <summary>
/// 生成缩略图
/// </summary>
/// <param name="sourceFile">原始图片文件</param>
/// <param name="quality">质量压缩比:0-100,越大质量越好</param>
/// <param name="multiple">压缩倍数</param>
/// <param name="outputFile">输出文件名</param>
/// <returns>成功返回true,失败返回false</returns>
/// 调用格式：GetThumImage("", 85L, 3, "");
public static bool GetThumImage(string sourceFile, long quality, int multiple, string outputFile)
{
try
{
// 获取图片信息
Bitmap sourceImage = new Bitmap(sourceFile);
ImageCodecInfo myImageCodecInfo = GetEncoderInfo(sourceImage.RawFormat);
if (null == myImageCodecInfo) {
return false;
}

// 压缩质量
System.Drawing.Imaging.Encoder myEncoder = System.Drawing.Imaging.Encoder.Quality;
EncoderParameters myEncoderParameters = new EncoderParameters(1);
EncoderParameter myEncoderParameter = new EncoderParameter(myEncoder, quality);
myEncoderParameters.Param[0] = myEncoderParameter;

// 按比例压缩
float _xWidth = sourceImage.Width;
float _yWidth = sourceImage.Height;
Bitmap newImage = new Bitmap((int)(_xWidth / multiple), (int)(_yWidth / multiple));
Graphics g = Graphics.FromImage(newImage);
/// 可按需配置属性
//g.CompositingQuality = CompositingQuality.HighQuality;
//g.CompositingMode = CompositingMode.SourceCopy;
//g.InterpolationMode = InterpolationMode.HighQualityBicubic;
g.DrawImage(sourceImage, 0, 0, (_xWidth / multiple), (_yWidth / multiple));
g.Dispose();

// 保存图片
newImage.Save(outputFile, myImageCodecInfo, myEncoderParameters);
return true;
}
catch
{
return false;
}
}

/// <summary>
/// 获取图片编码信息
/// </summary>
private static ImageCodecInfo GetEncoderInfo(ImageFormat format)
{
ImageCodecInfo[] encoders;
encoders = ImageCodecInfo.GetImageEncoders();
for (int j = 0; j < encoders.Length; ++j)
{
if (encoders[j].FormatID == format.Guid) {
return encoders[j];
}
}
return null;
}

Base64处理

['A', 'B', 'C', 'D', ... 'a', 'b', 'c', 'd', ... '0', '1', '2', ... '+', '/']

>>> base64.b64encode('i\xb7\x1d\xfb\xef\xff')
'abcd++//'
>>> base64.urlsafe_b64encode('i\xb7\x1d\xfb\xef\xff')
'abcd--__'

atob()

btoa()

// 编码
window.btoa()
// 解码
window.atob()

window.btoa()

window.atob()

function utf8_to_b64( str ) {
return window.btoa(
unescape(
encodeURIComponent( str )));
}
function b64_to_utf8( str ) {
return decodeURIComponent(
escape(
window.atob( str )));
}