/// <summary>
/// 调整大小
/// </summary>
/// <param name="image"></param>
/// <param name="width">宽</param>
/// <param name="height">高</param>
/// <param name="zoom">等比缩放</param>
/// <returns></returns>
public static Image Resize(this Image image, int? width, int? height, bool zoom = true)
{
if (width == null && height == null)
return image;
int w = image.Width, h = image.Height;
if (width != null && height != null)
{
double wW = (double)image.Width / width.Value, hH = (double)image.Height / height.Value;
if (zoom)
{
if (wW > hH)
{
w = width.Value;
h = (int)(image.Height / wW);
}
else
{
w = (int)(image.Width / hH);
h = height.Value;
}
}
else
{
w = width.Value;
h = height.Value;
}
}
else if (width != null)
{
w = width.Value;
h = zoom ? (int)(image.Height / ((double)image.Width / width.Value)) : image.Height;
}
else if (height != null)
{
w = zoom ? (int)(image.Width / ((double)image.Height / height.Value)) : image.Width;
h = height.Value;
}
if (image.Width == w && image.Height == h)
return image;
if (image.RawFormat.Guid == ImageFormat.Gif.Guid)
{
GifDecoder GifDecoder = new GifDecoder();
GifDecoder.Read(image);
int count = GifDecoder.FramesCount;
AnimatedGifEncoder e = new AnimatedGifEncoder();
MemoryStream ms = new MemoryStream();
e.Start(ms);
//int loopCount = 0;
e.SetRepeat(GifDecoder.LoopCount);
//int j = loopCount;
for (int i = 0; i < count; i++)
{
Image frame = GifDecoder.GetFrame(i).GetThumbnailImage(w, h, () => { return false; }, IntPtr.Zero);
e.SetDelay(GifDecoder.Delay(i));
e.AddFrame(frame);
}
e.Finish();
Image gif = Image.FromStream(ms);
ms.Dispose();
return gif;
}
else
{
Bitmap tmp1 = new Bitmap(image);
Image tmp2 = tmp1.GetThumbnailImage(w, h, () => { return false; }, IntPtr.Zero);
Bitmap result = new Bitmap(tmp2);
image.Dispose();
tmp1.Dispose();
tmp2.Dispose();
return result;
}
}
/// <summary>
/// 调整大小
/// </summary>
/// <param name="image"></param>
/// <param name="width">宽</param>
/// <param name="height">高</param>
/// <param name="zoom">等比缩放</param>
/// <returns></returns>
public static Image Resize(this Image image, int?width, int?height, bool zoom = true)
{
if (width == null && height == null)
{
return(image);
}
int w = image.Width, h = image.Height;
if (width != null && height != null)
{
double wW = (double)image.Width / width.Value, hH = (double)image.Height / height.Value;
if (zoom)
{
if (wW > hH)
{
w = width.Value;
h = (int)(image.Height / wW);
}
else
{
w = (int)(image.Width / hH);
h = height.Value;
}
}
else
{
w = width.Value;
h = height.Value;
}
}
else if (width != null)
{
w = width.Value;
h = zoom ? (int)(image.Height / ((double)image.Width / width.Value)) : image.Height;
}
else if (height != null)
{
w = zoom ? (int)(image.Width / ((double)image.Height / height.Value)) : image.Width;
h = height.Value;
}
if (image.Width == w && image.Height == h)
{
return(image);
}
if (image.RawFormat.Guid == ImageFormat.Gif.Guid)
{
GifDecoder GifDecoder = new GifDecoder();
GifDecoder.Read(image);
int count = GifDecoder.FramesCount;
AnimatedGifEncoder e = new AnimatedGifEncoder();
MemoryStream ms = new MemoryStream();
e.Start(ms);
//int loopCount = 0;
e.SetRepeat(GifDecoder.LoopCount);
//int j = loopCount;
for (int i = 0; i < count; i++)
{
Image frame = GifDecoder.GetFrame(i).GetThumbnailImage(w, h, () => { return(false); }, IntPtr.Zero);
e.SetDelay(GifDecoder.Delay(i));
e.AddFrame(frame);
}
e.Finish();
Image gif = Image.FromStream(ms);
ms.Dispose();
return(gif);
}
else
{
Bitmap tmp1 = new Bitmap(image);
Image tmp2 = tmp1.GetThumbnailImage(w, h, () => { return(false); }, IntPtr.Zero);
Bitmap result = new Bitmap(tmp2);
image.Dispose();
tmp1.Dispose();
tmp2.Dispose();
return(result);
}
}
/// <summary>
/// 裁剪图片
/// </summary>
/// <param name="image">源图片</param>
/// <param name="startX">裁剪开始 X 坐标</param>
/// <param name="startY">裁剪开始 Y 坐标</param>
/// <param name="width">裁剪宽度</param>
/// <param name="height">裁剪高度</param>
/// <returns></returns>
public static Image Crop(this Image image, int startX, int startY, int width, int height)
{
if (startX >= image.Width || startY >= image.Height || width <= 0 || height <= 0)
return image;
if (startX < 0)
startX = 0;
if (startY < 0)
startY = 0;
if (width > image.Width - startX)
width = image.Width - startX;
if (height > image.Height - startY)
height = image.Height - startY;
if (image.RawFormat.Guid == ImageFormat.Gif.Guid)
{
int w = image.Width;
int h = image.Height;
GifDecoder GifDecoder = new GifDecoder();
GifDecoder.Read(image);
int count = GifDecoder.FramesCount;
AnimatedGifEncoder age = new AnimatedGifEncoder();
MemoryStream ms = new MemoryStream();
age.Start(ms);
age.SetRepeat(GifDecoder.LoopCount);
for (int i = 0; i < count; i++)
{
Image frame = new Bitmap(width, height);
Graphics g = Graphics.FromImage(frame);
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;//设置高质量插值法
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;//设置高质量,低速度呈现平滑程度
g.Clear(Color.Transparent); //清空画布并以透明背景色填充
g.DrawImage(GifDecoder.GetFrame(i), -startX, -startY, w, h);
g.Dispose();
age.SetDelay(GifDecoder.Delay(i));
age.AddFrame(frame);
}
age.Finish();
return Image.FromStream(ms);
}
else
{
Image @new = new Bitmap(width, height);
Graphics g = Graphics.FromImage(@new);
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;//设置高质量插值法
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;//设置高质量,低速度呈现平滑程度
g.Clear(Color.Transparent); //清空画布并以透明背景色填充
g.DrawImage(image, -startX, -startY, image.Width, image.Height);
g.Dispose();
return @new;
}
}
