Size, Width和Height都是System.Drawing.Image的Get()属性; 我如何在c#运行时调整图像对象的大小?
现在,我只是创建一个新的图像使用:
// objImage is the original Image
Bitmap objBitmap = new Bitmap(objImage, new Size(227, 171));
Size, Width和Height都是System.Drawing.Image的Get()属性; 我如何在c#运行时调整图像对象的大小?
现在,我只是创建一个新的图像使用:
// objImage is the original Image
Bitmap objBitmap = new Bitmap(objImage, new Size(227, 171));
当前回答
使用下面的函数和下面的例子来改变图像大小:
//Example :
System.Net.Mime.MediaTypeNames.Image newImage = System.Net.Mime.MediaTypeNames.Image.FromFile("SampImag.jpg");
System.Net.Mime.MediaTypeNames.Image temImag = FormatImage(newImage, 100, 100);
//image size modification unction
public static System.Net.Mime.MediaTypeNames.Image FormatImage(System.Net.Mime.MediaTypeNames.Image img, int outputWidth, int outputHeight)
{
Bitmap outputImage = null;
Graphics graphics = null;
try
{
outputImage = new Bitmap(outputWidth, outputHeight, System.Drawing.Imaging.PixelFormat.Format16bppRgb555);
graphics = Graphics.FromImage(outputImage);
graphics.DrawImage(img, new Rectangle(0, 0, outputWidth, outputHeight),
new Rectangle(0, 0, img.Width, img.Height), GraphicsUnit.Pixel);
return outputImage;
}
catch (Exception ex)
{
return img;
}
}
其他回答
使用下面的函数和下面的例子来改变图像大小:
//Example :
System.Net.Mime.MediaTypeNames.Image newImage = System.Net.Mime.MediaTypeNames.Image.FromFile("SampImag.jpg");
System.Net.Mime.MediaTypeNames.Image temImag = FormatImage(newImage, 100, 100);
//image size modification unction
public static System.Net.Mime.MediaTypeNames.Image FormatImage(System.Net.Mime.MediaTypeNames.Image img, int outputWidth, int outputHeight)
{
Bitmap outputImage = null;
Graphics graphics = null;
try
{
outputImage = new Bitmap(outputWidth, outputHeight, System.Drawing.Imaging.PixelFormat.Format16bppRgb555);
graphics = Graphics.FromImage(outputImage);
graphics.DrawImage(img, new Rectangle(0, 0, outputWidth, outputHeight),
new Rectangle(0, 0, img.Width, img.Height), GraphicsUnit.Pixel);
return outputImage;
}
catch (Exception ex)
{
return img;
}
}
为什么不用System.Drawing.Image.GetThumbnailImage方法呢?
public Image GetThumbnailImage(
int thumbWidth,
int thumbHeight,
Image.GetThumbnailImageAbort callback,
IntPtr callbackData)
例子:
Image originalImage = System.Drawing.Image.FromStream(inputStream, true, true);
Image resizedImage = originalImage.GetThumbnailImage(newWidth, (newWidth * originalImage.Height) / originalWidth, null, IntPtr.Zero);
resizedImage.Save(imagePath, ImageFormat.Png);
来源: http://msdn.microsoft.com/en-us/library/system.drawing.image.getthumbnailimage.aspx
注意:这将不适用于ASP。因为WebImage依赖于系统。Web,但在以前版本的ASP。我在Net中多次使用了这个片段,它很有用。
String ThumbfullPath = Path.GetFileNameWithoutExtension(file.FileName) + "80x80.jpg";
var ThumbfullPath2 = Path.Combine(ThumbfullPath, fileThumb);
using (MemoryStream stream = new MemoryStream(System.IO.File.ReadAllBytes(fullPath)))
{
var thumbnail = new WebImage(stream).Resize(80, 80);
thumbnail.Save(ThumbfullPath2, "jpg");
}
调整大小并保存图像以适应宽度和高度,就像画布保持图像成比例
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;
namespace Infra.Files
{
public static class GenerateThumb
{
/// <summary>
/// Resize and save an image to fit under width and height like a canvas keeping things proportional
/// </summary>
/// <param name="originalImagePath"></param>
/// <param name="thumbImagePath"></param>
/// <param name="newWidth"></param>
/// <param name="newHeight"></param>
public static void GenerateThumbImage(string originalImagePath, string thumbImagePath, int newWidth, int newHeight)
{
Bitmap srcBmp = new Bitmap(originalImagePath);
float ratio = 1;
float minSize = Math.Min(newHeight, newHeight);
if (srcBmp.Width > srcBmp.Height)
{
ratio = minSize / (float)srcBmp.Width;
}
else
{
ratio = minSize / (float)srcBmp.Height;
}
SizeF newSize = new SizeF(srcBmp.Width * ratio, srcBmp.Height * ratio);
Bitmap target = new Bitmap((int)newSize.Width, (int)newSize.Height);
using (Graphics graphics = Graphics.FromImage(target))
{
graphics.CompositingQuality = CompositingQuality.HighSpeed;
graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
graphics.CompositingMode = CompositingMode.SourceCopy;
graphics.DrawImage(srcBmp, 0, 0, newSize.Width, newSize.Height);
using (MemoryStream memoryStream = new MemoryStream())
{
target.Save(thumbImagePath);
}
}
}
}
}
如果你正在使用BitmapSource:
var resizedBitmap = new TransformedBitmap(
bitmapSource,
new ScaleTransform(scaleX, scaleY));
如果你想要更好的控制质量,首先运行这个:
RenderOptions.SetBitmapScalingMode(
bitmapSource,
BitmapScalingMode.HighQuality);
(默认为BitmapScalingMode。线性,相当于BitmapScalingMode.LowQuality。)