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
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");
}
在我做的应用程序中,有必要创建一个具有多个选项的函数。它相当大,但它可以调整图像的大小,可以保持纵横比,并可以切割边缘,只返回图像的中心:
/// <summary>
/// Resize image with a directory as source
/// </summary>
/// <param name="OriginalFileLocation">Image location</param>
/// <param name="heigth">new height</param>
/// <param name="width">new width</param>
/// <param name="keepAspectRatio">keep the aspect ratio</param>
/// <param name="getCenter">return the center bit of the image</param>
/// <returns>image with new dimentions</returns>
public Image resizeImageFromFile(String OriginalFileLocation, int heigth, int width, Boolean keepAspectRatio, Boolean getCenter)
{
int newheigth = heigth;
System.Drawing.Image FullsizeImage = System.Drawing.Image.FromFile(OriginalFileLocation);
// Prevent using images internal thumbnail
FullsizeImage.RotateFlip(System.Drawing.RotateFlipType.Rotate180FlipNone);
FullsizeImage.RotateFlip(System.Drawing.RotateFlipType.Rotate180FlipNone);
if (keepAspectRatio || getCenter)
{
int bmpY = 0;
double resize = (double)FullsizeImage.Width / (double)width;//get the resize vector
if (getCenter)
{
bmpY = (int)((FullsizeImage.Height - (heigth * resize)) / 2);// gives the Y value of the part that will be cut off, to show only the part in the center
Rectangle section = new Rectangle(new Point(0, bmpY), new Size(FullsizeImage.Width, (int)(heigth * resize)));// create the section to cut of the original image
//System.Console.WriteLine("the section that will be cut off: " + section.Size.ToString() + " the Y value is minimized by: " + bmpY);
Bitmap orImg = new Bitmap((Bitmap)FullsizeImage);//for the correct effect convert image to bitmap.
FullsizeImage.Dispose();//clear the original image
using (Bitmap tempImg = new Bitmap(section.Width, section.Height))
{
Graphics cutImg = Graphics.FromImage(tempImg);// set the file to save the new image to.
cutImg.DrawImage(orImg, 0, 0, section, GraphicsUnit.Pixel);// cut the image and save it to tempImg
FullsizeImage = tempImg;//save the tempImg as FullsizeImage for resizing later
orImg.Dispose();
cutImg.Dispose();
return FullsizeImage.GetThumbnailImage(width, heigth, null, IntPtr.Zero);
}
}
else newheigth = (int)(FullsizeImage.Height / resize);// set the new heigth of the current image
}//return the image resized to the given heigth and width
return FullsizeImage.GetThumbnailImage(width, newheigth, null, IntPtr.Zero);
}
为了更容易访问函数,可以添加一些重载函数:
/// <summary>
/// Resize image with a directory as source
/// </summary>
/// <param name="OriginalFileLocation">Image location</param>
/// <param name="heigth">new height</param>
/// <param name="width">new width</param>
/// <returns>image with new dimentions</returns>
public Image resizeImageFromFile(String OriginalFileLocation, int heigth, int width)
{
return resizeImageFromFile(OriginalFileLocation, heigth, width, false, false);
}
/// <summary>
/// Resize image with a directory as source
/// </summary>
/// <param name="OriginalFileLocation">Image location</param>
/// <param name="heigth">new height</param>
/// <param name="width">new width</param>
/// <param name="keepAspectRatio">keep the aspect ratio</param>
/// <returns>image with new dimentions</returns>
public Image resizeImageFromFile(String OriginalFileLocation, int heigth, int width, Boolean keepAspectRatio)
{
return resizeImageFromFile(OriginalFileLocation, heigth, width, keepAspectRatio, false);
}
现在是最后两个可选的布尔值。 像这样调用函数:
System.Drawing.Image ResizedImage = resizeImageFromFile(imageLocation, 800, 400, true, true);
下面的函数将返回显示图像的新大小。这在这里可能没有帮助。但它将返回调整大小的显示矩形大小。
public static class ResizeImage
{
/// <summary>
/// Return new resized size to display the image
/// </summary>
/// <param name="srcrectanle">source rectangle of image or you can pass the bitmap and set the size accrodingly</param>
/// <param name="initSize">initial size of the page to draw image</param>
/// <returns></returns>
public static SizeF getResizedRectangle(RectangleF srcrectanle, SizeF initSize)
{
float sw = srcrectanle.Width;
float sh = srcrectanle.Height;
float dw = initSize.Width;
float dh = initSize.Height;
float finalHeight, finalWidth;
float Sourceratio = sw / sh;
if (Sourceratio >= 1)
{
finalWidth = (int)dw;
float ratio = sw / dw;
finalHeight = (sh / ratio);
}
else
{
finalHeight = (int)dh;
float ratio = sh / dh;
finalWidth = (sw / ratio);
}
return new SizeF(finalHeight, finalHeight);
}
}
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。)
public static Image resizeImage(Image image, int new_height, int new_width)
{
Bitmap new_image = new Bitmap(new_width, new_height);
Graphics g = Graphics.FromImage((Image)new_image );
g.InterpolationMode = InterpolationMode.High;
g.DrawImage(image, 0, 0, new_width, new_height);
return new_image;
}