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
本遗嘱-
调整宽度和高度,不需要循环 不超过图像的原始尺寸
//////////////
private void ResizeImage(Image img, double maxWidth, double maxHeight)
{
double resizeWidth = img.Source.Width;
double resizeHeight = img.Source.Height;
double aspect = resizeWidth / resizeHeight;
if (resizeWidth > maxWidth)
{
resizeWidth = maxWidth;
resizeHeight = resizeWidth / aspect;
}
if (resizeHeight > maxHeight)
{
aspect = resizeWidth / resizeHeight;
resizeHeight = maxHeight;
resizeWidth = resizeHeight * aspect;
}
img.Width = resizeWidth;
img.Height = resizeHeight;
}
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);
public string CreateThumbnail(int maxWidth, int maxHeight, string path)
{
var image = System.Drawing.Image.FromFile(path);
var ratioX = (double)maxWidth / image.Width;
var ratioY = (double)maxHeight / image.Height;
var ratio = Math.Min(ratioX, ratioY);
var newWidth = (int)(image.Width * ratio);
var newHeight = (int)(image.Height * ratio);
var newImage = new Bitmap(newWidth, newHeight);
Graphics thumbGraph = Graphics.FromImage(newImage);
thumbGraph.CompositingQuality = CompositingQuality.HighQuality;
thumbGraph.SmoothingMode = SmoothingMode.HighQuality;
//thumbGraph.InterpolationMode = InterpolationMode.HighQualityBicubic;
thumbGraph.DrawImage(image, 0, 0, newWidth, newHeight);
image.Dispose();
string fileRelativePath = "newsizeimages/" + maxWidth + Path.GetFileName(path);
newImage.Save(Server.MapPath(fileRelativePath), newImage.RawFormat);
return fileRelativePath;
}
点击这里http://bhupendrasinghsaini.blogspot.in/2014/07/resize-image-in-c.html
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;
}
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