如何更改图像位图尺寸？ [英] how to change image bitmap dimensions?

问题描述

位图img;  //  当前方法之外。 
  private   void  Form1_Load（ object  sender ，EventArgs e）
 {
 pictureBox1.SizeMode = PictureBoxSizeMode.Zoom; 
 img =  new 位图（file.FullName）; 
  if （img.Height >  = pictureBox1.Height）
 {
  //  如何更改img维度？ 
  //  我想设置加载图像的高度或宽度，使其正确放入我的图片框。 
  //  如果图像模式是垂直的，我的图片框必须有高度>宽度。 img的高度将改变图片盒的高度。  
 
} 
 pictureBox1.Image = img; 
} 

解决方案

我几年前在博客上发现了这个，但找不到原版。这是我修改过的博客版本。这是C ++，但原则是相同的，将其转换为C＃应该不会太困难：

  //  获取目标坐标 
 :: GetClientRect（hWnd，& rectWindow）; 
 
 destRect.X = static_cast< real>（rectWindow.left）; 
 destRect.Y = static_cast< real>（rectWindow.top）; 
 destRect.Width = static_cast< real>（（rectWindow.right  -  rectWindow.left））; 
 destRect.Height = static_cast< real>（（rectWindow.bottom  -  rectWindow.top））; 
 
  / *   
 *在调整大小时保持正确宽高比的关键image是用于计算比率的算法
 *，即。 
 * 
 * NewHeight = GivenWidth *（OriginalHeight / OriginalWidth）
 *或
 * 
 * NewWidth = GivenHeight *（OriginalWidth / OriginalHeight）
 * 
 *此计算假定Given ...是图像
 *应调整大小的维度。 
 *一旦我们知道这一点，我们可以将它乘以原始图像的方面，
 *，这将为我们提供我们需要的另一方价值。因此，假设
 *原始图片的宽度为1000，高度为1600，我们希望将
 *的大小调整为宽度500：
 * 
 * First找到方面：（1600/1000）=方面1.6 
 *现在将方面乘以所需的新宽度：1.6 * 500 
 *乘法的结果是800，这是我们的高度应该是
 *换句话说：
 * 800 = 500 *（1600/1000）
 *因此得到的图像的高度为800，宽度为500. 
 * 
 * /  
 imageWidth = static_cast< real>（pImage-> GetWidth（））; 
 imageHeight = static_cast< real>（pImage-> GetHeight（））; 
  //  如果宽度或高度小于窗口，请使用图片大小 
  if （imageWidth< destRect.Width）
 destRect.Width = imageWidth; 
  if （imageHeight< destRect.Height）
 destRect.Height = imageHeight; 
 
  if （imageWidth> destRect.Width）
 {
  //  如果宽于窗口，则按纵横比调整高度 
 aspect = imageHeight / imageWidth; 
 REAL newHeight = destRect.Width * aspect; 
  //  但不要比窗口更深 
  if （newHeight< = destRect.Height）
 destRect.Height = newHeight; 
} 
  if （imageHeight> destRect.Height）
 {
  //  如果深于窗口，则按宽高比调整宽度 
 aspect = imageWidth / imageHeight; 
 destRect.Width = destRect.Height * aspect; 
} 

看起来我有点和蔼可亲...... :)

i使用了三条规则。

并且工作正常... yuhoo。

 uc.pictureBox1.SizeMode = PictureBoxSizeMode.StretchImage; 
 img =  new 位图（item.FullName）; 
 uc.pictureBox1.Image = img; 
  if （img.Height >  = uc.pictureBox1.Height）
 {
  //   10/5 = 8 / x>> x =（8 * 5）/ 10>> x = 4（10/5 = 2,8 / 4 = 2） 
 uc.Height =（uc.pictureBox1.Width * img.Height）/ img.Width; 
} 
  //  其中uc =包含公共pictureBox1的userControl。 

Bitmap img;//outside current method.
                   private void Form1_Load(object sender, EventArgs e)
                   {
                    pictureBox1.SizeMode = PictureBoxSizeMode.Zoom;
                    img = new Bitmap(file.FullName);
                    if (img.Height >= pictureBox1.Height )
                    {
                     //how do i change the img dimension?
                     //i want to Set the height or width of the loaded image, to fit it properly into my picturebox.
                     //if the image mode is vertical, my picturebox must have height> width. The height of the img will transform how high the picturebox high will be. 

                    }
                     pictureBox1.Image = img;
                   }

解决方案

I found this on a blog some years ago, but cannot find the original. This is my modified version of the blog. It's C++ but the principles are the same, converting it to C# should not be too difficult:

// get the destination co-ordinates
::GetClientRect(hWnd, &rectWindow);

destRect.X = static_cast<real>(rectWindow.left);
destRect.Y = static_cast<real>(rectWindow.top);
destRect.Width = static_cast<real>((rectWindow.right - rectWindow.left));
destRect.Height = static_cast<real>((rectWindow.bottom - rectWindow.top));

/*
 * The key to keeping the correct aspect ratio while resizing an image is the algorithm
 * used to calculate the ratio, viz.
 *
 *	NewHeight = GivenWidth * (OriginalHeight / OriginalWidth)
 * or
 *
 *	NewWidth = GivenHeight * (OriginalWidth / OriginalHeight)
 *
 * This calculation assumes that the "Given..." is the dimension the image
 * should be resized to.
 * Once we know this, we can multiply it by the original image’s aspect,
 * and that will give us the other side's value we need. So, assuming the
 * original image has a width of 1000 and a height of 1600 and we want it
 * to be resized to a width of 500:
 *
 *	First find the aspect: (1600 / 1000) = aspect of 1.6
 *	Now multiply the aspect by the desired new width: 1.6 * 500
 *	The result of that multiplication is 800, which is what our height should be
 *	In other words:
 *	800 = 500 * (1600 / 1000)
 * So the resulting image would have a height of 800 and a width of 500.
 *
 */
imageWidth =  static_cast<real>(pImage->GetWidth());
imageHeight =  static_cast<real>(pImage->GetHeight());
// if width or height is less than window, use image size
if (imageWidth < destRect.Width)
    destRect.Width = imageWidth;
if (imageHeight < destRect.Height)
    destRect.Height = imageHeight;

if (imageWidth > destRect.Width)
{
    // if wider than window then adjust height by aspect ratio
    aspect = imageHeight / imageWidth;
    REAL newHeight = destRect.Width * aspect;
    // but don't make it deeper than the window
    if (newHeight <= destRect.Height)
        destRect.Height = newHeight;
}
if (imageHeight > destRect.Height)
{
    // if deeper than window then adjust width by aspect ratio
    aspect = imageWidth / imageHeight;
    destRect.Width = destRect.Height * aspect;
}

it seem i got a stroke of geniality...:)
i used the three rule.
And is working perfectly... yuhoo.

                    uc.pictureBox1.SizeMode = PictureBoxSizeMode.StretchImage;
                    img = new Bitmap(item.FullName);
                    uc.pictureBox1.Image = img;
                    if (img.Height >= uc.pictureBox1.Height)
                    {
                        //10/5 = 8/x  >> x= (8*5)/10 >> x=4   (10/5=2, 8/4=2)
                        uc.Height = (uc.pictureBox1.Width * img.Height) / img.Width;
                    }
// where uc = userControl that contain a public pictureBox1.

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