c# - 如何在 monotouch Xamarin 中裁剪图像

Question

我正在 UIImageview 中显示图像，并且我想裁剪图像，以下是我的要求。

选择裁剪图标应显示一个固定大小 (600X600) 的正方形，该正方形固定在带有网格线的图像上，以帮助拉直图像。网格下会有一个允许图像翻转的控件。

Answer 1

这就是我最终用来居中裁剪图像的方法。

//Crops an image to even width and height
public UIImage CenterCrop(UIImage originalImage)
{
    // Use smallest side length as crop square length
    double squareLength = Math.Min(originalImage.Size.Width, originalImage.Size.Height);

    nfloat x, y;
    x = (nfloat)((originalImage.Size.Width - squareLength) / 2.0);
    y = (nfloat)((originalImage.Size.Height - squareLength) / 2.0);

    //This Rect defines the coordinates to be used for the crop
    CGRect croppedRect = CGRect.FromLTRB(x, y, x + (nfloat)squareLength, y + (nfloat)squareLength);

    // Center-Crop the image
    UIGraphics.BeginImageContextWithOptions(croppedRect.Size, false, originalImage.CurrentScale);
    originalImage.Draw(new CGPoint(-croppedRect.X, -croppedRect.Y));
    UIImage croppedImage = UIGraphics.GetImageFromCurrentImageContext();
    UIGraphics.EndImageContext();

    return croppedImage;
}