wpf使用bitmapimage作為TransformedBitmap的源

Question

在我的WPF中，我創建了一個名為“ image_box”的圖像框

在Window_Loaded上我用

image_box.Source = new BitmapImage(new Uri("pack://application:,,,/images/pic.png"));

我在Rotate_Click（對象發送者，RoutedEventArgs e）上有下一個代碼

BitmapImage bmp = new BitmapImage();
bmp.BeginInit();
bmp.UriSource = new Uri("pack://application:,,,/images/pic.png");
bmp.EndInit();

TransformedBitmap myRotatedBitmapSource = new TransformedBitmap();
myRotatedBitmapSource.BeginInit();
myRotatedBitmapSource.Source = bmp;
myRotatedBitmapSource.Transform = new RotateTransform(90);
myRotatedBitmapSource.EndInit();
image_box.Source = myRotatedBitmapSource;

我想要的是這段代碼

bmp.UriSource =新的Uri（“ pack：// application：,,, / images / pic.png”）;

使用

image_box的位置，例如

bmp.UriSource = image_box.Source;

我嘗試

Uri ur = new Uri(image_box.Source.ToString());
...
bmp.UriSource = ur;

但是第二次點擊我得到了無效的URL

Answer 1

表達方式

image_box.Source.ToString()

僅當Source是BitmapImage時才返回有效的URI字符串。 但是，在您的Click處理程序的第二次調用中，Source是一個TransformedBitmap 。

您應該簡單地重用原始源圖像並將旋轉角度增加（或減小）90的倍數。

private BitmapImage source = new BitmapImage(new Uri("pack://application:,,,/images/pic.png"));
private double rotation = 0;

private void Rotate_Click(object sender, RoutedEventArgs e)
{
    rotation += 90;
    image_box.Source = new TransformedBitmap(source, new RotateTransform(rotation));
}

或者也保留TransformedBitmap並僅更改其Transform屬性：

private BitmapImage source = new BitmapImage(new Uri("pack://application:,,,/images/pic.png"));
private double rotation = 0;
private TransformedBitmap transformedBitmap =
    new TransformedBitmap(source, new RotateTransform(rotation));
...
image_box.Source = transformedBitmap; // call this once
...

private void Rotate_Click(object sender, RoutedEventArgs e)
{
    rotation += 90;
    transformedBitmap.Transform = new RotateTransform(rotation);
}