How to Rotate Images in WinForms?

Detailed explanation of WinForms image rotation

Rotating images in WinForms applications is a practical technique for creating dynamic user interfaces and data visualizations. This article takes an in-depth look at how to rotate images in WinForms.

Use the RotateImage method

To rotate an image in WinForms, you can use the RotateImage method, which accepts two parameters:

1. img: The image to be rotated.
2. rotationAngle: The angle (in degrees) by which the image should be rotated. Positive values ​​rotate clockwise, negative values ​​rotate counterclockwise.

Code implementation

The following code demonstrates how to rotate an image 90 degrees clockwise:

<code class="language-csharp">// 获取要旋转的图像。
Image image = Image.FromFile("image.png");

// 旋转图像。
Image rotatedImage = RotateImage(image, 90);

// 显示旋转后的图像。
pictureBox.Image = rotatedImage;</code>

RotateImage method definition

The implementation of the RotateImage method is as follows:

<code class="language-csharp">public static Image RotateImage(Image img, float rotationAngle)
{
    // 创建一个空的位图图像。
    Bitmap bmp = new Bitmap(img.Width, img.Height);

    // 将位图转换为图形对象。
    Graphics gfx = Graphics.FromImage(bmp);

    // 将旋转点设置为图像的中心。
    gfx.TranslateTransform((float)bmp.Width / 2, (float)bmp.Height / 2);

    // 旋转图像。
    gfx.RotateTransform(rotationAngle);

    gfx.TranslateTransform(-(float)bmp.Width / 2, -(float)bmp.Height / 2);

    // 将InterpolationMode设置为HighQualityBicubic以进行高质量的图像转换。
    gfx.InterpolationMode = InterpolationMode.HighQualityBicubic;

    // 将新图像绘制到图形对象上。
    gfx.DrawImage(img, new Point(0, 0));

    // 释放图形对象。
    gfx.Dispose();

    // 返回旋转后的图像。
    return bmp;
}</code>

By using the RotateImage method, you can easily rotate images in your WinForms application to suit your specific needs.

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