Question

所以我一直在研究这个问题，但是结果总是回到将BackgroundImageLayout设置为“ Stretch”的情况。当然，对于保持原始图像的长宽比，或者在保持长宽比的情况下如何手动缩放PictureBox或其他加载的图像的教程上，这毫无用处，但是我（对我而言非常惊讶）无法找到任何有关如何获取WinForm来管理始终位于窗口中央，被拉伸以覆盖窗口的背景图像的信息，但是却保持与原始窗口相同的纵横比。

我尝试过：

public class CustomForm : Form
{
    protected Size _scale;
    protected Size _originalSize;
    protected float _aspectRatio;

    public CustomForm() : base()
    {
        this.DoubleBuffered = true;
    }

    private float AspectRatio() { return this.AspectRatio(this._originalSize); }
    private float AspectRatio(int width, int height) { return (float)width / height; }
    private float AspectRatio(Size value) { return this.AspectRatio(value.Width, value.Height); }

    protected override void OnBackgroundImageChanged(EventArgs e)
    {
        this._originalSize = new Size(this.BackgroundImage.Width, this.BackgroundImage.Height);
        this._aspectRatio = this.AspectRatio(this._originalSize);
        base.OnBackgroundImageChanged(e);
    }

    protected override void OnPaintBackground(PaintEventArgs e)
    {
        if (this.BackgroundImage == null) base.OnPaintBackground(e);
        else
        {
            e.Graphics.FillRectangle(new SolidBrush(this.BackColor), ClientRectangle);

            int x = (this._scale.Width > this.Width) ? (int)Math.Round((this._scale.Width - this.Width) / 2.0) : 0;
            int y = (this._scale.Height > this.Height) ? (int)Math.Round((this._scale.Height - this.Height) / 2.0) : 0;

            e.Graphics.DrawImage(this.BackgroundImage, new Rectangle(x, y, this._scale.Width, this._scale.Height));
        }
    }

    protected override void OnSizeChanged(EventArgs e)
    {
        if ( this._aspectRatio > this.AspectRatio(this.Size))
        {
            this._scale.Width = this.Width;
            this._scale.Height = (int)(this.Width / this._aspectRatio);
        }
        else
        {
            this._scale.Height = this.Height;
            this._scale.Width = (int)(this.Height * this._aspectRatio);
        }
        base.OnSizeChanged(e);
    }
}

但是，它所做的就是将图像固定在表单的左上角，并保持其基本尺寸，而不管表单的大小如何。

有人可以指出正确解决方案的方向，还是我到目前为止做错了什么？

谢谢！

Answer 1

好吧，经过一番研究之后，经过一番梳理，我终于找到了答案！将其发布在这里，供以后可能会使用它的任何人！

public class CustomForm : Form
{
    protected Size _scale;
    protected Size _originalSize;

    public CustomForm() : base()
    {
        this.InitializeComponent();
    }

    protected override void OnBackgroundImageChanged(EventArgs e)
    {
        this._originalSize = new Size(this.BackgroundImage.Width, this.BackgroundImage.Height);
        base.OnBackgroundImageChanged(e);
    }

    protected override void OnPaintBackground(PaintEventArgs e)
    {
        if ((BackgroundImage != null) && (BackgroundImageLayout == ImageLayout.None))
        {
            Point p = new Point(
                            (int)((this.Width - this._scale.Width) / 2),
                            (int)((this.Height - this._scale.Height) / 2)
                          );

            e.Graphics.DrawImage(this.BackgroundImage, new Rectangle(p, this._scale));
        }
        else
            base.OnPaintBackground(e);
    }

    protected override void OnSizeChanged(EventArgs e)
    {
        if ((BackgroundImage != null) && (BackgroundImageLayout == ImageLayout.None))
        {
            float rX = (float) this.Width / this._originalSize.Width;
            float rY = (float) this.Height / this._originalSize.Height;
            float r = (rX < rY) ? rY : rX;

            this._scale.Height = (int)(this._originalSize.Height * r);
            this._scale.Width = (int)(this._originalSize.Width * r);
        }
        base.OnSizeChanged(e);
    }

    private void InitializeComponent()
    {
        this._originalSize = new Size(0, 0);
        this._scale = new Size(0, 0);

        this.SuspendLayout();
        // 
        // CustomForm
        // 
        this.Name = "CustomForm";
        this.DoubleBuffered = true; // minimizes "flicker" when resizing
        this.ResizeRedraw = true; // forces a full redraw when resized!
        this.ResumeLayout(false);
    }
}

尝试设置始终覆盖表单但具有静态/固定纵横比的背景图像

1 个答案: