Question

我有一个放大/缩小的图像控件类，填充屏幕，并且比例为1：1（全部由4个不同的按钮控制。但是，当屏幕分辨率大于1280 x 1024时，我的填充屏幕并且1：1的比例没有达到应有的水平。

public void ZoomActual()
    {
        m_translateTransform.BeginAnimation(TranslateTransform.XProperty, CreateAnimation(0));
        m_translateTransform.BeginAnimation(TranslateTransform.YProperty, CreateAnimation(0));
        m_zoomFactor.BeginAnimation(ScaleTransform.ScaleXProperty, CreateAnimation(1));
        m_zoomFactor.BeginAnimation(ScaleTransform.ScaleYProperty, CreateAnimation(1));
    } //1:1 ratio button control

    /// <summary>
    /// This function is used to fill the screen with the current picture on the zoomandpan Control
    /// </summary>
    public void ZoomFit()
    {
        double screen_height = ActualHeight;
        double screen_width = ActualWidth;

        double image_width = m_source_child.ActualWidth;
        double image_height = m_source_child.ActualHeight;

        double image_ratio = image_width / image_height;
        double screen_ratio = screen_width / screen_height;

        if (image_width > image_height)
        {
            m_translateTransform.BeginAnimation(TranslateTransform.XProperty, CreateAnimation(0));
            m_translateTransform.BeginAnimation(TranslateTransform.YProperty, CreateAnimation(0));
            m_zoomFactor.BeginAnimation(ScaleTransform.ScaleXProperty, CreateAnimation(1 / screen_ratio * image_ratio)); //width
            m_zoomFactor.BeginAnimation(ScaleTransform.ScaleYProperty, CreateAnimation(1 / screen_ratio * image_ratio)); //height
        }
        else
        {
            m_translateTransform.BeginAnimation(TranslateTransform.XProperty, CreateAnimation(0));
            m_translateTransform.BeginAnimation(TranslateTransform.YProperty, CreateAnimation(0));
            m_zoomFactor.BeginAnimation(ScaleTransform.ScaleXProperty, CreateAnimation((screen_ratio * image_ratio))); //width
            m_zoomFactor.BeginAnimation(ScaleTransform.ScaleYProperty, CreateAnimation((screen_ratio * image_ratio))); //height
        }
    } //fillscreen button control

    /// <summary>
    /// This function is used to control the animations of the ZoomandPan. Animations consist of Zooming in
    /// and out of a picture and allows panning of the displayed image
    /// </summary>
    /// <param name="a_toValue">used for zoom in percentage [currently set at: 1.5 (150%)]</param>
    /// <returns>Animation values image</returns>
    private DoubleAnimation CreateAnimation(double a_toValue)
    {
        var dubAni = new DoubleAnimation(a_toValue, new Duration(TimeSpan.FromMilliseconds(300)))
        {
            AccelerationRatio = 0.1,
            DecelerationRatio = 0.9,
            FillBehavior = FillBehavior.HoldEnd
        };
        dubAni.Freeze();
        return dubAni;
    } //Animation value setter

    /// <summary>
    /// DoZoom is used for executing the physical zoom of the picture, enlarges or shrinks image depending
    /// on CreateAnimation values
    /// </summary>
    /// <param name="a_deltaZoom">Determinded to be + or -. can be set by mousewheel and/or buttons. Determines Zoom in/out</param>
    /// <param name="a_mousePosition">Current positon of mouse</param>
    /// <param name="a_physicalPositon">refrence to last area mousePosition was on image</param>
    private void DoZoom(Double a_deltaZoom, Point a_mousePosition, Point a_physicalPositon)
    {
        double currentZoom = m_zoomFactor.ScaleX;
        currentZoom *= a_deltaZoom;
        if (currentZoom < MinZoom)
            currentZoom = MinZoom;
        else if (currentZoom > MaxZoom)
            currentZoom = MaxZoom;

        m_translateTransform.BeginAnimation(TranslateTransform.XProperty, CreateAnimation(-1 * (a_mousePosition.X * currentZoom - a_physicalPositon.X)));
        m_translateTransform.BeginAnimation(TranslateTransform.YProperty, CreateAnimation(-1 * (a_mousePosition.Y * currentZoom - a_physicalPositon.Y)));

        m_zoomFactor.BeginAnimation(ScaleTransform.ScaleXProperty, CreateAnimation(currentZoom));
        m_zoomFactor.BeginAnimation(ScaleTransform.ScaleYProperty, CreateAnimation(currentZoom));
    } //Zoom animation

当我这样做时它没有做我想要的意思：如果我的屏幕分辨率为1280 x 1024或更低，填充屏幕将填满屏幕，1：1的比例将给出实际尺寸图片。任何大于1280 x 1024的分辨率都会导致填充屏幕控制使图像变小（在画布内），而不是将整个图像放在窗口上。并且1：1比例控制将在右边有一个小间隙，只是白色空间。非常感谢任何提供的帮助，我对图像控制有点新意，所以这看起来非常微不足道。对不起那个

Answer 1

我假设您在 ZoomFit 功能中想要填充，同时保持适当的宽高比。这就是我通常这样做的方式：

double ratio = Math.Min(destArea.Width / imageSize.Width, destArea.Height / imageSize.Height);

double imageWidth = imageSize.Width * ratio;
double imageHeight = imageSize.Height * ratio;

您应该能够直接向ScaleTransform提供比率。

如果要缩放以填充和保持纵横比但修剪多余部分，则只需使用Math.Max计算比率而不是Math.Min。

Answer 2

我认为你的基本问题是你在ZoomFit中计算出比例因子时有一些难以理解的数学。例如，如果屏幕宽高比为1：1，则始终使用等于图像宽高比的系数进行缩放。这意味着无论实际有多大，2：1的图像总是会放大200％。

缩放和图像填充屏幕

2 个答案: