如何用C#绘制流畅的图像？

Question

我正在尝试在C#表单上绘制图像(在PictureBoxes中,以及使用Graphics.DrawImage()),并且正在寻找一种平滑绘制它们的方法.图像必须是支持透明度的格式,因此PNG,GIF,SVG和WMF.C#不支持开箱即用的SVG文件,我还没有找到一个好的第三方库(我找到了SvgNet,但无法弄明白).

我需要绘制一个WMF文件,C#可以通过Image.FromFile()函数来完成,但它没有消除锯齿.我想知道是否有办法解决这个问题？

Answer 1

之前的答案虽然很有意,但只是部分正确.

什么是正确的？PictureBox不会公开InterpolationMode.

什么是基地？

1)虽然您可以通过图片框,父图标或派生类中的覆盖在Paint事件中轻松设置该属性...无论哪种方式都有效,两者都同样容易.但是,除非设置了SmoothingMode,否则将忽略InterpolationMode.如果没有将SmoothingMode设置为SmoothingMode.AnitAlias,您将不会获得任何抗锯齿.

2)当你明确表示有兴趣使用PictureBox的功能时使用Panel是错误的方向.如果没有明确编码这些属性,您将无法直接加载,保存或分配图像...为什么重新发明轮子？ 通过派生PictureBox,您可以免费获得所有这些.

这个消息变得更好,因为我已经为你完成了艰苦的工作,这比写这个消息花了我更少的时间.

我提供了两个版本,这两个版本都派生自PictureBox.首先是一个简单的例子,它总是使用最好的质量渲染.这也是最慢的渲染.第二个是允许任何人通过派生类的属性设置各种渲染参数的类.一旦设置,这些将在OnPaint覆盖中使用.

public class HighQualitySmoothPictureBox : PictureBox
{
    protected override void OnPaint(PaintEventArgs pe)
    {
        // This is the only line needed for anti-aliasing to be turned on.
        pe.Graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;

        // the next two lines of code (not comments) are needed to get the highest 
        // possible quiality of anti-aliasing. Remove them if you want the image to render faster.
        pe.Graphics.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
        pe.Graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
        // this line is needed for .net to draw the contents.
        base.OnPaint(pe);
    }
}

...

public class ConfigurableQualityPictureBox : PictureBox
{
    // Note: the use of the "?" indicates the value type is "nullable."  
    // If the property is unset, it doesn't have a value, and therefore isn't 
    // used when the OnPaint method executes.
    System.Drawing.Drawing2D.SmoothingMode? smoothingMode;
    System.Drawing.Drawing2D.CompositingQuality? compositingQuality;
    System.Drawing.Drawing2D.InterpolationMode? interpolationMode;

    public System.Drawing.Drawing2D.SmoothingMode? SmoothingMode
    {
        get { return smoothingMode; }
        set { smoothingMode = value; }
    }

    public System.Drawing.Drawing2D.CompositingQuality? CompositingQuality
    {
        get { return compositingQuality; }
        set { compositingQuality = value; }
    }

    public System.Drawing.Drawing2D.InterpolationMode? InterpolationMode
    {
        get { return interpolationMode; }
        set { interpolationMode = value; }
    }

    protected override void OnPaint(PaintEventArgs pe)
    {
        if (smoothingMode.HasValue)
            pe.Graphics.SmoothingMode = smoothingMode.Value;
        if (compositingQuality.HasValue)
            pe.Graphics.CompositingQuality = compositingQuality.Value;
        if (interpolationMode.HasValue)
            pe.Graphics.InterpolationMode = interpolationMode.Value;

        // this line is needed for .net to draw the contents.
        base.OnPaint(pe);
    }
}

Answer 2

将图像绘制到画布时,可以将插值模式更改为比最近邻居更好的值,以使调整大小的图像平滑:

Graphics g = ...
g.InterpolationMode = InterpolationMode.HighQualityBicubic;
g.DrawImage(...);

您需要添加System.Drawing.Drawing2D以获取InterpolationMode枚举.

使用PictureBox将是一个问题 - 它不会公开InterpolationMode属性,因此您需要自己滚动或下载一个.