C#调整图像大小而无需插值 [英] C# Resize Image with No Interpolation

问题描述

我知道这个问题经常被问到，但是没有一个典型的答案能给我我所需要的结果.我正在尝试像Paint.exe一样缩放灰度位图.我不希望插值，因此可以观察到原始的单个像素.我已经尝试了经常建议使用的NearestNeighbor方法，这种方法很接近，但并不是我想要的.

I know this question has been asked frequently, but none of the typical answers have given me the result I need. I am attempting to zoom a grayscale bitmap much like Paint.exe. I want no interpolation so the original, individual pixels can be observed. I have tried the oft-suggested NearestNeighbor approach which gets close, but not exactly what I want.

这就是我想要的:

这就是我得到的:

这是我用来缩放和重绘图像的代码.

This is the code I am using to zoom and redraw the image.

protected override void OnPaint(PaintEventArgs e)
{
    e.Graphics.PixelOffsetMode = PixelOffsetMode.Half;
    e.Graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.NearestNeighbor;            
    e.Graphics.SmoothingMode = SmoothingMode.None;

    Matrix m = new Matrix();
    m.Scale(mScale, mScale, MatrixOrder.Append);
    e.Graphics.Transform = m;

    e.Graphics.TranslateTransform(this.AutoScrollPosition.X / mScale,this.AutoScrollPosition.Y / mScale);

    if (mImage != null) 
        e.Graphics.DrawImage(mImage, 0, 0);

    base.OnPaint(e);
}

当缩放起作用时，代码确实对图像有影响，更改InterpolationMode确实会更改图像.但是，没有任何设置组合可以得到我需要的结果.

The code does have an affect on the image as the zoom works and changing the InterpolationMode does change the image. However, no combination of settings gets the result I need.

有什么想法吗?

推荐答案

我正在尝试使用C#显示16位图像.我遇到了同样的麻烦，即完全相同的像素中的颜色不相同.最后，我用下面的示例代码解决了这一麻烦:

I'm trying to display 16-bit images with C#. I came across the same trouble that the colors in the totally same pixel is not the same. Finally I solved this trouble with the sample code below:

        protected override void OnPaint(PaintEventArgs e)
        {
            e.Graphics.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
            e.Graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.NearestNeighbor; 
            e.Graphics.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.HighSpeed;
            e.Graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.None;

            e.Graphics.Clear(Color.Black); //Clear the background with the black color

            if(m_bmp != null)  //if m_bmp == null, then do nothing.
            {
                //To calculate the proper display area's width and height that fit the window.
                if (this.Width / (double)this.Height > m_bmp.Width / (double)m_bmp.Height)
                {
                    m_draw_height = (int)(this.Height * m_roomRatio);
                    m_draw_width = (int)(m_bmp.Width / (double)m_bmp.Height * m_draw_height);
                }
                else
                {
                    m_draw_width = (int)(this.Width * m_roomRatio);
                    m_draw_height = (int)(m_bmp.Height / (double)m_bmp.Width * m_draw_width);
                }

                //To calculate the starting point.
                m_draw_x = (int)((this.Width - m_draw_width) / 2.0 + m_offsetX / 2.0);
                m_draw_y = (int)((this.Height - m_draw_height) / 2.0 + m_offsetY / 2.0);
                e.Graphics.DrawImage(m_bmp, m_draw_x, m_draw_y, m_draw_width, m_draw_height);

                //draw some useful information
                string window_info = "m_draw_x" + m_draw_x.ToString() + "m_draw_width" + m_draw_width.ToString();
                e.Graphics.DrawString(window_info, this.Font, new SolidBrush(Color.Yellow), 0, 20);
            }

顺便说一句，为什么不尝试使用双缓冲区来提高绘图图像的性能?

BTW, why don't you try to use double buffer to increase the performance of drawing images?

这里是效果:

希望会有所帮助.

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