如何调整图像不失去质量 [英] How resize image without losing quality

问题描述

我有良好的质量大图像（我需要），我需要调整到小尺寸（30×30像素），我graphic.DrawImage调整其大小。但是，当我调整它的大小变得模糊，有点轻。
我也有尝试CompositingQuality和InterpolationMode，但是这一切是坏的。

例如，质量我想要得到什么。

我的结果

编辑图标的
图片我画我自己，也许这将是更好地绘制小没有调整？

EDIT2

Resizeing代码：

 位图TBMP; 
 //画我的TBMP所有功能与图形
 BMP =新位图（宽+ 5，高度+ 5）; 
 bmp.MakeTransparent（Color.Black）;使用
（VAR GG = Graphics.FromImage（BMP））
 {
 gg.CompositingQuality = CompositingQuality.HighQuality; 
 // gg.Smoothi​​ngMode = Smoothi​​ngMode.HighQuality; 
 gg.InterpolationMode = InterpolationMode.HighQualityBicubic; 
 
 gg.DrawImage（TBMP，新的Rectangle（0，0，宽度，高度），新的Rectangle（GXMin，GYMin，GXMax + 20，+ GYMax 20），GraphicsUnit.Pixel）; 
 gg.Dispose（）; 
} 
  

解决方案

我用这个方法作为方式从（任意大小的）的原始得到（任意大小的）的缩略图图像。请注意，有固有的问题时，要求的尺寸比从原始的变化很大。最好问一下对于那些规模到另一个尺寸：

 公共静态图像GetThumbnailImage（图片OriginalImage，大小ThumbSize）
 {
的Int32 thWidth = ThumbSize.Width; 
的Int32 thHeight = ThumbSize.Height; 
图像I = OriginalImage; 
的Int32 W = i.Width; 
的Int32 H = i.Height; 
的Int32日= thWidth; 
的Int32 TW = thWidth; 
如果（H> W）
 {
双率=（双人间）W /（双人间）H; 
 TH = thHeight< H ？ thHeight：H; 
 TW = thWidth< W' （Int32）已（比* thWidth）：W; 
} 
，否则
 {
双率=（双人间）H /（双人间）瓦; 
 TH = thHeight< H ？ （Int32）已（比* thHeight）：H; 
 TW = thWidth< W' thWidth：W; 
} 
位图的目标=新位图（TW，TH）; 
图形G = Graphics.FromImage（目标）; 
 g.Smoothi​​ngMode = Smoothi​​ngMode.HighQuality; 
 g.CompositingQuality = CompositingQuality.HighQuality; 
 g.InterpolationMode = InterpolationMode.High; 
矩形RECT =新的Rectangle（0，0，TW，TH）; 
 g.DrawImage（ⅰ，矩形，0，0，W，H，GraphicsUnit.Pixel）; 
返回（图像）的目标; 
} 
  

I have a big image in good quality (for my needs), i need resize to small size (30 x 30px), I resize it with graphic.DrawImage. But when i resize it become blurred and little lighter. also I have try CompositingQuality and InterpolationMode, but it all was bad.

Example, that quality i'm trying get.

My result

Edited Image of icon i draw myself, maybe it will be better draw it small without resizing?

Edit2

Resizeing code:

                Bitmap tbmp;
                //drawing all my features in tbmp with graphics
                bmp = new Bitmap(width + 5, height + 5);
                bmp.MakeTransparent(Color.Black);
                using (var gg = Graphics.FromImage(bmp))
                {
                    gg.CompositingQuality = CompositingQuality.HighQuality;
                  //  gg.SmoothingMode = SmoothingMode.HighQuality;
                    gg.InterpolationMode = InterpolationMode.HighQualityBicubic;

                    gg.DrawImage(tbmp, new Rectangle(0, 0, width, height), new Rectangle(GXMin, GYMin, GXMax + 20, GYMax + 20), GraphicsUnit.Pixel);
                    gg.Dispose();
                }

解决方案

I use this method as a way to get a thumbnail image (of any size) from an original (of any size). Note that there are inherent issues when you ask for a size ratio that varies greatly from that of the original. Best to ask for sizes that are in scale to one another:

public static Image GetThumbnailImage(Image OriginalImage, Size ThumbSize)
{
    Int32 thWidth = ThumbSize.Width;
    Int32 thHeight = ThumbSize.Height;
    Image i = OriginalImage;
    Int32 w = i.Width;
    Int32 h = i.Height;
    Int32 th = thWidth;
    Int32 tw = thWidth;
    if (h > w)
    {
        Double ratio = (Double)w / (Double)h;
        th = thHeight < h ? thHeight : h;
        tw = thWidth < w ? (Int32)(ratio * thWidth) : w;
    }
    else
    {
        Double ratio = (Double)h / (Double)w;
        th = thHeight < h ? (Int32)(ratio * thHeight) : h;
        tw = thWidth < w ? thWidth : w;
    }
    Bitmap target = new Bitmap(tw, th);
    Graphics g = Graphics.FromImage(target);
    g.SmoothingMode = SmoothingMode.HighQuality;
    g.CompositingQuality = CompositingQuality.HighQuality;
    g.InterpolationMode = InterpolationMode.High;
    Rectangle rect = new Rectangle(0, 0, tw, th);
    g.DrawImage(i, rect, 0, 0, w, h, GraphicsUnit.Pixel);
    return (Image)target;
}

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