如何在不损失质量的情况下调整图像大小 [英] How resize image without losing quality

问题描述

我有一个质量好的大图像(满足我的需要)，我需要调整到小尺寸(30 x 30px)，我用graphic.DrawImage调整它的大小.但是当我调整大小时，它变得模糊并且变轻了.我也尝试过 CompositingQuality 和 InterpolationMode，但都不好.

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.

例如，我正在尝试获得的质量.

Example, that quality i'm trying get.

我的结果

已编辑我自己画的图标图像，也许不调整大小就画小一点会更好?

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

Edit2

调整代码大小:

                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();
                }

推荐答案

我使用此方法作为从原始(任何大小)获取缩略图(任何大小)的一种方式.请注意，当您要求与原始尺寸比例差异很大的尺寸比例时，存在固有问题.最好询问彼此成比例的尺寸:

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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