using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using UnityEngine;

public class ImageUtil
{
    public static Bitmap ResizeImage(Image bitmap, int maxSize)
    {
        float aspect = (float)bitmap.Width / bitmap.Height;
        int w;
        int h;
        if (aspect > 1.0f)
        {
            w = maxSize;
            h = (int)Mathf.Round(w / aspect);
        }
        else
        {
            h = maxSize;
            w = (int)Mathf.Round(h * aspect);
        }
        return ResizeImage(bitmap, w, h);
    }
    public static Bitmap ResizeImage(Image image, int width, int height)
    {        
        var destImage = new Bitmap(width, height);
        destImage.SetResolution(image.HorizontalResolution, image.VerticalResolution);
        using (var graphics = System.Drawing.Graphics.FromImage(destImage))
        {
            graphics.CompositingMode = CompositingMode.SourceCopy;
            graphics.CompositingQuality = CompositingQuality.HighQuality;
            graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
            graphics.SmoothingMode = SmoothingMode.HighQuality;
            graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
            using (var wrapMode = new ImageAttributes())
            {
                wrapMode.SetWrapMode(System.Drawing.Drawing2D.WrapMode.Clamp);                
                try
                {                  
                    var destRect = new Rectangle(0, 0, width, height);
                    graphics.DrawImage(image, destRect, 0, 0, image.Width, image.Height, GraphicsUnit.Pixel, wrapMode);
                }catch(Exception err)
                {
                    Debug.Log("err:" + err.StackTrace);
                }
            }
        }
        destImage.RotateFlip(RotateFlipType.RotateNoneFlipY);
        return destImage;
    }
}