using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Media;
using System.Windows;
using System.Windows.Media.Imaging;
using System.Windows.Controls;

namespace Txgy.EWS.Client.Common.Helpers
{
    public static class BitmapHelper
    {
        public static BitmapImage ConvertToBitmap(byte[] bytes)
        {
            var bitmapImage = new BitmapImage();
            bitmapImage.BeginInit();
            bitmapImage.StreamSource = new MemoryStream(bytes);
            bitmapImage.EndInit();
            return bitmapImage;
        }
        public static byte[] ConvertToBytes(BitmapSource bitmapSource)
        {
            byte[] buffer = null;
            PngBitmapEncoder encoder = new PngBitmapEncoder();
            MemoryStream memoryStream = new MemoryStream();
            encoder.Frames.Add(BitmapFrame.Create(bitmapSource));
            encoder.Save(memoryStream);
            memoryStream.Position = 0;
            if (memoryStream.Length > 0)
            {
                using (BinaryReader br = new BinaryReader(memoryStream))
                {
                    buffer = br.ReadBytes((int)memoryStream.Length);
                }
            }
            memoryStream.Close();
            return buffer;
        }
        public static BitmapImage ConvertToBitmap(BitmapSource bitmapSource)
        {
            PngBitmapEncoder encoder = new PngBitmapEncoder();
            MemoryStream memoryStream = new MemoryStream();
            BitmapImage bImg = new BitmapImage();
            encoder.Frames.Add(BitmapFrame.Create(bitmapSource));
            encoder.Save(memoryStream);
            memoryStream.Position = 0;
            bImg.BeginInit();
            bImg.StreamSource = memoryStream;
            bImg.EndInit();
            memoryStream.Close();
            return bImg;
        }
        public static byte[] BitmapImageToBytes(BitmapImage bmp)
        {
            byte[] buffer = null;
            try
            {
                Stream stream = bmp.StreamSource;
                if (stream != null && stream.Length > 0)
                {
                    //很重要，因为Position经常位于Stream的末尾，导致下面读取到的长度为0。   
                    stream.Position = 0;
                    using (BinaryReader br = new BinaryReader(stream))
                    {
                        buffer = br.ReadBytes((int)stream.Length);
                    }
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
            return buffer;
        }
        public static byte[] ElementToBytes(UIElement element)
        {
            var rect = new Rect(element.RenderSize);
            var visual = new DrawingVisual();

            using (var dc = visual.RenderOpen())
            {
                dc.DrawRectangle(new VisualBrush(element), null, rect);
            }

            var bitmap = new RenderTargetBitmap(
                (int)rect.Width, (int)rect.Height, 96, 96, PixelFormats.Default);
            bitmap.Render(visual);
            return BitmapHelper.ConvertToBytes(bitmap);          
        }
        public static void SaveImageToFile(UIElement element, string fileName)
        {
            var rect = new Rect(element.RenderSize);
            System.IO.FileStream fs = new System.IO.FileStream(fileName, System.IO.FileMode.Create);
            RenderTargetBitmap bmp = new RenderTargetBitmap((int)rect.X, (int)rect.Y, 96d, 96d, PixelFormats.Pbgra32);
            bmp.Render(element);
            BitmapEncoder encoder = new PngBitmapEncoder();
            encoder.Frames.Add(BitmapFrame.Create(bmp));
            encoder.Save(fs);
            fs.Close();
        }
    }
}