using System;

using System.Collections.Generic;

using System.Drawing.Imaging;

using System.Text;

using System.Drawing;



namespace eBlog.Common

{

    public class ImageHelper

    {



        /// <summary>

        /// 生成缩略图

        /// </summary>

        /// <param name="originalImagePath">源图路径（物理路径）</param>

        /// <param name="thumbnailPath">缩略图路径（物理路径）</param>

        /// <param name="width">缩略图宽度</param>

        /// <param name="height">缩略图高度</param>

        /// <param name="mode">生成缩略图的方式</param>    

        public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode)

        {

            Image originalImage = Image.FromFile(originalImagePath);



            int towidth = width;

            int toheight = height;



            int x = 0;

            int y = 0;

            int ow = originalImage.Width;

            int oh = originalImage.Height;



            switch (mode)

            {

                case "HW"://指定高宽缩放（可能变形）                

                    break;

                case "W"://指定宽，高按比例                    

                    toheight = originalImage.Height * width / originalImage.Width;

                    break;

                case "H"://指定高，宽按比例

                    towidth = originalImage.Width * height / originalImage.Height;

                    break;

                case "Cut"://指定高宽裁减（不变形）                

                    if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)

                    {

                        oh = originalImage.Height;

                        ow = originalImage.Height * towidth / toheight;

                        y = 0;

                        x = (originalImage.Width - ow) / 2;

                    }

                    else

                    {

                        ow = originalImage.Width;

                        oh = originalImage.Width * height / towidth;

                        x = 0;

                        y = (originalImage.Height - oh) / 2;

                    }

                    break;

                default:

                    break;

            }



            //新建一个bmp图片

            Image bitmap = new System.Drawing.Bitmap(towidth, toheight);



            //新建一个画板

            Graphics g = System.Drawing.Graphics.FromImage(bitmap);



            //设置高质量插值法

            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;



            //设置高质量,低速度呈现平滑程度

            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;



            //清空画布并以透明背景色填充

            g.Clear(Color.Transparent);



            //在指定位置并且按指定大小绘制原图片的指定部分

            g.DrawImage(originalImage, new Rectangle(0, 0, towidth, toheight),

                new Rectangle(x, y, ow, oh),

                GraphicsUnit.Pixel);



            try

            {

                //以jpg格式保存缩略图

                bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);

            }

            catch (System.Exception e)

            {

                throw e;

            }

            finally

            {

                originalImage.Dispose();

                bitmap.Dispose();

                g.Dispose();

            }

        }



        /// <summary>

        /// 添加图片水印

        /// </summary>

        /// <param name="oldFilePath">原始图片路径</param>

        /// <param name="newFilePath">将要添加水印图片路径</param>

        /// <param name="waterPosition">水印位置</param>

        /// <param name="waterImagePath">水印图片路径</param>

        /// <param name="watermarkTransparency"></param>

        /// <param name="quality">质量</param>

        public static void CreateWaterImage(string oldFilePath, string newFilePath, int waterPosition, string waterImagePath, int watermarkTransparency, int quality)

        {

            System.Drawing.Image image = System.Drawing.Image.FromFile(oldFilePath);



            Bitmap bmp = new Bitmap(image.Width, image.Height, PixelFormat.Format32bppArgb);



            Graphics g = Graphics.FromImage(bmp);

            g.Clear(Color.White);



            g.DrawImage(image, 0, 0, image.Width, image.Height);



            //设置透明度

            System.Drawing.Image watermark = new Bitmap(waterImagePath);

            ImageAttributes imageAttributes = new ImageAttributes();

            ColorMap colorMap = new ColorMap();

            colorMap.OldColor = Color.FromArgb(255, 0, 255, 0);

            colorMap.NewColor = Color.FromArgb(0, 0, 0, 0);

            ColorMap[] remapTable = { colorMap };

            imageAttributes.SetRemapTable(remapTable, ColorAdjustType.Bitmap);



            float transparency = 0.5F;

            if (watermarkTransparency >= 1 && watermarkTransparency <= 10)

            {

                transparency = (watermarkTransparency / 10.0F);

            }



            float[][] colorMatrixElements = {

													new float[] {1.0f,  0.0f,  0.0f,  0.0f, 0.0f},

													new float[] {0.0f,  1.0f,  0.0f,  0.0f, 0.0f},

													new float[] {0.0f,  0.0f,  1.0f,  0.0f, 0.0f},

													new float[] {0.0f,  0.0f,  0.0f,  transparency, 0.0f}, //注意：倒数第二处为0.0f为完全透明，1.0f为完全不透明

													new float[] {0.0f,  0.0f,  0.0f,  0.0f, 1.0f}

												};

            ColorMatrix colorMatrix = new ColorMatrix(colorMatrixElements);

            imageAttributes.SetColorMatrix(colorMatrix, ColorMatrixFlag.Default, ColorAdjustType.Bitmap);



            int _width = image.Width;

            int _height = image.Height;

            int xpos = 0;

            int ypos = 0;

            int WatermarkWidth = 0;

            int WatermarkHeight = 0;

            double bl = 1d;

            //计算水印图片的比率

            //取背景的1/4宽度来比较

            if ((_width > watermark.Width * 2) && (_height > watermark.Height * 2))

            {

                bl = 1;

            }

            else if ((_width > watermark.Width * 2) && (_height < watermark.Height * 2))

            {

                bl = Convert.ToDouble(_height / 2) / Convert.ToDouble(watermark.Height);



            }

            else if ((_width < watermark.Width * 2) && (_height > watermark.Height * 2))

            {

                bl = Convert.ToDouble(_width / 2) / Convert.ToDouble(watermark.Width);

            }

            else

            {

                if ((_width * watermark.Height) > (_height * watermark.Width))

                {

                    bl = Convert.ToDouble(_height / 2) / Convert.ToDouble(watermark.Height);

                }

                else

                {

                    bl = Convert.ToDouble(_width / 2) / Convert.ToDouble(watermark.Width);

                }

            }

            WatermarkWidth = Convert.ToInt32(watermark.Width * bl);

            WatermarkHeight = Convert.ToInt32(watermark.Height * bl);

            switch (waterPosition)

            {

                case 3:

                    xpos = _width - WatermarkWidth - 10;

                    ypos = 10;

                    break;

                case 2:

                    xpos = 10;

                    ypos = _height - WatermarkHeight - 10;

                    break;

                case 5:

                    xpos = _width / 2 - WatermarkWidth / 2;

                    ypos = _height / 2 - WatermarkHeight / 2;

                    break;

                case 1:

                    xpos = 10;

                    ypos = 10;

                    break;

                case 4:

                default:

                    xpos = _width - WatermarkWidth - 10;

                    ypos = _height - WatermarkHeight - 10;

                    break;

            }

            g.DrawImage(watermark, new Rectangle(xpos, ypos, WatermarkWidth, WatermarkHeight), 0, 0, watermark.Width, watermark.Height, GraphicsUnit.Pixel, imageAttributes);

            try

            {

                ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();

                ImageCodecInfo ici = null;

                foreach (ImageCodecInfo codec in codecs)

                {

                    if (codec.MimeType.IndexOf("jpeg") > -1)

                    {

                        ici = codec;

                    }

                }

                EncoderParameters encoderParams = new EncoderParameters();

                long[] qualityParam = new long[1];



                if (quality < 0 || quality > 100)

                {

                    quality = 80;

                }



                qualityParam[0] = quality;



                EncoderParameter encoderParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qualityParam);

                encoderParams.Param[0] = encoderParam;



                if (ici != null)

                {

                    bmp.Save(newFilePath, ici, encoderParams);

                }

                else

                {

                    bmp.Save(newFilePath);

                }

            }

            catch (Exception ex)

            {

                throw ex;

            }

            finally

            {

                watermark.Dispose();

                imageAttributes.Dispose();

                image.Dispose();

                bmp.Dispose();

            }

        }



        /// <summary>

        /// 添加文字水印

        /// </summary>

        /// <param name="oldFilePath">原始图片路径</param>

        /// <param name="newFilePath">将要添加水印图片路径</param>

        /// <param name="waterPosition">水印位置</param>

        /// <param name="waterText">水印内容</param>

        /// <param name="quality"></param>

        /// <param name="fontname"></param>

        /// <param name="fontsize"></param>

        public static void CreateWaterText(string oldFilePath, string newFilePath, int waterPosition, string waterText, int quality, string fontname, int fontsize)

        {

            System.Drawing.Image image = System.Drawing.Image.FromFile(oldFilePath);

            Bitmap bmp = new Bitmap(image.Width, image.Height, PixelFormat.Format32bppArgb);



            Graphics g = Graphics.FromImage(bmp);

            g.Clear(Color.White);



            g.DrawImage(image, 0, 0, image.Width, image.Height);



            int _width = bmp.Width;

            int _height = bmp.Height;



            Font crFont = new Font(fontname, fontsize, FontStyle.Bold, GraphicsUnit.Pixel);

            SizeF crSize = g.MeasureString(waterText, crFont);



            float xpos = 0;

            float ypos = 0;

            switch (waterPosition)

            {

                case 3:

                    xpos = ((float)_width * (float).99) - (crSize.Width / 2);

                    ypos = (float)_height * (float).01;

                    break;

                case 2:

                    xpos = ((float)_width * (float).01) + (crSize.Width / 2);

                    ypos = ((float)_height * (float).99) - crSize.Height;

                    break;

                case 5:

                    xpos = ((_width - crSize.Width) / 2) + crSize.Width / 2;    //奇怪的表达式

                    ypos = (_height - crSize.Height) / 2 + crSize.Height / 2;

                    break;

                case 1:



                    xpos = ((float)_width * (float).01) + (crSize.Width / 2);

                    ypos = (float)_height * (float).01;

                    break;



                case 4:

                default:

                    xpos = ((float)_width * (float).99) - (crSize.Width / 2);

                    ypos = ((float)_height * (float).99) - crSize.Height;

                    break;

            }



            StringFormat StrFormat = new StringFormat();

            StrFormat.Alignment = StringAlignment.Center;



            //可设置透明度

            SolidBrush semiTransBrush = new SolidBrush(Color.FromArgb(255, 255, 255, 255));

            g.DrawString(waterText, crFont, semiTransBrush, xpos, ypos, StrFormat);



            try

            {

                ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();

                ImageCodecInfo ici = null;

                foreach (ImageCodecInfo codec in codecs)

                {

                    if (codec.MimeType.IndexOf("jpeg") > -1)

                    {

                        ici = codec;

                    }

                }

                EncoderParameters encoderParams = new EncoderParameters();

                long[] qualityParam = new long[1];



                if (quality < 0 || quality > 100)

                {

                    quality = 80;

                }



                qualityParam[0] = quality;





                EncoderParameter encoderParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qualityParam);

                encoderParams.Param[0] = encoderParam;



                if (ici != null)

                {

                    bmp.Save(newFilePath, ici, encoderParams);

                }

                else

                {

                    bmp.Save(newFilePath);

                }

            }

            catch (Exception ex)

            {

                throw ex;

            }

            finally

            {

                semiTransBrush.Dispose();

                image.Dispose();

                bmp.Dispose();

            }

        }

    }

}