/// <summary>
/// 对gif图像文件进行解码
/// </summary>
/// <param name="gifPath">gif文件路径</param>
internal static GifImage Decode(string gifPath)
{
FileStream fs = null;
StreamHelper streamHelper = null;
GifImage gifImage = new GifImage();
List <GraphicEx> graphics = new List <GraphicEx>();
int frameCount = 0;
try
{
fs = new FileStream(gifPath, FileMode.Open);
streamHelper = new StreamHelper(fs);
//读取文件头
gifImage.Header = streamHelper.ReadString(6);
//读取逻辑屏幕标示符
gifImage.LogicalScreenDescriptor = streamHelper.GetLCD(fs);
if (gifImage.LogicalScreenDescriptor.GlobalColorTableFlag)
{
//读取全局颜色列表
gifImage.GlobalColorTable = streamHelper.ReadByte(gifImage.LogicalScreenDescriptor.GlobalColorTableSize * 3);
}
int nextFlag = streamHelper.Read();
while (nextFlag != 0)
{
if (nextFlag == GifExtensions.ImageLabel)
{
ReadImage(streamHelper, fs, gifImage, graphics, frameCount);
frameCount++;
}
else if (nextFlag == GifExtensions.ExtensionIntroducer)
{
int gcl = streamHelper.Read();
switch (gcl)
{
case GifExtensions.GraphicControlLabel:
{
GraphicEx graphicEx = streamHelper.GetGraphicControlExtension(fs);
graphics.Add(graphicEx);
break;
}
case GifExtensions.CommentLabel:
{
CommentEx comment = streamHelper.GetCommentEx(fs);
gifImage.CommentExtensions.Add(comment);
break;
}
case GifExtensions.ApplicationExtensionLabel:
{
ApplicationEx applicationEx = streamHelper.GetApplicationEx(fs);
gifImage.ApplictionExtensions.Add(applicationEx);
break;
}
case GifExtensions.PlainTextLabel:
{
PlainTextEx textEx = streamHelper.GetPlainTextEx(fs);
gifImage.PlainTextEntensions.Add(textEx);
break;
}
}
}
else if (nextFlag == GifExtensions.EndIntroducer)
{
//到了文件尾
break;
}
nextFlag = streamHelper.Read();
}
}
catch
{
throw;
}
finally
{
fs.Close();
}
return(gifImage);
}
/// <summary>
/// 合并多个gif动画,在空间坐标上
/// </summary>
/// <param name="sourceGifs">原图像</param>
/// <param name="outPath">合并后图像</param>
public void Merge(List <string> sourceGifs, string outPath)
{
List <List <GifFrame> > frames = new List <List <GifFrame> >();
foreach (string source in sourceGifs)
{
if (!File.Exists(source))
{
throw new IOException(string.Format("文件{0}不存在!", source));
}
using (Bitmap ora_Img = new Bitmap(source))
{
if (ora_Img.RawFormat.Guid != ImageFormat.Gif.Guid)
{
throw new IOException(string.Format("文件{0}!", source));
}
}
GifImage gifImage = GifDecoder.Decode(source);
ThinkDisposalMethod(gifImage);
int index = 0;
foreach (GifFrame f in gifImage.Frames)
{
if (frames.Count <= index)
{
List <GifFrame> list = new List <GifFrame>();
frames.Add(list);
}
List <GifFrame> frameList = frames[index];
frameList.Add(f);
index++;
}
}
List <GifFrame> frameCol = new List <GifFrame>();
int frameIndex = 0;
foreach (List <GifFrame> fs in frames)
{
GifFrame frame = Merge(fs);
frameCol.Add(frame);
if (frame.Image.Width != frameCol[0].Image.Width ||
frame.Image.Height != frameCol[0].Image.Height)
{
frame.ImageDescriptor.XOffSet = frames[frameIndex][0].ImageDescriptor.XOffSet;
frame.ImageDescriptor.YOffSet = frames[frameIndex][0].ImageDescriptor.YOffSet;
frame.GraphicExtension.DisposalMethod = frames[frameIndex][0].GraphicExtension.DisposalMethod;
}
frame.GraphicExtension.Delay = frame.Delay = frames[frameIndex][0].Delay;
frameIndex++;
}
GifImage gifImg = new GifImage();
gifImg.Header = "GIF89a";
LogicalScreenDescriptor lcd = new LogicalScreenDescriptor();
lcd.Width = (short)frameCol[0].Image.Width;
lcd.Height = (short)frameCol[0].Image.Height;
gifImg.LogicalScreenDescriptor = lcd;
ApplicationEx ape = new ApplicationEx();
List <ApplicationEx> apps = new List <ApplicationEx>();
apps.Add(ape);
gifImg.ApplictionExtensions = apps;
gifImg.Frames = frameCol;
GifEncoder.Encode(gifImg, outPath);
}
/// <summary>
/// 合并多个gif文件
/// </summary>
/// <param name="sourceGifs">原图像路径集合</param>
/// <param name="outGif">合并后图像路径</param>
/// <param name="delay">间隔时间</param>
/// <param name="repeat">是否重复播放</param>
public void Merge(List <string> sourceGifs, string outGif, short delay, bool repeat)
{
GifImage gifImage = null;
int index = 0;
short lastDelay = delay;
foreach (string source in sourceGifs)
{
if (!File.Exists(source))
{
throw new IOException(string.Format("文件{0}不存在!", source));
}
using (Bitmap ora_Img = new Bitmap(source))
{
if (ora_Img.RawFormat.Guid != ImageFormat.Gif.Guid)
{
throw new IOException(string.Format("文件{0}!", source));
}
}
GifImage gif = GifDecoder.Decode(source);
if (index == 0)
{
gifImage = gif;
}
int frameCount = 0;
foreach (GifFrame f in gif.Frames)
{
if (frameCount == 0 && f.GraphicExtension.DisposalMethod == 0)
{
f.GraphicExtension.DisposalMethod = 2;
}
if (!f.ImageDescriptor.LctFlag)
{
f.ImageDescriptor.LctSize = f.LocalColorTable.Length / 3;
f.ImageDescriptor.LctFlag = true;
f.GraphicExtension.TranIndex = gif.LogicalScreenDescriptor.BgColorIndex;
f.LocalColorTable = gif.GlobalColorTable;
}
if (frameCount == 0)
{
f.Delay = f.GraphicExtension.Delay = lastDelay;
}
if (f.Delay == 0)
{
f.Delay = f.GraphicExtension.Delay = lastDelay;
}
f.ColorDepth = (byte)(Math.Log(f.ImageDescriptor.LctSize, 2));
lastDelay = f.GraphicExtension.Delay;
frameCount++;
}
gifImage.Frames.AddRange(gif.Frames);
index++;
}
if (repeat && gifImage.ApplictionExtensions.Count == 0)
{
ApplicationEx ae = new ApplicationEx();
gifImage.ApplictionExtensions.Add(ae);
}
gifImage.LogicalScreenDescriptor.PixcelAspect = 0;
Size maxSize = FindMaxSize(sourceGifs);
gifImage.LogicalScreenDescriptor.Width = (short)maxSize.Width;
gifImage.LogicalScreenDescriptor.Height = (short)maxSize.Height;
GifEncoder.Encode(gifImage, outGif);
}
/// <summary>
/// Gif动画单色化
/// </summary>
/// <param name="gifFilePath">原动画路径</param>
/// <param name="outputPath">单色后动画路径</param>
public void Monochrome(string gifFilePath, string outputPath)
{
if (!File.Exists(gifFilePath))
{
throw new IOException(string.Format("文件{0}不存在!", gifFilePath));
}
using (Bitmap ora_Img = new Bitmap(gifFilePath))
{
if (ora_Img.RawFormat.Guid != ImageFormat.Gif.Guid)
{
throw new IOException(string.Format("文件{0}!", gifFilePath));
}
}
GifImage gifImage = GifDecoder.Decode(gifFilePath);
int transIndex = gifImage.LogicalScreenDescriptor.BgColorIndex;
int c1 = (255 << 24) | (158 << 16) | (128 << 8) | 128;
int c2 = (255 << 24) | (0 << 16) | (0 << 8) | 0;
int c3 = (255 << 24) | (255 << 16) | (255 << 8) | 255;
int c4 = (255 << 24) | (0 << 16) | (0 << 8) | 0;
int[] palette = new int[] { c1, c2, c3, c4 };
byte[] buffer = new byte[12] {
128, 128, 128, 0, 0, 0, 255, 255, 255, 0, 0, 0
};
gifImage.GlobalColorTable = buffer;
gifImage.LogicalScreenDescriptor.BgColorIndex = 0;
gifImage.LogicalScreenDescriptor.GlobalColorTableSize = 4;
gifImage.LogicalScreenDescriptor.GlobalColorTableFlag = true;
int index = 0;
foreach (GifFrame f in gifImage.Frames)
{
Color32[] act = PaletteHelper.GetColor32s(f.LocalColorTable);
f.LocalColorTable = buffer;
Color bgC = act[(transIndex / 3)].Color;
byte bgGray = (byte)(bgC.R * 0.3 + bgC.G * 0.59 + bgC.B * 0.11);
BitmapData bmpData = f.Image.LockBits(new Rectangle(0, 0, f.Image.Width, f.Image.Height), ImageLockMode.ReadWrite, f.Image.PixelFormat);
unsafe
{
int *p = (int *)bmpData.Scan0.ToPointer();
for (int i = 0; i < f.Image.Width * f.Image.Height; i++)
{
if (p[i] == 0)
{
p[i] = c1;
}
else
{
Color c = Color.FromArgb(p[i]);
int gray = (byte)(c.R * 0.3 + c.G * 0.59 + c.B * 0.11);
if (gray > bgGray)
{
if (bgGray > 128)
{
p[i] = c2;
}
else
{
p[i] = c3;
}
}
else if (gray < bgGray)
{
if (bgGray > 128)
{
p[i] = c3;
}
else
{
p[i] = c2;
}
}
else
{
p[i] = c1;
}
}
}
}
f.Image.UnlockBits(bmpData);
f.GraphicExtension.TranIndex = 0;
f.ColorDepth = 2;
f.ImageDescriptor.LctFlag = false;
index++;
}
GifEncoder.Encode(gifImage, outputPath);
}
/// <summary>
/// 对gif动画添加水印
/// </summary>
/// <param name="gifFilePath">原gif动画的路径</param>
/// <param name="text">水印文字</param>
/// <param name="textForceColor">水印文字的颜色，因为gif不是真彩色图片，所以在显示的时候，该颜色可能有所误差，但基本上可以确定颜色范围</param>
/// <param name="font">字体</param>
/// <param name="x">水印位置横坐标</param>
/// <param name="y">水印位置纵坐标</param>
/// <param name="outputPath">输出路径</param>
public void WaterMark(string gifFilePath, SizeMode sizeMode, string text, Color textForceColor, Font font, float x, float y, string outputPath)
{
if (!File.Exists(gifFilePath))
{
throw new IOException(string.Format("文件{0}不存在!", gifFilePath));
}
using (Bitmap ora_Img = new Bitmap(gifFilePath))
{
if (ora_Img.RawFormat.Guid != ImageFormat.Gif.Guid)
{
throw new IOException(string.Format("文件{0}!", gifFilePath));
}
}
GifImage gifImage = GifDecoder.Decode(gifFilePath);
if (sizeMode == SizeMode.Large)
{
ThinkDisposalMethod(gifImage);
}
Color textColor = textForceColor;
int frameCount = 0;
foreach (GifFrame f in gifImage.Frames)
{
if ((sizeMode == SizeMode.Normal && frameCount++ == 0) || sizeMode == SizeMode.Large)
{
Graphics g = Graphics.FromImage(f.Image);
g.DrawString(text, font, new SolidBrush(textColor), new PointF(x, y));
g.Dispose();
bool hasTextColor = false;
Color32[] colors = PaletteHelper.GetColor32s(f.LocalColorTable);
foreach (Color32 c in colors)
{
if (c.ARGB == textColor.ToArgb())
{
hasTextColor = true;
break;
}
}
if (!hasTextColor)
{
if (f.Palette.Length < 256)
{
int newSize = f.Palette.Length * 2;
Color32[] newColors = new Color32[newSize];
newColors[f.Palette.Length] = new Color32(textColor.ToArgb());
Array.Copy(colors, newColors, colors.Length);
byte[] lct = new byte[newColors.Length * 3];
int index = 0;
foreach (Color32 c in newColors)
{
lct[index++] = c.Red;
lct[index++] = c.Green;
lct[index++] = c.Blue;
}
f.LocalColorTable = lct;
f.ImageDescriptor.LctFlag = true;
f.ImageDescriptor.LctSize = newSize;
f.ColorDepth = f.ColorDepth + 1;
}
else
{
OcTreeQuantizer q = new OcTreeQuantizer(8);
Color32[] cs = q.Quantizer(f.Image);
byte[] lct = new byte[cs.Length * 3];
int index = 0;
int colorCount = 0;
foreach (Color32 c in cs)
{
lct[index++] = c.Red;
lct[index++] = c.Green;
lct[index++] = c.Blue;
if (c.ARGB == f.BgColor.ARGB)
{
f.GraphicExtension.TranIndex = (byte)colorCount;
}
colorCount++;
}
Quantizer(f.Image, cs);
f.LocalColorTable = lct;
f.ImageDescriptor.LctFlag = true;
f.ImageDescriptor.LctSize = 256;
f.ColorDepth = 8;
}
}
}
}
GifEncoder.Encode(gifImage, outputPath);
}
/// <summary>
/// 获取gif动画的缩略图
/// </summary>
/// <param name="gifFilePath">原gif图片路径</param>
/// <param name="p_width">图像大于该宽度将会被调整为该宽度尺寸</param>
/// <param name="p_height">图像大于该高度将会被调整为该高度尺寸</param>
/// <param name="p_bool">是否保持比例</param>
/// <param name="outputPath">输出缩略图</param>
public void GetThumbnail(string gifFilePath, string outputPath, int p_width, int p_height, bool p_bool)
{
if (!File.Exists(gifFilePath))
{
throw new IOException(string.Format("文件{0}不存在!", gifFilePath));
}
using (Bitmap ora_Img = new Bitmap(gifFilePath))
{
if (ora_Img.RawFormat.Guid != ImageFormat.Gif.Guid)
{
throw new IOException(string.Format("文件{0}!", gifFilePath));
}
}
GifImage gifImage = GifDecoder.Decode(gifFilePath);
//计算比例
int originalWidth = gifImage.Width;
int originalHeight = gifImage.Height;
double scaleWidth = 0;
double scaleHeight = 0;
double scale;
int newWidth = 0;
int newHeight = 0;
if (p_bool)
{
// 计算图像缩小的比例
if (originalWidth > p_width)
{
scaleWidth = (double)originalWidth / (double)p_width;
}
if (originalHeight > p_height)
{
scaleHeight = (double)originalHeight / (double)p_height;
}
if (scaleWidth != 0 || scaleHeight != 0)
{
// 比较缩小比例, 取缩小比例大的值
if (scaleWidth > scaleHeight)
{
scale = scaleWidth;
newWidth = p_width;
newHeight = (int)((double)originalHeight / scale);
}
else
{
scale = scaleHeight;
newWidth = (int)((double)originalWidth / scale);
newHeight = p_height;
}
}
else
{
newWidth = originalWidth;
newHeight = originalHeight;
}
}
else
{
newWidth = p_width;
newHeight = p_height;
}
double rate1 = (double)newWidth / (double)originalWidth;
double rate2 = (double)newHeight / (double)originalHeight;
gifImage.LogicalScreenDescriptor.Width = (short)(gifImage.LogicalScreenDescriptor.Width * rate1);
gifImage.LogicalScreenDescriptor.Height = (short)(gifImage.LogicalScreenDescriptor.Height * rate2);
int index = 0;
foreach (GifFrame f in gifImage.Frames)
{
f.ImageDescriptor.XOffSet = (short)(f.ImageDescriptor.XOffSet * rate1);
f.ImageDescriptor.YOffSet = (short)(f.ImageDescriptor.YOffSet * rate2);
f.ImageDescriptor.Width = (short)(f.ImageDescriptor.Width * rate1);
f.ImageDescriptor.Height = (short)(f.ImageDescriptor.Height * rate2);
if (f.ImageDescriptor.Width == 0)
{
f.ImageDescriptor.Width = 1;
}
if (f.ImageDescriptor.Height == 0)
{
f.ImageDescriptor.Height = 1;
}
Bitmap bmp = new Bitmap(f.ImageDescriptor.Width, f.ImageDescriptor.Height);
Graphics g = Graphics.FromImage(bmp);
g.DrawImage(f.Image, new Rectangle(0, 0, f.ImageDescriptor.Width, f.ImageDescriptor.Height));
g.Dispose();
Quantizer(bmp, f.Palette);
f.Image.Dispose();
f.Image = bmp;
index++;
}
if (string.IsNullOrEmpty(outputPath))
{
GifEncoder.Encode(gifImage, gifFilePath);
}
else
{
GifEncoder.Encode(gifImage, outputPath);
}
}