/// <summary>
/// 对gif动画添加图片水印
/// </summary>
/// <param name="gifFilePath">原图片路径</param>
/// <param name="waterImg">水印图片</param>
/// <param name="x">横坐标</param>
/// <param name="y">纵坐标</param>
/// <param name="outputPath">输出路径</param>
public static void WaterMark(string gifFilePath, Bitmap waterImg, 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);
ThinkDisposalMethod(gifImage);
foreach (GifFrame f in gifImage.Frames)
{
Graphics g = Graphics.FromImage(f.Image);
g.DrawImage(waterImg, new PointF(x, y));
g.Dispose();
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>
/// 对gif动画添加水印
/// </summary>
/// <param name="gifFilePath">原gif动画的路径</param>
/// <param name="sizeMode"></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 static 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);
}