C#基于两种需求向图片添加水印

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使用场景

1、也就是大家经常用的，一般是图片的4个角落，基于横纵坐标来添加。

2、在图片内基于固定位置，文字始终居中。刚开始我基于第一种场景来根据水印汉字的长度来计算坐标，后来发现方法始终不可靠。现在是先在图片固定区域(水印区域)画一个矩形，然后再矩形内添加水印汉字，并使用画刷保持文字居中。

场景一效果

场景二效果

场景一添加水印方法

static void addWatermarkText(Graphics picture,int fontsize, string _watermarkText, string _watermarkPosition, int _width, int _height)
{
int[] sizes = new int[] {32, 14, 12, 10, 8, 6, 4 };
Font crFont = null;
SizeF crSize = new SizeF(); crFont = new Font("微软雅黑", fontsize, FontStyle.Bold);
crSize = picture.MeasureString(_watermarkText, crFont); float xpos = 0;
float ypos = 0;
Color color =Color.Firebrick; switch (_watermarkPosition)
{
case "WM_TOP_LEFT":
xpos = ((float)_width * (float).01) + (crSize.Width / 2);
ypos = (float)_height * (float).01;
break;
case "WM_TOP_RIGHT":
xpos = ((float)_width * (float).99) - (crSize.Width / 2);
ypos = (float)_height * (float).01;
break;
case "WM_BOTTOM_RIGHT":
xpos = ((float)_width * (float).99) - (crSize.Width / 2);
ypos = ((float)_height * (float).99) - crSize.Height;
break;
case "WM_BOTTOM_LEFT":
xpos = ((float)_width * (float).01) + (crSize.Width / 2);
ypos = ((float)_height * (float).99) - crSize.Height;
break; } StringFormat StrFormat = new StringFormat();
StrFormat.Alignment = StringAlignment.Center;
SolidBrush semiTransBrush2 = new SolidBrush(Color.FromArgb(153, 0, 0, 0));//加阴影
picture.DrawString(_watermarkText, crFont, semiTransBrush2, xpos + 1, ypos + 1, StrFormat); SolidBrush semiTransBrush = new SolidBrush(color); //添加水印
picture.DrawString(_watermarkText, crFont, semiTransBrush, xpos, ypos, StrFormat); semiTransBrush2.Dispose();
semiTransBrush.Dispose();
}

场景二添加水印方法

static void addWatermarkText(Graphics picture,string type, int fontsize, string _watermarkText)
{
//1、先画矩形
RectangleF drawRect;
Color color;
if (type == "Top")
{
drawRect = new RectangleF(73, 135, 450, 64);
color = Color.FromArgb(255, 255, 255);
}
else
{
drawRect = new RectangleF(194, 245, 250, 39);
color = Color.FromArgb(244, 226, 38);
} //2、在基于矩形画水印文字
Font crFont = null; StringFormat StrFormat = new StringFormat();
StrFormat.Alignment = StringAlignment.Center; crFont = new Font("微软雅黑", fontsize, FontStyle.Bold);
SolidBrush semiTransBrush = new SolidBrush(color); //添加水印
picture.DrawString(_watermarkText, crFont, semiTransBrush, drawRect, StrFormat); semiTransBrush.Dispose();
}