/// <summary>
/// Add watermark.
/// </summary>
/// <param name="fileName"></param>
public MemoryStream AddWatermark(string fileName,
string watermark,
Color foregroundColor,
float fontSize = 12.0f,
string fontFamily = "微软雅黑",
WatermarkPlacement watermarkPlacement = WatermarkPlacement.BottomRight)
{
if (string.IsNullOrWhiteSpace(fileName))
{
throw new System.ArgumentException("message", nameof(fileName));
}
if (string.IsNullOrWhiteSpace(watermark))
{
throw new System.ArgumentException("message", nameof(watermark));
}
var ext = Path.GetExtension(fileName);
var dirName = Path.GetDirectoryName(fileName);
var fileNameWithoutExt = Path.GetFileNameWithoutExtension(fileName);
var saveName = Path.Combine(dirName, $"{fileNameWithoutExt}_wm{ext}");
var ms = new MemoryStream();
using (var img = Image.FromStream(File.OpenRead(fileName)))
using (var g = Graphics.FromImage(img))
{
#region font & background.
var font = new Font(fontFamily, fontSize, FontStyle.Bold, GraphicsUnit.Pixel);
var foregroundBrush = new SolidBrush(foregroundColor); //笔刷，画文字用
//Brush blackBrush = new SolidBrush(backgroundColor); //笔刷，画背景用
#endregion
float textWidth = watermark.Length * fontSize; //文本的长度
//下面定义一个矩形区域，以后在这个矩形里画上白底黑字
float rectX = 0;
float rectY = 0;
float rectWidth = watermark.Length * (fontSize * 1.113f);
float rectHeight = fontSize * 1.4f;
//声明矩形域
RectangleF textArea = new RectangleF(rectX, rectY, rectWidth, rectHeight);
#region text placement.
SizeF crSize;
crSize = g.MeasureString(watermark, font);
var point = GetRectangleFPoint(watermarkPlacement, img, crSize);
textArea.X = point.Item1;
textArea.Y = point.Item2;
#endregion
//g.FillRectangle(blackBrush, textArea);
g.DrawString(watermark, font, foregroundBrush, textArea);
img.Save(ms, ImageFormat.Png);
img.Save(saveName, ImageFormat.Png);
return(ms);
}
}
public Watermark(System.Drawing.Image image, WatermarkPlacement placement)
{
if ((placement < WatermarkPlacement.TopLeft) || (placement > WatermarkPlacement.Center))
{
throw new ArgumentOutOfRangeException("placement");
}
this._image = image;
this._placement = placement;
}
private (float, float) GetRectangleFPoint(WatermarkPlacement watermarkPlacement, Image img, SizeF crSize)
{
float xpos = 0;
float ypos = 0;
switch (watermarkPlacement)
{
case WatermarkPlacement.TopLeft:
xpos = img.Width * (float).01;
ypos = img.Height * (float).01;
break;
case WatermarkPlacement.Top:
xpos = img.Width * (float).50 - (crSize.Width / 2);
ypos = img.Height * (float).01;
break;
case WatermarkPlacement.TopRight:
xpos = img.Width * (float).99 - crSize.Width;
ypos = img.Height * (float).01;
break;
case WatermarkPlacement.Left:
xpos = img.Width * (float).01;
ypos = img.Height * (float).50 - (crSize.Height / 2);
break;
case WatermarkPlacement.Center:
xpos = img.Width * (float).50 - (crSize.Width / 2);
ypos = img.Height * (float).50 - (crSize.Height / 2);
break;
case WatermarkPlacement.Right:
xpos = img.Width * (float).99 - crSize.Width;
ypos = img.Height * (float).50 - (crSize.Height / 2);
break;
case WatermarkPlacement.BottomLeft:
xpos = img.Width * (float).01;
ypos = img.Height * (float).99 - crSize.Height;
break;
case WatermarkPlacement.BottomCenter:
xpos = img.Width * (float).50 - (crSize.Width / 2);
ypos = img.Height * (float).99 - crSize.Height;
break;
case WatermarkPlacement.BottomRight:
default:
xpos = img.Width * (float).99 - crSize.Width;
ypos = img.Height * (float).99 - crSize.Height;
break;
}
return(xpos, ypos);
}
private void SelectWmImagePlacement()
{
switch (this.lstWMImagePlacement.SelectedItem.ToString())
{
case "Top Left":
this.wmImagePlacement = WatermarkPlacement.TopLeft;
break;
case "Top Center":
this.wmImagePlacement = WatermarkPlacement.TopCenter;
break;
case "Top Right":
this.wmImagePlacement = WatermarkPlacement.TopRight;
break;
case "Middle Left":
this.wmImagePlacement = WatermarkPlacement.MiddleLeft;
break;
case "Middle Center":
this.wmImagePlacement = WatermarkPlacement.MiddleCenter;
break;
case "Middle Right":
this.wmImagePlacement = WatermarkPlacement.MiddleRight;
break;
case "Bottom Left":
this.wmImagePlacement = WatermarkPlacement.BottomLeft;
break;
case "Bottom Center":
this.wmImagePlacement = WatermarkPlacement.BottomCenter;
break;
case "Bottom Right":
this.wmImagePlacement = WatermarkPlacement.BottomRight;
break;
}
}
