public void DrawCore(string imagePath, WatermarkMode mode, Action <SKData> postAction)
{
Logger.LogDebug($"Watermark image file: {imagePath}");
Logger.LogDebug($"Watermark mode: {mode.AsEnumName()}");
using (var bmp = SKBitmap.Decode(imagePath))
{
using (var canvas = new SKCanvas(bmp))
{
var imageSize = new Size(bmp.Width, bmp.Height);
DrawCore(canvas, imageSize, mode);
}
using (var img = SKImage.FromBitmap(bmp))
using (var data = img.Encode(CurrentImageFormat, Options.Quality))
{
if (data.IsNull())
{
throw new InvalidOperationException(InternalResource.InvalidOperationExceptionUnsupportedImageFormat);
}
postAction.Invoke(data);
}
}
}
internal void DrawCore(SKCanvas canvas, Size imageSize, WatermarkMode mode)
{
var coordinate = ImageHelper.CalculateCoordinate(imageSize,
Options.Watermark.Location, Options.Watermark.IsRandom);
switch (mode)
{
case WatermarkMode.Text:
{
using (var foreFont = CreatePaint(Options.Watermark.Colors.Fore))
using (var alternFont = CreatePaint(Options.Watermark.Colors.Alternate))
{
var text = Options.Watermark.Text;
for (int i = 0; i < text.Length; i++)
{
// 当前字符
var character = text.Substring(i, 1);
// 测算水印文本内容矩形尺寸
var rect = new SKRect();
foreFont.MeasureText(character, ref rect);
// 绘制文本水印
canvas.DrawText(character, coordinate.X + (int)rect.Width, coordinate.Y,
i % 2 > 0 ? alternFont : foreFont);
// 递增字符宽度
coordinate.X += (int)rect.Width;
}
}
}
break;
case WatermarkMode.Image:
{
using (var watermark = SKBitmap.Decode(_watermarkImagePath))
{
// 绘制图像水印
canvas.DrawBitmap(watermark, coordinate.X, coordinate.Y);
}
}
break;
default:
break;
}
}
public Task <byte[]> DrawBytesAsync(string imagePath, WatermarkMode mode = WatermarkMode.Text,
CancellationToken cancellationToken = default)
{
return(cancellationToken.RunOrCancelAsync(() =>
{
var buffer = default(byte[]);
DrawCore(imagePath, mode, data =>
{
buffer = data.ToArray();
Logger.LogDebug($"Watermark image file save as byte[]: length={buffer.Length}");
});
return buffer;
}));
}
public Task <bool> DrawStreamAsync(string imagePath, Stream target,
WatermarkMode mode = WatermarkMode.Text, CancellationToken cancellationToken = default)
{
return(cancellationToken.RunOrCancelAsync(() =>
{
var result = false;
DrawCore(imagePath, mode, data =>
{
data.SaveTo(target);
Logger.LogDebug($"Watermark image file save as stream");
result = true;
});
return result;
}));
}
public Task <bool> DrawFileAsync(string imagePath, string savePath,
WatermarkMode mode = WatermarkMode.Text, CancellationToken cancellationToken = default)
{
return(cancellationToken.RunOrCancelAsync(() =>
{
var result = false;
DrawCore(imagePath, mode, data =>
{
using (var fs = new FileStream(savePath, FileMode.OpenOrCreate))
{
data.SaveTo(fs);
}
Logger.LogDebug($"Watermark image file save as: {savePath}");
result = true;
});
return result;
}));
}
