public static Stream GenerateFilePreview(int fileHW, Stream stream, ImageModelEnum model, ref int width, ref int height)
{
string type = GetImageType2(stream);
bool isGif = type == "GIF";
if (type == "XML")
{
width = fileHW;
height = fileHW;
return(GenerateSvg(stream, model, ref width, ref height));
}
else
{
using (Image image = Image.FromStream(stream))
{
//原图比较宽
if (image.Width >= image.Height)
{
width = image.Width > fileHW ? fileHW : image.Width; //原图比指定的宽度要宽，就是用指定的宽度，否则使用原图宽
height = image.Height * width / image.Width;
}
//原图比较高
if (image.Width < image.Height)
{
height = image.Height > fileHW ? fileHW : image.Height; //原图比指定的高度要高，就是用指定的高度，否则使用原图高
width = image.Width * height / image.Height;
}
return(ConvertImage(image, image.RawFormat, 0, 0, width, height, false));
}
}
}
public static Stream GenerateThumbnail(Stream stream, ImageModelEnum model, int x, int y, ref int width, ref int height)
{
string type = GetImageType2(stream);
bool cut = false;
if (type == "XML")
{
return(GenerateSvg(stream, model, ref width, ref height));
}
else
{
using (Image image = Image.FromStream(stream))
{
switch (model)
{
case ImageModelEnum.scale:
if (width == 0 && height == 0)
{
width = image.Width;
height = image.Height;
}
else if (width == 0 && height > 0)
{
width = image.Width * height / image.Height;
}
else if (width > 0 && height == 0)
{
height = image.Height * width / image.Width;
}
break;
case ImageModelEnum.height:
width = image.Width * height / image.Height;
break;
case ImageModelEnum.width:
height = image.Height * width / image.Width;
break;
case ImageModelEnum.cut:
cut = true;
break;
}
if (width > image.Width)
{
width = image.Width;
}
if (height > image.Height)
{
height = image.Height;
}
return(ConvertImage(image, image.RawFormat, x, y, width, height, cut));
}
}
}
private static Stream GenerateSvg(Stream stream, ImageModelEnum model, ref int width, ref int height)
{
string text = stream.ToStr();
string pattern = @"<svg\s*(.|\n)+?>";
string widthPattern = @"width=""(\d+)(px)?""";
string heightPattern = @"height=""(\d+)(px)?""";
string svgTag = Regex.Match(text, pattern).Groups[0].Value;
string newSvgTag = svgTag;
var widthMath = Regex.Match(svgTag, widthPattern);
int swidth = widthMath.Success ? int.Parse(widthMath.Groups[1].Value) : 1024;
var heightMath = Regex.Match(svgTag, heightPattern);
int sheight = heightMath.Success ? int.Parse(widthMath.Groups[1].Value) : 1024;
switch (model)
{
case ImageModelEnum.scale:
if (width == 0 && height == 0)
{
width = swidth;
height = sheight;
}
else if (width == 0 && height > 0)
{
width = swidth * height / sheight;
}
else if (width > 0 && height == 0)
{
height = sheight * width / swidth;
}
break;
case ImageModelEnum.height:
if (sheight != 0 && swidth != 0)
{
width = swidth * height / sheight;
}
else
{
width = height;
}
break;
case ImageModelEnum.width:
if (sheight != 0 && swidth != 0)
{
height = sheight * width / swidth;
}
else
{
height = width;
}
break;
}
if (newSvgTag.Contains("width"))
{
newSvgTag = Regex.Replace(newSvgTag, widthPattern, "width=\"" + width + "\"");
}
else
{
newSvgTag = newSvgTag.TrimEnd('>') + " width=\"" + width + "\"" + ">";
}
if (newSvgTag.Contains("height"))
{
newSvgTag = Regex.Replace(newSvgTag, heightPattern, "height=\"" + height + "\"");
}
else
{
newSvgTag = newSvgTag.TrimEnd('>') + " height=\"" + height + "\"" + ">";
}
text = text.Replace(svgTag, newSvgTag);
return(text.ToStream());
}
