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我正在创建一张 PNG 图片，使用该Bitmap对象，使用Drawing.Graphics. 我创建一个位图，插入背景图像并绘制一些字符串。

现在，当我将图像保存在磁盘上时，文件没有我的字符串！

我在 ASP.NET MVC 中执行此操作，这是我的控制器签名：

    [AcceptVerbs(HttpVerbs.Get)]
    public string GetNewsletterPicture(string headline, string tagline)

当我不将图像保存在磁盘上而是FileStreamResult从 a返回 a 时MemoryStream，图像看起来很完美。

所以存在一些问题，当我将图像保存到磁盘时，字符串不知何故被“遗忘”了。

有任何想法吗？

我的代码：

ColorConverter converter = new ColorConverter();
        Color textColor = (Color)converter.ConvertFromString("#FF58595B");
        int width = 598;
        int height = 77;
        int offSet = 40;
        int shadowOffset = 1;

        var bmp = new Bitmap(width, height);
        using (Graphics g = Graphics.FromImage(bmp))
        {
            g.Clear(Color.LightGray);
            Image backgroundImg = new Bitmap(Server.MapPath("~/Static/Images/bgimg.png"));
            g.DrawImage(backgroundImg,0,0);

            StringFormat sf= new StringFormat();
            sf.Alignment = StringAlignment.Center;

            var rectangleTop = new RectangleF(0, 0, width, height);
            var rectangleTopShadowHack = new RectangleF(shadowOffset, shadowOffset, width + shadowOffset, height + shadowOffset);
            g.TextRenderingHint = TextRenderingHint.AntiAliasGridFit;

            // only show headline and center it
            if (!string.IsNullOrEmpty(tagline))
            {
                var rectangleBottomShadowHack = new RectangleF(shadowOffset, offSet + shadowOffset, width + shadowOffset, height - offSet + shadowOffset);
                var rectangleBottom = new RectangleF(0, offSet, width, height - offSet);

                g.DrawString(tagline, new Font("Verdana", 18), new SolidBrush(Color.White), rectangleBottomShadowHack, sf);
                g.DrawString(tagline, new Font("Verdana", 18), new SolidBrush(textColor), rectangleBottom, sf);
            }
            else
            {
                sf.LineAlignment = StringAlignment.Center;
            }
            g.DrawString(headline, GetFont("Sentinel-Bold", 28, FontStyle.Bold), new SolidBrush(Color.White), rectangleTopShadowHack, sf);
            g.DrawString(headline, GetFont("Sentinel-Bold", 28, FontStyle.Bold), new SolidBrush(textColor), rectangleTop, sf);

            g.Save();

            var fileName = Guid.NewGuid().ToString() + ".png";
            var path = Server.MapPath("~/Static/Previews/" + fileName);
            bmp.Save(path, ImageFormat.Png);

            return fileName;

如果有疑问，是 g.DrawString 没有保存在图片上。

新尝试（仍然无效）：

[AcceptVerbs(HttpVerbs.Get)]
        public string GetNewsletterPicture(string headline, string tagline)
        {
            ColorConverter converter = new ColorConverter();
            Color textColor = (Color)converter.ConvertFromString("#FF58595B");
            int width = 598;
            int height = 77;
            int offSet = 40;
            int shadowOffset = 1;

            var bmp = new Bitmap(width, height);
            using (Graphics g = Graphics.FromImage(bmp))
            {
                g.Clear(Color.LightGray);
                Image backgroundImg = new Bitmap(Server.MapPath("~/Static/Images/bgimg.png"));
                g.DrawImage(backgroundImg,0,0);

                StringFormat sf= new StringFormat();
                sf.Alignment = StringAlignment.Center;

                var rectangleTop = new RectangleF(0, 0, width, height);
                var rectangleTopShadowHack = new RectangleF(shadowOffset, shadowOffset, width + shadowOffset, height + shadowOffset);
                g.TextRenderingHint = TextRenderingHint.AntiAliasGridFit;

                // only show headline and center it
                if (!string.IsNullOrEmpty(tagline))
                {
                    var rectangleBottomShadowHack = new RectangleF(shadowOffset, offSet + shadowOffset, width + shadowOffset, height - offSet + shadowOffset);
                    var rectangleBottom = new RectangleF(0, offSet, width, height - offSet);

                    g.DrawString(tagline, new Font("Verdana", 18), new SolidBrush(Color.White), rectangleBottomShadowHack, sf);
                    g.DrawString(tagline, new Font("Verdana", 18), new SolidBrush(textColor), rectangleBottom, sf);
                }
                else
                {
                    sf.LineAlignment = StringAlignment.Center;
                }
                g.DrawString(headline, GetFont("Sentinel-Bold", 28, FontStyle.Bold), new SolidBrush(Color.White), rectangleTopShadowHack, sf);
                g.DrawString(headline, GetFont("Sentinel-Bold", 28, FontStyle.Bold), new SolidBrush(textColor), rectangleTop, sf);

                g.Flush(FlushIntention.Sync);
            }

            var fileName = Guid.NewGuid().ToString() + ".png";
            var path = Server.MapPath("~/Static/Previews/" + fileName);
            bmp.Save(path, ImageFormat.Png);

            return fileName;


            //MemoryStream stm = new MemoryStream();
            //bmp.Save(stm,System.Drawing.Imaging.ImageFormat.Png);
            //stm.Position = 0;

            //return new FileStreamResult(stm, "image/png");
        }
4

1 回答 1

1

我不能确定，但​​看起来你可能g.Save()对g.Flush().

您需要调用g.Flush(FlushIntention.Sync)而不是g.Save(). 您可能还应该在 using 块之外调用 bmp.Save() ：

var bmp = new Bitmap(width, height);
using (Graphics g = Graphics.FromImage(bmp))
{
  //...
  g.Flush(FlushIntention.Sync);
}

var fileName = Guid.NewGuid().ToString() + ".png";
var path = Server.MapPath("~/Static/Previews/" + fileName);

bmp.Save(path, ImageFormat.Png)

Save()用于保存当前的图形状态，以便您可以修改它，然后再恢复它。：

GraphicsState oldState = g.Save();

// Make some changes to the graphics state...

g.Restore(oldState);

Flush()另一方面，用于强制图形对象完成任何挂起的操作。通过FlushIntention.Sync作为参数传递，Flush()在刷新完成之前不会返回。

于 2013-08-07T10:51:47.043 回答