我正在使用GetUserMedia API来捕获图像并将其绘制到画布上。使用canvas的toDataURL()我得到“ImageUrl”。该URL将作为png图像保存到本地文件。我所看到的是,在保存图像之前,在图像底部(而不是图像上方)添加一些关于图像的注释,就像页脚一样。我有以下代码。任何人都可以建议我在c#中如何做到这一点。
imageByte= Convert.FromBase64String(ImageUrl);
using (var streamBitmap = new MemoryStream(imageByte))
{
using (var img = Image.FromStream(streamBitmap))
{
img.Save(localPath);
}
}
答案 0 :(得分:2)
您可以创建新的位图,该位图将比原始图像更高,以适应下面的页脚。接下来将原始图像和页脚复制到该位图并保存新位图。
要做的方法是这样的(假设页脚宽度< =图像宽度):
public Bitmap AppendImageFooter(System.Drawing.Image bmp, System.Drawing.Image footer)
{
//Create new image that will be bigger then original image to make place for footer
Bitmap newImage = new Bitmap(bmp.Height+footer.Height,bmp.Width);
//Get graphics from new Image and copy original image and next footer below
Graphics g = Graphics.FromImage(newImage);
g.DrawImage(bmp, new Point(0, 0));
g.DrawImage(footer, new Point(0, bmp.Height));
g.Dispose();
return newImage;
}
你可以在这个地方的代码中加入它:
var footer = Image.FromFile("path_to_your_footer.png");
imageByte= Convert.FromBase64String(ImageUrl);
using (var streamBitmap = new MemoryStream(imageByte))
{
using (var img = Image.FromStream(streamBitmap))
{
var imageWithFooter = AppendImageFooter(img, footer);
imageWithFooter.Save(localPath);
}
}
编辑回复评论中的其他问题:
您可以在运行时构建页脚。下面的示例代码,当然您可以以您喜欢的任何风格绘制任何您喜欢的内容:
public Bitmap AppendImageFooter(System.Drawing.Image bmp, string text)
{
//Create new image that will be bigger then original image to make place for footer
Bitmap newImage = new Bitmap(bmp.Height+200,bmp.Width);
//Get graphics and copy image and below the footer
Graphics g = Graphics.FromImage(bmp);
g.DrawImage(bmp, new Point(0, 0));
g.FillRectangle(new SolidBrush(Color.Black), 0, bmp.Height, bmp.Width, 200);
g.DrawString(text, new Font("Arial", 14), new SolidBrush(Color.White), 20, bmp.Height + 20);
//Anything else you like, circles, rectangles, texts etc..
g.Dispose();
return newImage;
}
答案 1 :(得分:1)
这是最简单的方法:我刚刚创建了新图像(页脚),一个新图像,上面绘制了旧图像和页脚图像。
int footerHeight = 30;
Bitmap bitmapImg = new Bitmap(img);// Original Image
Bitmap bitmapComment = new Bitmap(img.Width, footerHeight);// Footer
Bitmap bitmapNewImage = new Bitmap(img.Width, img.Height + footerHeight);//New Image
Graphics graphicImage = Graphics.FromImage(bitmapNewImage);
graphicImage.Clear(Color.White);
graphicImage.DrawImage(bitmapImg, new Point(0, 0));
graphicImage.DrawImage(bitmapComment, new Point(bitmapComment.Width, 0));
graphicImage.DrawString("Hi, This is Vivek !", new Font("Arial", 15), new SolidBrush(Color.Black), 0, bitmapImg.Height + footerHeight / 6);
bitmapNewImage.Save(yourImagePath);
bitmapImg.Dispose();
bitmapComment.Dispose();
bitmapNewImage.Dispose();
'img'是原始图片。