[英]How to convert Graphics to bitmap and save it in c#?
目前我正在学习使用图形方法绘制条形码并将其处理为位图。 但是当我要保存它时,虽然可以保存成功,但结果是黑色图像,从那里看不到任何东西。 发生了什么问题?
private void buttonDraw_Click(object sender, EventArgs e)
{
System.Drawing.Graphics g = this.pictureBoxBarcode.CreateGraphics();
g.FillRectangle(new System.Drawing.SolidBrush(System.Drawing.SystemColors.Control),
new Rectangle(0, 0, pictureBoxBarcode.Width, pictureBoxBarcode.Height));
ean13.DrawEan13Barcode(g, new System.Drawing.Point(0, 0));
g.Dispose();
}
这是我的保存功能
public void Save(Bitmap original)
{
// Displays a SaveFileDialog so the user can save the Image
// assigned to Button2.
SaveFileDialog saveFileDialog1 = new SaveFileDialog();
saveFileDialog1.Filter = "JPeg Image|*.jpg|Bitmap Image|*.bmp|Gif Image|*.gif|Png Image|*.png";
saveFileDialog1.Title = "Save an Image File";
saveFileDialog1.ShowDialog();
// If the file name is not an empty string open it for saving.
if (saveFileDialog1.FileName != "")
{
// Saves the Image via a FileStream created by the OpenFile method.
System.IO.FileStream fs =
(System.IO.FileStream)saveFileDialog1.OpenFile();
// Saves the Image in the appropriate ImageFormat based upon the
// File type selected in the dialog box.
// NOTE that the FilterIndex property is one-based.
switch (saveFileDialog1.FilterIndex)
{
case 1:
original.Save(fs,
System.Drawing.Imaging.ImageFormat.Jpeg);
break;
case 2:
original.Save(fs,
System.Drawing.Imaging.ImageFormat.Bmp);
break;
case 3:
original.Save(fs,
System.Drawing.Imaging.ImageFormat.Gif);
break;
case 4:
original.Save(fs,
System.Drawing.Imaging.ImageFormat.Png);
break;
}
fs.Close();
}
}
我无法提供任何图片来证明我的声誉还不够。 对不起。
要绘制Bitmap
使用以下代码:
private void buttonDraw_Click(object sender, EventArgs e)
{
Bitmap bmp = new Bitmap(pictureBoxBarcode.ClientSize.Width,
pictureBoxBarcode.ClientSize.Height);
using (Graphics g = Graphics.FromImage(bmp))
{
g.Clear(SystemColors.Control);
ean13.DrawEan13Barcode(g, new System.Drawing.Point(0, 0));
}
// display:
pictureBoxBarcode.Image = bmp;
// save:
bmp.Save(yourfilename, ImageFormat.Png);
// ..or..:
Save(bmp);
}
或者:
private void buttonSave_Click(object sender, EventArgs e)
{
Save( (Bitmap) pictureBoxBarcode.Image);
}
我已经复制了你的绘图代码。
我不知道你为什么想让它看起来是灰色的..?
我假设ean13.DrawEan13Barcode
是一个函数,它使用传入的Graphics
对象在与Graphics
对象关联的Bitmap
上绘制一些东西。
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