背景打开黑色当保存位图 - C＃ [英] Background Turns Black When Saving Bitmap - C#

问题描述

目前我正在试图挽救一个位图图像，但背景正在改变为黑色。

我可以在另存为的形象完美的罚款。我也可以拯救的形象为好。这是更为困难，因为我不得不覆盖现有的图像。

然而，当我拯救我的形象的背景变黑。我不知道是什么原因造成的。

下面是我的code：

 位图tempImage =新位图（DrawArea）;DrawArea.Dispose（）;如果（扩展名==.JPEG）
    tempImage.Save（文件名，System.Drawing.Imaging.ImageFormat.Jpeg）;
其他
    tempImage.Save（文件名，System.Drawing.Imaging.ImageFormat.Bmp）;DrawArea =新位图（tempImage）;
pictureBox1.Image = DrawArea;tempImage.Dispose（）;
 

解决方案

创建一个空白位图。创建一个图形对象与空白位图写。清除位图，并改变其颜色为白色。然后绘制图像，然后保存该位图。

 位图空白=新位图（DrawArea.Width，DrawArea.Height）;
            图形G = Graphics.FromImage（空白）;
            g.Clear（Color.White）;
            g.DrawImage（DrawArea，0，0，DrawArea.Width，DrawArea.Height）;            位图tempImage =新位图（空白）;
            blank.Dispose（）;
            DrawArea.Dispose（）;            如果（扩展名==.JPEG）
                tempImage.Save（文件名，System.Drawing.Imaging.ImageFormat.Jpeg）;
            其他
                tempImage.Save（文件名，System.Drawing.Imaging.ImageFormat.Bmp）;            DrawArea =新位图（tempImage）;
            pictureBox1.Image = DrawArea;            tempImage.Dispose（）;
 

I am currently trying to save a bitmap image, but the background is changing to black.

I can "Save As" the image perfectly fine. I can also "Save" the image as well. Which was much more difficult because I had to overwrite the existing image.

However, when I "save" my image the background is turning black. And I have no idea what is causing it.

Here is my code:

Bitmap tempImage = new Bitmap(DrawArea);

DrawArea.Dispose();

if (extension == ".jpeg")
    tempImage.Save(fileName, System.Drawing.Imaging.ImageFormat.Jpeg);
else
    tempImage.Save(fileName, System.Drawing.Imaging.ImageFormat.Bmp);

DrawArea = new Bitmap(tempImage);
pictureBox1.Image = DrawArea;

tempImage.Dispose();

解决方案

Create a blank bitmap. Create a graphics object to write on with that blank bitmap. Clear the bitmap and change its color to white. Then draw the image then save the bitmap.

            Bitmap blank = new Bitmap(DrawArea.Width, DrawArea.Height);
            Graphics g = Graphics.FromImage(blank);
            g.Clear(Color.White);
            g.DrawImage(DrawArea, 0, 0, DrawArea.Width, DrawArea.Height);

            Bitmap tempImage = new Bitmap(blank);
            blank.Dispose();
            DrawArea.Dispose();

            if (extension == ".jpeg")
                tempImage.Save(fileName, System.Drawing.Imaging.ImageFormat.Jpeg);
            else
                tempImage.Save(fileName, System.Drawing.Imaging.ImageFormat.Bmp);

            DrawArea = new Bitmap(tempImage);
            pictureBox1.Image = DrawArea;

            tempImage.Dispose();

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