Graphics.DrawImage 并不总是绘制整个位图？

发布于 2024-08-13 01:05:15 字数 1165 浏览 4 评论 0原文

我在使用 Graphics.DrawImage 时遇到了一个奇怪的问题。

当在 OnPaint 中使用 e.Graphics.DrawImage(Image, Point) 在控件上绘制位图“缓冲区”时，图像的某些部分似乎被省略。缓冲区填充在一个辅助方法中，该方法使用从其构造的Graphics直接绘制到Bitmap上。当控件绘制时，缓存的位图将绘制在控件上。

位图本身似乎没有遗漏任何内容，因为当我将位图保存到光盘并检查它时，它都在那里。（见下图）

位图缓冲区如下所示：

_{（来源：zachjohnson.net）}

控件上显示的内容如下：

_{（来源：zachjohnson.net）}

这就是我在 OnPaint 中所做的一切：

protected override void OnPaint(PaintEventArgs e)
{
    base.OnPaint(e);
    if (this.bufferInvalid)
    {
        this.UpdateBuffer();
    }

    if (this.buffer != null)
    {
        e.Graphics.DrawImage(this.buffer, Point.Empty);
    }
}

原文

I have run into a strange problem when using Graphics.DrawImage.

When using e.Graphics.DrawImage(Image, Point) in OnPaint to paint a bitmap 'buffer' on the control, it appears that parts of the image are omitted. The buffer is populated in a helper method which draws directly onto the Bitmap using a Graphics constructed from it. When the control paints, the cached bitmap is drawn on the control.

Nothing appears to be omitted on the bitmap itself, because when I saved the bitmap to disc and examined it, it was all there. (see images below)

This is what the bitmap buffer looks like:

_{(source: zachjohnson.net)}

This what appears on the control:

_{(source: zachjohnson.net)}

This is all I am doing in OnPaint:

protected override void OnPaint(PaintEventArgs e)
{
    base.OnPaint(e);
    if (this.bufferInvalid)
    {
        this.UpdateBuffer();
    }

    if (this.buffer != null)
    {
        e.Graphics.DrawImage(this.buffer, Point.Empty);
    }
}

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