Question

我想调整文件上传器中的图像大小。为此我被提到以下内容：

How to set Bitmap.Width and Bitmap.height

（Javed Akram的回答）

制作以下代码：

Dim imgSmall As Bitmap = New Bitmap(FUpload.PostedFile.InputStream, False)
imgSmall.Size = New Size(250, 300)

但是给我错误：

Size is read-only property.

在这种情况下如何调整图像大小？

Answer 1

它是只读的;你必须从它创建一个新的位图。试试这个： -

internal static Image ScaleByPercent(Image image, Size size, float percent)
{
    int sourceWidth  = image.Width,
        sourceHeight = image.Height;

    int destWidth  = (int)(sourceWidth * percent),
        destHeight = (int)(sourceHeight * percent);

    if (destWidth <= 0)
    {
        destWidth = 1;
    }

    if (destHeight <= 0)
    {
        destHeight = 1;
    }

    var resizedImage = new Bitmap(destWidth, destHeight, PixelFormat.Format24bppRgb);
    resizedImage.SetResolution(image.HorizontalResolution, image.VerticalResolution);

    // get handle to new bitmap
    using (var graphics = Graphics.FromImage(resizedImage))
    {
        InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;

        // create a rect covering the destination area
        var destRect = new Rectangle(0, 0, destWidth, destHeight);
        var brush    = new SolidBrush(drawing.Color.White);
        graphics.FillRectangle(brush, destRect);

        // draw the source image to the destination rect
        graphics.DrawImage(image,
                            destRect,
                            new Rectangle(0, 0, sourceWidth, sourceHeight),
                            GraphicsUnit.Pixel);
    }

    return resizedImage;
}

这来自我制作的网站;如果你愿意我可以发送代码，以便在调整大小时确定如何保持正确的宽高比（即在'size'参数中传递的内容）

希望有所帮助

在asp.net中调整图像大小只读错误

1 个答案: