本文实例讲述了JS实现按比例缩放图片的方法。分享给大家供大家参考,具体如下:
js版本:
function resizeImage(obj, MaxW, MaxH) { var imageObject = obj; var state = imageObject.readyState; if(state!='complete') { setTimeout("resizeImage("+imageObject+","+MaxW+","+MaxH+")",50); return; } var oldImage = new Image(); oldImage.src = imageObject.src; var dW = oldImage.width; var dH = oldImage.height; if(dW>MaxW || dH>MaxH) { a = dW/MaxW; b = dH/MaxH; if( b>a ) a = b; dW = dW/a; dH = dH/a; } if(dW > 0 && dH > 0) { imageObject.width = dW; imageObject.height = dH; } }
使用很简单:
/// <summary>
/// 按比例缩放图片
/// </summary>
/// <param name="imgUrl">图片的路径</param>
/// <param name="imgHeight">图片的高度</param>
/// <param name="imgWidth">图片的宽度</param>
/// <returns></returns>
public static string GetImageSize(string imgUrl,int imgHeight,int imgWidth)
{
string fileName = System.Web.HttpContext.Current.Server.MapPath(imgUrl);
string strResult = string.Empty;
if(System.IO.File.Exists(fileName) && imgHeight != 0 && imgWidth != 0)
{
decimal desWidth;decimal desHeight;//目标宽高
System.Drawing.Image objImage = System.Drawing.Image.FromFile(fileName);
decimal radioAct = (decimal)objImage.Width/(decimal)objImage.Height;//原始图片的宽高比
decimal radioLoc = (decimal)imgWidth/(decimal)imgHeight;//图片位的宽高比
if(radioAct > radioLoc)//原始图片比图片位宽
{
decimal dcmZoom = (decimal)imgWidth/(decimal)objImage.Width;
desHeight = objImage.Height*dcmZoom;
desWidth = imgWidth;
}
else
{
decimal dcmZoom = (decimal)imgHeight/(decimal)objImage.Height;
desWidth = objImage.Width*dcmZoom;
desHeight = imgHeight;
}
objImage.Dispose(); //释放资源
strResult = "width=\"" + Convert.ToString((int)desWidth) + "\" height=\""
+ Convert.ToString((int)desHeight) + "\" ";
}
return strResult;
}
希望本文所述对大家JavaScript程序设计有所帮助。