常用函數

本文收集常用的函數。

一、等比縮放函數。

/*
×××等比縮放函數×××，9種判斷條件
xh:新高
xw:新寬
oldH:容高
oldW:容寬
LoadImgH:原高
LoadIngW:原寬
*/
function Scale() {
  if (LoadImgH == oldH && LoadImgW == (oldW/2)) {//1.正常顯示
    xh = LoadImgH;
    xw = LoadImgW;
  }
  if (LoadImgH == oldH && LoadImgW>(oldW/2)) {//2、原高==容高，原寬>容寬 以原寬爲基礎
    xw = (oldW/2);
    xh = LoadImgH*xw/LoadImgW;
  }
  if (LoadImgH == oldH && LoadImgW<(oldW/2)) {//3、原高==容高，原寬<容寬  正常顯示    
    xw = LoadImgW;
    xh = LoadImgH;
  }
  if (LoadImgH>oldH && LoadImgW == (oldW/2)) {//4、原高>容高，原寬==容寬 以原高爲基礎    
    xh = oldH;
    xw = LoadImgW*xh/LoadImgH;
  }
  if (LoadImgH>oldH && LoadImgW>(oldW/2)) {//5、原高>容高，原寬>容寬            
    if ((LoadImgH/oldH)>(LoadImgW/(oldW/2))) {//原高大的多，以原高爲基礎
      xh = oldH;
      xw = LoadImgW*xh/LoadImgH;
    } else {//以原寬爲基礎
      xw = (oldW/2);
      xh = LoadImgH*xw/LoadImgW;
    }
  }
  if (LoadImgH>oldH && LoadImgW<(oldW/2)) {//6、原高>容高，原寬<容寬 以原高爲基礎        
    xh = oldH;
    xw = LoadImgW*xh/LoadImgH;
  }
  if (LoadImgH<oldH && LoadImgW == (oldW/2)) {//7、原高<容高，原寬=容寬 正常顯示        
    xh = LoadImgH;
    xw = LoadImgW;
  }
  if (LoadImgH<oldH && LoadImgW>(oldW/2)) {//8、原高<容高，原寬>容寬 以原寬爲基礎    
    xw = (oldW/2);
    xh = LoadImgH*xw/LoadImgW;
  }
  if (LoadImgH<oldH && LoadImgW<(oldW/2)) {//9、原高<容高，原寬<容寬//正常顯示    
    xh = LoadImgH;
    xw = LoadImgW;
  }
}