Proportional adaptation, leaving black bars

var ratio:Number=designW/designH;

var sx:Number=stageWidth/designW;
var sy:Number=stageHeight/designH;
var scale:Number=Math.min(sx,sy);//取min所有内容一定显示在舞台内，取max就会拉伸超出
sprite.scaleX=scale;
sprite.scaleY=scale;

//sprite以左上角为注册点,坐标为(0,0)
//居中
sprite.x=(stageWidth-designW*scale)*0.5;
sprite.y=(stageHeight-designH*scale)*0.5;

If designW = 960, designH = 640, then the sprite can be displayed in the high 960 also preferably wide sprite can be displayed on the wide viewing screen may be