oimage.lib.js

asp的bbs程序

/*
  By Hangring
  #2008.08.04#
  ---
  <img>
*/

$Defined('oImage');
var oImage = {};
// 图片在容器内等比例缩放
// ow,oh图片原尺寸，dw,dh容器尺寸, mt顶部偏移量
oImage.Scale = function (ow, oh, dw, dh, mt) {
    var s = {w:0, h:0, mt:0};
    if (ow / oh > dw / dh) {
        if (ow > dw) {
            s.w = dw;
            s.h = dw / ow * oh;
            mt && (mt = (dh - dw / ow * oh) / 2);
        }
        else {
            s.w = ow;
            s.h = oh;
            mt && (mt = (dh - oh) / 2);
        }
    }
    else {
        if (oh > dh) {
            s.h = dh;
            s.w = dh / oh * ow;
        }
        else {
            s.w = ow;
            s.h = oh;
            mt && (mt = (dh - oh) / 2);
        }
    }
    mt && (s.mt = Math.floor(mt));
    return s;
}