? 從www.infoq.com上看到一篇文章,講的是一個(gè)高效程序員五個(gè)好習(xí)慣,特摘錄如下:
1.Constructor Performs Minimal Work(不要讓構(gòu)造函數(shù)太累著)
2.Methods Clearly Convey Their Intent(人如其名)
3.An Object Performs a Focused Set of Services(不要狗拿耗子多管閑事)
?? how to categorize these object is worthy of considering.(entity object,service object,facade object)
4.State-Changing Methods Contain Minimal Behavior Logic(是非分明,不要糾纏不清)
?? determine the boundary is a litttle difficult.
5.Behavior Methods Can Be Called in Any Order(讓依賴(lài)離我們遠(yuǎn)點(diǎn))
?? 個(gè)人覺(jué)得3,4,5體現(xiàn)的是如何劃分領(lǐng)域模型和領(lǐng)域?qū)ο舐氊?zé)劃分的問(wèn)題.我想Martin flower的SRP應(yīng)該是我們應(yīng)該遵守的原則之一.其它的暫時(shí)沒(méi)有想到啊,大家有建議么?

前幾天到網(wǎng)上搜了一個(gè)用來(lái)縮放圖片的程序,結(jié)果發(fā)現(xiàn)有時(shí)候圖片會(huì)變的很小,要重新刷新一下才會(huì)變成合適的大小,覺(jué)得很納悶,也沒(méi)找出原因.干脆就又到網(wǎng)上搜了一個(gè),這次是老外寫(xiě)的一個(gè),感覺(jué)代碼少了好多,效果還不錯(cuò),代碼如下: 原來(lái)的:
function drawImage(imgD, maxW, maxH) {
? if(!imgD)return; var image = new Image();
? image.src = imgD.src;
? var dW=imgD.width;
? var dH=imgD.height;
? if(dW>maxW||dH>maxH){
? ? var rationW=dW/maxW;
? ? var rationH=dH/maxH;
??? if(rationW<rationH)rationW=rationH;
??? dW=dW/rationW;
??? dH=dH/rationW;
??? if(dW>0&&dH>0){
? ? ? imgD.width=dW; imgD.height=dH;
? }
}
新搜到的:
function scaleImage(img,v) {
?? if(!img)return;
?? floorSize = .26;
?? ceilingSize = 1.0;
?? v = floorSize + (v * (ceilingSize - floorSize));
?? img.style.width = (v*190)+'px';
}
綜合一下,得到:
function scaleImage(img,maxW,maxH) {
??? if (!img) return;
??? var dW=img.width;
??? var dH=img.height;
??? if(dW>maxW||dH>maxH){
????? var rationW=dW/maxW;
????? var rationH=dH/maxH;
????? if(rationW<rationH)rationW=rationH;
??? ? dW=dW/rationW;
??? ? dH=dH/rationW;
??? ? if(dW>0&&dH>0){
??? ??? ?img.style.width =dW+"px";
??? ??? ?img.style.height =dH+"px";
??? ? }
??? }
}