整理代码，较复杂的单行if-then-end拆成多行

parts/backgrounds/welcome.lua

@@ -4,10 +4,10 @@ local sin=math.sin
 local back={}
 
 local t
-local txt
+local textObj
 function back.init()
     t=math.random()*2600
-    txt=gc.newText(getFont(80),"Welcome To Techmino")
+    textObj=gc.newText(getFont(80),"Welcome To Techmino")
 end
 function back.update(dt)
     t=t+dt
@@ -21,7 +21,7 @@ function back.draw()
     gc.push('transform')
     gc.translate(SCR.cx,SCR.cy+20*sin(t*.02))
     gc.scale(SCR.k)
-    gc.scale(1.1626,1.26)
+    gc.scale(1.26,1.36)
     if -t%6.26<.1355 then
         gc.translate(60*sin(t*.26),100*sin(t*.626))
     end
@@ -29,11 +29,11 @@ function back.draw()
         gc.rotate(t+5*sin(.26*t)+5*sin(.626*t))
     end
     gc.setColor(.4,.6,1,.3)
-    gc.draw(txt,-883*.5+4*sin(t*.7942),-110*.5+4*sin(t*.7355))
+    mDraw(textObj,4*sin(t*.7942),4*sin(t*.7355))
     gc.setColor(.5,.7,1,.4)
-    gc.draw(txt,-883*.5+2*sin(t*.77023),-110*.5+2*sin(t*.7026))
+    mDraw(textObj,2*sin(t*.77023),2*sin(t*.7026))
     gc.setColor(1,1,1,.5)
-    gc.draw(txt,-883*.5+3*sin(t*.7283),-110*.5+3*sin(t*.7626))
+    mDraw(textObj,3*sin(t*.7283),3*sin(t*.7626))
     gc.pop()
 end
 return back