AS3/ AIR Alternative to PrevFrame() (too slow if big movieclip)

Question

I'm having a problem with prevFrame(). In my previous projects, I never had a trouble with it (usage is pretty straightforward), but this one... I don't understand. Everything does what it needs to do, but when I try to go to the prevFrame of my "main movieclip", it takes ages. Some context: I'm making a dictionary for an ancient language (non-latin alphabet). There are 6.000 glyphs so I had to find a way to make such a complex "keyboard".

var gArray: Array = [gEmpty, clavierUI.g1, clavierUI.g2, clavierUI.g3, (...)
    clavierUI.g50
]; //array contaning the buttons for the keyboard (50 instances of the same
//movieclip. This movieclip is made of 6.000 frames, each containing a 
//glyph), the fnClavier function makes each of the fifty instances go to its
//respective frame)


var myXML2: XML = new XML();
var XML_URL2: String = "assets/glyphs.xml";
var myXMLURL2: URLRequest = new URLRequest(XML_URL2);
var myLoader2: URLLoader = new URLLoader(myXMLURL2);
myLoader2.addEventListener("complete", xmlLoaded2);
//import the codename for each glyph

function xmlLoaded2(event: Event): void {
    myXML2 = XML(myLoader2.data);
}

var xml2: XMLList = myXML2.glyph.code;

function fnClavier(e: Event): void { //transforms the keyboard
    for each(var glyph: MovieClip in gArray) { 
        glyph.gotoAndStop(gArray.indexOf(glyph) + (50 * (clavierUI.currentFrame - 1))); 
//the seconde half (50 * (...) -1))) can be explained like that : 
//50 = 50 keys by keyboard "page".
// clavier.currentFrame - 1 = modifier, tells which set of the 6000 glyphs 
//needs to appear (and later, correspond with the codename from xml)
    }
}

clavierUI.nextPage.addEventListener(MouseEvent.CLICK, fnNextPage);
function fnNextPage(e: Event): void {
    clavierUI.nextFrame(); //no problem here, goes fast.
    fnClavier(null);
}

clavierUI.prevPage.addEventListener(MouseEvent.CLICK, fnPrevPage);
function fnPrevPage(e: Event): void {
    clavierUI.prevFrame(); //takes about 20secondes to go back.
    fnClavier(null);
}

My code is probably far from being perfect (i'm still learning), but I don't know why it wouldn't work. Jumping around the frames and going to the next works perfectly, so anyone know why going back one frame takes forever? Thank you.

Answer 1

You'd better use containers instead of frames. Frames get constructed and deconstructed each time you move between keyframes, while you con construct all the containers once and then display them as needed, one container at a time. I expect that Flash has optimization somewhere that constructs the next frame prior to it being shown via nextFrame() while an abrupt calling of prevFrame() forces Flash to construct it at once, and if it's very complex, it can take a lot of time.

You have 6000 glyphs? That's a lot, but not too much. You can create a set of containers, each holding 120 glyphs, for example. To do that, you create an array of Sprites, each having a grid of glyphs 12x10, there will be 50 of these. Then, when you need another page, display another sprite from the array. Also, if your glyph is a static vector object, you should convert it to vector graphics, and add as library item (Shape descendant, these eat less memory). If it's raster, use Bitmap and underlying BitmapData classes to use them.