Best way to get the color where a mouse was clicked in AS3

Question

I have an image (mx) and i want to get the uint of the pixel that was clicked.

Any ideas?

Answer 1

Here's an even simpler implementation. All you do is take a snapshot of the stage using the draw() method of bitmapData, then use getPixel() on the pixel under the mouse. The advantage of this is that you can sample anything that's been drawn to the stage, not just a given bitmap.

import flash.display.Bitmap;
import flash.display.BitmapData;
import flash.events.*;

stage.addEventListener(MouseEvent.CLICK, getColorSample);

function getColorSample(e:MouseEvent):void {
    var bd:BitmapData = new BitmapData(stage.width, stage.height);
    bd.draw(stage);
    var b:Bitmap = new Bitmap(bd);
    trace(b.bitmapData.getPixel(stage.mouseX,stage.mouseX));
}

Hope this is helpful!

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Edit:

This edited version uses a single BitmapData, and removes the unnecessary step of creating a Bitmap. If you're sampling the color on MOUSE_MOVE then this is essential to avoid memory issues.

Note: if you're using a custom cursor sprite you'll have to use an object other than 'state' or else you'll be sampling the color of the custom sprite instead of what's under it.

import flash.display.Bitmap;
import flash.display.BitmapData;
import flash.events.*;

private var _stageBitmap:BitmapData;

stage.addEventListener(MouseEvent.CLICK, getColorSample);

function getColorSample(e:MouseEvent):void 
{
    if (_stageBitmap == null) {
        _stageBitmap = new BitmapData(stage.width, stage.height);
    }
    _stageBitmap.draw(stage);

    var rgb:uint = _stageBitmap.getPixel(stage.mouseX,stage.mouseY);

    var red:int =  (rgb >> 16 & 0xff);
    var green:int =  (rgb >> 8 & 0xff);
    var blue:int =  (rgb & 0xff);

    trace(red + "," + green + "," + blue);
}