Question

Is there an example of a bitmap color replacement implementation that actually works?

I’m trying to achieve the following:

Before:

After:

Note: I’m not trying to use a color matrix transformation here. I want the ability to select 1 color, then select a threshold, and then select a new color which would effectively shift all the colors in the threshold.

Is this idea possible to execute very accurately? If so can you point me to a proof-of-concept?

Answer 1

Just to get the ball rolling on this… I don’t know that this is going to be the right solution for you but it’s a start.

This answer shows how to use the BitmapData.threshold method to replace colors. You could replace a color with a transparent pixel, then put a background behind your MovieClip and animate between colors.

var inputBitmapData:BitmapData = new BitmapData(200, 200, true, 0xFF0000FF);
inputBitmapData.fillRect(new Rectangle(10, 10, 180, 180), 0xFFFF0000);

var outputBitmapData:BitmapData = new BitmapData(200, 200, true); 
var destPoint:Point = new Point(0, 0); var sourceRect:Rectangle = new Rectangle(0, 0, outputBitmapData.width, outputBitmapData.height); 
var threshold:uint =  0xFFFF0000;  
var color:uint = 0x00000000;     
outputBitmapData.threshold(inputBitmapData, sourceRect, destPoint, "==", threshold, color, 0xFFFFFFFF, true);

var input:Bitmap = new Bitmap(inputBitmapData); addChild(input);
var output:Bitmap = new Bitmap(outputBitmapData); output.x = input.x + input.width + 10; 

addChild(output);

You could also loop through the bitmapdata pixel by pixel to replace one color with another.

for (var j = 0; j < bitmap.height; j++) {
    for (var i = 0; i < bitmap.width; i++) {
        if(bitmapData.getPixel(i,j)==0xFFFF00)  {
            bitmapData.setPixel(i,j, 0xFF0000);
        }
    }
}