ixels_j] == 1) {
            pixel_field.data[i + 0] = 0xAA;
            pixel_field.data[i + 1] = 0xAA;
            pixel_field.data[i + 2] = 0xFF;
            pixel_field.data[i + 3] = 0xFF;
        }else{
            pixel_field.data[i + 0] = 0;
            pixel_field.data[i + 1] = 0;
            pixel_field.data[i + 2] = 0;
            pixel_field.data[i + 3] = 0;
        }
    }
    context.putImageData(pixel_field, -0.5, -0.5);
    
    // pixel grid
    context.beginPath();
    for(var i = pixel_siz