The images are generated as transparent png – you can style their color scheme via renderVisualAdviceImage – it should be something similar to the following:
public void onVisualAdviceChanged(final boolean firstVisualAdviceChanged, final boolean secondVisualAdviceChanged,
final SKNavigationState navigationState) {
if (firstVisualAdviceChanged) {
SKCrossingDescriptor currentImageCrossingDescriptor =
navigationState.getFirstCrossingDescriptor();
String currentVisualAdviceImage = "[base path of map resouces]/current_advice_image.png";
final SKVisualAdviceColor firstVisualAdviceColor = new SKVisualAdviceColor();
firstVisualAdviceColor.setAllowedStreetColor(new
float[]{0.2f, 0.2f, 0.2f, 0.4f});
firstVisualAdviceColor.setForbiddenStreetColor(new
float[]{0.2f, 0.2f, 0.2f, 0.7f});
firstVisualAdviceColor.setRouteStreetColor(new
float[]{0.2f, 0.2f, 0.2f, 1});
SKNavigationManager.getInstance().renderVisualAdviceImage(currentImageCrossingDescriptor,
currentVisualAdviceImage, firstVisualAdviceColor);
}
Where the array expected by SKVisualAdviceColor is made of 0 to 1 values matched to red/green/blue/alpha values.