Coding a Renderer

As with many of the classes in this chapter, Renderer will be very similar to the earlier project, so we can zip through it and move on.

Create a new class called Renderer then add the following members and constructor.

class Renderer {
    private Canvas mCanvas;
    private SurfaceHolder mSurfaceHolder;
    private Paint mPaint;

    // Here is our new camera
    private Camera mCamera;

    Renderer(SurfaceView sh, Point screenSize){
        mSurfaceHolder = sh.getHolder();
        mPaint = new Paint();

        // Initialize the camera
        mCamera = new Camera(screenSize.x, screenSize.y);
    }
}

The Renderer has the Canvas, SurfaceHolder and Paint instances as we have come to expect. It also has a Camera instance called mCamera. We at last get to code the Camera class when we are done with Renderer.

In the constructor the SurfaceHolder, Paint and Camera instances are initialized.

Now add the getPixelsPerMetre and draw methods.

int getPixelsPerMetre(){
   return mCamera...