sketchpad.cpp

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#include "canvas.h"

// illustrates MKAdapter with SketchAnEtch (stealing shamelessly
// from EtchASketch, a trademarked product)

class SketchPad : public MKAdapter
{
  public:
    
    SketchPad(const Point& start);   // begin to draw at start
    void processKey(const Key& key, AnimatedCanvas& c);
   
  private:
    static const int DELTA;          // each key click moves this amount
    Point myPoint;                   // current point in drawing
};

const int SketchPad::DELTA = 2;
SketchPad::SketchPad(const Point& start)
  : myPoint(start)
{

}

void SketchPad::processKey(const Key& key, AnimatedCanvas& c)
// post: line drawn from oldpoint to newpoint in given direction
//       specified by key (arrow key)
{
    Point newPoint = myPoint;
    
    if (key.isuparrow())
    {   newPoint.y -= DELTA;
    }
    else if (key.isdownarrow())
    {   newPoint.y += DELTA;
    }
    else if (key.isleftarrow())
    {   newPoint.x -= DELTA;
    }
    else if (key.isrightarrow())
    {   newPoint.x += DELTA;
    }
    c.DrawLine(myPoint,newPoint);
    myPoint = newPoint;
}

int main()
{
    const int WIDTH=200, HEIGHT=200;
    Canvas c(WIDTH,HEIGHT,20,20);     // double buffering off
    c.SetColor(CanvasColor::BLACK);
    c.SetTitle("Tapestry SketchAnEtch");
    
    SketchPad sp = SketchPad(Point(WIDTH/2,HEIGHT/2)); // start in middle
    c.addShape(sp); 
    c.runUntilEscape(10);
    
    return 0;
}