Transformation

To add scale, rotation and translation to a sample program

Start with the project you created in Vector Load and Save.

1. Add this local variable under L_INT nRet; in the WndProc function:

   VECTORPOINT Point; 

2. Add these cases under the WM_COMMAND case:

   case WM_CHAR: 
   switch( wParam ) 
   { 
      case 'x': 
      case 'X': 
      case 'y': 
      case 'Y': 
      case 'z': 
      case 'Z': 
      // get current rotation value 
      L_VecGetRotation ( &Vector, &Point ); 
      Point.x += ( wParam == 'x' || wParam == 'X' ) ? 5.0 : 0; 
      Point.y += ( wParam == 'y' || wParam == 'Y' ) ? 5.0 : 0; 
      Point.z += ( wParam == 'z' || wParam == 'Z' ) ? 5.0 : 0; 
      // set new rotation value 
      L_VecSetRotation ( &Vector, &Point, NULL, NULL, 0 ); 
      InvalidateRect( hWnd, NULL, FALSE ); 
      break; 
       
      case '+': 
      case '-': 
      // get current scale value 
      L_VecGetScale ( &Vector, &Point ); 
      Point.x += ( wParam == '+' ) ? 0.1 : -0.1; 
      Point.y += ( wParam == '+' ) ? 0.1 : -0.1; 
      Point.z += ( wParam == '+' ) ? 0.1 : -0.1; 
      // set new scale value 
      L_VecSetScale ( &Vector, &Point, NULL, NULL, 0 ); 
      InvalidateRect( hWnd, NULL, FALSE ); 
      break; 
   } 
   break; 
    
   case WM_KEYDOWN: 
   switch( wParam ) 
   { 
      case VK_UP: 
      case VK_DOWN: 
      case VK_LEFT: 
      case VK_RIGHT: 
      // get current translation 
      L_VecGetTranslation ( &Vector, &Point ); 
      if( wParam == VK_LEFT ) Point.x -= 1.0; 
         if( wParam == VK_RIGHT ) Point.x += 1.0; 
         if( wParam == VK_UP ) Point.y += 1.0; 
         if( wParam == VK_DOWN ) Point.y -= 1.0; 
         // set new translation value 
         L_VecSetTranslation ( &Vector, &Point, NULL, 0 ); 
      InvalidateRect( hWnd, NULL, FALSE ); 
      break; 
   } 
   break; 

3. Compile and run the demo.

4. Select File/Open from the program menu. Browse to C:\LEADTOOLS23\Resources\Images\random.dxf and click OK.

5. Now you should be able to rotate the vector drawing around any axis using the x, y and z keys on your keyboard and scale up and down using the + and keys.