Working with Layers
Take the following steps to show/hide layers from a vector drawing:
Start with the project you created in Implementing Hit Testing.
1. |
Add these local variables under the HDC hDC; statement in the WndProc function: |
L_INT nIndex;
VECTORLAYER Layer;
VECTORLAYERDESC LayerDesc;
2. |
Add the following lines in WM_CREATE handler right after L_VecInit ( &Vector ); statement: |
L_VecLoadFile ( TEXT("C:\\Program Files\\LEAD Technologies\\LEADTOOLS EVAL 15\\Images\\random.dxf"), &Vector, NULL, NULL );
3. |
Add the following lines before the case 'x' statement of the WM_CHAR message: |
case '1':
case '2':
// get layer from index
if( wParam == '1' )
nIndex = 0;
else
nIndex = 1;
L_VecGetLayerByIndex ( &Vector, nIndex, &Layer );
L_VecGetLayer ( &Vector, &Layer, &LayerDesc );
// flip the visible state of the layer
LayerDesc.bVisible = !LayerDesc.bVisible;
// update
L_VecSetLayer ( &Vector, &Layer, &LayerDesc );
L_VecFreeLayer ( &LayerDesc );
InvalidateRect( hWnd, NULL, FALSE );
break;
4. |
Compile and run the demo. |
5. |
The sample image (random.dxf) shipped with LEADTOOLS has 2 layers. You should be able to hide/show those layers by pressing 1 and 2 on your keyboard. |