Extra large (256x256) icon shortcut to the control panel applet (CPL) ?

[Maxwell Chen]

We have the extra large icon view (256 x 256) since Windows Vista. Now I have a control panel applet running under Win7 and Vista. I have added the icon resources with images of size 256 x 256 into the CPL. But the shortcut (on the Desktop) to this CPL applet does not display the icon correctly. It is said that assigning the value CPL_DYNAMIC_RES for the idIcon member of CPLINFO structure in the CPL_INQUIRE message handler triggers Windows to send a CPL_NEWINQUIRE message. And then we assign the hIcon member of NEWCPLINFO in the CPL_NEWINQUIRE message handler for the icon information. But no matter AfxGetApp()->LoadIcon or ::LoadImage (even with the LR_DEFAULTSIZE flag) fails to make the icon image of the shortcut on the Desktop display the correct sized image. Does anyone know the correct way to handle the CPL_INQUIRE and CPL_NEWINQUIRE to make it display 256 x 256 image for the shortcut on the Desktop? Thanks in advance.

Maxwell Chen

[Maxwell Chen]

The root cause is in the ico file. Do not use PNG (do not compress) for the 256 x 256 and 128 x 128 frames. Use BMP (uncompressed) instead. And the issue is resolved.

Maxwell Chen