Pasting image over lines in wx DC

I have the same code as wx Doodle pad in the wx demos.

I added a tool to paste images from the clipboard to the pad. us开发者_开发百科ing wx.DrawBitmap() function , but whenever i refresh the buffer .and call functions ( drawSavedLines and drawSavedBitmap) it keeps putting bitmap above line no matter what I did even if I called draw bitmap first and then draw lines.

Is there anyway to put a line above the bitmap?

Please inform me if I miss anything.