Program received signal SIGSEGV, Segmentation fault.
0x408cf747 in _pixmap_combine_alpha (context=0x824af28, source_im=0x8575ae8, 
    source_alpha=0x8433ce8, dest_im=0x84fbed0, dest_alpha=0x84e9f18, srect={
      x = 0, y = 0, width = 254, height = 162}, op=NSCompositeSourceOver, 
    drawMechanism=XGDM_FAST32, fraction=1) at XGBitmap.m:153
153                   pixel = XGetPixel(source_im->image, 
(gdb) backtrace
#0  0x408cf747 in _pixmap_combine_alpha (context=0x824af28, 
    source_im=0x8575ae8, source_alpha=0x8433ce8, dest_im=0x84fbed0, 
    dest_alpha=0x84e9f18, srect={x = 0, y = 0, width = 254, height = 162}, 
    op=NSCompositeSourceOver, drawMechanism=XGDM_FAST32, fraction=1)
    at XGBitmap.m:153
#1  0x408e327f in _i_XGGState___compositeGState_fromRect_toPoint_op_fraction_ (
    self=0x84fabc0, _cmd=0x40916910, source=0x84fb740, fromRect={origin = {
        x = 0, y = 0}, size = {width = 253.000015, height = 162.482224}}, 
    toPoint={x = 1.99999237, y = 36.2588882}, op=NSCompositeSourceOver, 
    delta=1) at XGGState.m:599
#2  0x408e3be3 in _i_XGGState__compositeGState_fromRect_toPoint_op_ (
    self=0x84fabc0, _cmd=0x40913da0, source=0x84fb740, aRect={origin = {x = 0, 
        y = 0}, size = {width = 253.000015, height = 162.482224}}, aPoint={
      x = 1.99999237, y = 36.2588882}, op=NSCompositeSourceOver)
    at XGGState.m:745
#3  0x408df689 in _i_XGContext_Ops_DPScomposite________ (self=0x821b950, 
    _cmd=0x402e85c8, x=0, y=0, w=253.000015, h=162.482224, gstateNum=37, 
    dx=1.99999237, dy=36.2588882, op=2) at XGContext.m:1939
#4  0x4014562a in DPScomposite (ctxt=0x821b950, x=0, y=0, w=253.000015, 
    h=162.482224, gstateNum=37, dx=1.99999237, dy=36.2588882, op=2)
    at ../Headers/AppKit/DPSOperators.h:2169
#5  0x4014555a in PScomposite (x=0, y=0, w=253.000015, h=162.482224, 
    gstateNum=37, dx=1.99999237, dy=36.2588882, op=2)
    at ../Headers/AppKit/PSOperators.h:1787
#6  0x40141a33 in _i_NSImage__compositeToPoint_fromRect_operation_ (
    self=0x846c2f0, _cmd=0x402e8b78, aPoint={x = 1.99999237, y = 36.2588882}, 
    aRect={origin = {x = 0, y = 0}, size = {width = 253.000015, 
        height = 162.482224}}, op=NSCompositeSourceOver) at NSImage.m:684
#7  0x401416cc in _i_NSImage__compositeToPoint_operation_ (self=0x846c2f0,