Cfrgtkky

I want to have a letterhead format with the corporate logo at the very top of the paper. I have figured out how the fill the graphics with the full breadth of the page with the information on this webpage-
How to have a figure touch the edge of the page?.

documentclass{article}

usepackage{lipsum}

usepackage{graphicx}



begin{document}



%

newcommand{dimtorightedge}{%

  dimexprpaperwidth-1in-hoffset-oddsidemarginrelax}

%



begin{flushleft}

        mbox

        {%

            makebox[dimtorightedge]{}%

            makebox[0pt][r]

            {includegraphics[width=paperwidth]{logo}}%

        }

end{flushleft}



section{A test section}

lipsum[4]



end{document}

I got the result like this -

However I'm still struggling to align the top side of the graphics (logo) with the top edge of the paper.

Appreciate any help!

You need to raise the image into the upper margin. This can be done using raisebox. I used the layout package with the layout macro to display all length used by LaTeX to create the top of the page. The distance is 1in+voffset+topmargin+headheight+headsep. You need to use the optional argument to set the new height by subtracting that value from the original height, which is defined as height here. This also works if put into a header by simply removing headheight and headsep from the equation.

Of course you can also my adjustbox package to do all this with less code.

documentclass{article}

usepackage{lipsum}

usepackage{graphicx}

usepackage{adjustbox}





newcommand{dimtorightedge}{%

  dimexprpaperwidth-1in-hoffset-oddsidemarginrelax}



newcommand{dimtotop}{%

  dimexprheight-1in-voffset-topmargin-headheight-headseprelax}





begin{document}



clearpage

begin{flushleft}

        hbox

        {%

            makebox[dimtorightedge]{}%

            makebox[0pt][r]

            {raisebox{0pt}[dimtotop]{includegraphics[width=paperwidth]{example-image}}}%

        }

end{flushleft}



section{A test section}

lipsum[4]



clearpage

noindentadjustimage{width=paperwidth,

    lap={textwidth}{-1in-hoffset-ifoddpageoddsidemarginelseevensidemarginfi+.5paperwidth-.5width-csname @totalleftmarginendcsname}, % adjustbox version v1.2 2019/01/04 provides this as 'pagecenter' key

    set height=height-1in-voffset-topmargin-headheight-headsep}{example-image}



section{A test section}

lipsum[4]





end{document}