On Thu, 1 May 2014, Mikael P. Sundqvist wrote:
\startluacode
userdata = userdata or {}
function userdata.lundklippfyllbild(str, bredd, hojd)
if tex.dimen[0] / tex.dimen[2] < tex.dimen[4] / tex.dimen[6] then
local skalning =
-0.5*(tex.dimen[4]/tex.dimen[0]*tex.dimen[2]-tex.dimen[6])
context("\\vskip%ssp", skalning)
context.externalfigure({str},{width=bredd})
context.sprint("foo")
else
local skalning =
-0.5*(tex.dimen[6]/tex.dimen[2]*tex.dimen[0]-tex.dimen[4])
context("\\hskip%ssp", skalning)
context.externalfigure({str},{height=hojd})
context.sprint("bar")
end
end
\stopluacode
\unexpanded\def\lundklippfyllbild#1#2#3{%
\startexternalfigurecollection[#1]%
\useexternalfigure[#1][#1]%
\stopexternalfigurecollection%
\clip[
width=#2,
height=#3,
hoffset=0mm,
voffset=0mm,
]{%
\framed[width=#2,height=#3,align={middle,lohi},offset=overlay,frame=off]{%
\dimen0=\externalfigurecollectionminwidth{#1}%
\dimen2=\externalfigurecollectionmaxheight{#1}%
\dimen4=#2%
\dimen6=#3%
{\ctxlua{userdata.lundklippfyllbild([==[#1]==],[==[#2]==],[==[#3]==])}}}}}
and then run
\lundklippfyllbild{k.jpg}{\textwidth}{\textheight}
Here is an eTeX solution.
\unprotect
\newdimen\d_scaleandclip_actual_wd
\newdimen\d_scaleandclip_actual_ht
\newdimen\d_scaleandclip_requested_wd
\newdimen\d_scaleandclip_requested_ht
\newbox\scaleandclip_box
\installnamespace{scaleandclip}
\installcommandhandler \????scaleandclip {scaleandclip} \????scaleandclip
\setupscaleandclip
[width=\textwidth,
height=\textheight]
\unexpanded\def\scaleandclip{\dodoubleempty\doscaleandclip}
\def\doscaleandclip[#1][#2]%
{\bgroup
\ifsecondargument
\edef\currentscaleandclip{#1}%
\setupcurrentscaleandclip[#2]%
\else\iffirstargument
\doifassignmentelse{#1}
{\let\currentscaleandclip\empty
\setupcurrentscaleandclip[#1]}
{\edef\currentscaleandclip{#1}}
\else
\let\currentscaleandclip\empty
\fi\fi
\dowithnextboxcs\scaleandclip_finish\hbox}
\def\scaleandclip_finish
{%
\d_scaleandclip_requested_wd \dimexpr\scaleandclipparameter\c!width\relax
\d_scaleandclip_requested_ht \dimexpr\scaleandclipparameter\c!height\relax
%
\d_scaleandclip_actual_wd\wd\nextbox
\d_scaleandclip_actual_ht\dimexpr\ht\nextbox + \dp\nextbox\relax
%
\ifdim\dimexpr\d_scaleandclip_actual_wd*100/\d_scaleandclip_requested_wd <
\dimexpr\d_scaleandclip_actual_ht*100/\d_scaleandclip_requested_ht
\relax
\setbox\scaleandclip_box\hbox
{\scale[\c!width=\d_scaleandclip_requested_wd]{\box\nextbox}}%
\scratchdimen=\the\dimexpr(\ht\scaleandclip_box -
\d_scaleandclip_requested_ht)/2\relax
\clip
[
\c!voffset=\scratchdimen,
\c!height=\d_scaleandclip_requested_ht,
]{\box\scaleandclip_box}%
\else
\setbox\scaleandclip_box\hbox
{\scale[\c!height=\d_scaleandclip_requested_ht]{\box\nextbox}}%
\scratchdimen=\the\dimexpr(\wd\scaleandclip_box -
\d_scaleandclip_requested_wd)/2\relax
\clip
[
\c!hoffset=\scratchdimen,
\c!width=\d_scaleandclip_requested_wd,
]{\box\scaleandclip_box}%
\fi
\egroup}
\protect
The usage is:
\scaleandclip[width=..., height=...]{ ... any box ...}
simimlar to the usage of \scale macro.
\starttext
\dontleavehmode
\scaleandclip[width=3cm,
height=3cm]{\externalfigure[cow.pdf][width=3cm,frame=on]}
\scale[maxwidth=3cm,
maxheight=3cm]{\externalfigure[cow.pdf][width=3cm,frame=on]}
\dontleavehmode
\scaleandclip[width=3cm,
height=3cm]{\externalfigure[cow.pdf][width=3cm,height=10cm,frame=on]}
\scale[maxwidth=3cm,
maxheight=3cm]{\externalfigure[cow.pdf][width=3cm,height=10cm,frame=on]}
\dontleavehmode
\scaleandclip[width=3cm,
height=3cm]{\externalfigure[cow.pdf][width=10cm,height=3cm,frame=on]}
\scale[maxwidth=3cm,
maxheight=3cm]{\externalfigure[cow.pdf][width=10cm,height=3cm,frame=on]}
\stoptext
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