* Unexpected result when using PaperHeight and MetaFUun
@ 2020-04-19 11:15 Keith McKay
2020-04-19 12:04 ` Wolfgang Schuster
0 siblings, 1 reply; 3+ messages in thread
From: Keith McKay @ 2020-04-19 11:15 UTC (permalink / raw)
To: mailing list for ConTeXt users
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Dear All
I have problem understanding what is happening in the MWE below which is
different from what I expected.
I have created a shaded background using MetaFun with dimensions
PaperWidth by PaperHeight which mimics \setuppapersize[A4,landscape} as
expected. I then within \starttext \startMPpage... \stopMPpage
\stoptext created a stripe of the shaded background, xscaled 2cm y
scaled PaperHeight, but reversed, expecting it to cover the background
top to bottom. However the top of the stripe seems to start at 10.5cm
which is suspiciously half the height of A4, Landscape i.e. 21cm. I
confirmed this by changing the shifted command to, shifted
(19cm,10.5cm), and the stripe is positioned as expected.
Am I missing something obvious in how MetaFun handles coordinates? I
have asumed that in MetaFun, (0,0) is the bottom left corner. Or is it
how I applied the shifted command?
I'm using LuaMetaTex Version 2.05.01 ConTeXt ver: 2020.04.03 10:31 MKIV
beta fmt: 2020.4.6 int: english/english
Thanks and stay safe.
Best Wishes
Keith McKay
%%%%%%%%%%% MWE %%%%%%%%%%%%%%% \setuppapersize[A4,landscape]
\definelayer[mybg]
[x=0mm, y=0mm,
width=\paperwidth, height=\paperheight] % let the layer cover the full paper
\startuniqueMPgraphic{blueShade}
draw lmt_shade [
path = fullsquare xyscaled(PaperWidth,PaperHeight),
direction = "up",
alternative = "linear",
colors = { "red", "blue" },
];
\stopuniqueMPgraphic
\setlayer[mybg]{\uniqueMPgraphic{blueShade}}
\setupbackgrounds[page][background={mybg}]
\starttext
\startMPpage
StartPage ;
%Result Left
draw lmt_shade [
path = fullsquare xscaled 2cm yscaled PaperHeight,
direction = "down",
alternative = "linear",
colors = { "red", "blue" },
]shifted (12cm,0cm);
%Result Right
draw lmt_shade [
path = fullsquare xscaled 2cm yscaled PaperHeight,
direction = "down",
alternative = "linear",
colors = { "red", "blue" },
] shifted (19cm,10.5cm);
StopPage ;
\stopMPpage
\stoptext
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___________________________________________________________________________________
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___________________________________________________________________________________
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: Unexpected result when using PaperHeight and MetaFUun
2020-04-19 11:15 Unexpected result when using PaperHeight and MetaFUun Keith McKay
@ 2020-04-19 12:04 ` Wolfgang Schuster
2020-04-19 12:21 ` Keith McKay
0 siblings, 1 reply; 3+ messages in thread
From: Wolfgang Schuster @ 2020-04-19 12:04 UTC (permalink / raw)
To: mailing list for ConTeXt users, Keith McKay
Keith McKay schrieb am 19.04.2020 um 13:15:
> Dear All
>
> I have problem understanding what is happening in the MWE below which is
> different from what I expected.
>
> I have created a shaded background using MetaFun with dimensions
> PaperWidth by PaperHeight which mimics \setuppapersize[A4,landscape} as
> expected. I then within \starttext \startMPpage... \stopMPpage
> \stoptext created a stripe of the shaded background, xscaled 2cm y
> scaled PaperHeight, but reversed, expecting it to cover the background
> top to bottom. However the top of the stripe seems to start at 10.5cm
> which is suspiciously half the height of A4, Landscape i.e. 21cm. I
> confirmed this by changing the shifted command to, shifted
> (19cm,10.5cm), and the stripe is positioned as expected.
>
> Am I missing something obvious in how MetaFun handles coordinates? I
> have asumed that in MetaFun, (0,0) is the bottom left corner. Or is it
> how I applied the shifted command?
1. When you need page backgrounds you can use a overlay and don't have
to create a layer for it.
2. Use unitsquare for your bars which has the origin in the lower left
corner because fullsquare has the origin in the center (look at page 383
in the metafun manual).
\setuppapersize [A4,landscape]
\startuniqueMPgraphic{blueShade}
draw lmt_shade [
path = fullsquare xyscaled (OverlayWidth,OverlayHeight) ,
direction = "up",
alternative = "linear",
colors = { "red", "blue" },
] ;
\stopuniqueMPgraphic
\defineoverlay [mybg] [\uniqueMPgraphic{blueShade}]
\setupbackgrounds [page] [background=mybg]
\starttext
\startMPpage
StartPage ;
% Result Left
draw lmt_shade [
path = unitsquare xscaled 2cm yscaled PaperHeight,
direction = "down",
alternative = "linear",
colors = { "red", "blue" },
] shifted (12cm,0) ;
% Result Right
draw lmt_shade [
path = unitsquare xscaled 2cm yscaled PaperHeight,
direction = "down",
alternative = "linear",
colors = { "red", "blue" },
] shifted (19cm,0cm) ;
StopPage ;
\stopMPpage
\stoptext
Wolfgang
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!
maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage : http://www.pragma-ade.nl / http://context.aanhet.net
archive : https://bitbucket.org/phg/context-mirror/commits/
wiki : http://contextgarden.net
___________________________________________________________________________________
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: Unexpected result when using PaperHeight and MetaFUun
2020-04-19 12:04 ` Wolfgang Schuster
@ 2020-04-19 12:21 ` Keith McKay
0 siblings, 0 replies; 3+ messages in thread
From: Keith McKay @ 2020-04-19 12:21 UTC (permalink / raw)
To: Wolfgang Schuster, mailing list for ConTeXt users
Thank you Wolfgang!
I thought it must be simple! And if I had stayed the course and got to
the end of the MetaFun manual I would have found it.
Thanks for your help.
Keith
On 19/04/2020 13:04, Wolfgang Schuster wrote:
> Keith McKay schrieb am 19.04.2020 um 13:15:
>> Dear All
>>
>> I have problem understanding what is happening in the MWE below which
>> is different from what I expected.
>>
>> I have created a shaded background using MetaFun with dimensions
>> PaperWidth by PaperHeight which mimics \setuppapersize[A4,landscape}
>> as expected. I then within \starttext \startMPpage... \stopMPpage
>> \stoptext created a stripe of the shaded background, xscaled 2cm y
>> scaled PaperHeight, but reversed, expecting it to cover the
>> background top to bottom. However the top of the stripe seems to
>> start at 10.5cm which is suspiciously half the height of A4,
>> Landscape i.e. 21cm. I confirmed this by changing the shifted command
>> to, shifted (19cm,10.5cm), and the stripe is positioned as expected.
>>
>> Am I missing something obvious in how MetaFun handles coordinates? I
>> have asumed that in MetaFun, (0,0) is the bottom left corner. Or is
>> it how I applied the shifted command?
>
> 1. When you need page backgrounds you can use a overlay and don't have
> to create a layer for it.
>
> 2. Use unitsquare for your bars which has the origin in the lower left
> corner because fullsquare has the origin in the center (look at page
> 383 in the metafun manual).
>
> \setuppapersize [A4,landscape]
>
> \startuniqueMPgraphic{blueShade}
> draw lmt_shade [
> path = fullsquare xyscaled (OverlayWidth,OverlayHeight) ,
> direction = "up",
> alternative = "linear",
> colors = { "red", "blue" },
> ] ;
> \stopuniqueMPgraphic
>
> \defineoverlay [mybg] [\uniqueMPgraphic{blueShade}]
>
> \setupbackgrounds [page] [background=mybg]
>
> \starttext
>
> \startMPpage
> StartPage ;
> % Result Left
> draw lmt_shade [
> path = unitsquare xscaled 2cm yscaled PaperHeight,
> direction = "down",
> alternative = "linear",
> colors = { "red", "blue" },
> ] shifted (12cm,0) ;
> % Result Right
> draw lmt_shade [
> path = unitsquare xscaled 2cm yscaled PaperHeight,
> direction = "down",
> alternative = "linear",
> colors = { "red", "blue" },
> ] shifted (19cm,0cm) ;
> StopPage ;
> \stopMPpage
>
> \stoptext
>
> Wolfgang
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!
maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage : http://www.pragma-ade.nl / http://context.aanhet.net
archive : https://bitbucket.org/phg/context-mirror/commits/
wiki : http://contextgarden.net
___________________________________________________________________________________
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-04-19 11:15 Unexpected result when using PaperHeight and MetaFUun Keith McKay
2020-04-19 12:04 ` Wolfgang Schuster
2020-04-19 12:21 ` Keith McKay
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