On 2/23/2019 12:37 PM, Rudolf Bahr wrote:
On Sat, Feb 23, 2019 at 11:56:32AM +0100, Hans Hagen wrote:
On 2/23/2019 11:08 AM, Rudolf Bahr wrote:
On Fri, Feb 22, 2019 at 12:59:55PM +0100, Peter Münster wrote:
On Fri, Feb 22 2019, Rudolf Bahr wrote:
The picture sizes in px One gets by invoking for instance graphics Magick's
identify
in a lua program:
Or just img.scan():
\startluacode
local image = img.scan{filename = "my-image.jpg"}
logs.report("xsize", image.xsize)
logs.report("ysize", image.ysize)
\stopluacode
--
Peter
Hi Peter,
thank you for pointing to img.scan{}! It's indeed shorter than to invoke
Graphics Magick
in Lua. Remains the conversion of image sizes into pt. There is an example in
the chapter
"Calculations in Lua" in "https://wiki.contextgarden.net/Image_Placement"; (a
work in
progress). According to there it's necessary to know the resolution in order to
convert
image sizes from px to pt which at least I don't know. Mostly I can preset one
size of
a picture (say the width in pt) to be able to place it on a page and assuming
x-resolution = y-resolution and keeping width-to-height ratio I calculate the
missing
size (here the height in pt) in Lua by
picture-height-in-px
asked-picture-height-in-pt = preset-picture-width-in-pt * --------------------
picture-width-in-px
This is simple and normally it suffices for me.
Better use the built-in methods:
\starttext
\getfiguredimensions[t:/sources/mill.png]
(\figurewidth,\figureheight)
(\figurexsize,\figureysize)
\stoptext
as it prevents opening the files multiple times. It's also more futureproof.
Hans
Hi Hans,
I fear it doesn't work. I used the above code with a test-picture of mine
(in .png and .jpg version) and got:
(0sp,0sp)
(0,0)
Now I'm baffled what the explanation could be. Are "mill" or "cow" somehow
specially prepared? I used:
ConTeXt ver: 2018.03.16 22:20 MKIV beta fmt: 2018.3.21 and
getfiguredimensions[~/my-test-picture.png]
maybe the image is not found ... what if you replace the ~
--
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