[Solved] Shift image 1 pixel to the right, keep size

[ddrirc]

Hi, I'm trying to move all pixels (effectively the whole image) over by one pixel to the right and retain the original size of 120x150.

The below code does ALMOST what I want - it copies the image and moves it over a pixel, but it doesn't get rid of the original image pixels.

Code: Select all

convert test.png -alpha set \( +clone -crop  120x150+0+0 +repage \) \( -clone 0--1 -geometry +1+0 -composite \) -swap 0 +delete \( +clone -alpha opaque \) +swap +delete -gravity east -geometry +119+0 -compose DstOut -composite newtest.png

Any idea how I can fix (or simplify this) to move every pixel over 1 to the right while retaining the 120x150 original size/format?

Thanks!

What I ended up using in the end:

Code: Select all

convert -page +1+0 test.png -background none -flatten newtest.png

Much simpler Thanks, fmw42

[fmw42]

You can use -roll to shift the image to the right, but it will wrap the rightmost pixel to the left side. Is that what you want to happen? If not what do you want to be on the left side of the image? You can insert a color if you want using -compose over -composite.

see
http://www.imagemagick.org/script/comma ... eilg1#roll


Alternately, you can crop the image and just mosaic or flatten or composite over some background color or background image, which could be a color or the image itself. Mosaic will expand the canvas.

see
http://www.imagemagick.org/Usage/layers/#mosaic
http://www.imagemagick.org/Usage/layers/#flatten


Another approach is to use -virtual-pixel .... -define distort:viewport=... -distort SRT 0 to shift the image

The virtual-pixel setting will control what fills in the left side.

see
http://www.imagemagick.org/Usage/distor ... t_viewport

[ddrirc]

I actually want the furthest right pixel to just be lost, no wrapping. And the background needs to remain transparent/alpha so I'm not sure how well flattening would work

[fmw42]

I actually want the furthest right pixel to just be lost, no wrapping. And the background needs to remain transparent/alpha so I'm not sure how well flattening would work

So you want to drop the right column and fill the left with transparency? Is that correct?

Try this:

convert rose: rose.png
convert -page +1+0 rose: -background none -flatten rose_tmp.png

Then alternate each image to see that it is shifted to the right and the same size.

[ddrirc]

I actually want the furthest right pixel to just be lost, no wrapping. And the background needs to remain transparent/alpha so I'm not sure how well flattening would work

So you want to drop the right column and fill the left with transparency? Is that correct?

Try this:

convert rose: rose.png
convert -page +1+0 rose: -background none -flatten rose_tmp.png

Then alternate each image to see that it is shifted to the right and the same size.

Works perfectly, thank you!

[anthony]

Subject: [Solved] Shift image 1 pixel to the right, keep size

What I ended up using in the end:

Code: Select all

convert test.png -page +1+0 -background none -flatten newtest.png

Much simpler Thanks, fmw42

Note that that will fail! -page is for setting virtual canvas size/offset BEFORE they are read. While -repage is for image already in memory, AFTER they have been read.

[fmw42]

Anthony is right. That is not what I wrote above:

convert -page +1+0 rose: -background none -flatten rose_tmp.png

[ddrirc]

Really? I get no error and it seems to do the job, but I will switch the order if you say so.

[fmw42]

Really? I get no error and it seems to do the job, but I will switch the order if you say so.

or try

convert test.png -repage +1+0 -background none -flatten newtest.png

see
http://www.imagemagick.org/Usage/layers/#flatten for use of -page

also see for repage
http://www.imagemagick.org/Usage/basics/#page