Legacy ImageMagick Discussions Archive

I would like to know how to tell IM to extend only one dimension (X or Y as per my wish), center the image in it and fill the rest with background colour. For example:
...will certainly center the rose in the middle of the 1000x1000 white field. But say I want to specify that the rose should be centered in a white field of:

1. 1000 px width and height same as rose, or
2. width same as rose and 1000 px height

then how do I do it? Preferably the solution should work with other gravity options such as N, S, E, W too (though the NE, NW etc would be not meaningful). Thanks!

If you want to shift the position relative to the gravity, then add -geometry +Xoffset+Yoffset after -gravity .

You can also just use -extent. See viewtopic.php?f=1&t=33012

jamadagni wrote: ↑2017-11-02T10:15:22-07:00But say I want to specify that the rose should be centered in a white field of:

1. 1000 px width and height same as rose, or
2. width same as rose and 1000 px height

then how do I do it?

As fmw42 mentioned, you can use "-extent" in a fairly simple command like this...
That would create your first example with the rose centered in a white canvas of 1000 pixels wide and the height of the rose. Using zero in that geometry argument tells "-extent" to just use that dimension from the input image. Of course you'd swap the width and height arguments to make the canvas 1000 pixels high and the width of the rose.

You actually do not need the 0 for height. IM will take the full image height. So you can just do

☺ to both of you!