I have 2 methods of making gradients with ibisPaint X. it's a drawing app, so making gradients isn't that hard.
1st way:
put some colors onto a canvas then press the filter effect by pressing the paint brush.
select the option 'moving blur'
set the strength to 150 and change the direction until it makes a nice blended gradient.
this way might not always work if there are more than 2 colors that are in different places since the way you adjust the direction might make it look weird :(
there's a second way that can fix that though
2nd way:
place colors onto the canvas and resize the canvas to about 250 pixels.
select the blur option from pressing the paint brush.
select the biggest size of the blur brush by moving the scale with the dark blue stuffs to the right.
blend the intersection of the colors until it's blended to however you like.
and that's it! two ways of making gradients on ibisPaint X :) this might seem a bit weird to have a tutorial on, but sometimes the internet doesn't have pictures of specific colors of gradients, so this does help quite a bit!