Problem jumping in Swordigo
Solution 1:
In order to reach the highest point you need to have unlocked the Dragon's Grasp spell. It acts as a sort of grappling hook and will latch on to that bright purple blob you see in the top right of the image.
If you have the spell, try doing a double jump, then activate the spell to fly up to the blob. Then you can do another jump to make it the platform.
See here for a list of the spells and where you can get them if you are having trouble finding it.
This is what it says about the Dragons Spell:
SPOILERS
This spell is used to grapple to the unknown things resembling purple blobs located on various ceilings. This can also be used to pull enemies to you, dealing a minimal amount of damage depending upon the level of the enemy you are fighting.
Unlike your magic bolt, Dragon's Grasp cannot be reflected by enemies at all.
This spell is not required, but is very useful in defeating the third gatekeeper of the third shard of the Mageblade.
This spell is gained in the Fiery Depths.