Resent calling out characters in mid-canvas (4)
I believe the answer is:
envy
'resent calling' is the definition.
'envy' can be an answer for 'resent' (thesaurus). I am not certain of the 'calling' bit.
'out characters in mid-canvas' is the wordplay.
'out characters in' becomes 'env' (I can't justify this - if you can you should believe this answer much more).
'mid' means to look at the middle letters.
'canvas' becomes 'royal' (royal is a kind of canvas).
The middle of 'royal' is 'y'.
'env'+'y'='ENVY'
(Other definitions for envy that I've seen before include "grudging discontent" , "Jealousy, resentment" , "Desire to possess another's attributes etc" , "Resentment at another's success" , "grudge" .)