cyccommute Rolla sjanzeir Jeff Neese
'Direct pull' brakes are absolutely defined by the way the cable is oriented across the top of the arms. These brakes fix a design flaw with centre-pull cantilever brakes - that the more you pull on the brake, the higher the yoke goes and therefore the less leverage the brake has working to stop the bike. 'Direct pull' brakes have the cable pulling the arms straight together, so doubling force at the lever will approximately double the force at the brake, while doubling the force at the lever for a centre-pull cantilever makes some increase less than double the force at the brake. This is not to say cantis are necessarily bad brakes - I have had many great rides on canti equipped bikes on rough terrain, but decent quality V brakes (direct pull) were an immediate upgrade when they came out.
And how do we know that it is the cable orientation and not the amount of cable pull that defines linear-pull brakes? Because there are 'short pull' linear pull brakes for touring/Cx/bmx bikes that use the same short-pull levers as you would use with road calipers or cantilever brakes. There are also cable-actuated disc brakes that work with short pull levers. The difference between the brakes is the way the cable actuates the arms, not the amount of cable puleld.
As for the... *ahem*
'people' splitting hairs on whether what is called a 'cantilever' brake can be described as a 'centre pull' canrtilever brake, please, . . . . . The 'road centre pull' brakes like the Weinmanns pictured above haven't been included on a new bike in decades, so in a discussion of 'cantis vs Vs', it is absolutely appropriate to differentiate by calling 'cantis' 'centre pull', because that's literally what they are, just like how 'direct pull' brakes are literally also a type of 'cantilever' brakes. Kind of like how what used to be called 'clipless' pedals are now regularly, and not incorrectly, called 'clip in' or 'clip' pedals - the toe clip and cleat pedals that 'clipless' pedals replaced aren't really a thing anymore, so correcting people on the distinction only indicates who in the discussion thinks too highly of their own intelligence.