Bug 325549

Summary: Constrained straight lines while painting with 'Paint with brush' tool
Product: [Applications] krita Reporter: David REVOY <info>
Component: UsabilityAssignee: Krita Bugs <krita-bugs-null>
Status: RESOLVED FIXED    
Severity: wishlist CC: ghevan, halla
Priority: NOR    
Version First Reported In: git master (please specify the git hash!)   
Target Milestone: ---   
Platform: Compiled Sources   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description David REVOY 2013-10-02 13:06:25 UTC 
Yet another [wish] to the bug tracker : Constrained straight lines while painting with 'Paint with brush' tool.

The principle is to hold a key on the keyboard while painting to get brush stroke magnetised to 0° , 45° and 90° . So it's ease creation of straight strokes and 45° angle too. 

The advantage over 'Draw a straight line with current brush" current tool  , is management of the pression of stylus on the 'fly'. It's usefull for detailing, creating sharp edges to design ( in perspective system ; horyzontal and vertical lines are often used ). I also lake of this feature when painting concept art front/top/side view ; of car/weapon and every hardware. Making believable vertical or horyzontal painted hard edge in Krita is still not optimal.  A feature like this would not replace 'Draw a straight line with current brush" current tool  and it's not the purpose of this proposition. 

This type of tool and ergonomic exist already on Corel Painter and Adobe Photoshop, the key to trigger it is 'Shift' ; but 'Shift' is used by the brush resizer on Krita. I would propose 'Alt' on Krita , currently free slot for  'Paint with brush'.
Comment 1 Halla Rempt 2013-10-02 13:16:22 UTC 
Alt is tricky, too -- but maybe ctrl-alt-shift :-)

All joking aside, this should be easy to implement (it basically already works if there is a guide, so all we have to do if fake guides radiating from the stroke start.
Comment 2 David REVOY 2013-10-02 20:18:03 UTC 
Ha ha for ctrl-alt-shift  :-D 
I thought about 'Alt' because there is the need to 'hold' a key while tracing in other software I experienced it, and it sounds like a 'modifier' key. But that's probably an old (hold) school keyboard/shortcut design... 

It could probably work using a single 'letter' on the keyboard and do a 'toggle' with it constrained/unconstrained ( as for the brush eraser with E ) ,  especially if there is a little feedback for user. Ex: around the brush outliner showing the mode activated ( as a little/tiny icon on the bottom-right corner of the 'bounding box' of the outliner area.
Comment 3 vanyossi 2014-03-24 18:26:57 UTC 
No toggles for this :( , it has to feel like "holding a ruler", so it should only work while pressing the key. The good thing is that it seems krita allows to use normal keys as modifiers. Or Am I wrong? At least on the Canvas input settings works that way.

Alt is the key to go. It is tricky but recently found Path move uses "alt" for a bunch of stuff and CTRL as the sidekick (which does the same as alt in case alt is taken). We could use "V" as the sidekick for this.
Comment 4 David REVOY 2014-03-25 09:05:13 UTC 
I understand. Holding a key continuously is not something I like either. 
Toggling a key is better ( similar to the 'eraser' ) ;  'V' sounds good.

Scenario :
========
1.User paint in freehand painting mode
2. User press 'V'
3. It toggle a mode where all his stroke are magnetised to each 45°
4. User paint vertical or horizontal lines into his composition, with benefit of pressure
5. User press 'V' to go back into freehand mode.