Re: [Inkscape-devel] Canvas rotation and flip update.

22 Apr 2017

      That's amazing Yale! Can't wait to use Inkcape in a tablet in the near
future to test this new gestures.
Cheers.
--Victor Westmann
2017-04-22 5:04 GMT-07:00 Tavmjong Bah <tavmjong@...8...>:
...
Looks nice.
I'll try to set some time aside next week to have a good look at the
code and hopefully merge it.
Tav
On Sat, 2017-04-22 at 04:27 -0700, Yale Zhang wrote:
...
Rotate should be useful. I think most people find it easier to draw
vertical lines than horizontal since there's less wrist motion.
I've updated my touchscreen code to support canvas rotation. Anyone
want to use it?
https://youtu.be/-8v1EVKqcaM
transform math:
https://1drv.ms/u/s!AngRQgSreBCehTiw0R_rGV7gxQIP
A couple of notes:
*awkward coordinate system - Why is the canvas completely off the
screen when rotation=0, offset=0? It seems the window's Y axis points
down while the document's Y axis points up?

why is a positive rotation counter clockwise? In a left handed

coordinate system, it should be clockwise.
*I couldn't figure out how to set the rotation, zoom, and offset
using
the functions in the desktop class (scroll_to_point(),
zoom_absolute_keep_point() and had to access the private affine
matrix
directly. Calling those functions in sequence seems to add unwanted
offsets on top of each other instead of letting me set the offset
directly.
*had to roll back r15548 or else touch screen events get lost
somehow.

I couldn't figure out how to use the GTK gesture classes (which are

probably more robust), so wrote my own code for detecting zoom,
rotate, and scroll gestures. When I tried, the gesture classes
weren't
receiving any events. 2nd, it seems only 2 finger rotation and zoom
gestures are recognized, but not 2 finger scrolling. There is a 1
finger scroll gesture.
-Yale
On Tue, Apr 4, 2017 at 8:35 PM, Raghavendra Kamath
<raghu@...3496...> wrote:
...
Hi Tav,
On 2017 Mar 30 13:29:23, Tavmjong Bah wrote:
...
Hi,
I've just checked in code to quickly preview canvas rotation.
Like
Jabier's code, it is triggered by Ctrl-Middle-Mouse-Button. It
lacks
all the fancy graphics of Jabier's version. Some of this can be
added
back if there is user demand. There is certainly some tweaking to
do.
I also implemented canvas flip (Horizontal and Vertical). This is
not
in the GUI yet. Flipping can be bound to keys (not done by
default
since there are few keys free).
So here is a summary of what you can do:

Rotate canvas

Via GUI spin-entry box:
Directly enter a number.
Mouse up/down to change by ±1°.
Click on + or − to change by ±1°.
Left click to open pop-up.

Via Key shortcut
Inkscape Preferences->Interface->Keyboard Shortcuts, View

Rotate Clockwise          (Recommended: 'Shift-(')
Rotate Counter-Clockwise  (Recommended: 'Shift-)')
Rotate 0                  (Recommended: '0')

Uses /options/rotateincrement/value for step size if set.

Via Ctrl-Middle-Mouse-Button.
 Drag cursor keeping Middle-Mouse-Button down to rotate.
 Release mouse button to end.
No auxilary key: ±1°.
Shift: ±15°.
Alt: arbitrary rotation.
Shift + Ctrl: reset to zero.

Flip canvas

Via Key shortcut
Inkscape Preferences->Interface->Keyboard Shortcuts, View

Flip Horizontal  (Recommended: 'Shift-H')
Flip Vertical    (Recommended: 'Shift-V')
Flip None

Thank you very much for the work. The shortcut keys are great now
:)
--
Raghavendra Kamath
Illustrator
raghukamath.com

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