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
Tav