[FEATURE] Add preview modes for composer - needs feedback!

[nyalldawson]

This pull request adds a new QGraphicsEffect to QGIS for simulating grayscale, monochrome and color blindness (see http://hub.qgis.org/issues/9886 for the original inspiration). I've added it to the composer, so that interactive previews in any of these modes are possible. It should also be possible to add this effect to the map canvas so that map layer symbology can be tweaked with immediate feedback.

HOWEVER - there's an issue somewhere in the code which I can't track down (or replicate). In Nathan's testing switching on any of the preview modes stops the composer view widget from repainting (effectively freezing the control) until the effect is disabled. I've tested on a range of windows and linux environments but can't reproduce this or figure out what is happening. So, any advice on what is going wrong here would be appreciated

[nirvn]

Nyall, very useful. I'd love to see an ebook preview mode too, finding myself producing maps specifically for that type of media more & more. Amazon has a free app to show what images would look like on an ebook reader, that'd be your point of reference. Cheers.

[mhugent]

Assigned to @NathanW2

[NathanW2]

Nyall and I will try to work though this one. I'm really not sure why it
doesn't work on my Windows build but does on Nyalls

On Mon, May 12, 2014 at 5:12 PM, mhugent notifications@github.com wrote:

Assigned to @NathanW2 https://github.com/NathanW2

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Reply to this email directly or view it on GitHubhttps://github.com//pull/1294#issuecomment-42801859
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[nyalldawson]

@NathanW2 I've just rebased this against master - do you mind testing and seeing if you still have issues? if so, we'll take this conversation offline and try again to debug....

[nyalldawson]

Merged and confirmed working for Nathan!