Enabled the choice between OpenCV 2.4.x or OpenCV 3.x

[madduci]

Selecting OpenCV version during CMake configuration, defining variable OPENCV_3 for newer OpenCV 3.x and OPENCV_2 for older API (2.4.6+).
Added the fix for imread to solve the compiling error

[Nerei]

@blackibiza I think this PR should be canceled. Your changes are not actually required, CV_LOAD_IMAGE_COLOR exits in 3.0

Offtopic, but fyi: #1667 (at least your linking error is fixed)

[Nerei]

But according to our plans API will diverge extremely in future. Imagine that we will remove STL from OpenCV interface in 3.x :-)

[Nerei]

From other side, It seems now #inckude <opencv2/imgcodes/imgcodes_c.h> causes conditional compilation anyway and the picture in my mind is obsolete. (I pefer 2.4.x only). And umbrella header opencv2/opencv.hpp doesn't help anymore. So might worth merging if very needed.

IMHO, better to create caffe::imread() function, call cv::imread() with default parameter and convert to gray-scale manually to define the constants in caffe code. But this (that is better) is just my speculations.

[madduci]

But how long will be OpenCV 2.x around? I am of the opinion that OpenCV 3.x will break somehow the API in future. But Travis still uses 2.3.1 version of OpenCV. I believe there's still a need to have both the possibilities implemented, so in this way it's possible to keep them.

[sanchom]

@Nerei Where is CV_LOAD_IMAGE_COLOR in OpenCV 3.0? As far as I can tell, it isn't part of the C++ code anymore.

[Nerei]

@sanchom #inckude <opencv2/imgcodes/imgcodes_c.h>

[Nerei]

@blackball

Don't know. For stable commercial products we stick to 2.x. Some of us advocate 3.x

Update: Just looked more precisely, it seems Android Manager will be released for 3.0 and and that means even binary compatibility must be supported. It seems removing STL is canseled or postponed till 4.x

[sanchom]

In my opinion the 2.3.x branch of OpenCV is outdated and is not necessary to support, other than for its use by Travis CI.

From 2.4.0 and onward into 3.x, the cv::IMREAD_COLOR, etc. constants were available.

Including opencv2/imgcodecs/imgcodecs_c.h is non-standard, and isn't automatically included by opencv2/imgcodecs.h. If we're using C++, we should avoid introducing global C constants and functions.

[Nerei]

Should to remove OPENCV_3/OPENCV_2 definitions and replace with CV_MAJOR_VERSION from <opencv2/opencv.hpp>, and link errors are fixed in #1667.

#include <opencv2/core/version.hpp>

#if CV_MAJOR_VERSION >= 3
  ... (use 3.x API here) ...
#else
  ... (use 2.x API here) ...
#endif

[Nerei]

All required changes are done in #1667. It compiles with OpenCV 3.x (master) update: and with 2.x. This PR to be closed.

[madduci]

But this change enables both OpenCV 2.x and OpenCV 3.0 to be compiled. 2.3
for Travis CI, OpenCV > 2.4 for everyone else.
It's a different solution. To me, out of the box, caffe didn't compile
using OpenCV 3.0
Am 18.01.2015 20:42 schrieb "Anatoly Baksheev" notifications@github.com:

All required changes are done in #1667
#1667. It compiles with OpenCV 3.0.
This PR to be closed.

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Reply to this email directly or view it on GitHub
#1714 (comment).

[Nerei]

yes. both opencv branches should compile after merging #1667

[Nerei]

@blackibiza I believe this can be closed. Just take the latest dev branch.

[madduci]

no problem!