Bug#785477: libopencv-highgui2.4: Cannot render UTF-8 text unless we link against Qt

[Adam Wight]

Package: libopencv-highgui2.4
Version: 2.4.9.1+dfsg-1+b1
Severity: normal
Tags: patch

libopencv-highgui2.4: Cannot render UTF-8 text unless we link against Qt

I'm writing and packaging an application for Debian, and ran into an issue
while testing my pre-release.  Non-ASCII text cannot be rendered with the
stock opencv packages.

I'd like to suggest that we link against the Qt library by enabling the WITH_QT
flag in debian/rules, which causes the highgui library to provide text
rendering functions that work on the full UTF-8 character set.

(See patch below.)

OpenCV has two functions to render text,
[putText](http://docs.opencv.org/modules/core/doc/drawing_functions.html#puttext)
and
[addText](http://docs.opencv.org/modules/highgui/doc/qt_new_functions.html?highlight=addtext#addtext).
putText only supports ASCII text.  addText relies on the Qt libraries, and will
throw an exception if highgui is compiled without Qt support.

There is some recent work (as of version 2.4.11) to expand on putText's
character range, but only Cyrillic has been implemented so far.  If
there is an alternative to addText and Qt integration, please mention
it here.

Thanks,
Adam

--- a/debian/control    2015-05-16 12:59:24.585515384 -0700
+++ b/debian/control    2015-05-16 12:59:54.897515090 -0700
@@ -7,6 +7,7 @@
 Build-Depends: debhelper (>= 9),
  cmake (>= 2.8.7),
  libavcodec-dev, libavformat-dev, libswscale-dev, libgtk2.0-dev,
libgtkglext1-dev,
+ libqt4-dev,
  libgl1-mesa-dev, libglu1-mesa-dev,
  libjasper-dev (>= 1.900.1),
  libjpeg-dev,
--- a/debian/rules  2015-05-16 12:53:55.309518569 -0700
+++ b/debian/rules  2015-05-16 12:58:13.997516067 -0700
@@ -45,6 +45,7 @@
    -DWITH_FFMPEG=ON    \
    -DWITH_GSTREAMER=OFF    \
    -DWITH_GTK=ON   \
+   -DWITH_QT=ON    \
    -DWITH_OPENGL=ON    \
    -DWITH_JASPER=ON    \
    -DWITH_JPEG=ON  \