qt5base-lts/examples/widgets/painting
Edward Welbourne 02b7ec05d5 Be (somewhat more) consistent about the value of pi
Use M_PI (and friends), where possible, in favor of hand-coded
approximations of various (in)accuracies.  Where that's not available
(e.g. fragment shaders), use the same value that qmath.h uses for
M_PI, for consistency.  Replaced math.h with qmath.h in places that
defined a fall-back in case math.h omits it (it's not in the C++
standard, although M_PI is in POSIX); or removed this entirely where
it wasn't used.

Reworked some code to reduce the amount of arithmetic needed, in the
process; e.g. pulling common factors out of loops.  Revised an
example's doc to not waste time talking about using a six-sig-fig
value for pi (which we no longer do) - it really wasn't relevant, or
anything to be proud of; nor did the doc mention its later use.

Task-number: QTBUG-58083
Change-Id: I5a31e3a2b6a823b97a43209bed61a37b9aa6c05f
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
2017-06-20 09:53:46 +00:00
..
affine Examples: Replace 'Q_DECL_OVERRIDE' by 'override' 2016-06-15 09:32:30 +00:00
basicdrawing Examples: Replace 'Q_DECL_OVERRIDE' by 'override' 2016-06-15 09:32:30 +00:00
composition Use qtConfig throughout in qtbase 2016-08-19 04:28:05 +00:00
concentriccircles Examples: Replace 'Q_DECL_OVERRIDE' by 'override' 2016-06-15 09:32:30 +00:00
deform Examples: Replace 'Q_DECL_OVERRIDE' by 'override' 2016-06-15 09:32:30 +00:00
fontsampler Convert features.printdialog to QT_[REQUIRE_]CONFIG 2017-05-30 17:21:26 +00:00
gradients Examples: Replace 'Q_DECL_OVERRIDE' by 'override' 2016-06-15 09:32:30 +00:00
imagecomposition Unify license header usage. 2016-03-29 10:20:03 +00:00
painterpaths Be (somewhat more) consistent about the value of pi 2017-06-20 09:53:46 +00:00
pathstroke Merge remote-tracking branch 'origin/5.7' into dev 2016-07-19 20:14:40 +02:00
shared Example: migrate the arthur code sample to use QRegularExpression 2017-02-15 14:45:45 +00:00
transformations Examples: Replace 'Q_DECL_OVERRIDE' by 'override' 2016-06-15 09:32:30 +00:00
painting.pro don't build shared demo library which is not used anyway 2013-01-31 15:51:09 +01:00
README Moving .qdoc files under examples/widgets/doc 2012-08-20 12:20:55 +02:00

Qt's painting system is able to render vector graphics, images, and outline
font-based text with sub-pixel accuracy accuracy using anti-aliasing to
improve rendering quality.

These examples show the most common techniques that are used when painting
with Qt, from basic concepts such as drawing simple primitives to the use of
transformations.


Documentation for these examples can be found via the Examples
link in the main Qt documentation.