- remove obsolete svn '$Id$' tags from all source files
- update .fl files and generated files accordingly
- replace 'http://www.fltk.org' URL's with 'https://...'
- replace bug report URL 'str.php' with 'bugs.php'
- remove trailing whitespace
- fix other whitespace errors flagged by Git
- add and/or fix missing or wrong standard headers
- convert tabs to spaces in all source files
The only relevant code changes are in the fluid/ folder where
some .fl files and other source files were used to generate
the '$Id' headers and footers.
The case was under macOS with a non-GL parent window mapped to a retina display
containing a GL subwindow and if the app did not call Fl::use_high_res_GL(1).
The new argument gives the window to be captured, or NULL to indicate capture
from the current offscreen.
Calling this function becomes easier because less dependent on global variables.
The procedure to set screen scaling factors becomes:
1) each screen scaling factor is set to 1
2) the OS is queried according to each platform to get screen scaling factor
values
3) The value of FLTK_SCALING_FACTOR, if present, is used to multiply
scaling factors
