Under non-macOS platforms, the key is to call glUseProgram(0); after having used OpenGL 3
which allows to then use OpenGL 1 and draw FLTK widgets over the OpenGL3 scene.
Under macOS, this is impossible because macOS GL3 contexts are not compatible
with GL1. The solution implemented here is to create an additional Fl_Gl_Window
placed above and sized as the GL3-based window, to give it a non opaque,
GL1-based context, and to put the FLTK widgets in that additional window.
Elaborated on Fl_Cairo_Window's use of FLTK style coordinates,
and how this differs from cairo's default native normalized
coordinate system, and shows how to switch from one to the other.
Also, small comment fix to the cairo example regarding the "X" color.
Albrecht submitted this in issue 358.
Tested the variations:
cmake .. -- examples and cairo off
cmake -D FLTK_BUILD_EXAMPLES=on -- examples on, cairo off
cmake -D FLTK_BUILD_EXAMPLES=on -D OPTION_CAIRO=on .. -- examples on, cairo on
When examples are 'on', they build into the bin/examples directory.
Since this is the first cairo example in the examples directory,
it necessarily involved changes to the Makefile and to fltk-config
to properly handle the absence/existance of the cairo libs.
TBD: Add docs to the cario widget describing coordinate system
and how it differs from the default cairo normalized coordinate system.
I compiled with `-Wextra-semi -Werror=extra-semi` on Linux and Windows
(cross-compiled on Linux) and removed all "extra semicolon" warnings
I could find. I didn't check on macOS (yet).
Note: Linux configured with and w/o Pango but not w/o Xft. Compilation
with other options (e.g. Cairo) might still emit such warnings.
Also small but unnecessary code change to reset row_edit/col
to zero after editing for example clarity.
Unnecessary b/c those vars are ignored anyway when input
visibility turned off, so change is more cosmetic codewise.
- 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.
