Corresponds to STR #3320
1) HiDPI support consists in detecting the adequate scaling factor for the screen on which
FLTK maps a window, and scaling all FLTK units by this factor. FLTK tries to detect the correct
value of this factor at startup (see more details below). Environment variable
FLTK_SCALING_FACTOR can also be used to set this value.
2) Rescaling support consists in changing the scaling factor of all FLTK windows
in reply to ctrl/+/-/0/ keystrokes.
More details for the various platforms :
- X11: Support is very advanced. Some details need still to be improved.
Automatic detection of the correct starting value of the scaling factor works well
with the gnome desktop. The present code contains no support for this on
other desktops. FLTK_SCALING_FACTOR provides a workaround.
-WIN32: Support is incomplete at this point, although many test
applications have partial or complete HiDPI and scaling support.
The current value of the system's scaling factor is correctly detected
at application startup. Apps respond to changes of this value in real time.
Support needs to define the FLTK_HIDPI_SUPPORT preprocessor variable
at compile time. This way, standard builds produce a code with the
default WIN32 HiDPI support, that is, where all graphics goes to an internal
buffer that gets enlarged by the system and then mapped to the HiDPI
display. To experiment with (or develop) the new HiDPI support requires
a modified build procedure in which FLTK_HIDPI_SUPPORT is defined
at compile time. When the support will be complete, the requirement for the
definition of this preprocessor variable will be removed. The present commit
contains support for a single scaling factor. Eventually, per-screen scaling
factors should be implemented, as done for X11.
- MacOS: this commit does not give new HiDPI for this platform.
Eventually, window rescaling in reply to command/+/-/0/ is desirable.
Per-screen scaling factor makes no sense on this platform because
the OS itself takes care of the difference between the resolutions of
traditional and retina displays.
git-svn-id: file:///fltk/svn/fltk/branches/branch-1.4@12239 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
With this, fl_copy_offscreen() can be used with any drawing surface (e.g., PostScript) and any Fl_Offscreen
argument (e.g., returned by Fl_image_Surface::offscreen()).
git-svn-id: file:///fltk/svn/fltk/branches/branch-1.4@12148 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
There is a deeper issue here: regions should be handled by the graphics driver that is associated with the Fl_Window of this widget... .
git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3-porting@11643 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
- change image caching variable types to uintptr_t
- added driver function to uncache image data
- cleaning up (Xlib and GDI will likely throw syntax errors. Trying to fix ASAP)
git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3-porting@11138 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
