diff options
| author | ManoloFLTK <41016272+ManoloFLTK@users.noreply.github.com> | 2022-03-18 06:51:56 +0100 |
|---|---|---|
| committer | ManoloFLTK <41016272+ManoloFLTK@users.noreply.github.com> | 2022-03-18 06:52:06 +0100 |
| commit | ace51a4b8d840bee232758185b274afa5c0ae43a (patch) | |
| tree | e642eea2cd60a10b3f648c24934b41c04fd51a89 /src/Fl_Device.cxx | |
| parent | 618eb8f105e131052c2ed206bf4f271f2f9acf45 (diff) | |
More detailed doc of how to change the current drawing surface.
Diffstat (limited to 'src/Fl_Device.cxx')
| -rw-r--r-- | src/Fl_Device.cxx | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/src/Fl_Device.cxx b/src/Fl_Device.cxx index 7344ff151..135a8a344 100644 --- a/src/Fl_Device.cxx +++ b/src/Fl_Device.cxx @@ -62,8 +62,16 @@ /** Make this surface the current drawing surface. This surface will receive all future graphics requests. - \p Starting from FLTK 1.4.0, another convenient API to set/unset the current drawing surface - is Fl_Surface_Device::push_current( ) / Fl_Surface_Device::pop_current().*/ + \p Starting from FLTK 1.4.0, the preferred API to change the current drawing surface + is Fl_Surface_Device::push_current( ) / Fl_Surface_Device::pop_current(). + \note It's recommended to use this function only as follows : + \li The current drawing surface is the display; + \li make current another surface, e.g., an Fl_Printer or an Fl_Image_Surface object, calling set_current() on this object; + \li draw to that surface; + \li make the display current again with Fl_Display_Device::display_device()->set_current(); . Don't do any other call to set_current() before this one. + + Other scenarios of drawing surface changes should be performed via Fl_Surface_Device::push_current( ) / Fl_Surface_Device::pop_current(). + */ void Fl_Surface_Device::set_current(void) { if (surface_) surface_->end_current(); @@ -109,7 +117,11 @@ static Fl_Surface_Device *surface_stack[16]; /** Pushes \p new_current on top of the stack of current drawing surfaces, and makes it current. \p new_current will receive all future graphics requests. - \version 1.4.0 */ + + Any call to push_current() must be matched by a subsequent call to Fl_Surface_Device::pop_current(). + The max height of this stack is 16. + \version 1.4.0 + */ void Fl_Surface_Device::push_current(Fl_Surface_Device *new_current) { if (surface_stack_height < sizeof(surface_stack)/sizeof(void*)) { @@ -122,6 +134,7 @@ void Fl_Surface_Device::push_current(Fl_Surface_Device *new_current) /** Removes the top element from the current drawing surface stack, and makes the new top element current. \return A pointer to the new current drawing surface. + \see Fl_Surface_Device::push_current(Fl_Surface_Device *) \version 1.4.0 */ Fl_Surface_Device *Fl_Surface_Device::pop_current() { |