diff options
Diffstat (limited to 'FL')
| -rw-r--r-- | FL/Fl_Device.H | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/FL/Fl_Device.H b/FL/Fl_Device.H index 7228d3cd7..2f1a8d80f 100644 --- a/FL/Fl_Device.H +++ b/FL/Fl_Device.H @@ -40,24 +40,24 @@ class Fl_Widget; A drawing surface other than the computer's display, is typically used as follows: <ol><li> Create \c surface, an object from a particular Fl_Surface_Device derived class (e.g., Fl_Copy_Surface, Fl_Printer). - <li> Memorize what is the current drawing surface with <tt> Fl_Surface_Device *old_current = Fl_Surface_Device::surface();</tt> - <li> Call \c surface->set_current(); to redirect all graphics requests to \c surface which becomes the new + <li> Call \c Fl_Surface_Device::push_current(surface); to redirect all graphics requests to \c surface which becomes the new current drawing surface (not necessary with class Fl_Printer because it is done by Fl_Printer::start_job()). - <li> At this point any of the \ref fl_drawings (e.g., fl_rect()) or the \ref fl_attributes or \ref drawing_images functions - (e.g., fl_draw_image(), Fl_Image::draw()) operates on the new current drawing surface. + <li> At this point all of the \ref fl_drawings (e.g., fl_rect()) or the \ref fl_attributes or \ref drawing_images functions + (e.g., fl_draw_image(), Fl_Image::draw()) operate on the new current drawing surface. Certain drawing surfaces allow additional ways to draw to them (e.g., Fl_Printer::print_widget(), Fl_Image_Surface::draw()). <li> After all drawing requests have been performed, redirect graphics requests back to their previous destination - with \c old_current->set_current();. + with \c Fl_Surface_Device::pop_current();. <li> Delete \c surface. </ol> + For back-compatibility, it is also possible to use the Fl_Surface_Device::set_current() member function + to change the current drawing surface, once to the new surface, once to the previous one. */ class FL_EXPORT Fl_Surface_Device { /** The graphics driver in use by this surface. */ Fl_Graphics_Driver *pGraphicsDriver; - static Fl_Surface_Device *surface_; // the surface that currently receives graphics output + static Fl_Surface_Device *surface_; // the surface that currently receives graphics requests static Fl_Surface_Device *default_surface(); // create surface if none exists yet - static Fl_Surface_Device *pre_surface_; - // Some drawing surfaces (e.g., Fl_XXX_Image_Surface_Driver) need to re-implement this. + // Some drawing surfaces (e.g., Fl_XXX_Image_Surface_Driver) re-implement this. // Gets called each time a surface ceases to be the current drawing surface. virtual void end_current_() {} protected: @@ -70,12 +70,14 @@ public: /** \brief Returns the graphics driver of this drawing surface. */ inline Fl_Graphics_Driver *driver() {return pGraphicsDriver; }; /** The current drawing surface. - In other words, the Fl_Surface_Device object that currently receives all graphics output */ + In other words, the Fl_Surface_Device object that currently receives all graphics requests */ static inline Fl_Surface_Device *surface() { return surface_ ? surface_ : default_surface(); }; /** \brief The destructor. */ virtual ~Fl_Surface_Device(); + static void push_current(Fl_Surface_Device *new_current); + static Fl_Surface_Device *pop_current(); }; /** |