mirrors/fltk
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Doc change only: clearly document that FLTK has at any time a current drawing surface and a current graphics device.

Browse Source 
git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@10976 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
This commit is contained in:
Manolo Gouy 2015-12-22 10:15:28 +00:00
parent 25fc85190e
commit 6eb4354996
1 changed files with 10 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
FL/Fl_Device.H
View File

@ -98,7 +98,9 @@ public:
Typically, FLTK applications do not use directly objects from this class. Rather, they perform
drawing operations (e.g., fl_rectf()) that operate on the current drawing surface (see Fl_Surface_Device).
Drawing operations are functionally presented in \ref drawing and as function lists
in the \ref fl_drawings and \ref fl_attributes modules.
in the \ref fl_drawings and \ref fl_attributes modules. The \ref fl_graphics_driver global variable
gives at any time the graphics driver used by all drawing operations. Its value changes when
drawing operations are directed to another drawing surface by Fl_Surface_Device::set_current().
\p The Fl_Graphics_Driver class is of interest if one wants to perform new kinds of drawing operations.
An example would be to draw to a PDF file. This would involve creating a new Fl_Graphics_Driver derived
@ -532,8 +534,13 @@ public:
#endif
/**
\brief A drawing surface that's susceptible to receive graphical output.
A drawing surface is typically used as follows:
A drawing surface that's susceptible to receive graphical output.
Any FLTK application has at any time a current drawing surface to which all drawing requests are directed.
The current surface is given by Fl_Surface_Device::surface().
When main() begins running, the current drawing surface has been set to the computer's display,
an instance of the Fl_Display_Device class.
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
@ -545,7 +552,6 @@ public:
with \c old_current->set_current();.
<li> Delete \c surface.
</ol>
The current drawing surface is initially the computer's display, an instance of the Fl_Display_Device class.
*/
class FL_EXPORT Fl_Surface_Device : public Fl_Device {
/** \brief The graphics driver in use by this surface. */