mirrors
/
fltk
mirror of https://github.com/fltk/fltk
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Add implementation explanatory comments about how the screen driver supports public function fl_read_image(). 

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.4@12157 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
This commit is contained in:
Manolo Gouy 2017-01-04 07:44:31 +00:00
parent 06b98099f9
commit 06924c37cb
1 changed files with 15 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
FL/Fl_Screen_Driver.H
View File

@ -123,6 +123,21 @@ public:
#if defined(FL_PORTING)
# pragma message "FL_PORTING: implement code to read RGB data from screen"
#endif
/* Both member functions read_image() and read_win_rectangle() support
the public function fl_read_image() which captures pixel data either from
the current window or from an offscreen buffer.
A platform re-implements either read_image() or read_win_rectangle().
In the 1st case and for capture from a window, the returned pixel array
also contains data from any embedded sub-window.
In the 2nd case and for capture from a window, only data from the current
window is collected, and read_image()'s default implementation captures
pixels from any subwindow.
A platform may also use its read_win_rectangle() implementation to capture
window decorations (e.g., title bar). In that case, it is called by
Fl_XXX_Window_Driver::capture_titlebar_and_borders().
*/
virtual uchar *read_image(uchar *p, int x, int y, int w, int h, int alpha);
virtual Fl_RGB_Image *read_win_rectangle(uchar *p, int X, int Y, int w, int h, int alpha) {return NULL;}
static void write_image_inside(Fl_RGB_Image *to, Fl_RGB_Image *from, int to_x, int to_y);