Complete the platform-neutral implementation of fl_XXX_offscreen() functions.

It is necessary to have a stack of the fl_begin_offscreen() calls, so that nested
such calls apply fl_end_offscreen() to the matching fl_begin_offscreen().

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3-porting@11289 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

FL/Fl_Graphics_Driver.H

@@ -221,7 +221,6 @@ public:
   // --- implementation is in src/fl_image.cxx which includes src/drivers/xxx/Fl_xxx_Graphics_Driver_font.cxx
   virtual Fl_Bitmask create_bitmask(int w, int h, const uchar *array) = 0;
   virtual fl_uintptr_t cache(Fl_Pixmap *img, int w, int h, const char *const*array) { return 0; }
-  virtual void uncache(Fl_Pixmap *img) { }
   virtual fl_uintptr_t cache(Fl_Bitmap *img, int w, int h, const uchar *array) { return 0; }
   virtual void uncache(Fl_RGB_Image *img, fl_uintptr_t &id_, fl_uintptr_t &mask_) { }
   virtual void delete_bitmask(Fl_Bitmask bm) = 0;

src/Fl_Image_Surface.cxx

@@ -132,7 +132,6 @@ Fl_Offscreen Fl_Image_Surface::get_offscreen_before_delete() {
 
 static Fl_Image_Surface **offscreen_api_surface = NULL;
 static int count_offscreens = 0;
-static int current_offscreen;
 
 static int find_slot(void) { // return an available slot to memorize an Fl_Image_Surface::Helper object
   static int max = 0;
@@ -175,14 +174,21 @@ void fl_delete_offscreen(Fl_Offscreen ctx) {
   }
 }
 
+static int stack_current_offscreen[16];
+static int stack_height = 0;
+
 /**  Send all subsequent drawing commands to this offscreen buffer.
    \param ctx     the offscreen buffer.
    */
 void fl_begin_offscreen(Fl_Offscreen ctx) {
-  for (current_offscreen = 0; current_offscreen < count_offscreens; current_offscreen++) {
-    if (offscreen_api_surface[current_offscreen] &&
-        offscreen_api_surface[current_offscreen]->offscreen() == ctx) {
-      offscreen_api_surface[current_offscreen]->set_current();
+  for (int i = 0; i < count_offscreens; i++) {
+    if (offscreen_api_surface[i] && offscreen_api_surface[i]->offscreen() == ctx) {
+      offscreen_api_surface[i]->set_current();
+      if (stack_height < sizeof(stack_current_offscreen)/sizeof(int)) {
+        stack_current_offscreen[stack_height++] = i;
+      } else {
+        fprintf(stderr, "FLTK fl_begin_offscreen Stack overflow error\n");
+      }
       return;
     }
   }
@@ -191,7 +197,10 @@ void fl_begin_offscreen(Fl_Offscreen ctx) {
 /** Quit sending drawing commands to the current offscreen buffer.
    */
 void fl_end_offscreen() {
-  offscreen_api_surface[current_offscreen]->end_current();
+  if (stack_height > 0) {
+    int i = stack_current_offscreen[--stack_height];
+    offscreen_api_surface[i]->end_current();
+  }
 }
 
 /** @} */

src/Fl_Pixmap.cxx

@@ -101,11 +101,7 @@ Fl_Pixmap::~Fl_Pixmap() {
 
 void Fl_Pixmap::uncache() {
   if (id_) {
-#ifdef __APPLE__
-    fl_graphics_driver->uncache(this);
-#else
     fl_delete_offscreen((Fl_Offscreen)id_);
-#endif
     id_ = 0;
   }
 

src/drivers/Quartz/Fl_Quartz_Graphics_Driver.H

@@ -59,7 +59,6 @@ public:
   void draw_image_mono(const uchar* buf, int X,int Y,int W,int H, int D=1, int L=0);
   void draw_image_mono(Fl_Draw_Image_Cb cb, void* data, int X,int Y,int W,int H, int D=1);
   fl_uintptr_t cache(Fl_Pixmap *img, int w, int h, const char *const*array);
-  void uncache(Fl_Pixmap *img);
   fl_uintptr_t cache(Fl_Bitmap *img, int w, int h, const uchar *array);
   void uncache(Fl_RGB_Image *img, fl_uintptr_t &id_, fl_uintptr_t &mask_);
   void copy_offscreen(int x, int y, int w, int h, Fl_Offscreen pixmap, int srcx, int srcy);

src/drivers/Quartz/Fl_Quartz_Graphics_Driver_image.cxx

@@ -25,7 +25,6 @@
 #include <FL/fl_draw.H>
 #include <FL/Fl_Printer.H>
 #include <FL/x.H>
-#include <FL/Fl_Image_Surface.H>
 
 #define MAXBUFFER 0x40000 // 256k
 
@@ -273,25 +272,13 @@ fl_uintptr_t Fl_Quartz_Graphics_Driver::cache(Fl_Bitmap*, int w, int h, const uc
 }
 
 fl_uintptr_t Fl_Quartz_Graphics_Driver::cache(Fl_Pixmap *img, int w, int h, const char *const*data) {
-  Fl_Image_Surface *surface = new Fl_Image_Surface(w,h);
-  surface->set_current();
+  Fl_Offscreen id = fl_create_offscreen(w, h);
+  fl_begin_offscreen(id);
   fl_draw_pixmap(data, 0, 0, FL_BLACK);
-  surface->end_current();
-  Fl_Offscreen id = surface->get_offscreen_before_delete();
-  delete surface;
+  fl_end_offscreen();
   return (fl_uintptr_t)id;
 }
 
-void Fl_Quartz_Graphics_Driver::uncache(Fl_Pixmap *img)
-{
-  if (img->id_) {
-    void *data = CGBitmapContextGetData((CGContextRef)img->id_);
-    free(data);
-    CGContextRelease((CGContextRef)img->id_);
-    img->id_ = NULL;
-  }
-}
-
 void Fl_Quartz_Graphics_Driver::draw_CGImage(CGImageRef cgimg, int x, int y, int w, int h, int srcx, int srcy, int sw, int sh)
 {
   CGRect rect = CGRectMake(x, y, w, h);