Stop creating cairo contexts in haiku_begin_cr_clip

* src/haikufont.c (haikufont_draw):
* src/ftcrfont.c (ftcrfont_draw): Stop holding the draw lock.
* src/haiku_support.cc (class EmacsView): New field
`cairo_context'.
(DetachCairoSurface): Destroy cairo_context.
(AttachCairoSurface): Create cairo_context from the surface.
(EmacsView_cairo_surface): Delete function.
(EmacsView_cairo_context): New function.
* src/haiku_support.h: Update prototypes.
* src/haikuterm.c (haiku_begin_cr_clip):
(haiku_end_cr_clip): Retrieve the existing cairo context instead
of creating a new one.
* src/haikuterm.h (FRAME_CR_CONTEXT): New macro.

src/ftcrfont.c

@@ -538,12 +538,12 @@ ftcrfont_draw (struct glyph_string *s,
   cr = pgtk_begin_cr_clip (f);
 #endif
 #else
-  BView_draw_lock (FRAME_HAIKU_VIEW (f));
+  /* Presumably the draw lock is already held by
+     haiku_draw_glyph_string.  */
   EmacsWindow_begin_cr_critical_section (FRAME_HAIKU_WINDOW (f));
   cr = haiku_begin_cr_clip (f, s);
   if (!cr)
     {
-      BView_draw_unlock (FRAME_HAIKU_VIEW (f));
       EmacsWindow_end_cr_critical_section (FRAME_HAIKU_WINDOW (f));
       unblock_input ();
       return 0;
@@ -610,7 +610,6 @@ ftcrfont_draw (struct glyph_string *s,
 #else
   haiku_end_cr_clip (cr);
   EmacsWindow_end_cr_critical_section (FRAME_HAIKU_WINDOW (f));
-  BView_draw_unlock (FRAME_HAIKU_VIEW (f));
 #endif
   unblock_input ();
 

src/haiku_support.cc

@@ -1184,6 +1184,7 @@ public:
 
 #ifdef USE_BE_CAIRO
   cairo_surface_t *cr_surface = NULL;
+  cairo_t *cr_context = NULL;
   BLocker cr_surface_lock;
 #endif
 
@@ -1215,8 +1216,10 @@ public:
       gui_abort ("Could not lock cr surface during detachment");
     if (!cr_surface)
       gui_abort ("Trying to detach window cr surface when none exists");
+    cairo_destroy (cr_context);
     cairo_surface_destroy (cr_surface);
     cr_surface = NULL;
+    cr_context = NULL;
     cr_surface_lock.Unlock ();
   }
 
@@ -1236,6 +1239,10 @@ public:
        offscreen_draw_bitmap_1->BytesPerRow ());
     if (!cr_surface)
       gui_abort ("Cr surface allocation failed for double-buffered view");
+
+    cr_context = cairo_create (cr_surface);
+    if (!cr_context)
+      gui_abort ("cairo_t allocation failed for double-buffered view");
     cr_surface_lock.Unlock ();
   }
 #endif
@@ -3178,12 +3185,12 @@ BView_show_tooltip (void *view)
 
 
 #ifdef USE_BE_CAIRO
-/* Return VIEW's cairo surface.  */
-cairo_surface_t *
-EmacsView_cairo_surface (void *view)
+/* Return VIEW's cairo context.  */
+cairo_t *
+EmacsView_cairo_context (void *view)
 {
   EmacsView *vw = (EmacsView *) view;
-  return vw->cr_surface;
+  return vw->cr_context;
 }
 
 /* Transfer each clip rectangle in VIEW to the cairo context

src/haiku_support.h

@@ -827,8 +827,8 @@ extern "C"
   BView_show_tooltip (void *view);
 
 #ifdef USE_BE_CAIRO
-  extern cairo_surface_t *
-  EmacsView_cairo_surface (void *view);
+  extern cairo_t *
+  EmacsView_cairo_context (void *view);
 
   extern void
   BView_cr_dump_clipping (void *view, cairo_t *ctx);

src/haikufont.c

@@ -955,7 +955,8 @@ haikufont_draw (struct glyph_string *s, int from, int to,
   block_input ();
   prepare_face_for_display (s->f, face);
 
-  BView_draw_lock (view);
+  /* Presumably the draw lock is already held by
+     haiku_draw_glyph_string; */
   if (with_background)
     {
       int height = FONT_HEIGHT (s->font), ascent = FONT_BASE (s->font);
@@ -1014,7 +1015,7 @@ haikufont_draw (struct glyph_string *s, int from, int to,
       BView_DrawString (view, b, b_len);
       xfree (b);
     }
-  BView_draw_unlock (view);
+
   unblock_input ();
   return 1;
 }

src/haikuterm.c

@@ -3618,18 +3618,22 @@ haiku_set_offset (struct frame *frame, int x, int y,
 cairo_t *
 haiku_begin_cr_clip (struct frame *f, struct glyph_string *s)
 {
-  cairo_surface_t *surface = FRAME_CR_SURFACE (f);
-  if (!surface)
+  cairo_t *cr = FRAME_CR_CONTEXT (f);
+
+  if (!cr)
     return NULL;
 
-  cairo_t *context = cairo_create (surface);
-  return context;
+  cairo_save (cr);
+  return cr;
 }
 
 void
 haiku_end_cr_clip (cairo_t *cr)
 {
-  cairo_destroy (cr);
+  if (!cr)
+    return NULL;
+
+  cairo_restore (cr);
 }
 #endif
 

src/haikuterm.h

@@ -231,8 +231,10 @@ struct scroll_bar
 #define FRAME_CURSOR_COLOR(f) (FRAME_OUTPUT_DATA (f)->cursor_color)
 
 #ifdef USE_BE_CAIRO
-#define FRAME_CR_SURFACE(f) \
-  (FRAME_HAIKU_VIEW (f) ? EmacsView_cairo_surface (FRAME_HAIKU_VIEW (f)) : 0);
+#define FRAME_CR_CONTEXT(f)					\
+  (FRAME_HAIKU_VIEW (f)						\
+   ? EmacsView_cairo_context (FRAME_HAIKU_VIEW (f))		\
+   : NULL)
 #endif
 
 extern void syms_of_haikuterm (void);