From 8bd3ea6c8ac066002b035f10f3657449f6beadb1 Mon Sep 17 00:00:00 2001
From: Manolo Gouy <Manolo>
Date: Thu, 3 Mar 2016 08:32:16 +0000
Subject: A hopefully clearer implementation of the fl_XXX_offscreen()
 functions.

The Xlib driver is tricky because it uses two kinds of offscreen buffers.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3-porting@11277 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
---
 src/drivers/Xlib/Fl_Xlib_Graphics_Driver_image.cxx | 27 ++++++++++++----------
 1 file changed, 15 insertions(+), 12 deletions(-)

(limited to 'src/drivers/Xlib/Fl_Xlib_Graphics_Driver_image.cxx')

diff --git a/src/drivers/Xlib/Fl_Xlib_Graphics_Driver_image.cxx b/src/drivers/Xlib/Fl_Xlib_Graphics_Driver_image.cxx
index 069fc925e..f9cc87c82 100644
--- a/src/drivers/Xlib/Fl_Xlib_Graphics_Driver_image.cxx
+++ b/src/drivers/Xlib/Fl_Xlib_Graphics_Driver_image.cxx
@@ -49,6 +49,7 @@
 #  include <FL/Fl.H>
 #  include <FL/fl_draw.H>
 #  include <FL/x.H>
+#  include <FL/Fl_Image_Surface.H>
 #  include "../../Fl_XColor.H"
 #  include "../../flstring.h"
 #include <X11/Xregion.h>
@@ -713,18 +714,20 @@ void Fl_Xlib_Graphics_Driver::draw(Fl_RGB_Image *img, int XP, int YP, int WP, in
     return;
   }
   if (!img->id_) {
-    if (img->d() == 1 || img->d() == 3) {
-      img->id_ = fl_create_offscreen(img->w(), img->h());
-      fl_begin_offscreen((Fl_Offscreen)img->id_);
-      fl_draw_image(img->array, 0, 0, img->w(), img->h(), img->d(), img->ld());
-      fl_end_offscreen();
-    } else if (img->d() == 4 && fl_can_do_alpha_blending()) {
-      img->id_ = (fl_uintptr_t)fl_create_offscreen_with_alpha(img->w(), img->h());
-      fl_begin_offscreen((Fl_Offscreen)img->id_);
-      fl_draw_image(img->array, 0, 0, img->w(), img->h(), img->d() | FL_IMAGE_WITH_ALPHA,
-                    img->ld());
-      fl_end_offscreen();
+    Fl_Image_Surface *surface;
+    int depth = img->d();
+    if (depth == 1 || depth == 3) {
+      surface = new Fl_Image_Surface(img->w(), img->h());
+    } else if (depth == 4 && fl_can_do_alpha_blending()) {
+      Fl_Offscreen pixmap = XCreatePixmap(fl_display, RootWindow(fl_display, fl_screen), img->w(), img->h(), 32);
+      surface = new Fl_Image_Surface(pixmap, img->w(), img->h());
+      depth |= FL_IMAGE_WITH_ALPHA;
     }
+    surface->set_current();
+    fl_draw_image(img->array, 0, 0, img->w(), img->h(), depth, img->ld());
+    surface->end_current();
+    img->id_ = surface->get_offscreen_before_delete();
+    delete surface;
   }
   if (img->id_) {
     if (img->mask_) {
@@ -759,7 +762,7 @@ void Fl_Xlib_Graphics_Driver::draw(Fl_RGB_Image *img, int XP, int YP, int WP, in
 void Fl_Xlib_Graphics_Driver::uncache(Fl_RGB_Image*, fl_uintptr_t &id_, fl_uintptr_t &mask_)
 {
   if (id_) {
-    fl_delete_offscreen((Fl_Offscreen)id_);
+    XFreePixmap(fl_display, (Fl_Offscreen)id_);
     id_ = 0;
   }
 
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