Improve Fl_Graphics_Driver::copy_offscreen() so it accepts an Fl_Offscreen argument even if not created by fl_create_offscreen().

With this, fl_copy_offscreen() can be used with any drawing surface (e.g., PostScript) and any Fl_Offscreen
argument (e.g., returned by Fl_image_Surface::offscreen()).

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.4@12148 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

4 files changed, 26 insertions, 12 deletions

diff --git a/src/Fl_Graphics_Driver.cxx b/src/Fl_Graphics_Driver.cxx
index 0429eac0c..b47b8fd88 100644
--- a/src/Fl_Graphics_Driver.cxx
+++ b/src/Fl_Graphics_Driver.cxx
@@ -22,6 +22,7 @@
 #include <FL/Fl_Screen_Driver.H>
 #include <FL/Fl_Image.H>
 #include <FL/fl_draw.H>
+#include <FL/Fl_Image_Surface.H>
 
 FL_EXPORT Fl_Graphics_Driver *fl_graphics_driver; // the current driver of graphics operations
 
@@ -75,8 +76,10 @@ int Fl_Graphics_Driver::draw_scaled(Fl_Image *img, int X, int Y, int W, int H) {
 /** see fl_copy_offscreen() */
 void Fl_Graphics_Driver::copy_offscreen(int x, int y, int w, int h, Fl_Offscreen pixmap, int srcx, int srcy)
 {
-  // This platform-independent version is used when the current graphics driver is PostScript.
-  // It requires that pixmap has been created by fl_create_offscreen().
+  // This platform-independent version can be used by any graphics driver,
+  // noticeably the PostScript driver.
+  // More efficient platform-specific implementations exist for other graphics drivers.
+  Fl_Image_Surface *surface = NULL;
   int px_width = w, px_height = h;
   Fl::screen_driver()->offscreen_size(pixmap, px_width, px_height);
   int px = srcx, py = srcy, pw = w, ph = h;
@@ -84,9 +87,19 @@ void Fl_Graphics_Driver::copy_offscreen(int x, int y, int w, int h, Fl_Offscreen
   if (py < 0) {py = 0; ph += srcy; y -= srcy;}
   if (px + pw > px_width) {pw = px_width - px;}
   if (py + ph > px_height) {ph = px_height - py;}
+  Fl_Surface_Device *current = Fl_Surface_Device::surface();
   fl_begin_offscreen(pixmap);
+  // test whether pixmap was not created by fl_create_offscreen()
+  if (current == Fl_Surface_Device::surface()) {
+    surface = new Fl_Image_Surface(px_width, px_height, 0, pixmap);
+    Fl_Surface_Device::push_current(surface);
+  }
   uchar *img = fl_read_image(NULL, px, py, pw, ph, 0);
-  fl_end_offscreen();
+  if (surface) {
+    Fl_Surface_Device::pop_current();
+    surface->get_offscreen_before_delete(); // so deleting surface does not touch pixmap
+    delete surface;
+  } else fl_end_offscreen();
   if (img) {
     fl_draw_image(img, x, y, pw, ph, 3, 0);
     delete[] img;
diff --git a/src/Fl_Image_Surface.cxx b/src/Fl_Image_Surface.cxx
index 2fa60fd1f..632bc3de0 100644
--- a/src/Fl_Image_Surface.cxx
+++ b/src/Fl_Image_Surface.cxx
@@ -146,6 +146,7 @@ void fl_delete_offscreen(Fl_Offscreen ctx) {
     if (offscreen_api_surface[i] && offscreen_api_surface[i]->offscreen() == ctx) {
       delete offscreen_api_surface[i];
       offscreen_api_surface[i] = NULL;
+      return;
     }
   }
 }
diff --git a/src/drivers/GDI/Fl_GDI_Image_Surface_Driver.cxx b/src/drivers/GDI/Fl_GDI_Image_Surface_Driver.cxx
index 54a4a038f..933593e6d 100644
--- a/src/drivers/GDI/Fl_GDI_Image_Surface_Driver.cxx
+++ b/src/drivers/GDI/Fl_GDI_Image_Surface_Driver.cxx
@@ -34,7 +34,7 @@ public:
   Window pre_window;
   HDC _sgc;
   int _savedc;
-  Fl_GDI_Image_Surface_Driver(int w, int h, int high_res);
+  Fl_GDI_Image_Surface_Driver(int w, int h, int high_res, Fl_Offscreen off);
   ~Fl_GDI_Image_Surface_Driver();
   void set_current();
   void translate(int x, int y);
@@ -45,13 +45,13 @@ public:
 
 Fl_Image_Surface_Driver *Fl_Image_Surface_Driver::newImageSurfaceDriver(int w, int h, int high_res, Fl_Offscreen off)
 {
-  return new Fl_GDI_Image_Surface_Driver(w, h, high_res);
+  return new Fl_GDI_Image_Surface_Driver(w, h, high_res, off);
 }
 
 
-Fl_GDI_Image_Surface_Driver::Fl_GDI_Image_Surface_Driver(int w, int h, int high_res) : Fl_Image_Surface_Driver(w, h, high_res, 0) {
+Fl_GDI_Image_Surface_Driver::Fl_GDI_Image_Surface_Driver(int w, int h, int high_res, Fl_Offscreen off) : Fl_Image_Surface_Driver(w, h, high_res, 0) {
   previous = 0;
-  offscreen = CreateCompatibleBitmap( (fl_graphics_driver->gc() ? (HDC)fl_graphics_driver->gc() : fl_GetDC(0) ) , w, h);
+  offscreen = off ? off : CreateCompatibleBitmap( (fl_graphics_driver->gc() ? (HDC)fl_graphics_driver->gc() : fl_GetDC(0) ) , w, h);
   driver(new Fl_Translated_GDI_Graphics_Driver);
   _sgc = NULL;
 }
diff --git a/src/drivers/Quartz/Fl_Quartz_Image_Surface_Driver.cxx b/src/drivers/Quartz/Fl_Quartz_Image_Surface_Driver.cxx
index cb22904aa..2404c531f 100644
--- a/src/drivers/Quartz/Fl_Quartz_Image_Surface_Driver.cxx
+++ b/src/drivers/Quartz/Fl_Quartz_Image_Surface_Driver.cxx
@@ -30,7 +30,7 @@ class Fl_Quartz_Image_Surface_Driver : public Fl_Image_Surface_Driver {
   virtual void end_current_();
 public:
   Window pre_window;
-  Fl_Quartz_Image_Surface_Driver(int w, int h, int high_res);
+  Fl_Quartz_Image_Surface_Driver(int w, int h, int high_res, Fl_Offscreen off);
   ~Fl_Quartz_Image_Surface_Driver();
   void set_current();
   void translate(int x, int y);
@@ -39,17 +39,17 @@ public:
 };
 
 
-Fl_Image_Surface_Driver *Fl_Image_Surface_Driver::newImageSurfaceDriver(int w, int h, int high_res, Fl_Offscreen)
+Fl_Image_Surface_Driver *Fl_Image_Surface_Driver::newImageSurfaceDriver(int w, int h, int high_res, Fl_Offscreen off)
 {
-  return new Fl_Quartz_Image_Surface_Driver(w, h, high_res);
+  return new Fl_Quartz_Image_Surface_Driver(w, h, high_res, off);
 }
 
 
-Fl_Quartz_Image_Surface_Driver::Fl_Quartz_Image_Surface_Driver(int w, int h, int high_res) : Fl_Image_Surface_Driver(w, h, high_res, 0) {
+Fl_Quartz_Image_Surface_Driver::Fl_Quartz_Image_Surface_Driver(int w, int h, int high_res, Fl_Offscreen off) : Fl_Image_Surface_Driver(w, h, high_res, 0) {
   int W = high_res ? 2*w : w;
   int H = high_res ? 2*h : h;
   CGColorSpaceRef lut = CGColorSpaceCreateDeviceRGB();
-  offscreen = CGBitmapContextCreate(calloc(W*H,4), W, H, 8, W*4, lut, kCGImageAlphaPremultipliedLast);
+  offscreen = off ? off : CGBitmapContextCreate(calloc(W*H,4), W, H, 8, W*4, lut, kCGImageAlphaPremultipliedLast);
   CGColorSpaceRelease(lut);
   driver(new Fl_Quartz_Graphics_Driver);
   CGContextTranslateCTM(offscreen, 0.5, -0.5); // as when drawing to a window