From 3ae2b1d74e35a4ac0d80b35e3eaa23088ccffeb4 Mon Sep 17 00:00:00 2001
From: Manolo Gouy <Manolo>
Date: Sun, 30 Oct 2016 07:26:13 +0000
Subject: Add virtual Fl_RGB_Image* Fl_Image::as_rgb_image() to detect whether
 an Fl_Image is derived from Fl_RGB_Image

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3-porting@12061 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
---
 FL/Fl_Image.H                                    | 8 ++++++++
 src/Fl_Shared_Image.cxx                          | 2 +-
 src/drivers/GDI/Fl_GDI_Graphics_Driver_image.cxx | 4 ++--
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/FL/Fl_Image.H b/FL/Fl_Image.H
index 203a91d3b..09d84a6de 100644
--- a/FL/Fl_Image.H
+++ b/FL/Fl_Image.H
@@ -30,6 +30,7 @@ class Fl_Widget;
 class Fl_Pixmap;
 struct Fl_Menu_Item;
 struct Fl_Label;
+class Fl_RGB_Image;
 
 
 /** \enum Fl_RGB_Scaling
@@ -186,6 +187,12 @@ public:
 
   // get RGB image scaling method
   static Fl_RGB_Scaling RGB_scaling();
+  /** Use this method if you have an Fl_Image object and want to know whether it is derived 
+   from class Fl_RGB_Image. 
+   If the method returns non-NULL, then the image in question is
+   derived from Fl_RGB_Image, and the returned value is a pointer to this image.
+   */
+  virtual Fl_RGB_Image *as_rgb_image() {return NULL;}
 };
 
 
@@ -249,6 +256,7 @@ public:
    \sa  void Fl_RGB_Image::max_size(size_t)
    */
   static size_t max_size() {return max_size_;}
+  virtual Fl_RGB_Image *as_rgb_image() {return this;}
 };
 
 #endif // !Fl_Image_H
diff --git a/src/Fl_Shared_Image.cxx b/src/Fl_Shared_Image.cxx
index 216387aa7..f94d28f11 100644
--- a/src/Fl_Shared_Image.cxx
+++ b/src/Fl_Shared_Image.cxx
@@ -378,7 +378,7 @@ void Fl_Graphics_Driver::draw(Fl_Shared_Image *shared, int X, int Y) {
     return;
   }
   // don't call Fl_Graphics_Driver::draw_scaled(Fl_Image*,...) for an enlarged Fl_Bitmap or Fl_Pixmap
-  if ((shared->d() != 0 && shared->count() < 2) || (shared->w() <= shared->image_->w() && shared->h() <= shared->image_->h())) {
+  if (shared->as_rgb_image() || (shared->w() <= shared->image_->w() && shared->h() <= shared->image_->h())) {
     int done = fl_graphics_driver->draw_scaled(shared->image_, X, Y, shared->w(), shared->h());
     if (done) return;
   }
diff --git a/src/drivers/GDI/Fl_GDI_Graphics_Driver_image.cxx b/src/drivers/GDI/Fl_GDI_Graphics_Driver_image.cxx
index a9ecae8e0..cbd6f591a 100644
--- a/src/drivers/GDI/Fl_GDI_Graphics_Driver_image.cxx
+++ b/src/drivers/GDI/Fl_GDI_Graphics_Driver_image.cxx
@@ -542,9 +542,9 @@ int Fl_GDI_Printer_Graphics_Driver::draw_scaled(Fl_Image *img, int XP, int YP, i
 }
 
 int Fl_GDI_Graphics_Driver::draw_scaled(Fl_Image *img, int XP, int YP, int WP, int HP) {
-  if (img->d() == 0 || img->count() >= 2) return 0; // for bitmaps and pixmaps
+  Fl_RGB_Image *rgb = img->as_rgb_image();
+  if (!rgb || !rgb->array) return 0; // for bitmaps and pixmaps
   
-  Fl_RGB_Image *rgb = (Fl_RGB_Image*)img;
   if (!rgb->id_) rgb->id_ = (fl_uintptr_t)build_id(rgb, (void**)&(rgb->mask_));
   HDC new_gc = CreateCompatibleDC(gc_);
   int save = SaveDC(new_gc);
-- 
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