3 files changed, 3 insertions, 3 deletions
diff --git a/src/drivers/GDI/Fl_GDI_Graphics_Driver_image.cxx b/src/drivers/GDI/Fl_GDI_Graphics_Driver_image.cxx
index f66adba1e..b393175a3 100644
--- a/src/drivers/GDI/Fl_GDI_Graphics_Driver_image.cxx
+++ b/src/drivers/GDI/Fl_GDI_Graphics_Driver_image.cxx
@@ -699,7 +699,7 @@ void Fl_GDI_Graphics_Driver::cache(Fl_Pixmap *img) {
   Fl_Image_Surface *surf = new Fl_Image_Surface(img->data_w(), img->data_h());
   Fl_Surface_Device::push_current(surf);
   uchar **pbitmap = surf->driver()->mask_bitmap();
-  *pbitmap = 0;
+  *pbitmap = (uchar*)1;// will instruct fl_draw_pixmap() to compute the image's mask
   fl_draw_pixmap(img->data(), 0, 0, FL_BLACK);
   uchar *bitmap = *pbitmap;
   if (bitmap) {
diff --git a/src/drivers/PostScript/Fl_PostScript_image.cxx b/src/drivers/PostScript/Fl_PostScript_image.cxx
index c007d9460..7c977bdf7 100644
--- a/src/drivers/PostScript/Fl_PostScript_image.cxx
+++ b/src/drivers/PostScript/Fl_PostScript_image.cxx
@@ -575,7 +575,7 @@ void Fl_PostScript_Graphics_Driver::draw_pixmap(Fl_Pixmap * pxm,int XP, int YP,
   const char * const * di =pxm->data();
   int w,h;
   if (!fl_measure_pixmap(di, w, h)) return;
-  mask=0;
+  mask=(uchar*)1;// will instruct fl_draw_pixmap() to compute the image's mask
   mx = w;
   my = h;
   fl_draw_pixmap(di, 0, 0, FL_BLACK); // assigns mask to an array
diff --git a/src/drivers/Xlib/Fl_Xlib_Graphics_Driver_image.cxx b/src/drivers/Xlib/Fl_Xlib_Graphics_Driver_image.cxx
index 05f3bd598..68cb70833 100644
--- a/src/drivers/Xlib/Fl_Xlib_Graphics_Driver_image.cxx
+++ b/src/drivers/Xlib/Fl_Xlib_Graphics_Driver_image.cxx
@@ -870,7 +870,7 @@ void Fl_Xlib_Graphics_Driver::cache(Fl_Pixmap *pxm) {
   Fl_Image_Surface *surf = new Fl_Image_Surface(pxm->data_w(), pxm->data_h());
   Fl_Surface_Device::push_current(surf);
   uchar **pbitmap = surf->driver()->mask_bitmap();
-  *pbitmap = 0;
+  *pbitmap = (uchar*)1;// will instruct fl_draw_pixmap() to compute the image's mask
   fl_draw_pixmap(pxm->data(), 0, 0, FL_BLACK);
   uchar *bitmap = *pbitmap;
   if (bitmap) {