Fix negative 'd' and 'ld' args in fl_draw_image() (X11 + Windows).

This commit fixes a regression in FLTK 1.3.x, where negative values
of 'd' (pixel delta) and 'ld' (line delta) didn't work anymore under
Unix/Linux (X11) and Windows.

With this commit the regression is fixed on all supported platforms.

Equivalent of branch-1.3, svn r11270.


git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3-porting@11272 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

2 files changed, 15 insertions, 10 deletions

diff --git a/src/drivers/GDI/Fl_GDI_Graphics_Driver_image.cxx b/src/drivers/GDI/Fl_GDI_Graphics_Driver_image.cxx
index f750e1785..070c65568 100644
--- a/src/drivers/GDI/Fl_GDI_Graphics_Driver_image.cxx
+++ b/src/drivers/GDI/Fl_GDI_Graphics_Driver_image.cxx
@@ -106,6 +106,8 @@ static void monodither(uchar* to, const uchar* from, int w, int delta) {
 
 #endif // USE_COLORMAP
 
+static int fl_abs(int v) { return v<0 ? -v : v; }
+
 static void innards(const uchar *buf, int X, int Y, int W, int H,
 		    int delta, int linedelta, int depth,
 		    Fl_Draw_Image_Cb cb, void* userdata, HDC gc)
@@ -120,7 +122,7 @@ static void innards(const uchar *buf, int X, int Y, int W, int H,
   if (indexed || !fl_can_do_alpha_blending()) 
     depth = (depth-1)|1;
 
-  if (!linedelta) linedelta = W*delta;
+  if (!linedelta) linedelta = W*fl_abs(delta);
 
   int x, y, w, h;
   fl_clip_box(X,Y,W,H,x,y,w,h);
@@ -281,8 +283,6 @@ static void innards(const uchar *buf, int X, int Y, int W, int H,
   }
 }
 
-static int fl_abs(int v) { return v<0 ? -v : v; }
-
 void Fl_GDI_Graphics_Driver::draw_image(const uchar* buf, int x, int y, int w, int h, int d, int l){
   if (fl_abs(d)&FL_IMAGE_WITH_ALPHA) {
     d ^= FL_IMAGE_WITH_ALPHA;
diff --git a/src/drivers/Xlib/Fl_Xlib_Graphics_Driver_image.cxx b/src/drivers/Xlib/Fl_Xlib_Graphics_Driver_image.cxx
index 723c22838..069fc925e 100644
--- a/src/drivers/Xlib/Fl_Xlib_Graphics_Driver_image.cxx
+++ b/src/drivers/Xlib/Fl_Xlib_Graphics_Driver_image.cxx
@@ -458,7 +458,7 @@ static void innards(const uchar *buf, int X, int Y, int W, int H,
 		    Fl_Draw_Image_Cb cb, void* userdata,
 		    const bool alpha, GC gc)
 {
-  if (!linedelta) linedelta = W*delta;
+  if (!linedelta) linedelta = W*abs(delta);
 
   int dx, dy, w, h;
   fl_clip_box(X,Y,W,H,dx,dy,w,h);
@@ -565,22 +565,27 @@ static void innards(const uchar *buf, int X, int Y, int W, int H,
 
 void Fl_Xlib_Graphics_Driver::draw_image(const uchar* buf, int x, int y, int w, int h, int d, int l){
 
-  const bool alpha = !!(d & FL_IMAGE_WITH_ALPHA);
-  d &= ~FL_IMAGE_WITH_ALPHA;
+  const bool alpha = !!(abs(d) & FL_IMAGE_WITH_ALPHA);
+  if (alpha) d ^= FL_IMAGE_WITH_ALPHA;
+  const int mono = (d>-3 && d<3);
 
-  innards(buf,x,y,w,h,d,l,(d<3&&d>-3),0,0,alpha,gc_);
+  innards(buf,x,y,w,h,d,l,mono,0,0,alpha,gc_);
 }
+
 void Fl_Xlib_Graphics_Driver::draw_image(Fl_Draw_Image_Cb cb, void* data,
 		   int x, int y, int w, int h,int d) {
 
-  const bool alpha = !!(d & FL_IMAGE_WITH_ALPHA);
-  d &= ~FL_IMAGE_WITH_ALPHA;
+  const bool alpha = !!(abs(d) & FL_IMAGE_WITH_ALPHA);
+  if (alpha) d ^= FL_IMAGE_WITH_ALPHA;
+  const int mono = (d>-3 && d<3);
 
-  innards(0,x,y,w,h,d,0,(d<3&&d>-3),cb,data,alpha,gc_);
+  innards(0,x,y,w,h,d,0,mono,cb,data,alpha,gc_);
 }
+
 void Fl_Xlib_Graphics_Driver::draw_image_mono(const uchar* buf, int x, int y, int w, int h, int d, int l){
   innards(buf,x,y,w,h,d,l,1,0,0,0,gc_);
 }
+
 void Fl_Xlib_Graphics_Driver::draw_image_mono(Fl_Draw_Image_Cb cb, void* data,
 		   int x, int y, int w, int h,int d) {
   innards(0,x,y,w,h,d,0,1,cb,data,0,gc_);