Fixed drawing artifacts when scrolling round boxes (FL_ROUND_UP_BOX and

FL_ROUND_DOWN_BOX) on Linux (STR #2615). This was done by

 (a) setting the line width in the box drawing function (was undefined, maybe 0)
 (b) taking care of zero and negative line width in X11 clipping functions.

Both solutions would have solved the particular problem individually.

Additionally made local helper function fl_arc_i() in src/fl_round_box.cxx
static to avoid name clashes.


git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@8630 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

2 files changed, 13 insertions, 5 deletions

diff --git a/src/fl_rect.cxx b/src/fl_rect.cxx
index da2ef4154..f893d8b22 100644
--- a/src/fl_rect.cxx
+++ b/src/fl_rect.cxx
@@ -82,6 +82,10 @@ extern float fl_quartz_line_width_;
   
   In this example case, no clipping would be done, because X can
   handle it and clip unneeded pixels.
+  
+  Note that we must also take care of the case where fl_line_width_
+  is zero (maybe unitialized). If this is the case, we assume a line
+  width of 1.
 
   Todo: Arbitrary line drawings (e.g. polygons) and clip regions
   are not yet done.
@@ -120,8 +124,9 @@ extern float fl_quartz_line_width_;
 
 static int clip_to_short(int &x, int &y, int &w, int &h) {
 
-  int kmin = -fl_line_width_;
-  int kmax = SHRT_MAX - fl_line_width_;
+  int lw = (fl_line_width_ > 0) ? fl_line_width_ : 1;
+  int kmin = -lw;
+  int kmax = SHRT_MAX - lw;
 
   if (w <= 0 || h <= 0) return 1;		// (a)
   if (x+w < kmin || y+h < kmin) return 1;	// (b)
@@ -145,8 +150,9 @@ static int clip_to_short(int &x, int &y, int &w, int &h) {
 */
 static int clip_x (int x) {
 
-  int kmin = -fl_line_width_;
-  int kmax = SHRT_MAX - fl_line_width_;
+  int lw = (fl_line_width_ > 0) ? fl_line_width_ : 1;
+  int kmin = -lw;
+  int kmax = SHRT_MAX - lw;
 
   if (x < kmin)
     x = kmin;
diff --git a/src/fl_round_box.cxx b/src/fl_round_box.cxx
index b98e47b7d..bb734dbcd 100644
--- a/src/fl_round_box.cxx
+++ b/src/fl_round_box.cxx
@@ -35,7 +35,7 @@
 // A compiler from a certain very large software company will not compile
 // the function pointer assignment due to the name conflict with fl_arc.
 // This function is to fix that:
-void fl_arc_i(int x,int y,int w,int h,double a1,double a2) {
+static void fl_arc_i(int x,int y,int w,int h,double a1,double a2) {
   fl_arc(x,y,w,h,a1,a2);
 }
 
@@ -52,6 +52,7 @@ static void draw(int which, int x,int y,int w,int h, int inset, Fl_Color color)
   int d = w <= h ? w : h;
   if (d <= 1) return;
   fl_color(color);
+  fl_line_style(0,1);
   void (*f)(int,int,int,int,double,double);
   f = (which==FILL) ? fl_pie : fl_arc_i;
   if (which >= CLOSED) {
@@ -78,6 +79,7 @@ static void draw(int which, int x,int y,int w,int h, int inset, Fl_Color color)
       if (which != LOWER_RIGHT) fl_xyline(x+d/2-1, y, x+w-d/2+1);
     }
   }
+  fl_line_style(0);
 }
 
 extern uchar* fl_gray_ramp();