Fl_Scroll mods for global scrollbar size control.

    Also, unittest added (scrollbar size) to test these changes.
    Thanks to Albrecht for testing/peer review.



git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@6828 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

1 files changed, 160 insertions, 72 deletions

diff --git a/src/Fl_Scroll.cxx b/src/Fl_Scroll.cxx
index 77c35d7a4..085d47bf0 100644
--- a/src/Fl_Scroll.cxx
+++ b/src/Fl_Scroll.cxx
@@ -52,6 +52,9 @@ void Fl_Scroll::fix_scrollbar_order() {
   }
 }
 
+// Draw widget's background and children within a specific clip region
+//    So widget can just redraw damaged parts.
+//
 void Fl_Scroll::draw_clip(void* v,int X, int Y, int W, int H) {
   fl_push_clip(X,Y,W,H);
   Fl_Scroll* s = (Fl_Scroll*)v;
@@ -93,6 +96,126 @@ void Fl_Scroll::draw_clip(void* v,int X, int Y, int W, int H) {
 }
 
 /**
+   Calculate visibility/size/position of scrollbars, find children's bounding box.
+   The \p si paramater will be filled with data from the calculations.
+   Derived classes can make use of this call to figure out the scrolling area
+   eg. during resize() handling.
+   \param[in] si -- ScrollInfo structure
+   \returns Structure containing the calculated info.
+*/
+void Fl_Scroll::recalc_scrollbars(ScrollInfo &si) {
+
+  // inner box of widget (excluding scrollbars)
+  si.innerbox_x = x()+Fl::box_dx(box());
+  si.innerbox_y = y()+Fl::box_dy(box());
+  si.innerbox_w = w()-Fl::box_dw(box());
+  si.innerbox_h = h()-Fl::box_dh(box());
+
+  // accumulate a bounding box for all the children
+  si.child_l = si.innerbox_x;
+  si.child_r = si.innerbox_x;
+  si.child_b = si.innerbox_y;
+  si.child_t = si.innerbox_y;
+  int first = 1;
+  Fl_Widget*const* a = array();
+  for (int i=children()-2; i--;) {
+    Fl_Widget* o = *a++;
+    if ( first ) {
+        first = 0;
+	si.child_l = o->x();
+	si.child_r = o->x()+o->w();
+	si.child_b = o->y()+o->h();
+	si.child_t = o->y();
+    } else {
+	if (o->x() < si.child_l) si.child_l = o->x();
+	if (o->y() < si.child_t) si.child_t = o->y();
+	if (o->x()+o->w() > si.child_r) si.child_r = o->x()+o->w();
+	if (o->y()+o->h() > si.child_b) si.child_b = o->y()+o->h();
+    }
+  }
+
+  // Turn the scrollbars on and off as necessary.
+  // See if children would fit if we had no scrollbars...
+  {
+    int X = si.innerbox_x;
+    int Y = si.innerbox_y;
+    int W = si.innerbox_w;
+    int H = si.innerbox_h;
+
+    si.scrollsize = scrollbar_size_ ? scrollbar_size_ : Fl::scrollbar_size();
+    si.vneeded = 0;
+    si.hneeded = 0;
+    if (type() & VERTICAL) {
+      if ((type() & ALWAYS_ON) || si.child_t < Y || si.child_b > Y+H) {
+	si.vneeded = 1;
+	W -= si.scrollsize;
+	if (scrollbar.align() & FL_ALIGN_LEFT) X += si.scrollsize;
+      }
+    }
+    if (type() & HORIZONTAL) {
+      if ((type() & ALWAYS_ON) || si.child_l < X || si.child_r > X+W) {
+	si.hneeded = 1;
+	H -= si.scrollsize;
+	if (scrollbar.align() & FL_ALIGN_TOP) Y += si.scrollsize;
+	// recheck vertical since we added a horizontal scrollbar
+	if (!si.vneeded && (type() & VERTICAL)) {
+	  if ((type() & ALWAYS_ON) || si.child_t < Y || si.child_b > Y+H) {
+	    si.vneeded = 1;
+	    W -= si.scrollsize;
+	    if (scrollbar.align() & FL_ALIGN_LEFT) X += si.scrollsize;
+	  }
+	}
+      }
+    }
+    si.innerchild_x = X;
+    si.innerchild_y = Y;
+    si.innerchild_w = W;
+    si.innerchild_h = H;
+  }
+
+  // calculate hor scrollbar position
+  si.hscroll_x = si.innerchild_x;
+  si.hscroll_y = (scrollbar.align() & FL_ALIGN_TOP) 
+		     ? si.innerbox_y
+		     : si.innerbox_y + si.innerbox_h - si.scrollsize;
+  si.hscroll_w = si.innerchild_w;
+  si.hscroll_h = si.scrollsize;
+
+  // calculate ver scrollbar position
+  si.vscroll_x = (scrollbar.align() & FL_ALIGN_LEFT)
+                     ? si.innerbox_x
+		     : si.innerbox_x + si.innerbox_w - si.scrollsize;
+  si.vscroll_y = si.innerchild_y;
+  si.vscroll_w = si.scrollsize;
+  si.vscroll_h = si.innerchild_h;
+
+  // calculate h/v scrollbar values (pos/size/first/total)
+  si.hpos = si.innerchild_x - si.child_l;
+  si.hsize = si.innerchild_w;
+  si.hfirst = 0;
+  si.htotal = si.child_r - si.child_l;
+  if ( si.hpos < 0 ) { si.htotal += (-si.hpos); si.hfirst = si.hpos; }
+
+  si.vpos = si.innerchild_y - si.child_t;
+  si.vsize = si.innerchild_h;
+  si.vfirst = 0;
+  si.vtotal = si.child_b - si.child_t;
+  if ( si.vpos < 0 ) { si.vtotal += (-si.vpos); si.vfirst = si.vpos; }
+
+//  printf("DEBUG --- ScrollInfo ---\n");
+//  printf("DEBUG        scrollsize: %d\n", si.scrollsize);
+//  printf("DEBUG  hneeded, vneeded: %d %d\n", si.hneeded, si.vneeded);
+//  printf("DEBUG     innerbox xywh: %d %d %d %d\n", si.innerbox_x,   si.innerbox_y,   si.innerbox_w,   si.innerbox_h);
+//  printf("DEBUG   innerchild xywh: %d %d %d %d\n", si.innerchild_x, si.innerchild_y, si.innerchild_w, si.innerchild_h);
+//  printf("DEBUG        child lrbt: %d %d %d %d\n", si.child_l, si.child_r, si.child_b, si.child_t);
+//  printf("DEBUG      hscroll xywh: %d %d %d %d\n", si.hscroll_x, si.hscroll_y, si.hscroll_w, si.hscroll_h);
+//  printf("DEBUG      vscroll xywh: %d %d %d %d\n", si.vscroll_x, si.vscroll_y, si.vscroll_w, si.vscroll_h);
+//  printf("DEBUG  horz scroll vals: %d %d %d %d\n", si.hpos, si.hsize, si.hfirst, si.htotal);
+//  printf("DEBUG  vert scroll vals: %d %d %d %d\n", si.vpos, si.vsize, si.vfirst, si.vtotal);
+//  printf("DEBUG \n");
+}
+
+/**
   Returns the bounding box for the interior of the scrolling area, inside
   the scrollbars.
   
@@ -157,79 +280,43 @@ void Fl_Scroll::draw() {
     }
   }
 
-  // accumulate bounding box of children:
-  int l = X; int r = X; int t = Y; int b = Y;
-  Fl_Widget*const* a = array();
-  for (int i=children()-2; i--;) {
-    Fl_Object* o = *a++;
-    if (o->x() < l) l = o->x();
-    if (o->y() < t) t = o->y();
-    if (o->x()+o->w() > r) r = o->x()+o->w();
-    if (o->y()+o->h() > b) b = o->y()+o->h();
-  }
+  // Calculate where scrollbars should go, and draw them
+  {
+      ScrollInfo si;
+      recalc_scrollbars(si);
 
-  // turn the scrollbars on and off as necessary:
-  // See if children would fit if we had no scrollbars...
-  X = x()+Fl::box_dx(box());
-  Y = y()+Fl::box_dy(box());
-  W = w()-Fl::box_dw(box());
-  H = h()-Fl::box_dh(box());
-  int vneeded = 0;
-  int hneeded = 0;
-  if (type() & VERTICAL) {
-    if ((type() & ALWAYS_ON) || t < Y || b > Y+H) {
-      vneeded = 1;
-      W -= scrollbar.w();
-      if (scrollbar.align() & FL_ALIGN_LEFT) X += scrollbar.w();
-    }
-  }
-  if (type() & HORIZONTAL) {
-    if ((type() & ALWAYS_ON) || l < X || r > X+W) {
-      hneeded = 1;
-      H -= hscrollbar.h();
-      if (scrollbar.align() & FL_ALIGN_TOP) Y += hscrollbar.h();
-      // recheck vertical since we added a horizontal scrollbar
-      if (!vneeded && (type() & VERTICAL)) {
-	if ((type() & ALWAYS_ON) || t < Y || b > Y+H) {
-	  vneeded = 1;
-	  W -= scrollbar.w();
-	  if (scrollbar.align() & FL_ALIGN_LEFT) X += scrollbar.w();
-	}
+      // Now that we know what's needed, make it so.
+      if (si.vneeded && !scrollbar.visible()) {
+	scrollbar.set_visible();
+	d = FL_DAMAGE_ALL;
+      }
+      else if (!si.vneeded && scrollbar.visible()) {
+	scrollbar.clear_visible();
+	draw_clip(this, si.vscroll_x, si.vscroll_y, si.vscroll_w, si.vscroll_h);
+	d = FL_DAMAGE_ALL;
+      }
+      if (si.hneeded && !hscrollbar.visible()) {
+	hscrollbar.set_visible();
+	d = FL_DAMAGE_ALL;
+      }
+      else if (!si.hneeded && hscrollbar.visible()) {
+	hscrollbar.clear_visible();
+	draw_clip(this, si.hscroll_x, si.hscroll_y, si.hscroll_w, si.hscroll_h);
+	d = FL_DAMAGE_ALL;
+      }
+      else if ( hscrollbar.h() != si.scrollsize || scrollbar.w() != si.scrollsize ) {
+         // scrollsize changed
+         d = FL_DAMAGE_ALL;
       }
-    }
-  }
-  // Now that we know what's needed, make it so.
-  if (vneeded && !scrollbar.visible()) {
-    scrollbar.set_visible();
-    d = FL_DAMAGE_ALL;
-  }
-  else if (!vneeded && scrollbar.visible()) {
-    scrollbar.clear_visible();
-    draw_clip(this,
-	      scrollbar.align()&FL_ALIGN_LEFT ? X : X+W-scrollbar.w(),
-	      Y, scrollbar.w(), H);
-    d = FL_DAMAGE_ALL;
-  }
-  if (hneeded && !hscrollbar.visible()) {
-    hscrollbar.set_visible();
-    d = FL_DAMAGE_ALL;
-  }
-  else if (!hneeded && hscrollbar.visible()) {
-    hscrollbar.clear_visible();
-    draw_clip(this,
-	      X, scrollbar.align()&FL_ALIGN_TOP ? Y : Y+H-hscrollbar.h(),
-	      W, hscrollbar.h());
-    d = FL_DAMAGE_ALL;
-  }
 
-  scrollbar.resize(scrollbar.align()&FL_ALIGN_LEFT ? X-scrollbar.w() : X+W,
-		   Y, scrollbar.w(), H);
-  scrollbar.value(oldy = yposition_ = (Y-t), H, 0, b-t);
+      scrollbar.resize(si.vscroll_x, si.vscroll_y, si.vscroll_w, si.vscroll_h);
+      oldy = yposition_ = si.vpos;	// si.innerchild_y - si.child_t;
+      scrollbar.value(si.vpos, si.vsize, si.vfirst, si.vtotal);
 
-  hscrollbar.resize(X,
-		    scrollbar.align()&FL_ALIGN_TOP ? Y-hscrollbar.h() : Y+H,
-		    W, hscrollbar.h());
-  hscrollbar.value(oldx = xposition_ = (X-l), W, 0, r-l);
+      hscrollbar.resize(si.hscroll_x, si.hscroll_y, si.hscroll_w, si.hscroll_h);
+      oldx = xposition_ = si.hpos;	// si.innerchild_x - si.child_l;
+      hscrollbar.value(si.hpos, si.hsize, si.hfirst, si.htotal);
+  }
 
   // draw the scrollbars:
   if (d & FL_DAMAGE_ALL) {
@@ -254,7 +341,7 @@ void Fl_Scroll::resize(int X, int Y, int W, int H) {
   // move all the children:
   Fl_Widget*const* a = array();
   for (int i=children()-2; i--;) {
-    Fl_Object* o = *a++;
+    Fl_Widget* o = *a++;
     o->position(o->x()+dx, o->y()+dy);
   }
   if (dw==0 && dh==0) {
@@ -312,8 +399,9 @@ Fl_Scroll::Fl_Scroll(int X,int Y,int W,int H,const char* L)
     hscrollbar(X,Y+H-Fl::scrollbar_size(),
                W-Fl::scrollbar_size(),Fl::scrollbar_size()) {
   type(BOTH);
-  xposition_ = 0;
-  yposition_ = 0;
+  xposition_ = oldx = 0;
+  yposition_ = oldy = 0;
+  scrollbar_size_ = 0;
   hscrollbar.type(FL_HORIZONTAL);
   hscrollbar.callback(hscrollbar_cb);
   scrollbar.callback(scrollbar_cb);