Author: AlbrechtS
Date: 2010-11-23 09:18:42 -0800 (Tue, 23 Nov 2010)
New Revision: 7888
Log:
More clipping updates for X11 with coordinates > 32767.
All horizontal and vertical line drawings, as well as fl_rect(), fl_rectf(),
and fl_point() should be clipped correctly. Nothing has been done for
arbitrary (non-orthogonal) lines or other drawings, but this should suffice
for box drawings of large container widgets (STR #2304).


Modified:
   branches/branch-1.3/src/fl_line_style.cxx
   branches/branch-1.3/src/fl_rect.cxx

Modified: branches/branch-1.3/src/fl_line_style.cxx
===================================================================
--- branches/branch-1.3/src/fl_line_style.cxx   2010-11-23 15:00:06 UTC (rev 
7887)
+++ branches/branch-1.3/src/fl_line_style.cxx   2010-11-23 17:18:42 UTC (rev 
7888)
@@ -3,7 +3,7 @@
 //
 // Line style code for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 1998-2009 by Bill Spitzak and others.
+// Copyright 1998-2010 by Bill Spitzak and others.
 //
 // This library is free software; you can redistribute it and/or
 // modify it under the terms of the GNU Library General Public
@@ -37,6 +37,11 @@
 #include "flstring.h"
 #include <stdio.h>
 
+// We save the current line width (absolute value) here.
+// This is currently used only for X11 clipping, see src/fl_rect.cxx.
+// FIXME: this would probably better be in class Fl::
+int fl_line_width_ = 0;
+
 #ifdef __APPLE_QUARTZ__
 float fl_quartz_line_width_ = 1.0f;
 static enum CGLineCap fl_quartz_line_cap_ = kCGLineCapButt;
@@ -53,6 +58,10 @@
 
 void Fl_Graphics_Driver::line_style(int style, int width, char* dashes) {
 
+  // save line width in global variable for X11 clipping
+  if (width == 0) fl_line_width_ = 1;
+  else fl_line_width_ = width>0 ? width : -width;
+
 #if defined(USE_X11)
   int ndashes = dashes ? strlen(dashes) : 0;
   // emulate the WIN32 dash patterns on X

Modified: branches/branch-1.3/src/fl_rect.cxx
===================================================================
--- branches/branch-1.3/src/fl_rect.cxx 2010-11-23 15:00:06 UTC (rev 7887)
+++ branches/branch-1.3/src/fl_rect.cxx 2010-11-23 17:18:42 UTC (rev 7888)
@@ -3,7 +3,7 @@
 //
 // Rectangle drawing routines for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 1998-2009 by Bill Spitzak and others.
+// Copyright 1998-2010 by Bill Spitzak and others.
 //
 // This library is free software; you can redistribute it and/or
 // modify it under the terms of the GNU Library General Public
@@ -42,50 +42,119 @@
 #include <FL/fl_draw.H>
 #include <FL/x.H>
 
+// fl_line_width_ must contain the absolute value of the current
+// line width to be used for X11 clipping (see below).
+// This is defined in src/fl_line_style.cxx
+extern int fl_line_width_;
+
 #ifdef __APPLE_QUARTZ__
 extern float fl_quartz_line_width_;
 #define USINGQUARTZPRINTER  (Fl_Surface_Device::surface()->type() == 
Fl_Printer::device_type)
 #endif
 
 #ifdef USE_X11
-  
+
 #ifndef SHRT_MAX
 #define SHRT_MAX (32767)
 #endif
 
 /*
   We need to check some coordinates for areas for clipping before we
-  use X calls, because X can't handle coordinates outside the 16-bit
-  range. Since windows use relative coordinates > 0, we do also check
-  for negative values. X11 only, see also STR #2304.
+  use X functions, because X can't handle coordinates outside the 16-bit
+  range. Since all windows use relative coordinates > 0, we do also
+  check for negative values. X11 only, see also STR #2304.
+  
+  Note that this is only necessary for large objects, where only a
+  part of the object is visible. The draw() functions (e.g. box
+  drawing) must be clipped correctly. This is usually only a matter
+  for large container widgets. The individual child widgets will be
+  clipped completely.
 
+  We define the usable X coordinate space as [ -LW : SHRT_MAX - LW ]
+  where LW = current line width for drawing. This is done so that
+  horizontal and vertical line drawing works correctly, even in real
+  border cases, e.g. drawing a rectangle slightly outside the top left
+  window corner, but with a line width so that a part of the line should
+  be visible (in this case 2 of 5 pixels):
+
+    fl_line_style (FL_SOLID,5);        // line width = 5
+    fl_rect (-1,-1,100,100);   // top/left: 2 pixels visible
+  
+  In this example case, no clipping would be done, because X can
+  handle it and clip unneeded pixels.
+
+  Todo: Arbitrary line drawings (e.g. polygons) and clip regions
+  are not yet done.
+
   Note:
+
   We could use max. screen coordinates instead of SHRT_MAX, but that
-  would need more work and would probably be slower.
+  would need more work and would probably be slower. We assume that
+  all window coordinates are >= 0 and that no window extends up to
+  32767 - LW (where LW = current line width). Thus it is safe to clip
+  all coordinates to this range before calling X functions. If this
+  is not true, then clip_to_short() and clip_x() must be redefined.
 
-  returns 1, if the area is invisible (clipped), because ...
+  It would be somewhat easier if we had fl_clip_w and fl_clip_h, as
+  defined in FLTK 2.0 (for the upper clipping bounds)...
+*/
+
+/*
+  clip_to_short() returns 1, if the area is invisible (clipped),
+  because ...
+
     (a) w or h are <= 0                i.e. nothing is visible
-    (b) x+w or y+h are < 0     i.e. left of or above visible area
-    (c) x or y are > SHRT_MAX  i.e. right of or below visible area
+    (b) x+w or y+h are < kmin  i.e. left of or above visible area
+    (c) x or y are > kmax      i.e. right of or below visible area
 
-  returns 0, if the area is potentially visible and X can handle the
-    clipping. x, y, w, and h may have been adjusted to fit into the
-    X coordinate space.
+  kmin and kmax are the minimal and maximal X coordinate values,
+  as defined above. In this case x, y, w, and h are not changed.
+
+  It returns 0, if the area is potentially visible and X can handle
+  clipping. x, y, w, and h may have been adjusted to fit into the
+  X coordinate space.
+
+  Use this for clipping rectangles, as used in fl_rect() and
+  fl_rectf().
 */
+
 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_;
+
   if (w <= 0 || h <= 0) return 1;              // (a)
-  if (x+w < 0 || y+h < 0) return 1;            // (b)
-  if (x > SHRT_MAX || y > SHRT_MAX) return 1;  // (c)
+  if (x+w < kmin || y+h < kmin) return 1;      // (b)
+  if (x > kmax || y > kmax) return 1;          // (c)
 
-  if (x < 0) { w += x; x = 0; }
-  if (y < 0) { h += y; y = 0; }
-  if (x+w > SHRT_MAX) w = SHRT_MAX - x;
-  if (y+h > SHRT_MAX) h = SHRT_MAX - y;
+  if (x < kmin) { w -= (kmin-x); x = kmin; }
+  if (y < kmin) { h -= (kmin-y); y = kmin; }
+  if (x+w > kmax) w = kmax - x;
+  if (y+h > kmax) h = kmax - y;
 
   return 0;
 }
 
+/*
+  clip_x() returns a coordinate value clipped to the 16-bit coordinate
+  space (see above). This can be used to draw horizontal and vertical
+  lines that can be handled by X11. Each single coordinate value can
+  be clipped individually, and the result can be used directly, e.g.
+  in fl_xyline() and fl_yxline(). Note that this can't be used for
+  arbitrary lines (not horizontal or vertical).
+*/
+int clip_x (int x) {
+
+  int kmin = -fl_line_width_;
+  int kmax = SHRT_MAX - fl_line_width_;
+
+  if (x < kmin)
+    x = kmin;
+  else if (x > kmax)
+    x = kmax;
+  return x;
+}
+
 #endif // USE_X11
 
 
@@ -93,15 +162,7 @@
 
   if (w<=0 || h<=0) return;
 #if defined(USE_X11)
-  if (x+w < 0 || y+h < 0 || x > SHRT_MAX || y > SHRT_MAX ) return;
-
-  if (x+w > SHRT_MAX || y+h > SHRT_MAX ||
-        w > SHRT_MAX ||   h > SHRT_MAX) { // X can't handle clipping
-    xyline(x, y, x+w-1);
-    yxline(x+w-1, y, y+h-1);
-    xyline(x+w-1, y+h-1, x);
-    yxline(x, y+h-1, y);
-  } else
+  if (!clip_to_short(x, y, w, h))
     XDrawRectangle(fl_display, fl_window, fl_gc, x, y, w-1, h-1);
 #elif defined(WIN32)
   MoveToEx(fl_gc, x, y, 0L); 
@@ -122,10 +183,8 @@
 void Fl_Graphics_Driver::rectf(int x, int y, int w, int h) {
   if (w<=0 || h<=0) return;
 #if defined(USE_X11)
-  if (w && h) {
-    if (!clip_to_short(x,y,w,h))
-      XFillRectangle(fl_display, fl_window, fl_gc, x, y, w, h);
-  }
+  if (!clip_to_short(x, y, w, h))
+    XFillRectangle(fl_display, fl_window, fl_gc, x, y, w, h);
 #elif defined(WIN32)
   RECT rect;
   rect.left = x; rect.top = y;  
@@ -143,18 +202,7 @@
 
 void Fl_Graphics_Driver::xyline(int x, int y, int x1) {
 #if defined(USE_X11)
-  // get rid of coordinates outside the 16-bit range
-  if (y < 0 || y > SHRT_MAX) return;
-  if (x <= x1) {
-    if (x1 < 0 || x > SHRT_MAX) return;
-    if (x < 0) x = 0;
-    if (x1 > SHRT_MAX) x1 = SHRT_MAX;
-  } else { // x1 < x
-    if (x < 0 || x1 > SHRT_MAX) return;
-    if (x1 < 0) x1 = 0;
-    if (x > SHRT_MAX) x = SHRT_MAX;
-  }
-  XDrawLine(fl_display, fl_window, fl_gc, x, y, x1, y);
+  XDrawLine(fl_display, fl_window, fl_gc, clip_x(x), clip_x(y), clip_x(x1), 
clip_x(y));
 #elif defined(WIN32)
   MoveToEx(fl_gc, x, y, 0L); LineTo(fl_gc, x1+1, y);
 #elif defined(__APPLE_QUARTZ__)
@@ -171,8 +219,8 @@
 void Fl_Graphics_Driver::xyline(int x, int y, int x1, int y2) {
 #if defined (USE_X11)
   XPoint p[3];
-  p[0].x = x;  p[0].y = p[1].y = y;
-  p[1].x = p[2].x = x1; p[2].y = y2;
+  p[0].x = clip_x(x);  p[0].y = p[1].y = clip_x(y);
+  p[1].x = p[2].x = clip_x(x1); p[2].y = clip_x(y2);
   XDrawLines(fl_display, fl_window, fl_gc, p, 3, 0);
 #elif defined(WIN32)
   if (y2 < y) y2--;
@@ -195,9 +243,9 @@
 void Fl_Graphics_Driver::xyline(int x, int y, int x1, int y2, int x3) {
 #if defined(USE_X11)
   XPoint p[4];
-  p[0].x = x;  p[0].y = p[1].y = y;
-  p[1].x = p[2].x = x1; p[2].y = p[3].y = y2;
-  p[3].x = x3;
+  p[0].x = clip_x(x);  p[0].y = p[1].y = clip_x(y);
+  p[1].x = p[2].x = clip_x(x1); p[2].y = p[3].y = clip_x(y2);
+  p[3].x = clip_x(x3);
   XDrawLines(fl_display, fl_window, fl_gc, p, 4, 0);
 #elif defined(WIN32)
   if(x3 < x1) x3--;
@@ -221,18 +269,7 @@
 
 void Fl_Graphics_Driver::yxline(int x, int y, int y1) {
 #if defined(USE_X11)
-  // get rid of coordinates outside the 16-bit range
-  if (x < 0 || x > SHRT_MAX) return;
-  if (y <= y1) {
-    if (y1 < 0 || y > SHRT_MAX) return;
-    if (y < 0) y = 0;
-    if (y1 > SHRT_MAX) y1 = SHRT_MAX;
-  } else { // y1 < y
-    if (y < 0 || y1 > SHRT_MAX) return;
-    if (y1 < 0) y1 = 0;
-    if (y > SHRT_MAX) y = SHRT_MAX;
-  }
-  XDrawLine(fl_display, fl_window, fl_gc, x, y, x, y1);
+  XDrawLine(fl_display, fl_window, fl_gc, clip_x(x), clip_x(y), clip_x(x), 
clip_x(y1));
 #elif defined(WIN32)
   if (y1 < y) y1--;
   else y1++;
@@ -251,8 +288,8 @@
 void Fl_Graphics_Driver::yxline(int x, int y, int y1, int x2) {
 #if defined(USE_X11)
   XPoint p[3];
-  p[0].x = p[1].x = x;  p[0].y = y;
-  p[1].y = p[2].y = y1; p[2].x = x2;
+  p[0].x = p[1].x = clip_x(x);  p[0].y = clip_x(y);
+  p[1].y = p[2].y = clip_x(y1); p[2].x = clip_x(x2);
   XDrawLines(fl_display, fl_window, fl_gc, p, 3, 0);
 #elif defined(WIN32)
   if (x2 > x) x2++;
@@ -275,9 +312,9 @@
 void Fl_Graphics_Driver::yxline(int x, int y, int y1, int x2, int y3) {
 #if defined(USE_X11)
   XPoint p[4];
-  p[0].x = p[1].x = x;  p[0].y = y;
-  p[1].y = p[2].y = y1; p[2].x = p[3].x = x2;
-  p[3].y = y3;
+  p[0].x = p[1].x = clip_x(x);  p[0].y = clip_x(y);
+  p[1].y = p[2].y = clip_x(y1); p[2].x = p[3].x = clip_x(x2);
+  p[3].y = clip_x(y3);
   XDrawLines(fl_display, fl_window, fl_gc, p, 4, 0);
 #elif defined(WIN32)
   if(y3<y1) y3--;
@@ -454,7 +491,7 @@
 
 void Fl_Graphics_Driver::point(int x, int y) {
 #if defined(USE_X11)
-  XDrawPoint(fl_display, fl_window, fl_gc, x, y);
+  XDrawPoint(fl_display, fl_window, fl_gc, clip_x(x), clip_x(y));
 #elif defined(WIN32)
   SetPixel(fl_gc, x, y, fl_RGB());
 #elif defined(__APPLE_QUARTZ__)
@@ -481,6 +518,7 @@
 // MSWindows equivalent exists, implemented inline in win32.H
 Fl_Region XRectangleRegion(int x, int y, int w, int h) {
   XRectangle R;
+  clip_to_short(x, y, w, h);
   R.x = x; R.y = y; R.width = w; R.height = h;
   Fl_Region r = XCreateRegion();
   XUnionRectWithRegion(&R, r, r);
@@ -582,13 +620,12 @@
 int Fl_Graphics_Driver::not_clipped(int x, int y, int w, int h) {
   if (x+w <= 0 || y+h <= 0) return 0;
   Fl_Region r = rstack[rstackptr];
+  if (!r) return 1;
 #if defined (USE_X11)
-  if (!r) return 1;
   // get rid of coordinates outside the 16-bit range the X calls take.
   if (clip_to_short(x,y,w,h)) return 0;        // clipped
   return XRectInRegion(r, x, y, w, h);
 #elif defined(WIN32)
-  if (!r) return 1;
   RECT rect;
   if (Fl_Surface_Device::surface()->type() == Fl_Printer::device_type) { // in 
case of print context, convert coords from logical to device
     POINT pt[2] = { {x, y}, {x + w, y + h} };
@@ -599,7 +636,6 @@
   }
   return RectInRegion(r,&rect);
 #elif defined(__APPLE_QUARTZ__)
-  if (!r) return 1;
   CGRect arg = fl_cgrectmake_cocoa(x, y, w, h);
   for (int i = 0; i < r->count; i++) {
     CGRect test = CGRectIntersection(r->rects[i], arg);

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