From 46c9cf2f1033b847896e43d5dad6359f6b01decf Mon Sep 17 00:00:00 2001
From: Matthias Melcher <github@matthiasm.com>
Date: Thu, 4 Jan 2024 01:26:32 +0100
Subject: #797: Improves Fl_Tile resize behaviour

- if a tile with a size range is resize smaller than the
minimum size of all children, the children will now no
longer shrink, and expanding will make them work
again as expected.
---
 src/Fl_Tile.cxx | 58 ++++++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 49 insertions(+), 9 deletions(-)

(limited to 'src')

diff --git a/src/Fl_Tile.cxx b/src/Fl_Tile.cxx
index 5fc015e62..a8f24e67e 100644
--- a/src/Fl_Tile.cxx
+++ b/src/Fl_Tile.cxx
@@ -565,19 +565,59 @@ void Fl_Tile::drag_intersection(int oldx, int oldy, int newx, int newy) {
 void Fl_Tile::resize(int X,int Y,int W,int H) {
 
   if (size_range_) {
-    int dw = w() - W, dh = h() - H;
-    Fl_Widget *r = resizable();
-    if (r) {
-      int rr = r->x() + r->w(), rb = r->y() + r->h();
-      move_intersection(rr, rb, rr-dw, rb-dh);
+    // -- handle size_range style resizing
+    int dx = X - x();
+    int dy = Y - y();
+    int dw = w() - W;
+    int dh = h() - H;
+    // -- if the size does not change, Group resize will suffice
+    if ((dw==0) && (dh==0)) {
+      Fl_Group::resize(X, Y, W, H);
+      init_sizes();
+      redraw();
+      return;
     }
-    int tr = x() + w(), tb = y() + h();
-    move_intersection(tr, tb, tr-dw, tb-dh);
+    // -- if the position changes, move all widgets first
+    if ((dx!=0) || (dy!=0)) {
+      for (int i = 0; i < children(); i++) {
+        Fl_Widget *c = child(i);
+        c->position(c->x()+dx, c->y()+dy);
+      }
+    }
+    // check the bounding box of all children at minimum size
     init_sizes();
+    Fl_Rect *p = bounds();
+    int bbr = X, bbb = Y;
+    for (int i = 0; i < children(); i++) {
+      // find the current bounding box
+      bbr = fl_max(bbr, p[i+2].r());
+      bbb = fl_max(bbb, p[i+2].b());
+    }
+    // fix the dw to the maximum difference possible
+    int r2 = X+W;
+    request_shrink_r(bbr, r2, NULL);
+    dw = bbr - r2;
+    // fix the dh to the maximum difference possible
+    int b2 = Y+H;
+    request_shrink_b(bbb, b2, NULL);
+    dh = bbb - b2;
+    printf("%d %d %d %d  %d %d\n", X, Y, W, H, dw, dh);
+    // perform the actual resize within a safe range
+    if ((dw!=0) || (dh!=0)) {
+      Fl_Widget *r = resizable();
+      if (r) {
+        int rr = r->x() + r->w(), rb = r->y() + r->h();
+        move_intersection(rr, rb, rr-dw, rb-dh);
+      }
+      int tr = x() + w(), tb = y() + h();
+      move_intersection(bbr, bbb, bbr-dw, bbb-dh);
+      init_sizes();
+    }
+    // resize the tile itself
     if (Fl_Window::is_a_rescale())
-      Fl_Group::resize(X,Y,W,H);
+      Fl_Group::resize(X, Y, W, H);
     else
-      Fl_Widget::resize(X,Y,W,H);
+      Fl_Widget::resize(X, Y, W, H);
     return;
   }
 
-- 
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