From b2eb8cc0df5e8abc7dea607244ff044936871815 Mon Sep 17 00:00:00 2001
From: Harley Acheson <harley.acheson@gmail.com>
Date: Fri, 27 Sep 2024 00:56:52 +0200
Subject: [PATCH] UI: Edge Highlighting While Resizing Editors

Highlighting of the active edges of editors while resizing.

Pull Request: https://projects.blender.org/blender/blender/pulls/120998
---
 source/blender/editors/screen/screen_draw.cc  | 33 +++++++++++++++++++
 .../blender/editors/screen/screen_intern.hh   |  2 ++
 source/blender/editors/screen/screen_ops.cc   | 17 ++++++++++
 3 files changed, 52 insertions(+)

diff --git a/source/blender/editors/screen/screen_draw.cc b/source/blender/editors/screen/screen_draw.cc
index 12dc4213b33..d59b6d0c123 100644
--- a/source/blender/editors/screen/screen_draw.cc
+++ b/source/blender/editors/screen/screen_draw.cc
@@ -273,6 +273,39 @@ void ED_screen_draw_edges(wmWindow *win)
   }
 }
 
+void screen_draw_move_highlight(bScreen *screen, eScreenAxis dir_axis)
+{
+  rctf rect = {SHRT_MAX, SHRT_MIN, SHRT_MAX, SHRT_MIN};
+
+  LISTBASE_FOREACH (const ScrEdge *, edge, &screen->edgebase) {
+    if (edge->v1->editflag && edge->v2->editflag) {
+      if (dir_axis == SCREEN_AXIS_H) {
+        rect.xmin = std::min({rect.xmin, float(edge->v1->vec.x), float(edge->v2->vec.x)});
+        rect.xmax = std::max({rect.xmax, float(edge->v1->vec.x), float(edge->v2->vec.x)});
+        rect.ymin = rect.ymax = float(edge->v1->vec.y);
+      }
+      else {
+        rect.ymin = std::min({rect.ymin, float(edge->v1->vec.y), float(edge->v2->vec.y)});
+        rect.ymax = std::max({rect.ymax, float(edge->v1->vec.y), float(edge->v2->vec.y)});
+        rect.xmin = rect.xmax = float(edge->v1->vec.x);
+      }
+    };
+  }
+
+  if (dir_axis == SCREEN_AXIS_H) {
+    BLI_rctf_pad(&rect, 0.0f, 2.5f * U.pixelsize);
+  }
+  else {
+    BLI_rctf_pad(&rect, 2.5f * U.pixelsize, 0.0f);
+  }
+
+  float inner[4] = {1.0f, 1.0f, 1.0f, 0.7f};
+  float outline[4] = {0.0f, 0.0f, 0.0f, 0.8f};
+  UI_draw_roundbox_corner_set(UI_CNR_ALL);
+  UI_draw_roundbox_4fv_ex(
+      &rect, inner, nullptr, 1.0f, outline, 2.0f * U.pixelsize, 2.5f * U.pixelsize);
+}
+
 static void screen_draw_area_drag_tip(int x, int y, const ScrArea *source, const std::string &hint)
 {
   const char *area_name = IFACE_(ED_area_name(source).c_str());
diff --git a/source/blender/editors/screen/screen_intern.hh b/source/blender/editors/screen/screen_intern.hh
index 359830f226f..dbe8a2029de 100644
--- a/source/blender/editors/screen/screen_intern.hh
+++ b/source/blender/editors/screen/screen_intern.hh
@@ -93,6 +93,8 @@ void screen_draw_dock_preview(
     ScrArea *source, ScrArea *target, AreaDockTarget dock_target, float factor, int x, int y);
 void screen_draw_split_preview(ScrArea *area, eScreenAxis dir_axis, float factor);
 
+void screen_draw_move_highlight(bScreen *screen, eScreenAxis dir_axis);
+
 /* `screen_edit.cc` */
 
 /**
diff --git a/source/blender/editors/screen/screen_ops.cc b/source/blender/editors/screen/screen_ops.cc
index cc3d0c58036..502b588b072 100644
--- a/source/blender/editors/screen/screen_ops.cc
+++ b/source/blender/editors/screen/screen_ops.cc
@@ -1655,6 +1655,8 @@ struct sAreaMoveData {
   int bigger, smaller, origval, step;
   eScreenAxis dir_axis;
   AreaMoveSnapType snap_type;
+  bScreen *screen;
+  void *draw_callback; /* Call #screen_draw_move_highlight */
 };
 
 /* helper call to move area-edge, sets limits
@@ -1757,6 +1759,13 @@ static void area_move_set_limits(wmWindow *win,
   }
 }
 
+static void area_move_draw_cb(const wmWindow * /*win*/, void *userdata)
+{
+  const wmOperator *op = static_cast<const wmOperator *>(userdata);
+  const sAreaMoveData *md = static_cast<sAreaMoveData *>(op->customdata);
+  screen_draw_move_highlight(md->screen, md->dir_axis);
+}
+
 /* validate selection inside screen, set variables OK */
 /* return false: init failed */
 static bool area_move_init(bContext *C, wmOperator *op)
@@ -1799,6 +1808,9 @@ static bool area_move_init(bContext *C, wmOperator *op)
 
   md->snap_type = use_bigger_smaller_snap ? SNAP_BIGGER_SMALLER_ONLY : SNAP_AREAGRID;
 
+  md->screen = screen;
+  md->draw_callback = WM_draw_cb_activate(CTX_wm_window(C), area_move_draw_cb, op);
+
   return true;
 }
 
@@ -1988,6 +2000,11 @@ static void area_move_apply(bContext *C, wmOperator *op)
 
 static void area_move_exit(bContext *C, wmOperator *op)
 {
+  sAreaMoveData *md = static_cast<sAreaMoveData *>(op->customdata);
+  if (md->draw_callback) {
+    WM_draw_cb_exit(CTX_wm_window(C), md->draw_callback);
+  }
+
   MEM_SAFE_FREE(op->customdata);
 
   /* this makes sure aligned edges will result in aligned grabbing */