From 867d28ac6259c72a69b4ceac0badbc02f59f6d38 Mon Sep 17 00:00:00 2001
From: Alexander Batalov <alex.batalov@gmail.com>
Date: Thu, 20 Jul 2023 10:13:21 +0300
Subject: [PATCH] Add rect_clip

---
 src/geometry.cc | 56 +++++++++++++++++++++++++++++++++++++++++++++++++
 src/geometry.h  |  1 +
 2 files changed, 57 insertions(+)

diff --git a/src/geometry.cc b/src/geometry.cc
index e18eabb..9eb97fb 100644
--- a/src/geometry.cc
+++ b/src/geometry.cc
@@ -107,6 +107,62 @@ void _rect_clip_list(RectListNode** rectListNodePtr, Rect* rect)
     }
 }
 
+// 0x4C6AAC
+RectListNode* rect_clip(Rect* b, Rect* t)
+{
+    RectListNode* list = NULL;
+    Rect clipped_t;
+
+    if (rectIntersection(t, b, &clipped_t) == 0) {
+        RectListNode** next = &list;
+        Rect clipped_b[4];
+        int k;
+
+        clipped_b[0].left = b->left;
+        clipped_b[0].top = b->top;
+        clipped_b[0].right = b->right;
+        clipped_b[0].bottom = clipped_t.top - 1;
+
+        clipped_b[1].left = b->left;
+        clipped_b[1].top = clipped_t.top;
+        clipped_b[1].right = clipped_t.left - 1;
+        clipped_b[1].bottom = clipped_t.bottom;
+
+        clipped_b[2].left = clipped_t.right + 1;
+        clipped_b[2].top = clipped_t.top;
+        clipped_b[2].right = b->right;
+        clipped_b[2].bottom = clipped_t.bottom;
+
+        clipped_b[3].left = b->left;
+        clipped_b[3].top = clipped_t.bottom + 1;
+        clipped_b[3].right = b->right;
+        clipped_b[3].bottom = b->bottom;
+
+        for (k = 0; k < 4; k++) {
+            if (clipped_b[k].left <= clipped_b[k].right && clipped_b[k].top <= clipped_b[k].bottom) {
+                *next = _rect_malloc();
+                if (*next == NULL) {
+                    return NULL;
+                }
+
+                (*next)->rect = clipped_b[k];
+                (*next)->next = NULL;
+                next = &((*next)->next);
+            }
+        }
+    } else {
+        list = _rect_malloc();
+        if (list == NULL) {
+            return NULL;
+        }
+
+        list->rect = *b;
+        list->next = NULL;
+    }
+
+    return list;
+}
+
 // 0x4C6BB8
 RectListNode* _rect_malloc()
 {
diff --git a/src/geometry.h b/src/geometry.h
index da322fe..095258c 100644
--- a/src/geometry.h
+++ b/src/geometry.h
@@ -27,6 +27,7 @@ typedef struct RectListNode {
 
 void _GNW_rect_exit();
 void _rect_clip_list(RectListNode** rectListNodePtr, Rect* rect);
+RectListNode* rect_clip(Rect* b, Rect* t);
 RectListNode* _rect_malloc();
 void _rect_free(RectListNode* entry);
 void rectUnion(const Rect* s1, const Rect* s2, Rect* r);