From 82fe8b26eb41c3d18e1cc19cd23bc8d4fc0c70cb Mon Sep 17 00:00:00 2001
From: Benjamin Stover <bstover@mozilla.com>
Date: Fri, 4 Dec 2009 12:03:56 -0800
Subject: [PATCH] Bug 530835 -  Flash: Chrome UI shows up on background of
 flash videos [r=gavin.sharp]

---
 toolkit/content/Geometry.jsm                  | 37 +++++++++++++++++--
 .../content/tests/browser/browser_Geometry.js | 31 +++++++++++++++-
 2 files changed, 64 insertions(+), 4 deletions(-)

diff --git a/toolkit/content/Geometry.jsm b/toolkit/content/Geometry.jsm
index 25e93a056b0f..400bac0295f5 100644
--- a/toolkit/content/Geometry.jsm
+++ b/toolkit/content/Geometry.jsm
@@ -176,11 +176,15 @@ let Util = {
   }
 };
 
+/**
+ * Cache of commonly used elements.
+ */
 let Elements = {};
 
 [
   ["browserBundle",      "bundle_browser"],
   ["contentShowing",     "bcast_contentShowing"],
+  ["stack",              "stack"],
 ].forEach(function (elementGlobal) {
   let [name, id] = elementGlobal;
   Elements.__defineGetter__(name, function () {
@@ -314,7 +318,7 @@ Rect.prototype = {
     return this;
   },
 
-  setBounds: function(t, l, b, r) {
+  setBounds: function(l, t, r, b) {
     this.top = t;
     this.left = l;
     this.bottom = b;
@@ -452,8 +456,35 @@ Rect.prototype = {
   translateInside: function translateInside(other) {
     let offsetX = (this.left < other.left ? other.left - this.left :
         (this.right > other.right ? this.right - other.right : 0));
-   let offsetY = (this.top < other.top ? other.top - this.top :
+    let offsetY = (this.top < other.top ? other.top - this.top :
         (this.bottom > other.bottom ? this.bottom - other.bottom : 0));
     return this.translate(offsetX, offsetY);
-  }
+  },
+
+  /** Subtract other area from this. Returns array of rects whose union is this-other. */
+  subtract: function subtract(other) {
+    let r = new Rect(0, 0, 0, 0);
+    let result = [];
+    other = other.intersect(this);
+    if (other.isEmpty())
+      return [this.clone()];
+
+    // left strip
+    r.setBounds(this.left, this.top, other.left, this.bottom);
+    if (!r.isEmpty())
+      result.push(r.clone());
+    // inside strip
+    r.setBounds(other.left, this.top, other.right, other.top);
+    if (!r.isEmpty())
+      result.push(r.clone());
+    r.setBounds(other.left, other.bottom, other.right, this.bottom);
+    if (!r.isEmpty())
+      result.push(r.clone());
+    // right strip
+    r.setBounds(other.right, this.top, this.right, this.bottom);
+    if (!r.isEmpty())
+      result.push(r.clone());
+
+    return result;
+  },
 };
diff --git a/toolkit/content/tests/browser/browser_Geometry.js b/toolkit/content/tests/browser/browser_Geometry.js
index 1c7afc37d589..c422e6998c7a 100644
--- a/toolkit/content/tests/browser/browser_Geometry.js
+++ b/toolkit/content/tests/browser/browser_Geometry.js
@@ -69,5 +69,34 @@ let tests = {
     let r2 = new Rect(0, 0, 0, 0);
     r1.expandToContain(r2);
     ok(r1.isEmpty(), "expandToContain of empty and empty is empty");
-  }
+  },
+
+  testSubtract: function testSubtract() {
+    function equals(rects1, rects2) {
+      return rects1.length == rects2.length && rects1.every(function(r, i) {
+        return r.equals(rects2[i]);
+      });
+    }
+
+    let r1 = new Rect(0, 0, 100, 100);
+    let r2 = new Rect(500, 500, 100, 100);
+    ok(equals(r1.subtract(r2), [r1]), "subtract area outside of region yields same region");
+
+    let r1 = new Rect(0, 0, 100, 100);
+    let r2 = new Rect(-10, -10, 50, 120);
+    ok(equals(r1.subtract(r2), [new Rect(40, 0, 60, 100)]), "subtracting vertical bar from edge leaves one rect");
+
+    let r1 = new Rect(0, 0, 100, 100);
+    let r2 = new Rect(-10, -10, 120, 50);
+    ok(equals(r1.subtract(r2), [new Rect(0, 40, 100, 60)]), "subtracting horizontal bar from edge leaves one rect");
+
+    let r1 = new Rect(0, 0, 100, 100);
+    let r2 = new Rect(40, 40, 20, 20);
+    ok(equals(r1.subtract(r2), [
+      new Rect(0, 0, 40, 100),
+      new Rect(40, 0, 20, 40),
+      new Rect(40, 60, 20, 40),
+      new Rect(60, 0, 40, 100)]),
+      "subtracting rect in middle leaves union of rects");
+  },
 };