Devtools: Create layout editor experiment

Source/core/inspector/LayoutEditor.cpp

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "config.h"
+#include "core/inspector/LayoutEditor.h"
+
+#include "core/dom/Node.h"
+#include "core/frame/FrameView.h"
+#include "core/layout/LayoutBox.h"
+#include "core/layout/LayoutInline.h"
+#include "core/layout/LayoutObject.h"
+#include "platform/JSONValues.h"
+
+
+namespace blink {
+
+namespace {
+
+PassRefPtr<JSONObject> createAnchor(float x, float y, const String& propertyName, FloatPoint deltaVector)
+{
+    RefPtr<JSONObject> object = JSONObject::create();
+    object->setNumber("x", x);
+    object->setNumber("y", y);
+    object->setString("propertyName", propertyName);
+
+    RefPtr<JSONObject> deltaVectorJSON = JSONObject::create();
+    deltaVectorJSON->setNumber("x", deltaVector.x());
+    deltaVectorJSON->setNumber("y", deltaVector.y());
+    object->setObject("deltaVector", deltaVectorJSON.release());
+
+    return object.release();
+}
+
+void contentsQuadToViewport(const FrameView* view, FloatQuad& quad)
+{
+    quad.setP1(view->contentsToViewport(roundedIntPoint(quad.p1())));
+    quad.setP2(view->contentsToViewport(roundedIntPoint(quad.p2())));
+    quad.setP3(view->contentsToViewport(roundedIntPoint(quad.p3())));
+    quad.setP4(view->contentsToViewport(roundedIntPoint(quad.p4())));
+}
+
+FloatPoint orthogonalVector(FloatPoint from, FloatPoint to, FloatPoint defaultVector)
+{
+    if (from == to)
+        return defaultVector;
+
+    return FloatPoint(to.y() - from.y(), from.x() - to.x());
+}
+
+} // namespace
+
+LayoutEditor::LayoutEditor(Node* node)
+    : m_node(node)
+{
+}
+
+PassRefPtr<JSONObject> LayoutEditor::buildJSONInfo() const
+{
+    LayoutObject* layoutObject = m_node->layoutObject();
+
+    if (!layoutObject)
+        return nullptr;
+
+    FrameView* containingView = layoutObject->frameView();
+    if (!containingView)
+        return nullptr;
+    if (!layoutObject->isBox() && !layoutObject->isLayoutInline())
+        return nullptr;
+
+    LayoutRect paddingBox;
+
+    if (layoutObject->isBox()) {
+        LayoutBox* layoutBox = toLayoutBox(layoutObject);
+
+        // LayoutBox returns the "pure" content area box, exclusive of the scrollbars (if present), which also count towards the content area in CSS.
+        const int verticalScrollbarWidth = layoutBox->verticalScrollbarWidth();
+        const int horizontalScrollbarHeight = layoutBox->horizontalScrollbarHeight();
+
+        paddingBox = layoutBox->paddingBoxRect();
+        paddingBox.setWidth(paddingBox.width() + verticalScrollbarWidth);
+        paddingBox.setHeight(paddingBox.height() + horizontalScrollbarHeight);
+    } else {
+        LayoutInline* layoutInline = toLayoutInline(layoutObject);
+        LayoutRect borderBox = LayoutRect(layoutInline->linesBoundingBox());
+        paddingBox = LayoutRect(borderBox.x() + layoutInline->borderLeft(), borderBox.y() + layoutInline->borderTop(),
+            borderBox.width() - layoutInline->borderLeft() - layoutInline->borderRight(), borderBox.height() - layoutInline->borderTop() - layoutInline->borderBottom());
+    }
+
+    FloatQuad padding = layoutObject->localToAbsoluteQuad(FloatRect(paddingBox));
+    contentsQuadToViewport(containingView, padding);
+
+    float xLeft = (padding.p1().x() + padding.p4().x()) / 2;
+    float yLeft = (padding.p1().y() + padding.p4().y()) / 2;
+    FloatPoint orthoLeft = orthogonalVector(padding.p4(), padding.p1(), FloatPoint(-1, 0));
+
+    float xRight = (padding.p2().x() + padding.p3().x()) / 2;
+    float yRight = (padding.p2().y() + padding.p3().y()) / 2;
+    FloatPoint orthoRight = orthogonalVector(padding.p2(), padding.p3(), FloatPoint(1, 0));
+
+    RefPtr<JSONObject> object = JSONObject::create();
+    RefPtr<JSONArray> anchors = JSONArray::create();
+    anchors->pushObject(createAnchor(xLeft, yLeft, "padding-left", orthoLeft));
+    anchors->pushObject(createAnchor(xRight, yRight, "padding-right", orthoRight));
+    object->setArray("anchors", anchors.release());
+
+    return object.release();
+
+}
+
+} // namespace blink