# ************************************************************* # # Licensed to the Apache Software Foundation (ASF) under one # or more contributor license agreements. See the NOTICE file # distributed with this work for additional information # regarding copyright ownership. The ASF licenses this file # to you under the Apache License, Version 2.0 (the # "License"); you may not use this file except in compliance # with the License. You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, # software distributed under the License is distributed on an # "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY # KIND, either express or implied. See the License for the # specific language governing permissions and limitations # under the License. # # ************************************************************* VCL positioning Window coordinates are parent relative, with exception of maState fields, they have screen coordinates. Every window has a parent window, usually the client area of an existing window, otherwise the desktop window. When a window is to be sized/moved, SetPosSize is called. Since coordinates are the position/size of client area, we need to calculate current window frame size/position and map to screen coordinates using the owner window position as offset.