source/modules/juce_gui_basics/mouse/juce_ComponentDragger.cpp

   1 /*
   2   ==============================================================================
   3
   4    This file is part of the JUCE library.
   5    Copyright (c) 2022 - Raw Material Software Limited
   6
   7    JUCE is an open source library subject to commercial or open-source
   8    licensing.
   9
  10    By using JUCE, you agree to the terms of both the JUCE 7 End-User License
  11    Agreement and JUCE Privacy Policy.
  12
  13    End User License Agreement: www.juce.com/juce-7-licence
  14    Privacy Policy: www.juce.com/juce-privacy-policy
  15
  16    Or: You may also use this code under the terms of the GPL v3 (see
  17    www.gnu.org/licenses).
  18
  19    JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
  20    EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
  21    DISCLAIMED.
  22
  23   ==============================================================================
  24 */
  25
  26 namespace juce
  27 {
  28
  29 ComponentDragger::ComponentDragger() {}
  30 ComponentDragger::~ComponentDragger() {}
  31
  32 //==============================================================================
  33 void ComponentDragger::startDraggingComponent (Component* const componentToDrag, const MouseEvent& e)
  34 {
  35     jassert (componentToDrag != nullptr);
  36     jassert (e.mods.isAnyMouseButtonDown()); // The event has to be a drag event!
  37
  38     if (componentToDrag != nullptr)
  39         mouseDownWithinTarget = e.getEventRelativeTo (componentToDrag).getMouseDownPosition();
  40 }
  41
  42 void ComponentDragger::dragComponent (Component* const componentToDrag, const MouseEvent& e,
  43                                       ComponentBoundsConstrainer* const constrainer)
  44 {
  45     jassert (componentToDrag != nullptr);
  46     jassert (e.mods.isAnyMouseButtonDown()); // The event has to be a drag event!
  47
  48     if (componentToDrag != nullptr)
  49     {
  50         auto bounds = componentToDrag->getBounds();
  51
  52         // If the component is a window, multiple mouse events can get queued while it's in the same position,
  53         // so their coordinates become wrong after the first one moves the window, so in that case, we'll use
  54         // the current mouse position instead of the one that the event contains...
  55         if (componentToDrag->isOnDesktop())
  56             bounds += componentToDrag->getLocalPoint (nullptr, e.source.getScreenPosition()).roundToInt() - mouseDownWithinTarget;
  57         else
  58             bounds += e.getEventRelativeTo (componentToDrag).getPosition() - mouseDownWithinTarget;
  59
  60         if (constrainer != nullptr)
  61             constrainer->setBoundsForComponent (componentToDrag, bounds, false, false, false, false);
  62         else
  63             componentToDrag->setBounds (bounds);
  64     }
  65 }
  66
  67 } // namespace juce