JUCE/examples/GUI/MultiTouchDemo.h

/*
  ==============================================================================

   This file is part of the JUCE examples.
   Copyright (c) 2017 - ROLI Ltd.

   The code included in this file is provided under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license. Permission
   To use, copy, modify, and/or distribute this software for any purpose with or
   without fee is hereby granted provided that the above copyright notice and
   this permission notice appear in all copies.

   THE SOFTWARE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES,
   WHETHER EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR
   PURPOSE, ARE DISCLAIMED.

  ==============================================================================
*/

/*******************************************************************************
 The block below describes the properties of this PIP. A PIP is a short snippet
 of code that can be read by the Projucer and used to generate a JUCE project.

 BEGIN_JUCE_PIP_METADATA

 name:             MultiTouchDemo
 version:          1.0.0
 vendor:           JUCE
 website:          http://juce.com
 description:      Showcases multi-touch features.

 dependencies:     juce_core, juce_data_structures, juce_events, juce_graphics,
                   juce_gui_basics
 exporters:        xcode_mac, vs2017, linux_make, androidstudio, xcode_iphone

 type:             Component
 mainClass:        MultiTouchDemo

 useLocalCopy:     1

 END_JUCE_PIP_METADATA

*******************************************************************************/

#pragma once

#include "../Assets/DemoUtilities.h"

//==============================================================================
class MultiTouchDemo    : public Component
{
public:
    MultiTouchDemo()
    {
        setOpaque (true);

        setSize (500, 500);
    }

    void paint (Graphics& g) override
    {
        g.fillAll (getUIColourIfAvailable (LookAndFeel_V4::ColourScheme::UIColour::windowBackground,
                                           Colour::greyLevel (0.4f)));

        g.setColour (getUIColourIfAvailable (LookAndFeel_V4::ColourScheme::UIColour::defaultText,
                                             Colours::lightgrey));
        g.setFont (14.0f);
        g.drawFittedText ("Drag here with as many fingers as you have!",
                          getLocalBounds().reduced (30), Justification::centred, 4);

        for (auto* trail : trails)
            drawTrail (*trail, g);
    }

    void mouseDrag (const MouseEvent& e) override
    {
        auto* t = getTrail (e.source);

        if (t == nullptr)
        {
            t = new Trail (e.source);
            t->path.startNewSubPath (e.position);
            trails.add (t);
        }

        t->pushPoint (e.position, e.mods, e.pressure);
        repaint();
    }

    void mouseUp (const MouseEvent& e) override
    {
        trails.removeObject (getTrail (e.source));
        repaint();
    }

    struct Trail
    {
        Trail (const MouseInputSource& ms)
            : source (ms)
        {}

        void pushPoint (Point<float> newPoint, ModifierKeys newMods, float pressure)
        {
            currentPosition = newPoint;
            modifierKeys = newMods;

            if (lastPoint.getDistanceFrom (newPoint) > 5.0f)
            {
                if (lastPoint != Point<float>())
                {
                    Path newSegment;
                    newSegment.startNewSubPath (lastPoint);
                    newSegment.lineTo (newPoint);

                    auto diameter = 20.0f * (pressure > 0 && pressure < 1.0f ? pressure : 1.0f);

                    PathStrokeType (diameter, PathStrokeType::curved, PathStrokeType::rounded).createStrokedPath (newSegment, newSegment);
                    path.addPath (newSegment);
                }

                lastPoint = newPoint;
            }
        }

        MouseInputSource source;
        Path path;
        Colour colour  { getRandomBrightColour().withAlpha (0.6f) };
        Point<float> lastPoint, currentPosition;
        ModifierKeys modifierKeys;

        JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Trail)
    };

    OwnedArray<Trail> trails;

    void drawTrail (Trail& trail, Graphics& g)
    {
        g.setColour (trail.colour);
        g.fillPath (trail.path);

        auto radius = 40.0f;

        g.setColour (Colours::black);
        g.drawEllipse (trail.currentPosition.x - radius,
                       trail.currentPosition.y - radius,
                       radius * 2.0f, radius * 2.0f, 2.0f);

        g.setFont (14.0f);

        String desc ("Mouse #");
        desc << trail.source.getIndex();

        auto pressure = trail.source.getCurrentPressure();

        if (pressure > 0.0f && pressure < 1.0f)
            desc << "  (pressure: " << (int) (pressure * 100.0f) << "%)";

        if (trail.modifierKeys.isCommandDown()) desc << " (CMD)";
        if (trail.modifierKeys.isShiftDown())   desc << " (SHIFT)";
        if (trail.modifierKeys.isCtrlDown())    desc << " (CTRL)";
        if (trail.modifierKeys.isAltDown())     desc << " (ALT)";

        g.drawText (desc,
                    Rectangle<int> ((int) trail.currentPosition.x - 200,
                                    (int) trail.currentPosition.y - 60,
                                    400, 20),
                    Justification::centredTop, false);
    }

    Trail* getTrail (const MouseInputSource& source)
    {
        for (auto* trail : trails)
        {
            if (trail->source == source)
                return trail;
        }

        return nullptr;
    }
};