juce_gui_basics/lookandfeel/juce_LookAndFeel.cpp

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

   This file is part of the JUCE library.
   Copyright (c) 2020 - Raw Material Software Limited

   JUCE is an open source library subject to commercial or open-source
   licensing.

   By using JUCE, you agree to the terms of both the JUCE 6 End-User License
   Agreement and JUCE Privacy Policy (both effective as of the 16th June 2020).

   End User License Agreement: www.juce.com/juce-6-licence
   Privacy Policy: www.juce.com/juce-privacy-policy

   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).

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

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

namespace juce
{

static Typeface::Ptr getTypefaceForFontFromLookAndFeel (const Font& font)
{
    return LookAndFeel::getDefaultLookAndFeel().getTypefaceForFont (font);
}

using GetTypefaceForFont = Typeface::Ptr (*)(const Font&);
extern GetTypefaceForFont juce_getTypefaceForFont;

//==============================================================================
LookAndFeel::LookAndFeel()
{
    /* if this fails it means you're trying to create a LookAndFeel object before
       the static Colours have been initialised. That ain't gonna work. It probably
       means that you're using a static LookAndFeel object and that your compiler has
       decided to initialise it before the Colours class.
    */
    jassert (Colours::white == Colour (0xffffffff));

    juce_getTypefaceForFont = getTypefaceForFontFromLookAndFeel;
}

LookAndFeel::~LookAndFeel()
{
    /* This assertion is triggered if you try to delete a LookAndFeel object while something
       is still using it!

       Reasons may be:
         - it's still being used as the default LookAndFeel; or
         - it's set as a Component's current lookandfeel; or
         - there's a WeakReference to it somewhere else in your code

       Generally the fix for this will be to make sure you call
       Component::setLookandFeel (nullptr) on any components that were still using
       it before you delete it, or call LookAndFeel::setDefaultLookAndFeel (nullptr)
       if you had set it up to be the default one. This assertion can also be avoided by
       declaring your LookAndFeel object before any of the Components that use it as
       the Components will be destroyed before the LookAndFeel.

       Deleting a LookAndFeel is unlikely to cause a crash since most things will use a
       safe WeakReference to it, but it could cause some unexpected graphical behaviour,
       so it's advisable to clear up any references before destroying them!
    */
    jassert (masterReference.getNumActiveWeakReferences() == 0
              || (masterReference.getNumActiveWeakReferences() == 1
                   && this == &getDefaultLookAndFeel()));
}

//==============================================================================
Colour LookAndFeel::findColour (int colourID) const noexcept
{
    const ColourSetting c = { colourID, Colour() };
    auto index = colours.indexOf (c);

    if (index >= 0)
        return colours[index].colour;

    jassertfalse;
    return Colours::black;
}

void LookAndFeel::setColour (int colourID, Colour newColour) noexcept
{
    const ColourSetting c = { colourID, newColour };
    auto index = colours.indexOf (c);

    if (index >= 0)
        colours.getReference (index).colour = newColour;
    else
        colours.add (c);
}

bool LookAndFeel::isColourSpecified (const int colourID) const noexcept
{
    const ColourSetting c = { colourID, Colour() };
    return colours.contains (c);
}

//==============================================================================
LookAndFeel& LookAndFeel::getDefaultLookAndFeel() noexcept
{
    return Desktop::getInstance().getDefaultLookAndFeel();
}

void LookAndFeel::setDefaultLookAndFeel (LookAndFeel* newDefaultLookAndFeel) noexcept
{
    Desktop::getInstance().setDefaultLookAndFeel (newDefaultLookAndFeel);
}

//==============================================================================
Typeface::Ptr LookAndFeel::getTypefaceForFont (const Font& font)
{
    if (font.getTypefaceName() == Font::getDefaultSansSerifFontName())
    {
        if (defaultTypeface != nullptr)
            return defaultTypeface;

        if (defaultSans.isNotEmpty())
        {
            Font f (font);
            f.setTypefaceName (defaultSans);
            return Typeface::createSystemTypefaceFor (f);
        }
    }

    return Font::getDefaultTypefaceForFont (font);
}

void LookAndFeel::setDefaultSansSerifTypeface (Typeface::Ptr newDefaultTypeface)
{
    if (defaultTypeface != newDefaultTypeface)
    {
        defaultTypeface = newDefaultTypeface;
        Typeface::clearTypefaceCache();
    }
}

void LookAndFeel::setDefaultSansSerifTypefaceName (const String& newName)
{
    if (defaultSans != newName)
    {
        defaultTypeface.reset();
        Typeface::clearTypefaceCache();
        defaultSans = newName;
    }
}

//==============================================================================
MouseCursor LookAndFeel::getMouseCursorFor (Component& component)
{
    auto cursor = component.getMouseCursor();

    for (auto* parent = component.getParentComponent();
         parent != nullptr && cursor == MouseCursor::ParentCursor;
         parent = parent->getParentComponent())
    {
        cursor = parent->getMouseCursor();
    }

    return cursor;
}

std::unique_ptr<LowLevelGraphicsContext> LookAndFeel::createGraphicsContext (const Image& imageToRenderOn,
                                                                             Point<int> origin,
                                                                             const RectangleList<int>& initialClip)
{
    return std::make_unique<LowLevelGraphicsSoftwareRenderer> (imageToRenderOn, origin, initialClip);
}

//==============================================================================
void LookAndFeel::setUsingNativeAlertWindows (bool shouldUseNativeAlerts)
{
    useNativeAlertWindows = shouldUseNativeAlerts;
}

bool LookAndFeel::isUsingNativeAlertWindows()
{
   #if JUCE_LINUX
    return false; // not available currently..
   #else
    return useNativeAlertWindows;
   #endif
}

} // namespace juce