JUCE/modules/juce_gui_basics/widgets/juce_Label.cpp

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

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

   JUCE is an open source framework subject to commercial or open source
   licensing.

   By downloading, installing, or using the JUCE framework, or combining the
   JUCE framework with any other source code, object code, content or any other
   copyrightable work, you agree to the terms of the JUCE End User Licence
   Agreement, and all incorporated terms including the JUCE Privacy Policy and
   the JUCE Website Terms of Service, as applicable, which will bind you. If you
   do not agree to the terms of these agreements, we will not license the JUCE
   framework to you, and you must discontinue the installation or download
   process and cease use of the JUCE framework.

   JUCE End User Licence Agreement: https://juce.com/legal/juce-8-licence/
   JUCE Privacy Policy: https://juce.com/juce-privacy-policy
   JUCE Website Terms of Service: https://juce.com/juce-website-terms-of-service/

   Or:

   You may also use this code under the terms of the AGPLv3:
   https://www.gnu.org/licenses/agpl-3.0.en.html

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

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

namespace juce
{

Label::Label (const String& name, const String& labelText)
    : Component (name),
      textValue (labelText),
      lastTextValue (labelText)
{
    setColour (TextEditor::textColourId, Colours::black);
    setColour (TextEditor::backgroundColourId, Colours::transparentBlack);
    setColour (TextEditor::outlineColourId, Colours::transparentBlack);

    textValue.addListener (this);
}

Label::~Label()
{
    textValue.removeListener (this);

    if (ownerComponent != nullptr)
        ownerComponent->removeComponentListener (this);

    editor.reset();
}

//==============================================================================
void Label::setText (const String& newText, NotificationType notification)
{
    hideEditor (true);

    if (lastTextValue != newText)
    {
        lastTextValue = newText;
        textValue = newText;
        repaint();

        textWasChanged();

        if (ownerComponent != nullptr)
            componentMovedOrResized (*ownerComponent, true, true);

        if (notification != dontSendNotification)
            callChangeListeners();
    }
}

String Label::getText (bool returnActiveEditorContents) const
{
    return (returnActiveEditorContents && isBeingEdited())
                ? editor->getText()
                : textValue.toString();
}

void Label::valueChanged (Value&)
{
    if (lastTextValue != textValue.toString())
        setText (textValue.toString(), sendNotification);
}

//==============================================================================
void Label::setFont (const Font& newFont)
{
    if (font != newFont)
    {
        font = newFont;
        repaint();
    }
}

Font Label::getFont() const noexcept
{
    return font;
}

void Label::setEditable (bool editOnSingleClick,
                         bool editOnDoubleClick,
                         bool lossOfFocusDiscards)
{
    editSingleClick = editOnSingleClick;
    editDoubleClick = editOnDoubleClick;
    lossOfFocusDiscardsChanges = lossOfFocusDiscards;

    const auto isKeybordFocusable = (editOnSingleClick || editOnDoubleClick);

    setWantsKeyboardFocus (isKeybordFocusable);
    setFocusContainerType (isKeybordFocusable ? FocusContainerType::keyboardFocusContainer
                                              : FocusContainerType::none);

    invalidateAccessibilityHandler();
}

void Label::setJustificationType (Justification newJustification)
{
    if (justification != newJustification)
    {
        justification = newJustification;
        repaint();
    }
}

void Label::setBorderSize (BorderSize<int> newBorder)
{
    if (border != newBorder)
    {
        border = newBorder;
        repaint();
    }
}

//==============================================================================
Component* Label::getAttachedComponent() const
{
    return ownerComponent.get();
}

void Label::attachToComponent (Component* owner, bool onLeft)
{
    jassert (owner != this); // Not a great idea to try to attach it to itself!

    if (ownerComponent != nullptr)
        ownerComponent->removeComponentListener (this);

    ownerComponent = owner;
    leftOfOwnerComp = onLeft;

    if (ownerComponent != nullptr)
    {
        setVisible (ownerComponent->isVisible());
        ownerComponent->addComponentListener (this);
        componentParentHierarchyChanged (*ownerComponent);
        componentMovedOrResized (*ownerComponent, true, true);
    }
}

void Label::componentMovedOrResized (Component& component, bool /*wasMoved*/, bool /*wasResized*/)
{
    auto& lf = getLookAndFeel();
    auto f = lf.getLabelFont (*this);
    auto borderSize = lf.getLabelBorderSize (*this);

    if (leftOfOwnerComp)
    {
        auto width = jmin (roundToInt (GlyphArrangement::getStringWidth (f, textValue.toString()) + 0.5f)
                             + borderSize.getLeftAndRight(),
                           component.getX());

        setBounds (component.getX() - width, component.getY(), width, component.getHeight());
    }
    else
    {
        auto height = borderSize.getTopAndBottom() + 6 + roundToInt (f.getHeight() + 0.5f);

        setBounds (component.getX(), component.getY() - height, component.getWidth(), height);
    }
}

void Label::componentParentHierarchyChanged (Component& component)
{
    if (auto* parent = component.getParentComponent())
        parent->addChildComponent (this);
}

void Label::componentVisibilityChanged (Component& component)
{
    setVisible (component.isVisible());
}

//==============================================================================
void Label::textWasEdited() {}
void Label::textWasChanged() {}

void Label::editorShown (TextEditor* textEditor)
{
    Component::BailOutChecker checker (this);
    listeners.callChecked (checker, [this, textEditor] (Label::Listener& l) { l.editorShown (this, *textEditor); });

    if (checker.shouldBailOut())
        return;

    NullCheckedInvocation::invoke (onEditorShow);
}

void Label::editorAboutToBeHidden (TextEditor* textEditor)
{
    Component::BailOutChecker checker (this);
    listeners.callChecked (checker, [this, textEditor] (Label::Listener& l) { l.editorHidden (this, *textEditor); });

    if (checker.shouldBailOut())
        return;

    NullCheckedInvocation::invoke (onEditorHide);
}

void Label::showEditor()
{
    if (editor == nullptr)
    {
        editor.reset (createEditorComponent());
        editor->setSize (10, 10);
        addAndMakeVisible (editor.get());
        editor->setText (getText(), false);
        editor->setKeyboardType (keyboardType);
        editor->addListener (this);
        editor->grabKeyboardFocus();

        if (editor == nullptr) // may be deleted by a callback
            return;

        editor->setHighlightedRegion (Range<int> (0, textValue.toString().length()));

        resized();
        repaint();

        editorShown (editor.get());

        enterModalState (false);
        editor->grabKeyboardFocus();
    }
}

bool Label::updateFromTextEditorContents (TextEditor& ed)
{
    auto newText = ed.getText();

    if (textValue.toString() != newText)
    {
        lastTextValue = newText;
        textValue = newText;
        repaint();

        textWasChanged();

        if (ownerComponent != nullptr)
            componentMovedOrResized (*ownerComponent, true, true);

        return true;
    }

    return false;
}

void Label::hideEditor (bool discardCurrentEditorContents)
{
    if (editor != nullptr)
    {
        WeakReference<Component> deletionChecker (this);
        std::unique_ptr<TextEditor> outgoingEditor;
        std::swap (outgoingEditor, editor);

        editorAboutToBeHidden (outgoingEditor.get());

        const bool changed = (! discardCurrentEditorContents)
                               && updateFromTextEditorContents (*outgoingEditor);
        outgoingEditor.reset();

        if (deletionChecker != nullptr)
            repaint();

        if (changed)
            textWasEdited();

        if (deletionChecker != nullptr)
            exitModalState (0);

        if (changed && deletionChecker != nullptr)
            callChangeListeners();
    }
}

void Label::inputAttemptWhenModal()
{
    if (editor != nullptr)
    {
        if (lossOfFocusDiscardsChanges)
            textEditorEscapeKeyPressed (*editor);
        else
            textEditorReturnKeyPressed (*editor);
    }
}

bool Label::isBeingEdited() const noexcept
{
    return editor != nullptr;
}

static void copyColourIfSpecified (Label& l, TextEditor& ed, int colourID, int targetColourID)
{
    if (l.isColourSpecified (colourID) || l.getLookAndFeel().isColourSpecified (colourID))
        ed.setColour (targetColourID, l.findColour (colourID));
}

TextEditor* Label::createEditorComponent()
{
    auto* ed = new TextEditor (getName());
    ed->applyFontToAllText (getLookAndFeel().getLabelFont (*this));
    copyAllExplicitColoursTo (*ed);

    copyColourIfSpecified (*this, *ed, textWhenEditingColourId, TextEditor::textColourId);
    copyColourIfSpecified (*this, *ed, backgroundWhenEditingColourId, TextEditor::backgroundColourId);
    copyColourIfSpecified (*this, *ed, outlineWhenEditingColourId, TextEditor::focusedOutlineColourId);

    return ed;
}

TextEditor* Label::getCurrentTextEditor() const noexcept
{
    return editor.get();
}

//==============================================================================
void Label::paint (Graphics& g)
{
    getLookAndFeel().drawLabel (g, *this);
}

void Label::mouseUp (const MouseEvent& e)
{
    if (editSingleClick
         && isEnabled()
         && contains (e.getPosition())
         && ! (e.mouseWasDraggedSinceMouseDown() || e.mods.isPopupMenu()))
    {
        showEditor();
    }
}

void Label::mouseDoubleClick (const MouseEvent& e)
{
    if (editDoubleClick
         && isEnabled()
         && ! e.mods.isPopupMenu())
    {
        showEditor();
    }
}

void Label::resized()
{
    if (editor != nullptr)
        editor->setBounds (getLocalBounds());
}

void Label::focusGained (FocusChangeType cause)
{
    if (editSingleClick
         && isEnabled()
         && cause == focusChangedByTabKey)
    {
        showEditor();
    }
}

void Label::enablementChanged()
{
    repaint();
}

void Label::colourChanged()
{
    repaint();
}

void Label::setMinimumHorizontalScale (const float newScale)
{
    if (! approximatelyEqual (minimumHorizontalScale, newScale))
    {
        minimumHorizontalScale = newScale;
        repaint();
    }
}

//==============================================================================
// We'll use a custom focus traverser here to make sure focus goes from the
// text editor to another component rather than back to the label itself.
class LabelKeyboardFocusTraverser final : public KeyboardFocusTraverser
{
public:
    explicit LabelKeyboardFocusTraverser (Label& l)  : owner (l)  {}

    Component* getDefaultComponent (Component* parent) override
    {
        if (auto* container = getKeyboardFocusContainer (parent))
            return KeyboardFocusTraverser::getDefaultComponent (container);

        return nullptr;
    }

    Component* getNextComponent     (Component* c) override  { return KeyboardFocusTraverser::getNextComponent     (getComp (c)); }
    Component* getPreviousComponent (Component* c) override  { return KeyboardFocusTraverser::getPreviousComponent (getComp (c)); }

    std::vector<Component*> getAllComponents (Component* parent) override
    {
        if (auto* container = getKeyboardFocusContainer (parent))
            return KeyboardFocusTraverser::getAllComponents (container);

        return {};
    }

private:
    Component* getComp (Component* current) const
    {
        if (auto* ed = owner.getCurrentTextEditor())
            if (current == ed)
                return current->getParentComponent();

        return current;
    }

    Component* getKeyboardFocusContainer (Component* parent) const
    {
        if (owner.getCurrentTextEditor() != nullptr && parent == &owner)
            return owner.findKeyboardFocusContainer();

        return parent;
    }

    Label& owner;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (LabelKeyboardFocusTraverser)
};

std::unique_ptr<ComponentTraverser> Label::createKeyboardFocusTraverser()
{
    return std::make_unique<LabelKeyboardFocusTraverser> (*this);
}

//==============================================================================
void Label::addListener    (Label::Listener* l)     { listeners.add (l); }
void Label::removeListener (Label::Listener* l)     { listeners.remove (l); }

void Label::callChangeListeners()
{
    Component::BailOutChecker checker (this);
    listeners.callChecked (checker, [this] (Listener& l) { l.labelTextChanged (this); });

    if (checker.shouldBailOut())
        return;

    NullCheckedInvocation::invoke (onTextChange);
}

//==============================================================================
void Label::textEditorTextChanged (TextEditor& ed)
{
    if (editor != nullptr)
    {
        jassert (&ed == editor.get());

        if (! (hasKeyboardFocus (true) || isCurrentlyBlockedByAnotherModalComponent()))
        {
            if (lossOfFocusDiscardsChanges)
                textEditorEscapeKeyPressed (ed);
            else
                textEditorReturnKeyPressed (ed);
        }
    }
}

void Label::textEditorReturnKeyPressed (TextEditor& ed)
{
    if (editor != nullptr)
    {
        jassert (&ed == editor.get());

        WeakReference<Component> deletionChecker (this);
        bool changed = updateFromTextEditorContents (ed);
        hideEditor (true);

        if (changed && deletionChecker != nullptr)
        {
            textWasEdited();

            if (deletionChecker != nullptr)
                callChangeListeners();
        }
    }
}

void Label::textEditorEscapeKeyPressed ([[maybe_unused]] TextEditor& ed)
{
    if (editor != nullptr)
    {
        jassert (&ed == editor.get());

        editor->setText (textValue.toString(), false);
        hideEditor (true);
    }
}

void Label::textEditorFocusLost (TextEditor& ed)
{
    textEditorTextChanged (ed);
}

//==============================================================================
class LabelAccessibilityHandler final : public AccessibilityHandler
{
public:
    explicit LabelAccessibilityHandler (Label& labelToWrap)
        : AccessibilityHandler (labelToWrap,
                                labelToWrap.isEditable() ? AccessibilityRole::editableText : AccessibilityRole::label,
                                getAccessibilityActions (labelToWrap),
                                { std::make_unique<LabelValueInterface> (labelToWrap) }),
          label (labelToWrap)
    {
    }

    String getTitle() const override  { return label.getText(); }
    String getHelp() const override   { return label.getTooltip(); }

    AccessibleState getCurrentState() const override
    {
        if (label.isBeingEdited())
            return {}; // allow focus to pass through to the TextEditor

        return AccessibilityHandler::getCurrentState();
    }

private:
    class LabelValueInterface final : public AccessibilityTextValueInterface
    {
    public:
        explicit LabelValueInterface (Label& labelToWrap)
            : label (labelToWrap)
        {
        }

        bool isReadOnly() const override                 { return true; }
        String getCurrentValueAsString() const override  { return label.getText(); }
        void setValueAsString (const String&) override   {}

    private:
        Label& label;

        //==============================================================================
        JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (LabelValueInterface)
    };

    static AccessibilityActions getAccessibilityActions (Label& label)
    {
        if (label.isEditable())
            return AccessibilityActions().addAction (AccessibilityActionType::press, [&label] { label.showEditor(); });

        return {};
    }

    Label& label;

    //==============================================================================
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (LabelAccessibilityHandler)
};

std::unique_ptr<AccessibilityHandler> Label::createAccessibilityHandler()
{
    return std::make_unique<LabelAccessibilityHandler> (*this);
}

} // namespace juce