ProgressBar: Add style parameter

examples/GUI/WidgetsDemo.h

@@ -461,7 +461,8 @@ private:
 
 
 //==============================================================================
-struct MiscPage   : public Component
+struct MiscPage   : public Component,
+                    private Timer
 {
     MiscPage()
     {
@@ -482,6 +483,21 @@ struct MiscPage   : public Component
             comboBox.addItem ("combo box item " + String (i), i);
 
         comboBox.setSelectedId (1);
+
+        addAndMakeVisible (linearProgressBar);
+        linearProgressBar.setStyle (ProgressBar::Style::linear);
+        linearProgressBar.setBounds (10, 115, 200, 24);
+
+        addAndMakeVisible (circularProgressBar);
+        circularProgressBar.setStyle (ProgressBar::Style::circular);
+        circularProgressBar.setBounds (10, 145, 200, 100);
+
+        startTimerHz (10);
+    }
+
+    ~MiscPage() override
+    {
+        stopTimer();
     }
 
     void lookAndFeelChanged() override
@@ -490,10 +506,37 @@ struct MiscPage   : public Component
         textEditor2.applyFontToAllText (textEditor2.getFont());
     }
 
+    void timerCallback() override
+    {
+        constexpr auto minValue = -0.2;
+        constexpr auto maxValue = 1.2;
+        constexpr auto maxIncrement = 0.05;
+
+        if (progress >= maxValue)
+            progress = minValue;
+        else
+            progress += Random::getSystemRandom().nextDouble() * maxIncrement;
+
+        if (isPositiveAndNotGreaterThan (progress, 1.0))
+        {
+            linearProgressBar.setPercentageDisplay (true);
+            circularProgressBar.setPercentageDisplay (true);
+        }
+        else
+        {
+            linearProgressBar.setTextToDisplay ("Linear progress bar");
+            circularProgressBar.setTextToDisplay ("Circular progress bar");
+        }
+    }
+
     TextEditor textEditor1,
                textEditor2  { "Password", (juce_wchar) 0x2022 };
 
     ComboBox comboBox  { "Combo" };
+
+    double progress { 0.0 };
+    ProgressBar linearProgressBar { progress };
+    ProgressBar circularProgressBar { progress };
 };
 
 //==============================================================================

examples/GUI/WindowsDemo.h

@@ -228,6 +228,9 @@ public:
         addAndMakeVisible (closeWindowsButton);
         closeWindowsButton.onClick = [this] { closeAllWindows(); };
 
+        addAndMakeVisible (alertWindowResult);
+        alertWindowResult.setJustificationType (Justification::centred);
+
         setSize (250, 250);
     }
 
@@ -253,14 +256,27 @@ public:
 
     void resized() override
     {
-        Rectangle<int> buttonSize (0, 0, 108, 28);
+        FlexBox flexBox;
+        flexBox.flexDirection = FlexBox::Direction::column;
+        flexBox.justifyContent = FlexBox::JustifyContent::center;
+
+        constexpr auto buttonWidth = 108.0f;
+        constexpr auto componentHeight = 24.0f;
+        constexpr auto gap = 4.0f;
+
+        flexBox.items.add (FlexItem { showWindowsButton }.withHeight (componentHeight)
+                                                         .withMinWidth (buttonWidth)
+                                                         .withAlignSelf (FlexItem::AlignSelf::center));
 
-        Rectangle<int> area ((getWidth()  / 2) - (buttonSize.getWidth() / 2),
-                             (getHeight() / 2) -  buttonSize.getHeight(),
-                             buttonSize.getWidth(), buttonSize.getHeight());
+        flexBox.items.add (FlexItem{}.withHeight (gap));
+        flexBox.items.add (FlexItem { closeWindowsButton }.withHeight (componentHeight)
+                                                          .withMinWidth (buttonWidth)
+                                                          .withAlignSelf (FlexItem::AlignSelf::center));
 
-        showWindowsButton .setBounds (area.reduced (2));
-        closeWindowsButton.setBounds (area.translated (0, buttonSize.getHeight()).reduced (2));
+        flexBox.items.add (FlexItem{}.withHeight (gap));
+        flexBox.items.add (FlexItem { alertWindowResult }.withHeight (componentHeight));
+
+        flexBox.performLayout (getLocalBounds());
     }
 
 private:
@@ -272,6 +288,7 @@ private:
 
     TextButton showWindowsButton   { "Show Windows" },
                closeWindowsButton  { "Close Windows" };
+    Label alertWindowResult { "Alert Window result" };
 
     void showAllWindows()
     {
@@ -280,6 +297,7 @@ private:
         showDocumentWindow (false);
         showDocumentWindow (true);
         showTransparentWindow();
+        showAlertWindow();
         showDialogWindow();
     }
 
@@ -289,6 +307,12 @@ private:
             window.deleteAndZero();
 
         windows.clear();
+        alertWindowResult.setText ("", dontSendNotification);
+    }
+
+    static auto getDisplayArea()
+    {
+        return Desktop::getInstance().getDisplays().getPrimaryDisplay()->userArea.reduced (20);
     }
 
     void showDialogWindow()
@@ -333,8 +357,7 @@ private:
                                        | RectanglePlacement::yTop
                                        | RectanglePlacement::doNotResize);
 
-        auto result = placement.appliedTo (area, Desktop::getInstance().getDisplays()
-                                                         .getPrimaryDisplay()->userArea.reduced (20));
+        auto result = placement.appliedTo (area, getDisplayArea());
         dw->setBounds (result);
 
         dw->setResizable (true, ! native);
@@ -354,12 +377,113 @@ private:
                                        | RectanglePlacement::yBottom
                                        | RectanglePlacement::doNotResize);
 
-        auto result = placement.appliedTo (area, Desktop::getInstance().getDisplays()
-                                                         .getPrimaryDisplay()->userArea.reduced (20));
+        auto result = placement.appliedTo (area, getDisplayArea());
         balls->setBounds (result);
 
         balls->setVisible (true);
     }
 
+    void showAlertWindow()
+    {
+        auto* alertWindow = new AlertWindow ("Alert Window",
+                                             "For more complex dialogs, you can easily add components to an AlertWindow, such as...",
+                                             MessageBoxIconType::InfoIcon);
+        windows.add (alertWindow);
+
+        alertWindow->addTextBlock ("Text block");
+        alertWindow->addComboBox ("Combo box", {"Combo box", "Item 2", "Item 3"});
+        alertWindow->addTextEditor ("Text editor", "Text editor");
+        alertWindow->addTextEditor ("Password", "password", "including for passwords", true);
+        alertWindowCustomComponent.emplace();
+        alertWindow->addCustomComponent (&(*alertWindowCustomComponent));
+        alertWindow->addTextBlock ("Progress bar");
+        alertWindow->addProgressBarComponent (alertWindowCustomComponent->value, ProgressBar::Style::linear);
+        alertWindow->addProgressBarComponent (alertWindowCustomComponent->value, ProgressBar::Style::circular);
+        alertWindow->addTextBlock ("Press any button, or the escape key, to close the window");
+
+        enum AlertWindowResult
+        {
+            noButtonPressed,
+            button1Pressed,
+            button2Pressed
+        };
+
+        alertWindow->addButton ("Button 1", AlertWindowResult::button1Pressed);
+        alertWindow->addButton ("Button 2", AlertWindowResult::button2Pressed);
+
+        RectanglePlacement placement { RectanglePlacement::yMid
+                                       | RectanglePlacement::xLeft
+                                       | RectanglePlacement::doNotResize };
+
+        alertWindow->setBounds (placement.appliedTo (alertWindow->getBounds(), getDisplayArea()));
+
+        alertWindowResult.setText ("", dontSendNotification);
+        alertWindow->enterModalState (false, ModalCallbackFunction::create ([ref = SafePointer { this }] (int result)
+        {
+            if (ref == nullptr)
+                return;
+
+            const auto text = [&]
+            {
+                switch (result)
+                {
+                    case noButtonPressed:
+                        return "Dismissed the Alert Window without pressing a button";
+                    case button1Pressed:
+                        return "Dismissed the Alert Window using Button 1";
+                    case button2Pressed:
+                        return "Dismissed the Alert Window using Button 2";
+                }
+
+                return "Unhandled event when dismissing the Alert Window";
+            }();
+
+            ref->alertWindowResult.setText (text, dontSendNotification);
+        }), true);
+    }
+
+    class AlertWindowCustomComponent : public Component,
+                                       private Slider::Listener
+    {
+    public:
+        AlertWindowCustomComponent()
+        {
+            slider.setRange (0.0, 1.0);
+            slider.setValue (0.5, NotificationType::dontSendNotification);
+            slider.addListener (this);
+
+            addAndMakeVisible (label);
+            addAndMakeVisible (slider);
+
+            setSize (200, 50);
+        }
+
+        ~AlertWindowCustomComponent() override
+        {
+            slider.removeListener (this);
+        }
+
+        void resized() override
+        {
+            auto bounds =  getLocalBounds();
+            label.setBounds (bounds.removeFromTop (getHeight() / 2));
+            slider.setBounds (bounds);
+        }
+
+        void sliderValueChanged (Slider*) override
+        {
+            value = slider.getValue();
+        }
+
+        double value { -1.0 };
+
+    private:
+        Label label { "Label", "Custom component" };
+        Slider slider { Slider::SliderStyle::LinearHorizontal,
+                        Slider::TextEntryBoxPosition::NoTextBox };
+    };
+
+    std::optional<AlertWindowCustomComponent> alertWindowCustomComponent;
+
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (WindowsDemo)
 };

extras/Projucer/Source/Utility/UI/jucer_ProjucerLookAndFeel.cpp

@@ -367,71 +367,9 @@ void ProjucerLookAndFeel::drawTreeviewPlusMinusBox (Graphics& g, const Rectangle
     g.strokePath (getArrowPath (area, isOpen ? 2 : 1, false, Justification::centredRight), PathStrokeType (2.0f));
 }
 
-void ProjucerLookAndFeel::drawProgressBar (Graphics& g, ProgressBar& progressBar,
-                                           int width, int height, double progress, const String& textToShow)
+ProgressBar::Style ProjucerLookAndFeel::getDefaultProgressBarStyle (const ProgressBar&)
 {
-    ignoreUnused (width, height, progress);
-
-    const auto background = progressBar.findColour (ProgressBar::backgroundColourId);
-    const auto foreground = progressBar.findColour (defaultButtonBackgroundColourId);
-
-    const auto sideLength = jmin (width, height);
-
-    auto barBounds = progressBar.getLocalBounds().withSizeKeepingCentre (sideLength, sideLength).reduced (1).toFloat();
-
-    auto rotationInDegrees  = static_cast<float> ((Time::getMillisecondCounter() / 10) % 360);
-    auto normalisedRotation = rotationInDegrees / 360.0f;
-
-    const auto rotationOffset = 22.5f;
-    const auto maxRotation    = 315.0f;
-
-    auto startInDegrees = rotationInDegrees;
-    auto endInDegrees   = startInDegrees + rotationOffset;
-
-    if (normalisedRotation >= 0.25f && normalisedRotation < 0.5f)
-    {
-        const auto rescaledRotation = (normalisedRotation * 4.0f) - 1.0f;
-        endInDegrees = startInDegrees + rotationOffset + (maxRotation * rescaledRotation);
-    }
-    else if (normalisedRotation >= 0.5f && normalisedRotation <= 1.0f)
-    {
-        endInDegrees = startInDegrees + rotationOffset + maxRotation;
-        const auto rescaledRotation = 1.0f - ((normalisedRotation * 2.0f) - 1.0f);
-        startInDegrees = endInDegrees - rotationOffset - (maxRotation * rescaledRotation);
-    }
-
-    g.setColour (background);
-    Path arcPath2;
-    arcPath2.addCentredArc (barBounds.getCentreX(),
-                            barBounds.getCentreY(),
-                            barBounds.getWidth() * 0.5f,
-                            barBounds.getHeight() * 0.5f, 0.0f,
-                            0.0f,
-                            MathConstants<float>::twoPi,
-                            true);
-    g.strokePath (arcPath2, PathStrokeType (2.0f));
-
-    g.setColour (foreground);
-    Path arcPath;
-    arcPath.addCentredArc (barBounds.getCentreX(),
-                           barBounds.getCentreY(),
-                           barBounds.getWidth() * 0.5f,
-                           barBounds.getHeight() * 0.5f,
-                           0.0f,
-                           degreesToRadians (startInDegrees),
-                           degreesToRadians (endInDegrees),
-                           true);
-
-    arcPath.applyTransform (AffineTransform::rotation (normalisedRotation * MathConstants<float>::pi * 2.25f,
-                                                       barBounds.getCentreX(), barBounds.getCentreY()));
-    g.strokePath (arcPath, PathStrokeType (2.0f));
-
-    if (textToShow.isNotEmpty())
-    {
-        g.setColour (progressBar.findColour (TextButton::textColourOffId));
-        g.setFont (Font (12.0f, 2));
-        g.drawText (textToShow, barBounds, Justification::centred, false);
-    }
+    return ProgressBar::Style::circular;
 }
 
 //==============================================================================
@@ -583,5 +521,6 @@ void ProjucerLookAndFeel::setupColours()
     setColour (TreeView::selectedItemBackgroundColourId,        findColour (defaultHighlightColourId));
     setColour (PopupMenu::highlightedBackgroundColourId,        findColour (defaultHighlightColourId).withAlpha (0.75f));
     setColour (PopupMenu::highlightedTextColourId,              findColour (defaultHighlightedTextColourId));
+    setColour (ProgressBar::foregroundColourId,                 findColour (defaultButtonBackgroundColourId));
     setColour (0x1000440, /*LassoComponent::lassoFillColourId*/ findColour (defaultHighlightColourId).withAlpha (0.3f));
 }

extras/Projucer/Source/Utility/UI/jucer_ProjucerLookAndFeel.h

@@ -74,7 +74,7 @@ public:
     void drawTreeviewPlusMinusBox (Graphics&, const Rectangle<float>& area,
                                    Colour backgroundColour, bool isItemOpen, bool isMouseOver) override;
 
-    void drawProgressBar (Graphics&, ProgressBar&, int width, int height, double progress, const String& textToShow) override;
+    ProgressBar::Style getDefaultProgressBarStyle (const ProgressBar&) override;
 
     //==============================================================================
     static Path getArrowPath (Rectangle<float> arrowZone, const int direction,

modules/juce_gui_basics/components/juce_Component.h

@@ -2128,13 +2128,14 @@ public:
         The callback is an optional object which will receive a callback when the modal
         component loses its modal status, either by being hidden or when exitModalState()
         is called. If you pass an object in here, the system will take care of deleting it
-        later, after making the callback
+        later, after making the callback.
 
         If deleteWhenDismissed is true, then when it is dismissed, the component will be
         deleted and then the callback will be called. (This will safely handle the situation
         where the component is deleted before its exitModalState() method is called).
 
-        @see exitModalState, runModalLoop, ModalComponentManager::attachCallback
+        @see exitModalState, runModalLoop, ModalComponentManager::attachCallback,
+             ModalCallbackFunction
     */
     void enterModalState (bool takeKeyboardFocus = true,
                           ModalComponentManager::Callback* callback = nullptr,

modules/juce_gui_basics/lookandfeel/juce_LookAndFeel_V2.cpp

@@ -615,6 +615,11 @@ bool LookAndFeel_V2::isProgressBarOpaque (ProgressBar& progressBar)
     return progressBar.findColour (ProgressBar::backgroundColourId).isOpaque();
 }
 
+ProgressBar::Style LookAndFeel_V2::getDefaultProgressBarStyle (const ProgressBar&)
+{
+    return ProgressBar::Style::linear;
+}
+
 bool LookAndFeel_V2::areScrollbarButtonsVisible()
 {
     return true;

modules/juce_gui_basics/lookandfeel/juce_LookAndFeel_V2.h

@@ -97,6 +97,7 @@ public:
     void drawProgressBar (Graphics&, ProgressBar&, int width, int height, double progress, const String& textToShow) override;
     void drawSpinningWaitAnimation (Graphics&, const Colour& colour, int x, int y, int w, int h) override;
     bool isProgressBarOpaque (ProgressBar&) override;
+    ProgressBar::Style getDefaultProgressBarStyle (const ProgressBar&) override;
 
     //==============================================================================
     bool areScrollbarButtonsVisible() override;

modules/juce_gui_basics/lookandfeel/juce_LookAndFeel_V4.cpp

@@ -482,17 +482,30 @@ Font LookAndFeel_V4::getAlertWindowFont()           { return { 14.0f }; }
 
 //==============================================================================
 void LookAndFeel_V4::drawProgressBar (Graphics& g, ProgressBar& progressBar,
-                                      int width, int height, double progress, const String& textToShow)
+                                      int width, int height, double progress,
+                                      const String& textToShow)
 {
-    if (width == height)
-        drawCircularProgressBar (g, progressBar, textToShow);
-    else
-        drawLinearProgressBar (g, progressBar, width, height, progress, textToShow);
+    switch (progressBar.getResolvedStyle())
+    {
+        case ProgressBar::Style::linear:
+            drawLinearProgressBar (g, progressBar, width, height, progress, textToShow);
+            break;
+
+        case ProgressBar::Style::circular:
+            drawCircularProgressBar (g, progressBar, textToShow);
+            break;
+    }
+}
+
+ProgressBar::Style LookAndFeel_V4::getDefaultProgressBarStyle (const ProgressBar& progressBar)
+{
+    return progressBar.getWidth() == progressBar.getHeight() ? ProgressBar::Style::circular
+                                                             : ProgressBar::Style::linear;
 }
 
-void LookAndFeel_V4::drawLinearProgressBar (Graphics& g, ProgressBar& progressBar,
-                                            int width, int height,
-                                            double progress, const String& textToShow)
+void LookAndFeel_V4::drawLinearProgressBar (Graphics& g, const ProgressBar& progressBar,
+                                            int width, int height, double progress,
+                                            const String& textToShow)
 {
     auto background = progressBar.findColour (ProgressBar::backgroundColourId);
     auto foreground = progressBar.findColour (ProgressBar::foregroundColourId);
@@ -549,18 +562,20 @@ void LookAndFeel_V4::drawLinearProgressBar (Graphics& g, ProgressBar& progressBa
     }
 }
 
-void LookAndFeel_V4::drawCircularProgressBar (Graphics& g, ProgressBar& progressBar, const String& progressText)
+void LookAndFeel_V4::drawCircularProgressBar (Graphics& g, const ProgressBar& progressBar,
+                                              const String& textToShow)
 {
-    auto background = progressBar.findColour (ProgressBar::backgroundColourId);
-    auto foreground = progressBar.findColour (ProgressBar::foregroundColourId);
+    const auto background = progressBar.findColour (ProgressBar::backgroundColourId);
+    const auto foreground = progressBar.findColour (ProgressBar::foregroundColourId);
 
-    auto barBounds = progressBar.getLocalBounds().reduced (2, 2).toFloat();
+    const auto barBounds = progressBar.getLocalBounds().reduced (2, 2).toFloat();
+    const auto size = jmin (barBounds.getWidth(), barBounds.getHeight());
 
-    auto rotationInDegrees  = static_cast<float> ((Time::getMillisecondCounter() / 10) % 360);
-    auto normalisedRotation = rotationInDegrees / 360.0f;
+    const auto rotationInDegrees  = static_cast<float> ((Time::getMillisecondCounter() / 10) % 360);
+    const auto normalisedRotation = rotationInDegrees / 360.0f;
 
-    auto rotationOffset = 22.5f;
-    auto maxRotation    = 315.0f;
+    constexpr auto rotationOffset = 22.5f;
+    constexpr auto maxRotation    = 315.0f;
 
     auto startInDegrees = rotationInDegrees;
     auto endInDegrees   = startInDegrees + rotationOffset;
@@ -581,8 +596,8 @@ void LookAndFeel_V4::drawCircularProgressBar (Graphics& g, ProgressBar& progress
     Path arcPath2;
     arcPath2.addCentredArc (barBounds.getCentreX(),
                             barBounds.getCentreY(),
-                            barBounds.getWidth() * 0.5f,
-                            barBounds.getHeight() * 0.5f, 0.0f,
+                            size * 0.5f,
+                            size * 0.5f, 0.0f,
                             0.0f,
                             MathConstants<float>::twoPi,
                             true);
@@ -592,8 +607,8 @@ void LookAndFeel_V4::drawCircularProgressBar (Graphics& g, ProgressBar& progress
     Path arcPath;
     arcPath.addCentredArc (barBounds.getCentreX(),
                            barBounds.getCentreY(),
-                           barBounds.getWidth() * 0.5f,
-                           barBounds.getHeight() * 0.5f,
+                           size * 0.5f,
+                           size * 0.5f,
                            0.0f,
                            degreesToRadians (startInDegrees),
                            degreesToRadians (endInDegrees),
@@ -602,11 +617,11 @@ void LookAndFeel_V4::drawCircularProgressBar (Graphics& g, ProgressBar& progress
     arcPath.applyTransform (AffineTransform::rotation (normalisedRotation * MathConstants<float>::pi * 2.25f, barBounds.getCentreX(), barBounds.getCentreY()));
     g.strokePath (arcPath, PathStrokeType (4.0f));
 
-    if (progressText.isNotEmpty())
+    if (textToShow.isNotEmpty())
     {
         g.setColour (progressBar.findColour (TextButton::textColourOffId));
         g.setFont ({ 12.0f, Font::italic });
-        g.drawText (progressText, barBounds, Justification::centred, false);
+        g.drawText (textToShow, barBounds, Justification::centred, false);
     }
 }
 

modules/juce_gui_basics/lookandfeel/juce_LookAndFeel_V4.h

@@ -140,8 +140,9 @@ public:
     Font getAlertWindowFont() override;
 
     //==============================================================================
-    void drawProgressBar (Graphics&, ProgressBar&, int width, int height, double progress, const String& textToShow) override;
+    void drawProgressBar (Graphics&, ProgressBar&, int width, int height, double progress, const String&) override;
     bool isProgressBarOpaque (ProgressBar&) override    { return false; }
+    ProgressBar::Style getDefaultProgressBarStyle (const ProgressBar&) override;
 
     //==============================================================================
     int getDefaultScrollbarWidth() override;
@@ -242,9 +243,10 @@ public:
 
 private:
     //==============================================================================
-    void drawLinearProgressBar (Graphics&, ProgressBar&, int width, int height, double progress, const String&);
-    void drawCircularProgressBar (Graphics&, ProgressBar&, const String&);
+    static void drawLinearProgressBar (Graphics&, const ProgressBar&, int, int, double, const String&);
+    static void drawCircularProgressBar (Graphics&, const ProgressBar&, const String&);
 
+    //==============================================================================
     int getPropertyComponentIndent (PropertyComponent&);
 
     //==============================================================================

modules/juce_gui_basics/widgets/juce_ProgressBar.cpp

@@ -26,15 +26,14 @@
 namespace juce
 {
 
-ProgressBar::ProgressBar (double& progress_)
-   : progress (progress_),
-     displayPercentage (true),
-     lastCallbackTime (0)
+ProgressBar::ProgressBar (double& progress_, std::optional<Style> style_)
+   : progress { progress_ },
+     style { style_ }
 {
-    currentValue = jlimit (0.0, 1.0, progress);
 }
 
-ProgressBar::~ProgressBar()
+ProgressBar::ProgressBar (double& progress_)
+   : progress { progress_ }
 {
 }
 
@@ -51,6 +50,17 @@ void ProgressBar::setTextToDisplay (const String& text)
     displayedMessage = text;
 }
 
+void ProgressBar::setStyle (std::optional<Style> newStyle)
+{
+    style = newStyle;
+    repaint();
+}
+
+ProgressBar::Style ProgressBar::getResolvedStyle() const
+{
+    return style.value_or (getLookAndFeel().getDefaultProgressBarStyle (*this));
+}
+
 void ProgressBar::lookAndFeelChanged()
 {
     setOpaque (getLookAndFeel().isProgressBarOpaque (*this));
@@ -76,9 +86,11 @@ void ProgressBar::paint (Graphics& g)
         text = displayedMessage;
     }
 
-    getLookAndFeel().drawProgressBar (g, *this,
-                                      getWidth(), getHeight(),
-                                      currentValue, text);
+    const auto w = getWidth();
+    const auto h = getHeight();
+    const auto v = currentValue;
+
+    getLookAndFeel().drawProgressBar (g, *this, w, h, v, text);
 }
 
 void ProgressBar::visibilityChanged()

modules/juce_gui_basics/widgets/juce_ProgressBar.h

@@ -30,16 +30,14 @@ namespace juce
 /**
     A progress bar component.
 
-    To use this, just create one and make it visible. It'll run its own timer
-    to keep an eye on a variable that you give it, and will automatically
-    redraw itself when the variable changes.
+    To use this, just create one and make it visible. It'll run its own timer to keep an eye on a
+    variable that you give it, and will automatically redraw itself when the variable changes.
 
-    If using LookAndFeel_V4 a circular spinning progress bar will be drawn if
-    the width and height of the ProgressBar are equal, otherwise the standard,
-    linear ProgressBar will be drawn.
+    Two styles of progress bars are supported: circular, and linear bar. If a style isn't given the
+    look-and-feel will determine the style based on getDefaultProgressBarStyle().
 
-    For an easy way of running a background task with a dialog box showing its
-    progress, see the ThreadWithProgressWindow class.
+    For an easy way of running a background task with a dialog box showing its progress, see
+    the ThreadWithProgressWindow class.
 
     @see ThreadWithProgressWindow
 
@@ -50,9 +48,21 @@ class JUCE_API  ProgressBar  : public Component,
                                private Timer
 {
 public:
+    /** The types of ProgressBar styles available.
+
+        @see setStyle, getStyle, getResolvedStyle
+    */
+    enum class Style
+    {
+        linear,     /**< A linear progress bar. */
+        circular,   /**< A circular progress indicator. */
+    };
+
     //==============================================================================
     /** Creates a ProgressBar.
 
+        The ProgressBar's style will initially be determined by the look-and-feel.
+
         @param progress     pass in a reference to a double that you're going to
                             update with your task's progress. The ProgressBar will
                             monitor the value of this variable and will redraw itself
@@ -63,8 +73,21 @@ public:
     */
     explicit ProgressBar (double& progress);
 
+    /** Creates a ProgressBar with a specific style.
+
+        @param progress     pass in a reference to a double that you're going to
+                            update with your task's progress. The ProgressBar will
+                            monitor the value of this variable and will redraw itself
+                            when the value changes. The range is from 0 to 1.0 and JUCE
+                            LookAndFeel classes will draw a spinning animation for values
+                            outside this range. Obviously you'd better be careful not to
+                            delete this variable while the ProgressBar still exists!
+        @param style        the style of the progress bar.
+    */
+    ProgressBar (double& progress, std::optional<Style> style);
+
     /** Destructor. */
-    ~ProgressBar() override;
+    ~ProgressBar() override = default;
 
     //==============================================================================
     /** Turns the percentage display on or off.
@@ -81,6 +104,32 @@ public:
     */
     void setTextToDisplay (const String& text);
 
+    /** Sets the progress bar's current style.
+
+        You can use this to force getResolvedStyle() to return a particular value.
+        If a non-nullopt style is passed, that style will always be returned by
+        getResolvedStyle(). Otherwise, if nullopt is passed, getResolvedStyle() will
+        return its LookAndFeel's getDefaultProgressBarStyle().
+
+        @see getStyle, getResolvedStyle
+    */
+    void setStyle (std::optional<Style> newStyle);
+
+    /** Returns the progress bar's current style, as set in the constructor or in setStyle().
+
+        @see setStyle, getResolvedStyle
+    */
+    std::optional<Style> getStyle() const { return style; }
+
+    /** Returns the progress bar's current style if it has one, or a default style determined by
+        the look-and-feel if it doesn't.
+
+        Use this function in overrides of LookAndFeelMethods::drawProgressBar() in order to
+        determine which style to draw.
+
+        @see getStyle, setStyle, LookAndFeelMethods::getDefaultProgressBarStyle
+    */
+    Style getResolvedStyle() const;
 
     //==============================================================================
     /** A set of colour IDs to use to change the colour of various aspects of the bar.
@@ -109,12 +158,22 @@ public:
             bar that fills the whole space (i.e. to say that the app is still busy but the progress
             isn't known). It can use the current time as a basis for playing an animation.
 
+            To determine which style of progress-bar to draw call getResolvedStyle().
+
             (Used by progress bars in AlertWindow).
+
+            @see getResolvedStyle
         */
         virtual void drawProgressBar (Graphics&, ProgressBar&, int width, int height,
                                       double progress, const String& textToShow) = 0;
 
         virtual bool isProgressBarOpaque (ProgressBar&) = 0;
+
+        /** Returns the default style a progress bar should use if one hasn't been set.
+
+            @see setStyle, getResolvedStyle
+        */
+        virtual Style getDefaultProgressBarStyle (const ProgressBar&) = 0;
     };
 
     /** @internal */
@@ -133,10 +192,11 @@ protected:
 
 private:
     double& progress;
-    double currentValue;
-    bool displayPercentage;
+    std::optional<Style> style;
+    double currentValue { jlimit (0.0, 1.0, progress) };
+    bool displayPercentage { true };
     String displayedMessage, currentMessage;
-    uint32 lastCallbackTime;
+    uint32 lastCallbackTime { 0 };
 
     void timerCallback() override;
 

modules/juce_gui_basics/windows/juce_AlertWindow.cpp

@@ -294,9 +294,9 @@ void AlertWindow::addTextBlock (const String& textBlock)
 }
 
 //==============================================================================
-void AlertWindow::addProgressBarComponent (double& progressValue)
+void AlertWindow::addProgressBarComponent (double& progressValue, std::optional<ProgressBar::Style> style)
 {
-    auto* pb = new ProgressBar (progressValue);
+    auto* pb = new ProgressBar (progressValue, style);
     progressBars.add (pb);
     allComps.add (pb);
     addAndMakeVisible (pb);

modules/juce_gui_basics/windows/juce_AlertWindow.h

@@ -33,11 +33,11 @@ namespace juce
     some static methods for running these.
 
     For more complex dialogs, an AlertWindow can be created, then it can have some
-    buttons and components added to it, and its runModalLoop() method is then used to
-    show it. The value returned by runModalLoop() shows which button the
-    user pressed to dismiss the box.
+    buttons and components added to it, and its enterModalState() method is used to
+    show it. The value returned to the ModalComponentManager::Callback shows
+    which button the user pressed to dismiss the box.
 
-    @see ThreadWithProgressWindow
+    @see ThreadWithProgressWindow, Component::enterModalState
 
     @tags{GUI}
 */
@@ -188,8 +188,13 @@ public:
         @param progressValue    a variable that will be repeatedly checked while the
                                 dialog box is visible, to see how far the process has
                                 got. The value should be in the range 0 to 1.0
+        @param style            determines the style the ProgressBar should adopt.
+                                By default this use a style automatically chosen by
+                                the LookAndFeel, but you can force a particular style
+                                by passing a non-optional value.
+        @see ProgressBar::setStyle
     */
-    void addProgressBarComponent (double& progressValue);
+    void addProgressBarComponent (double& progressValue, std::optional<ProgressBar::Style> style = std::nullopt);
 
     //==============================================================================
     /** Adds a user-defined component to the dialog box.