Make every widget scrollable

examples/showcase/src/Messenger.cpp

@@ -74,8 +74,9 @@ RC<Widget> ShowcaseMessenger::build(RC<Notifications> notifications) {
         painter       = Painter(&backgroundPainter),
 
         rcnew VLayout{
-            flexGrow  = 1,
-            alignSelf = AlignSelf::Stretch,
+            flexGrow       = 1,
+            alignSelf      = AlignSelf::Stretch,
+            scrollBarColor = 0x32a852_rgb,
             rcnew VScrollBox{
                 flexGrow  = 1,
                 alignSelf = AlignSelf::Stretch,

include/brisk/gui/GUI.hpp

@@ -334,7 +334,7 @@ template <typename Callable, typename R, typename... Args>
 concept invocable_r = std::is_invocable_r_v<R, Callable, Args...>;
 
 namespace Internal {
-constexpr inline size_t numProperties = 101;
+constexpr inline size_t numProperties = 104;
 extern const std::string_view propNames[numProperties];
 
 template <typename T, int subfield = -1>
@@ -979,6 +979,14 @@ class WIDGET Widget : public BindingObject<Widget, &uiThread> {
 
     void reveal();
 
+    bool setScrollOffset(Point newOffset);
+    bool setScrollOffset(Orientation orientation, int newOffset);
+    Point scrollOffset() const;
+    int scrollOffset(Orientation orientation) const;
+    bool hasScrollBar(Orientation orientation) const noexcept;
+    int scrollSize(Orientation orientation) const noexcept;
+    Size scrollSize() const noexcept;
+
     using enum PropFlags;
 
     friend struct Rules;
@@ -1032,6 +1040,7 @@ class WIDGET Widget : public BindingObject<Widget, &uiThread> {
     Internal::Transition<ColorF> m_borderColor{ Palette::transparent };
     Internal::Transition<ColorF> m_color{ Palette::white };
     Internal::Transition<ColorF> m_shadowColor{ Palette::black.multiplyAlpha(0.4f) };
+    Internal::Transition<ColorF> m_scrollBarColor{ Palette::grey };
     float m_backgroundColorTransition      = 0;
     float m_borderColorTransition          = 0;
     float m_colorTransition                = 0;
@@ -1074,6 +1083,8 @@ class WIDGET Widget : public BindingObject<Widget, &uiThread> {
     Internal::Resolve<Length> m_tabSize{ 40, 40 };
     Internal::Resolve<Length> m_letterSpacing{ 0_px, 0.f };
     Internal::Resolve<Length> m_wordSpacing{ 0_px, 0.f };
+    Internal::Resolve<Length> m_scrollBarThickness{ 8_px, 8.f };
+    Internal::Resolve<Length> m_scrollBarRadius{ 0_px, 0.f };
 
     // uint8_t
     mutable WidgetState m_state         = WidgetState::None;
@@ -1091,7 +1102,7 @@ class WIDGET Widget : public BindingObject<Widget, &uiThread> {
     Placement m_placement               = Placement::Normal;
     ZOrder m_zorder                     = ZOrder::Normal;
     WidgetClip m_clip                   = WidgetClip::All;
-    Overflow m_overflow                 = Overflow::Hidden;
+    Overflow m_overflow                 = Overflow::None;
     AlignContent m_alignContent         = AlignContent::FlexStart;
     Wrap m_flexWrap                     = Wrap::NoWrap;
     BoxSizingPerAxis m_boxSizing        = BoxSizingPerAxis::BorderBox;
@@ -1112,6 +1123,19 @@ class WIDGET Widget : public BindingObject<Widget, &uiThread> {
     bool m_stateTriggersRestyle         = false;
     bool m_isHintExclusive              = false;
 
+    std::array<bool, 2> m_scrollBarDrag{ false, false };
+    int m_savedScrollOffset = 0;
+
+    struct ScrollBarGeometry {
+        Rectangle track;
+        Rectangle thumb;
+    };
+
+    Range<int> scrollBarRange(Orientation orientation) const noexcept;
+    ScrollBarGeometry scrollBarGeometry(Orientation orientation) const noexcept;
+
+    void updateScrollAxes();
+
     std::bitset<Internal::propStateBits * Internal::numProperties> m_propStates;
     Internal::PropState getPropState(size_t index) const noexcept;
     void setPropState(size_t index, Internal::PropState state) noexcept;
@@ -1170,10 +1194,13 @@ class WIDGET Widget : public BindingObject<Widget, &uiThread> {
     void doPaint(Canvas& canvas) const;
     virtual void paint(Canvas& canvas) const;
     virtual void postPaint(Canvas& canvas) const;
+    virtual void paintScrollBar(Canvas& canvas, Orientation orientation,
+                                const ScrollBarGeometry& geometry) const;
     void paintBackground(Canvas& canvas, Rectangle rect) const;
     void paintHint(Canvas& canvas) const;
     void paintFocusFrame(Canvas& canvas) const;
     void paintChildren(Canvas& canvas) const;
+    void paintScrollBars(Canvas& canvas) const;
 
     ///////////////////////////////////////////////////////////////////////////////
 
@@ -1422,6 +1449,11 @@ class WIDGET Widget : public BindingObject<Widget, &uiThread> {
         padding;
     GUIProperty<100, OpenTypeFeatureFlags, AffectLayout | AffectFont | Inheritable, &This::m_fontFeatures>
         fontFeatures;
+
+    GUIProperty<101, ColorF, Transition | Inheritable, &This::m_scrollBarColor> scrollBarColor;
+    GUIProperty<102, Length, Resolvable, &This::m_scrollBarThickness> scrollBarThickness;
+    GUIProperty<103, Length, Resolvable, &This::m_scrollBarRadius> scrollBarRadius;
+
     Property<This, bool, &This::m_state, &This::isDisabled, &This::setDisabled> disabled;
     BRISK_PROPERTIES_END
 };
@@ -1540,6 +1572,10 @@ extern const Argument<Tag::PropArg<decltype(Widget::disabled)>> disabled;
 
 extern const Argument<Tag::PropArg<decltype(Widget::fontFeatures)>> fontFeatures;
 
+extern const Argument<Tag::PropArg<decltype(Widget::scrollBarColor)>> scrollBarColor;
+extern const Argument<Tag::PropArg<decltype(Widget::scrollBarThickness)>> scrollBarThickness;
+extern const Argument<Tag::PropArg<decltype(Widget::scrollBarRadius)>> scrollBarRadius;
+
 } // namespace Arg
 
 namespace Tag {

include/brisk/gui/Layout.hpp

@@ -356,16 +356,13 @@ constexpr auto operator+(Wrap value) noexcept {
 }
 
 enum class Overflow : uint8_t {
-    Visible,
-    Hidden,
-    ScrollX,
-    ScrollY,
-    ScrollBoth,
+    None       = 0,
+    ScrollX    = 1,
+    ScrollY    = 2,
+    ScrollBoth = 3,
 };
 
-constexpr auto operator+(Overflow value) noexcept {
-    return static_cast<std::underlying_type_t<decltype(value)>>(value);
-}
+BRISK_FLAGS(Overflow)
 
 enum class Gutter : uint8_t {
     Column,

include/brisk/widgets/ScrollBox.hpp

@@ -21,7 +21,6 @@
 #pragma once
 
 #include <brisk/gui/GUI.hpp>
-#include "ScrollBar.hpp"
 
 namespace Brisk {
 
@@ -36,36 +35,11 @@ class WIDGET ScrollBox : public Widget {
         endConstruction();
     }
 
-    std::shared_ptr<ScrollBar> scrollBar() const;
-    bool scrollable() const;
-
 protected:
-    Orientation m_orientation;
-    float m_scrollPosition     = 0;
-    mutable float m_scrollSize = 0;
-
-    void onEvent(Event& event) override;
-    void onLayoutUpdated() override;
-    bool setScrollOffset(float value);
-    void updateOffsets();
-    void createScrollBar();
-    void revealChild(Widget* child) override;
     Ptr cloneThis() const override;
     explicit ScrollBox(Construction construction, Orientation orientation, ArgumentsView<ScrollBox> args);
-
-public:
-    BRISK_PROPERTIES_BEGIN
-    Property<ScrollBox, float, &ScrollBox::m_scrollPosition, nullptr, nullptr, &ScrollBox::updateOffsets>
-        scrollPosition;
-    Property<ScrollBox, float, &ScrollBox::m_scrollSize> scrollSize;
-    BRISK_PROPERTIES_END
 };
 
-inline namespace Arg {
-constexpr inline Argument<Tag::PropArg<decltype(ScrollBox::scrollPosition)>> scrollPosition{};
-constexpr inline Argument<Tag::PropArg<decltype(ScrollBox::scrollSize)>> scrollSize{};
-} // namespace Arg
-
 class WIDGET VScrollBox final : public ScrollBox {
 public:
     using Base = ScrollBox;

include/brisk/widgets/Widgets.hpp

@@ -46,7 +46,6 @@
 #include "PopupDialog.hpp"
 #include "Progress.hpp"
 #include "RadioButton.hpp"
-#include "ScrollBar.hpp"
 #include "ScrollBox.hpp"
 #include "Slider.hpp"
 #include "Spacer.hpp"