Add support for ScrollBar arrow buttons

In order to achieve this, it separates out QQuickSpinButton into a
separate file (and renames it since it's not only purposed for SpinBox
anymore). This allows it to be also used by QQuickScrollBar.

Fixes: QTBUG-88115
Pick-to: 6.0
Change-Id: I2dea42b29750b7bc619031f40a43717fc10c177b
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

5 files changed, 73 insertions, 19 deletions

diff --git a/src/imports/nativestyle/items/qquickstyleitem.h b/src/imports/nativestyle/items/qquickstyleitem.h
index fdfd7012..0a89454b 100644
--- a/src/imports/nativestyle/items/qquickstyleitem.h
+++ b/src/imports/nativestyle/items/qquickstyleitem.h
@@ -186,6 +186,7 @@ public:
         None = 0,
         AlwaysHovered,
         NeverHovered,
+        AlwaysSunken
     };
     Q_ENUM(OverrideState)
 
diff --git a/src/imports/nativestyle/items/qquickstyleitemscrollbar.cpp b/src/imports/nativestyle/items/qquickstyleitemscrollbar.cpp
index 1b94b22d..d6d41d96 100644
--- a/src/imports/nativestyle/items/qquickstyleitemscrollbar.cpp
+++ b/src/imports/nativestyle/items/qquickstyleitemscrollbar.cpp
@@ -56,6 +56,14 @@ StyleItemGeometry QQuickStyleItemScrollBar::calculateGeometry()
 
     StyleItemGeometry geometry;
     geometry.minimumSize = style()->sizeFromContents(QStyle::CT_ScrollBar, &styleOption, QSize(0, 0));
+    if (m_subControl == SubLine || m_subControl == AddLine) {
+        // So far, we know that only the windows style uses these subcontrols,
+        // so we can use hardcoded sizes...
+        QSize sz(16, 17);
+        if (styleOption.orientation == Qt::Vertical)
+            sz.transpose();
+        geometry.minimumSize = sz;
+    }
     geometry.implicitSize = geometry.minimumSize;
     styleOption.rect = QRect(QPoint(0, 0), geometry.implicitSize);
     geometry.layoutRect = style()->subElementRect(QStyle::SE_ScrollBarLayoutItem, &styleOption);
@@ -68,7 +76,27 @@ void QQuickStyleItemScrollBar::paintEvent(QPainter *painter) const
 {
     QStyleOptionSlider styleOption;
     initStyleOption(styleOption);
-    style()->drawComplexControl(QStyle::CC_ScrollBar, &styleOption, painter);
+    if (m_subControl == SubLine || m_subControl == AddLine) {
+        QStyle::SubControl sc = m_subControl == SubLine ? QStyle::SC_ScrollBarSubLine : QStyle::SC_ScrollBarAddLine;
+        QStyleOptionSlider opt = styleOption;
+        opt.subControls = QStyle::SC_ScrollBarAddLine
+                        | QStyle::SC_ScrollBarSubLine
+                        | QStyle::SC_ScrollBarGroove;
+
+        const qreal scale = window()->devicePixelRatio();
+        const QSize scrollBarMinSize = style()->sizeFromContents(QStyle::CT_ScrollBar, &opt, QSize(0, 0));
+        const QSize sz = scrollBarMinSize * scale;
+        QImage scrollBarImage(sz, QImage::Format_ARGB32_Premultiplied);
+        scrollBarImage.setDevicePixelRatio(scale);
+        QPainter p(&scrollBarImage);
+        opt.rect = QRect(QPoint(0, 0), scrollBarMinSize);
+        style()->drawComplexControl(QStyle::CC_ScrollBar, &opt, &p);
+        QRect sourceImageRect = style()->subControlRect(QStyle::CC_ScrollBar, &opt, sc);
+        sourceImageRect = QRect(sourceImageRect.topLeft() * scale, sourceImageRect.size() * scale);
+        painter->drawImage(QPoint(0, 0), scrollBarImage, sourceImageRect);
+    } else {
+        style()->drawComplexControl(QStyle::CC_ScrollBar, &styleOption, painter);
+    }
 }
 
 void QQuickStyleItemScrollBar::initStyleOption(QStyleOptionSlider &styleOption) const
@@ -76,9 +104,21 @@ void QQuickStyleItemScrollBar::initStyleOption(QStyleOptionSlider &styleOption)
     initStyleOptionBase(styleOption);
     auto scrollBar = control<QQuickScrollBar>();
 
-    styleOption.subControls = m_subControl == Groove
-                            ? QStyle::SC_ScrollBarGroove | QStyle::SC_ScrollBarAddLine | QStyle::SC_ScrollBarSubLine
-                            : QStyle::SC_ScrollBarSlider;
+    switch (m_subControl) {
+    case Groove:
+        styleOption.subControls = QStyle::SC_ScrollBarGroove | QStyle::SC_ScrollBarAddLine | QStyle::SC_ScrollBarSubLine;
+        break;
+    case Handle:
+        styleOption.subControls = QStyle::SC_ScrollBarSlider;
+        break;
+    case AddLine:
+        styleOption.subControls = QStyle::SC_ScrollBarAddLine;
+        break;
+    case SubLine:
+        styleOption.subControls = QStyle::SC_ScrollBarSubLine;
+        break;
+    }
+
     styleOption.activeSubControls = QStyle::SC_None;
     styleOption.orientation = scrollBar->orientation();
     if (styleOption.orientation == Qt::Horizontal)
@@ -90,12 +130,14 @@ void QQuickStyleItemScrollBar::initStyleOption(QStyleOptionSlider &styleOption)
     if (m_overrideState != None) {
         // In ScrollBar.qml we fade between two versions of
         // the handle, depending on if it's hovered or not
-        if (m_overrideState & AlwaysHovered) {
+
+        if (m_overrideState == AlwaysHovered) {
+            styleOption.activeSubControls = (styleOption.subControls & (QStyle::SC_ScrollBarSlider | QStyle::SC_ScrollBarGroove | QStyle::SC_ScrollBarAddLine | QStyle::SC_ScrollBarSubLine));
+        } else if (m_overrideState == NeverHovered) {
+            styleOption.activeSubControls &= ~(styleOption.subControls & (QStyle::SC_ScrollBarSlider | QStyle::SC_ScrollBarGroove | QStyle::SC_ScrollBarAddLine | QStyle::SC_ScrollBarSubLine));
+        } else if (m_overrideState  == AlwaysSunken) {
             styleOption.state |= QStyle::State_Sunken;
-            styleOption.activeSubControls = (styleOption.subControls & (QStyle::SC_ScrollBarSlider | QStyle::SC_ScrollBarGroove));
-        } else if (m_overrideState & NeverHovered) {
-            styleOption.state &= ~QStyle::State_Sunken;
-            styleOption.activeSubControls &= ~(styleOption.subControls & (QStyle::SC_ScrollBarSlider | QStyle::SC_ScrollBarGroove));
+            styleOption.activeSubControls = (styleOption.subControls & (QStyle::SC_ScrollBarSlider | QStyle::SC_ScrollBarGroove | QStyle::SC_ScrollBarAddLine | QStyle::SC_ScrollBarSubLine));
         }
     }
 
diff --git a/src/imports/nativestyle/items/qquickstyleitemscrollbar.h b/src/imports/nativestyle/items/qquickstyleitemscrollbar.h
index 9d86cb09..f89d8d3e 100644
--- a/src/imports/nativestyle/items/qquickstyleitemscrollbar.h
+++ b/src/imports/nativestyle/items/qquickstyleitemscrollbar.h
@@ -52,6 +52,8 @@ public:
     enum SubControl {
         Groove = 1,
         Handle,
+        AddLine,
+        SubLine
     };
     Q_ENUM(SubControl)
 
diff --git a/src/imports/nativestyle/items/qquickstyleitemspinbox.cpp b/src/imports/nativestyle/items/qquickstyleitemspinbox.cpp
index 46097567..2a232b8a 100644
--- a/src/imports/nativestyle/items/qquickstyleitemspinbox.cpp
+++ b/src/imports/nativestyle/items/qquickstyleitemspinbox.cpp
@@ -35,6 +35,7 @@
 ****************************************************************************/
 
 #include "qquickstyleitemspinbox.h"
+#include <QtQuickTemplates2/private/qquickindicatorbutton_p.h>
 
 QFont QQuickStyleItemSpinBox::styleFont(QQuickItem *control) const
 {
@@ -45,8 +46,8 @@ void QQuickStyleItemSpinBox::connectToControl() const
 {
     QQuickStyleItem::connectToControl();
     auto spinbox = control<QQuickSpinBox>();
-    connect(spinbox->up(), &QQuickSpinButton::pressedChanged, this, &QQuickStyleItem::markImageDirty);
-    connect(spinbox->down(), &QQuickSpinButton::pressedChanged, this, &QQuickStyleItem::markImageDirty);
+    connect(spinbox->up(), &QQuickIndicatorButton::pressedChanged, this, &QQuickStyleItem::markImageDirty);
+    connect(spinbox->down(), &QQuickIndicatorButton::pressedChanged, this, &QQuickStyleItem::markImageDirty);
 }
 
 StyleItemGeometry QQuickStyleItemSpinBox::calculateGeometry()
diff --git a/src/imports/nativestyle/qstyle/windows/qquickwindowsxpstyle.cpp b/src/imports/nativestyle/qstyle/windows/qquickwindowsxpstyle.cpp
index 0f07aef0..fd363d62 100644
--- a/src/imports/nativestyle/qstyle/windows/qquickwindowsxpstyle.cpp
+++ b/src/imports/nativestyle/qstyle/windows/qquickwindowsxpstyle.cpp
@@ -2552,14 +2552,16 @@ void QWindowsXPStyle::drawComplexControl(ComplexControl cc, const QStyleOptionCo
                 d->drawBackground(theme);
             }
             if (maxedOut) {
-                theme.rect = proxy()->subControlRect(CC_ScrollBar, option, SC_ScrollBarSlider);
-                theme.rect = theme.rect.united(proxy()->subControlRect(CC_ScrollBar, option, SC_ScrollBarSubPage));
-                theme.rect = theme.rect.united(proxy()->subControlRect(CC_ScrollBar, option, SC_ScrollBarAddPage));
-                partId = scrollbar->orientation == Qt::Horizontal ? SBP_LOWERTRACKHORZ : SBP_LOWERTRACKVERT;
-                stateId = SCRBS_DISABLED;
-                theme.partId = partId;
-                theme.stateId = stateId;
-                d->drawBackground(theme);
+                if (sub & SC_ScrollBarSlider) {
+                    theme.rect = proxy()->subControlRect(CC_ScrollBar, option, SC_ScrollBarSlider);
+                    theme.rect = theme.rect.united(proxy()->subControlRect(CC_ScrollBar, option, SC_ScrollBarSubPage));
+                    theme.rect = theme.rect.united(proxy()->subControlRect(CC_ScrollBar, option, SC_ScrollBarAddPage));
+                    partId = scrollbar->orientation == Qt::Horizontal ? SBP_LOWERTRACKHORZ : SBP_LOWERTRACKVERT;
+                    stateId = SCRBS_DISABLED;
+                    theme.partId = partId;
+                    theme.stateId = stateId;
+                    d->drawBackground(theme);
+                }
             } else {
                 if (sub & SC_ScrollBarSubPage) {
                     theme.rect = proxy()->subControlRect(CC_ScrollBar, option, SC_ScrollBarSubPage);
@@ -3536,6 +3538,12 @@ QSize QWindowsXPStyle::sizeFromContents(ContentsType ct, const QStyleOption *opt
             if (slider->subControls & (SC_ScrollBarSlider | SC_ScrollBarGroove)) {
                 szw = qMax(szw, scrollBarSliderMin + 2 * scrollBarHeight);
                 szh = scrollBarHeight;
+            } else if (slider->subControls & (SC_ScrollBarAddLine| SC_ScrollBarSubLine)) {
+                // Assume that the AddLine and SubLine buttons have the same size, and just query
+                // for the size of AddLine
+                const QSize s = proxy()->subControlRect(CC_ScrollBar, slider, SC_ScrollBarAddLine).size();
+                szw = qMax(szw, s.width());
+                szh = scrollBarHeight;
             }
         }
         break;