Fix and complete style sheet support for QToolButton

Amends 2b2e7b2ac50e5b4f6e1888e594f6e32338dd2a80, which rewrote the
rendering to remove the conflation of menu arrows and arrow icons, but
introduced double rendering of the arrow icons if only the border was
styled.

Add a baseline test for style sheets, with a test function for
QToolButton configured in various ways and styled with different style
sheets.
The new test case includes a Qt 5 build system so that we can compare Qt
5.15 with Qt 6.

Fixes: QTBUG-98286
Pick-to: 6.2 6.2.2
Change-Id: I09cdc829c1a7e7913df4c3768dbe44b6dba4778b
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>

1 files changed, 51 insertions, 39 deletions

diff --git a/src/widgets/styles/qstylesheetstyle.cpp b/src/widgets/styles/qstylesheetstyle.cpp
index 1697832d7f..0784f61747 100644
--- a/src/widgets/styles/qstylesheetstyle.cpp
+++ b/src/widgets/styles/qstylesheetstyle.cpp
@@ -3274,7 +3274,6 @@ void QStyleSheetStyle::drawComplexControl(ComplexControl cc, const QStyleOptionC
             rule.configurePalette(&toolOpt.palette, QPalette::ButtonText, QPalette::Button);
             toolOpt.font = rule.font.resolve(toolOpt.font);
             toolOpt.rect = rule.borderRect(opt->rect);
-            bool customArrow = tool->features & QStyleOptionToolButton::Arrow;
             const auto customArrowElement = [tool]{
                 switch (tool->arrowType) {
                 case Qt::DownArrow: return PseudoElement_DownArrow;
@@ -3285,9 +3284,29 @@ void QStyleSheetStyle::drawComplexControl(ComplexControl cc, const QStyleOptionC
                 }
                 return PseudoElement_None;
             };
-            bool customDropDown = tool->features & QStyleOptionToolButton::MenuButtonPopup;
+            // if arrow/menu/indicators are requested, either draw them using the available rule,
+            // or let the base style draw them; but not both
+            const bool drawArrow = tool->features & QStyleOptionToolButton::Arrow;
+            bool customArrow = drawArrow && hasStyleRule(w, customArrowElement());
+            if (customArrow) {
+                toolOpt.features &= ~QStyleOptionToolButton::Arrow;
+                toolOpt.text = QString(); // we need to draw the arrow and the text ourselves
+            }
+            const bool drawDropDown = tool->features & QStyleOptionToolButton::MenuButtonPopup;
+            bool customDropDown = drawDropDown && hasStyleRule(w, PseudoElement_ToolButtonMenu);
             bool customDropDownArrow = false;
-            bool customMenuIndicator = !customDropDown && (tool->features & QStyleOptionToolButton::HasMenu);
+            const bool drawMenuIndicator = tool->features & QStyleOptionToolButton::HasMenu;
+            if (customDropDown) {
+                toolOpt.subControls &= ~QStyle::SC_ToolButtonMenu;
+                customDropDownArrow = hasStyleRule(w, PseudoElement_ToolButtonMenuArrow);
+                if (customDropDownArrow)
+                    toolOpt.features &= ~(QStyleOptionToolButton::Menu | QStyleOptionToolButton::HasMenu);
+            }
+            bool customMenuIndicator = (!customDropDown && drawMenuIndicator)
+                                    && hasStyleRule(w, PseudoElement_ToolButtonMenuIndicator);
+            if (customMenuIndicator)
+                toolOpt.features &= ~QStyleOptionToolButton::HasMenu;
+
             if (rule.hasNativeBorder()) {
                 if (tool->subControls & SC_ToolButton) {
                     //in some case (eg. the button is "auto raised") the style doesn't draw the background
@@ -3301,28 +3320,12 @@ void QStyleSheetStyle::drawComplexControl(ComplexControl cc, const QStyleOptionC
                     if (!(bflags & (State_Sunken | State_On | State_Raised)))
                         rule.drawBackground(p, toolOpt.rect);
                 }
-                customArrow = customArrow && hasStyleRule(w, customArrowElement());
-                if (customArrow)
-                    toolOpt.features &= ~QStyleOptionToolButton::Arrow;
-                customDropDown = customDropDown && hasStyleRule(w, PseudoElement_ToolButtonMenu);
-                if (customDropDown) {
-                    toolOpt.subControls &= ~QStyle::SC_ToolButtonMenu;
-                    customDropDownArrow = hasStyleRule(w, PseudoElement_ToolButtonMenuArrow);
-                    if (customDropDownArrow)
-                        toolOpt.features &= ~(QStyleOptionToolButton::Menu | QStyleOptionToolButton::HasMenu);
-                }
-                customMenuIndicator = customMenuIndicator && hasStyleRule(w, PseudoElement_ToolButtonMenuIndicator);
-                if (customMenuIndicator)
-                    toolOpt.features &= ~QStyleOptionToolButton::HasMenu;
 
                 if (rule.baseStyleCanDraw() && !(tool->features & QStyleOptionToolButton::Arrow)) {
                     baseStyle()->drawComplexControl(cc, &toolOpt, p, w);
                 } else {
                     QWindowsStyle::drawComplexControl(cc, &toolOpt, p, w);
                 }
-
-                if (!customArrow && !customDropDown && !customMenuIndicator)
-                    return;
             } else {
                 rule.drawRule(p, opt->rect);
                 toolOpt.rect = rule.contentsRect(opt->rect);
@@ -3332,7 +3335,7 @@ void QStyleSheetStyle::drawComplexControl(ComplexControl cc, const QStyleOptionC
             }
 
             const QRect cr = toolOpt.rect;
-            if (customDropDown) {
+            if (drawDropDown) {
                 if (opt->subControls & QStyle::SC_ToolButtonMenu) {
                     QRenderRule subRule = renderRule(w, opt, PseudoElement_ToolButtonMenu);
                     QRect menuButtonRect = subControlRect(CC_ToolButton, opt, QStyle::SC_ToolButtonMenu, w);
@@ -3343,7 +3346,7 @@ void QStyleSheetStyle::drawComplexControl(ComplexControl cc, const QStyleOptionC
                         baseStyle()->drawPrimitive(PE_IndicatorButtonDropDown, &toolOpt, p, w);
                     }
 
-                    if (customDropDownArrow) {
+                    if (customDropDownArrow || drawMenuIndicator) {
                         QRenderRule arrowRule = renderRule(w, opt, PseudoElement_ToolButtonMenuArrow);
                         QRect arrowRect = arrowRule.hasGeometry()
                                         ? positionRect(w, arrowRule, PseudoElement_ToolButtonMenuArrow, menuButtonRect, toolOpt.direction)
@@ -3356,7 +3359,7 @@ void QStyleSheetStyle::drawComplexControl(ComplexControl cc, const QStyleOptionC
                         }
                     }
                 }
-            } else if (customMenuIndicator) {
+            } else if (drawMenuIndicator) {
                 QRenderRule subRule = renderRule(w, opt, PseudoElement_ToolButtonMenuIndicator);
                 QRect r = subRule.hasGeometry()
                         ? positionRect(w, subRule, PseudoElement_ToolButtonMenuIndicator, toolOpt.rect, toolOpt.direction)
@@ -3370,27 +3373,36 @@ void QStyleSheetStyle::drawComplexControl(ComplexControl cc, const QStyleOptionC
             }
             toolOpt.rect = cr;
 
+            // If we don't have a custom arrow, then the arrow will have been rendered
+            // already by the base style when drawing the label.
             if (customArrow) {
                 const auto arrowElement = customArrowElement();
                 QRenderRule subRule = renderRule(w, opt, arrowElement);
-                QRect r = subRule.hasGeometry() ? positionRect(w, subRule, arrowElement, toolOpt.rect, toolOpt.direction)
-                                                : subRule.contentsRect(toolOpt.rect);
-                if (subRule.hasDrawable()) {
-                    subRule.drawRule(p, r);
-                } else {
-                    toolOpt.rect = r;
-                    const auto arrowElement = [&toolOpt] {
-                        switch (toolOpt.arrowType) {
-                        case Qt::DownArrow: return QStyle::PE_IndicatorArrowDown;
-                        case Qt::UpArrow: return QStyle::PE_IndicatorArrowUp;
-                        case Qt::LeftArrow: return QStyle::PE_IndicatorArrowLeft;
-                        case Qt::RightArrow: return QStyle::PE_IndicatorArrowRight;
-                        case Qt::NoArrow: break;
-                        }
-                        return QStyle::PE_IndicatorArrowDown; // never happens
-                    };
-                    baseStyle()->drawPrimitive(arrowElement(), &toolOpt, p, w);
+                QRect arrowRect = subRule.hasGeometry() ? positionRect(w, subRule, arrowElement, toolOpt.rect, toolOpt.direction)
+                                                        : subRule.contentsRect(toolOpt.rect);
+
+                switch (toolOpt.toolButtonStyle) {
+                case Qt::ToolButtonIconOnly:
+                    break;
+                case Qt::ToolButtonTextOnly:
+                case Qt::ToolButtonTextBesideIcon:
+                case Qt::ToolButtonTextUnderIcon: {
+                    // The base style needs to lay out the contents and will render the styled
+                    // arrow icons, unless the geometry is defined in the style sheet.
+                    toolOpt.text = tool->text;
+                    if (!subRule.hasGeometry())
+                        toolOpt.features |= QStyleOptionToolButton::Arrow;
+                    drawControl(CE_ToolButtonLabel, &toolOpt, p, w);
+                    if (!subRule.hasGeometry())
+                        return;
+                    break;
+                }
+                case Qt::ToolButtonFollowStyle:
+                    // QToolButton handles this, so must never happen
+                    Q_ASSERT(false);
+                    break;
                 }
+                subRule.drawRule(p, arrowRect);
             }
 
             return;