[UnifiedPDF] Support radio buttons, checkboxes, and choice annotations.

https://bugs.webkit.org/show_bug.cgi?id=268196
rdar://problem/121692745

Reviewed by Simon Fraser.

Choice annotations are similar to text widget annotations, which we
already support, in that they use a PDFPluginAnnotation to support
user interaction and just commit the result to the underlying annotation
afterwards.

Radio buttons and checkboxes involve slightly more work as we must keep
track of the mouse as the user interacts with them. Holding the left
mouse button on them will create a highlight effect indicating that this
action is occuring and releasing it will trigger the effect of the
checkbox/radio button. If the mouse is dragged off while the left mouse
button is held down on it, then the highlight disappears and no effect
should occur when the button is released. In order to accomplish this,
we need to start tracking the annotation that is being interacted with
through various mouse events. m_trackedAnnotation was added for this
purpose and is updated through the various events.

* Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/UnifiedPDFPlugin.h:
* Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/UnifiedPDFPlugin.mm:
(WebKit::UnifiedPDFPlugin::annotationForRootViewPoint const):
(WebKit::UnifiedPDFPlugin::handleMouseEvent):
(WebKit::UnifiedPDFPlugin::startAnnotationTracking):
(WebKit::UnifiedPDFPlugin::finishAnnotationTracking):
(WebKit::UnifiedPDFPlugin::handleMouseDraggedOffTrackedAnnotation):

Canonical link: https://commits.webkit.org/273921@main

Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/UnifiedPDFPlugin.h

@@ -61,6 +61,9 @@ class UnifiedPDFPlugin final : public PDFPluginBase, public WebCore::GraphicsLay
 
     CGRect boundsForAnnotation(RetainPtr<PDFAnnotation>&) const final;
     void setActiveAnnotation(RetainPtr<PDFAnnotation>&&) final;
+    void startAnnotationTracking(RetainPtr<PDFAnnotation>&&);
+    void finishAnnotationTracking();
+    void handleMouseDraggedOffTrackedAnnotation();
     void focusNextAnnotation() final;
     void focusPreviousAnnotation() final;
 
@@ -218,6 +221,7 @@ class UnifiedPDFPlugin final : public PDFPluginBase, public WebCore::GraphicsLay
 
     WebCore::IntPoint convertFromPluginToDocument(const WebCore::IntPoint&) const;
     std::optional<PDFDocumentLayout::PageIndex> pageIndexForDocumentPoint(const WebCore::IntPoint&) const;
+    RetainPtr<PDFAnnotation> annotationForRootViewPoint(const WebCore::IntPoint&) const;
     WebCore::IntPoint convertFromDocumentToPage(const WebCore::IntPoint&, PDFDocumentLayout::PageIndex) const;
     WebCore::IntPoint convertFromPageToDocument(const WebCore::IntPoint&, PDFDocumentLayout::PageIndex) const;
     PDFElementTypes pdfElementTypesForPluginPoint(const WebCore::IntPoint&) const;
@@ -239,6 +243,9 @@ class UnifiedPDFPlugin final : public PDFPluginBase, public WebCore::GraphicsLay
 
     float m_scaleFactor { 1 };
     bool m_inMagnificationGesture { false };
+
+    RetainPtr<PDFAnnotation> m_trackedAnnotation;
+
 };
 
 } // namespace WebKit

Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/UnifiedPDFPlugin.mm

@@ -832,6 +832,17 @@
     return std::nullopt;
 }
 
+RetainPtr<PDFAnnotation> UnifiedPDFPlugin::annotationForRootViewPoint(const WebCore::IntPoint& point) const
+{
+    auto pointInDocumentSpace = convertFromPluginToDocument(convertFromRootViewToPlugin(point));
+    auto nearestPageIndex = pageIndexForDocumentPoint(pointInDocumentSpace);
+    if (!nearestPageIndex)
+        return nullptr;
+
+    auto page = m_documentLayout.pageAtIndex(nearestPageIndex.value());
+    return [page annotationAtPoint:convertFromDocumentToPage(pointInDocumentSpace, nearestPageIndex.value())];
+}
+
 static AffineTransform documentSpaceToPageSpaceTransform(const IntDegrees& pageRotation, const FloatRect& pageBounds)
 {
     return AffineTransform::makeRotation(pageRotation).translate([&pageBounds, pageRotation] () -> FloatPoint {
@@ -954,8 +965,17 @@ static AffineTransform documentSpaceToPageSpaceTransform(const IntDegrees& pageR
             auto altKeyIsActive = event.altKey() ? AltKeyIsActive::Yes : AltKeyIsActive::No;
             auto pdfElementTypes = pdfElementTypesForPluginPoint(m_lastMousePositionInPluginCoordinates);
             notifyCursorChanged(toWebCoreCursorType(pdfElementTypes, altKeyIsActive));
+            if (m_trackedAnnotation)
+                handleMouseDraggedOffTrackedAnnotation();
             return true;
         }
+        case WebMouseEventButton::Left: {
+            if (m_trackedAnnotation && m_trackedAnnotation != annotationForRootViewPoint(event.position())) {
+                handleMouseDraggedOffTrackedAnnotation();
+                return true;
+            }
+            return false;
+        }
         default:
             return false;
         }
@@ -966,18 +986,36 @@ static AffineTransform documentSpaceToPageSpaceTransform(const IntDegrees& pageR
             auto nearestPageIndex = pageIndexForDocumentPoint(pointInDocumentSpace);
             if (!nearestPageIndex)
                 return false;
-
-            auto page = m_documentLayout.pageAtIndex(nearestPageIndex.value());
-            auto pointInPDFPageSpace = convertFromDocumentToPage(pointInDocumentSpace, nearestPageIndex.value());
-            if (auto annotation = [page annotationAtPoint:pointInPDFPageSpace]; annotation && [annotation isKindOfClass:getPDFAnnotationTextWidgetClass()]) {
-                setActiveAnnotation(annotation);
-                return true;
+            if (RetainPtr<PDFAnnotation> annotation = annotationForRootViewPoint(event.position())) {
+                if (([annotation isKindOfClass:getPDFAnnotationButtonWidgetClass()] || [annotation isKindOfClass:getPDFAnnotationTextWidgetClass()] || [annotation isKindOfClass:getPDFAnnotationChoiceWidgetClass()]) && [annotation isReadOnly])
+                    return true;
+
+                if ([annotation isKindOfClass:getPDFAnnotationTextWidgetClass()] || [annotation isKindOfClass:getPDFAnnotationChoiceWidgetClass()]) {
+                    setActiveAnnotation(annotation.get());
+                    return true;
+                }
+                if ([annotation isKindOfClass:getPDFAnnotationButtonWidgetClass()]) {
+                    startAnnotationTracking(WTFMove(annotation));
+                    return true;
+                }
+                return false;
             }
             return false;
         }
         default:
             return false;
         }
+    case WebEventType::MouseUp:
+        switch (event.button()) {
+        case WebMouseEventButton::Left:
+            if (m_trackedAnnotation) {
+                finishAnnotationTracking();
+                return true;
+            }
+            return false;
+        default:
+            return false;
+        }
     default:
         return false;
     }
@@ -1241,6 +1279,46 @@ static AffineTransform documentSpaceToPageSpaceTransform(const IntDegrees& pageR
 #endif
 }
 
+void UnifiedPDFPlugin::startAnnotationTracking(RetainPtr<PDFAnnotation>&& annotation)
+{
+    ASSERT(!m_trackedAnnotation);
+    m_trackedAnnotation = annotation;
+
+    if ([annotation isKindOfClass:getPDFAnnotationButtonWidgetClass()])
+        [annotation setHighlighted:YES];
+
+    updateLayerHierarchy();
+}
+
+void UnifiedPDFPlugin::finishAnnotationTracking()
+{
+    ASSERT(m_trackedAnnotation);
+
+    if ([m_trackedAnnotation isHighlighted])
+        [m_trackedAnnotation setHighlighted:NO];
+
+    if ([m_trackedAnnotation isKindOfClass:getPDFAnnotationButtonWidgetClass()] && [m_trackedAnnotation widgetControlType] != kPDFWidgetPushButtonControl) {
+        auto currentButtonState = [m_trackedAnnotation buttonWidgetState];
+        if (currentButtonState == PDFWidgetCellState::kPDFWidgetOnState && [m_trackedAnnotation allowsToggleToOff])
+            [m_trackedAnnotation setButtonWidgetState:PDFWidgetCellState::kPDFWidgetOffState];
+        else if (currentButtonState == PDFWidgetCellState::kPDFWidgetOffState)
+            [m_trackedAnnotation setButtonWidgetState:PDFWidgetCellState::kPDFWidgetOnState];
+    } else
+        ASSERT_NOT_IMPLEMENTED_YET();
+    m_trackedAnnotation = nullptr;
+
+    updateLayerHierarchy();
+}
+
+void UnifiedPDFPlugin::handleMouseDraggedOffTrackedAnnotation()
+{
+    ASSERT(m_trackedAnnotation);
+
+    [m_trackedAnnotation setHighlighted:NO];
+    m_trackedAnnotation = nullptr;
+    updateLayerHierarchy();
+}
+
 void UnifiedPDFPlugin::attemptToUnlockPDF(const String& password)
 {
 }