Implement a paint offset cache for slimming paint v2

Source/core/paint/ImagePainter.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/paint/ImagePainter.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/editing/FrameSelection.h"
@@ skipping 11 matching lines @@
 #include "platform/geometry/LayoutPoint.h"
 #include "platform/graphics/Path.h"
 
 namespace blink {
 
 void ImagePainter::paint(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
     m_layoutImage.LayoutReplaced::paint(paintInfo, paintOffset);
 
     if (paintInfo.phase == PaintPhaseOutline)
-        paintAreaElementFocusRing(paintInfo);
+        paintAreaElementFocusRing(paintInfo, paintOffset);
 }
 
-void ImagePainter::paintAreaElementFocusRing(const PaintInfo& paintInfo)
+void ImagePainter::paintAreaElementFocusRing(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
     // TODO(wangxianzhu): In other places, we just paint focus ring if outline style is auto.
     // We should also do that here to keep consistency.
     Document& document = m_layoutImage.document();
 
     if (paintInfo.isPrinting() || !document.frame()->selection().isFocusedAndActive())
         return;
 
     Element* focusedElement = document.focusedElement();
     if (!isHTMLAreaElement(focusedElement))
         return;
 
     HTMLAreaElement& areaElement = toHTMLAreaElement(*focusedElement);
     if (areaElement.imageElement() != m_layoutImage.node())
         return;
 
     // Even if the theme handles focus ring drawing for entire elements, it won't do it for
     // an area within an image, so we don't call LayoutTheme::supportsFocusRing here.
 
     Path path = areaElement.computePath(&m_layoutImage);
     if (path.isEmpty())
         return;
 
     const ComputedStyle& areaElementStyle = *areaElement.ensureComputedStyle();
     int outlineWidth = areaElementStyle.outlineWidth();
     if (!outlineWidth)
         return;
 
-    if (LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(*paintInfo.context, m_layoutImage, paintInfo.phase))
+    if (LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(*paintInfo.context, m_layoutImage, paintInfo.phase, paintOffset))
         return;
 
     IntRect focusRect = m_layoutImage.absoluteContentBox();
-    LayoutObjectDrawingRecorder drawingRecorder(*paintInfo.context, m_layoutImage, paintInfo.phase, focusRect);
+    LayoutObjectDrawingRecorder drawingRecorder(*paintInfo.context, m_layoutImage, paintInfo.phase, focusRect, paintOffset);
 
     // FIXME: Clip path instead of context when Skia pathops is ready.
     // https://crbug.com/251206
 
     paintInfo.context->save();
     paintInfo.context->clip(focusRect);
     paintInfo.context->drawFocusRing(path, outlineWidth,
         areaElementStyle.outlineOffset(),
         m_layoutImage.resolveColor(areaElementStyle, CSSPropertyOutlineColor));
     paintInfo.context->restore();
 }
 
 void ImagePainter::paintReplaced(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
     LayoutUnit cWidth = m_layoutImage.contentWidth();
     LayoutUnit cHeight = m_layoutImage.contentHeight();
 
     GraphicsContext* context = paintInfo.context;
 
     if (!m_layoutImage.imageResource()->hasImage()) {
         if (paintInfo.phase == PaintPhaseSelection)
             return;
         if (cWidth > 2 && cHeight > 2) {
-            if (LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(*context, m_layoutImage, paintInfo.phase))
+            if (LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(*context, m_layoutImage, paintInfo.phase, paintOffset))
                 return;
             // Draw an outline rect where the image should be.
             IntRect paintRect = pixelSnappedIntRect(LayoutRect(paintOffset.x() + m_layoutImage.borderLeft() + m_layoutImage.paddingLeft(), paintOffset.y() + m_layoutImage.borderTop() + m_layoutImage.paddingTop(), cWidth, cHeight));
-            LayoutObjectDrawingRecorder drawingRecorder(*context, m_layoutImage, paintInfo.phase, paintRect);
+            LayoutObjectDrawingRecorder drawingRecorder(*context, m_layoutImage, paintInfo.phase, paintRect, paintOffset);
             context->setStrokeStyle(SolidStroke);
             context->setStrokeColor(Color::lightGray);
             context->setFillColor(Color::transparent);
             context->drawRect(paintRect);
         }
     } else if (cWidth > 0 && cHeight > 0) {
         LayoutRect contentRect = m_layoutImage.contentBoxRect();
         contentRect.moveBy(paintOffset);
         LayoutRect paintRect = m_layoutImage.replacedContentRect();
         paintRect.moveBy(paintOffset);
 
         Optional<FloatClipRecorder> clipRecorder;
         if (!contentRect.contains(paintRect)) {
             // TODO(chrishtr): this should be pixel-snapped.
             // TODO(fmalita): can we get rid of this clip and adjust the image src/dst rect instead?
             clipRecorder.emplace(*context, m_layoutImage, paintInfo.phase, FloatRect(contentRect));
         }
 
-        if (LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(*context, m_layoutImage, paintInfo.phase))
+        if (LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(*context, m_layoutImage, paintInfo.phase, paintOffset))
             return;
 
-        LayoutObjectDrawingRecorder drawingRecorder(*context, m_layoutImage, paintInfo.phase, contentRect);
+        LayoutObjectDrawingRecorder drawingRecorder(*context, m_layoutImage, paintInfo.phase, contentRect, paintOffset);
         paintIntoRect(context, paintRect);
     }
 }
 
 void ImagePainter::paintIntoRect(GraphicsContext* context, const LayoutRect& rect)
 {
     if (!m_layoutImage.imageResource()->hasImage() || m_layoutImage.imageResource()->errorOccurred())
         return; // FIXME: should we just ASSERT these conditions? (audit all callers).
 
     IntRect alignedRect = pixelSnappedIntRect(rect);
     if (alignedRect.width() <= 0 || alignedRect.height() <= 0)
         return;
 
     RefPtr<Image> image = m_layoutImage.imageResource()->image(alignedRect.width(), alignedRect.height());
     if (!image || image->isNull())
         return;
 
     // FIXME: why is interpolation quality selection not included in the Instrumentation reported cost of drawing an image?
     InterpolationQuality interpolationQuality = BoxPainter::chooseInterpolationQuality(m_layoutImage, context, image.get(), image.get(), LayoutSize(alignedRect.size()));
 
     TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "PaintImage", "data", InspectorPaintImageEvent::data(m_layoutImage));
 
     InterpolationQuality previousInterpolationQuality = context->imageInterpolationQuality();
     context->setImageInterpolationQuality(interpolationQuality);
     context->drawImage(image.get(), alignedRect, SkXfermode::kSrcOver_Mode, m_layoutImage.shouldRespectImageOrientation());
     context->setImageInterpolationQuality(previousInterpolationQuality);
 }
 
 } // namespace blink