Use Shadow DOM to display fallback content for images

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 57 matching lines @@
         m_renderImage.resolveColor(areaElementStyle, CSSPropertyOutlineColor));
 }
 
 void ImagePainter::paintReplaced(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
     LayoutUnit cWidth = m_renderImage.contentWidth();
     LayoutUnit cHeight = m_renderImage.contentHeight();
 
     GraphicsContext* context = paintInfo.context;
 
-    if (!m_renderImage.imageResource()->hasImage() || m_renderImage.imageResource()->errorOccurred()) {
+    if (!m_renderImage.imageResource()->hasImage()) {
         if (paintInfo.phase == PaintPhaseSelection)
             return;
 
         if (cWidth > 2 && cHeight > 2) {
-            const int borderWidth = 1;
-
-            LayoutUnit leftBorder = m_renderImage.borderLeft();
-            LayoutUnit topBorder = m_renderImage.borderTop();
-            LayoutUnit leftPad = m_renderImage.paddingLeft();
-            LayoutUnit topPad = m_renderImage.paddingTop();
-
             // Draw an outline rect where the image should be.
             context->setStrokeStyle(SolidStroke);
             context->setStrokeColor(Color::lightGray);
             context->setFillColor(Color::transparent);
-            context->drawRect(pixelSnappedIntRect(LayoutRect(paintOffset.x() + leftBorder + leftPad, paintOffset.y() + topBorder + topPad, cWidth, cHeight)));
-
-            bool errorPictureDrawn = false;
-            LayoutSize imageOffset;
-            // When calculating the usable dimensions, exclude the pixels of
-            // the ouline rect so the error image/alt text doesn't draw on it.
-            LayoutUnit usableWidth = cWidth - 2 * borderWidth;
-            LayoutUnit usableHeight = cHeight - 2 * borderWidth;
-
-            RefPtr<Image> image = m_renderImage.imageResource()->image();
-
-            if (m_renderImage.imageResource()->errorOccurred() && !image->isNull() && usableWidth >= image->width() && usableHeight >= image->height()) {
-                float deviceScaleFactor = blink::deviceScaleFactor(m_renderImage.frame());
-                // Call brokenImage() explicitly to ensure we get the broken image icon at the appropriate resolution.
-                pair<Image*, float> brokenImageAndImageScaleFactor = ImageResource::brokenImage(deviceScaleFactor);
-                image = brokenImageAndImageScaleFactor.first;
-                IntSize imageSize = image->size();
-                imageSize.scale(1 / brokenImageAndImageScaleFactor.second);
-                // Center the error image, accounting for border and padding.
-                LayoutUnit centerX = (usableWidth - imageSize.width()) / 2;
-                if (centerX < 0)
-                    centerX = 0;
-                LayoutUnit centerY = (usableHeight - imageSize.height()) / 2;
-                if (centerY < 0)
-                    centerY = 0;
-                imageOffset = LayoutSize(leftBorder + leftPad + centerX + borderWidth, topBorder + topPad + centerY + borderWidth);
-                context->drawImage(image.get(), pixelSnappedIntRect(LayoutRect(paintOffset + imageOffset, imageSize)), CompositeSourceOver, m_renderImage.shouldRespectImageOrientation());
-                errorPictureDrawn = true;
-            }
-
-            if (!m_renderImage.altText().isEmpty()) {
-                const Font& font = m_renderImage.style()->font();
-                const FontMetrics& fontMetrics = font.fontMetrics();
-                LayoutUnit ascent = fontMetrics.ascent();
-                LayoutPoint textRectOrigin = paintOffset;
-                textRectOrigin.move(leftBorder + leftPad + (RenderImage::paddingWidth / 2) - borderWidth, topBorder + topPad + (RenderImage::paddingHeight / 2) - borderWidth);
-                LayoutPoint textOrigin(textRectOrigin.x(), textRectOrigin.y() + ascent);
-
-                // Only draw the alt text if it'll fit within the content box,
-                // and only if it fits above the error image.
-                TextRun textRun = constructTextRun(&m_renderImage, font, m_renderImage.altText(), m_renderImage.style(), TextRun::AllowTrailingExpansion | TextRun::ForbidLeadingExpansion, DefaultTextRunFlags | RespectDirection);
-                float textWidth = font.width(textRun);
-                TextRunPaintInfo textRunPaintInfo(textRun);
-                textRunPaintInfo.bounds = FloatRect(textRectOrigin, FloatSize(textWidth, fontMetrics.height()));
-                context->setFillColor(m_renderImage.resolveColor(CSSPropertyColor));
-                if (textRun.direction() == RTL) {
-                    int availableWidth = cWidth - static_cast<int>(RenderImage::paddingWidth);
-                    textOrigin.move(availableWidth - ceilf(textWidth), 0);
-                }
-                if (errorPictureDrawn) {
-                    if (usableWidth >= textWidth && fontMetrics.height() <= imageOffset.height())
-                        context->drawBidiText(font, textRunPaintInfo, textOrigin);
-                } else if (usableWidth >= textWidth && usableHeight >= fontMetrics.height()) {
-                    context->drawBidiText(font, textRunPaintInfo, textOrigin);
-                }
-            }
+            context->drawRect(pixelSnappedIntRect(LayoutRect(paintOffset.x() + m_renderImage.borderLeft() + m_renderImage.paddingLeft(), paintOffset.y() + m_renderImage.borderTop() + m_renderImage.paddingTop(), cWidth, cHeight)));
         }
-    } else if (m_renderImage.imageResource()->hasImage() && cWidth > 0 && cHeight > 0) {
+    } else if (cWidth > 0 && cHeight > 0) {
         LayoutRect contentRect = m_renderImage.contentBoxRect();
         contentRect.moveBy(paintOffset);
         LayoutRect paintRect = m_renderImage.replacedContentRect();
         paintRect.moveBy(paintOffset);
         bool clip = !contentRect.contains(paintRect);
         if (clip) {
             context->save();
             context->clip(contentRect);
         }
 
@@ skipping 23 matching lines @@
     // FIXME(361045): remove InspectorInstrumentation calls once DevTools Timeline migrates to tracing.
     InspectorInstrumentation::willPaintImage(&m_renderImage);
     InterpolationQuality previousInterpolationQuality = context->imageInterpolationQuality();
     context->setImageInterpolationQuality(interpolationQuality);
     context->drawImage(image, alignedRect, compositeOperator, m_renderImage.shouldRespectImageOrientation());
     context->setImageInterpolationQuality(previousInterpolationQuality);
     InspectorInstrumentation::didPaintImage(&m_renderImage);
 }
 
 } // namespace blink