Change image document zooming logic.

third_party/WebKit/Source/core/html/ImageDocument.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2010 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 28 matching lines @@
 #include "core/frame/VisualViewport.h"
 #include "core/html/HTMLBodyElement.h"
 #include "core/html/HTMLHeadElement.h"
 #include "core/html/HTMLHtmlElement.h"
 #include "core/html/HTMLImageElement.h"
 #include "core/html/HTMLMetaElement.h"
 #include "core/layout/LayoutObject.h"
 #include "core/loader/DocumentLoader.h"
 #include "core/loader/FrameLoader.h"
 #include "core/loader/FrameLoaderClient.h"
+#include "platform/HostWindow.h"
 #include "wtf/text/StringBuilder.h"
 #include <limits>
 
 using namespace std;
 
 namespace blink {
 
 using namespace HTMLNames;
 
 class ImageEventListener : public EventListener {
@@ skipping 186 matching lines @@
     rootElement->appendChild(body);
 }
 
 float ImageDocument::scale() const
 {
     if (!m_imageElement || m_imageElement->document() != this)
         return 1.0f;
 
     FrameView* view = frame()->view();
     if (!view)
         return 1;

[brucedawson, 2016/09/15 23:21:21]

Would be nice to change this to return 1.0f, and maybe add a comment explaining
what this function is supposed to do, especially now that its semantics are more
subtle than before.

[Bret, 2016/09/16 00:21:41]

Done. Added the comment to the header file.

 
     DCHECK(m_imageElement->cachedImage());
-    LayoutSize imageSize = m_imageElement->cachedImage()->imageSize(LayoutObject::shouldRespectImageOrientation(m_imageElement->layoutObject()), pageZoomFactor(this));
-    LayoutSize windowSize = LayoutSize(view->width(), view->height());
+    const float zoom = pageZoomFactor(this);
+    LayoutSize imageSize = m_imageElement->cachedImage()->imageSize(LayoutObject::shouldRespectImageOrientation(m_imageElement->layoutObject()), zoom);
 
-    float widthScale = windowSize.width().toFloat() / imageSize.width().toFloat();
-    float heightScale = windowSize.height().toFloat() / imageSize.height().toFloat();
+    // We want to pretend the viewport is larger when the user has zoomed the
+    // page in (but not when the zoom is coming from device scale).
+    const float manualZoom = zoom / view->getHostWindow()->windowToViewportScalar(1.f);
+    float widthScale = view->width() * manualZoom / imageSize.width().toFloat();
+    float heightScale = view->height() * manualZoom / imageSize.height().toFloat();
 
     return min(widthScale, heightScale);
 }
 
-void ImageDocument::resizeImageToFit(ScaleType type)
+void ImageDocument::resizeImageToFit()
 {
-    if (!m_imageElement || m_imageElement->document() != this || (pageZoomFactor(this) > 1 && type == ScaleOnlyUnzoomedDocument))
+    if (!m_imageElement || m_imageElement->document() != this)
         return;
 
     DCHECK(m_imageElement->cachedImage());
-    LayoutSize imageSize = m_imageElement->cachedImage()->imageSize(LayoutObject::shouldRespectImageOrientation(m_imageElement->layoutObject()), pageZoomFactor(this));
+    LayoutSize imageSize = m_imageElement->cachedImage()->imageSize(LayoutObject::shouldRespectImageOrientation(m_imageElement->layoutObject()), 1.f);
 
-    float scale = this->scale();
+    const float scale = this->scale();
     m_imageElement->setWidth(static_cast<int>(imageSize.width() * scale));
     m_imageElement->setHeight(static_cast<int>(imageSize.height() * scale));
 
     m_imageElement->setInlineStyleProperty(CSSPropertyCursor, CSSValueZoomIn);
 }
 
 void ImageDocument::imageClicked(int x, int y)
 {
     DCHECK_EQ(m_shrinkToFitMode, Desktop);
 
     if (!m_imageSizeIsKnown || imageFitsInWindow())
         return;
 
     m_shouldShrinkImage = !m_shouldShrinkImage;
 
     if (m_shouldShrinkImage) {
-        windowSizeChanged(ScaleZoomedDocument);
+        windowSizeChanged();
     } else {
-        restoreImageSize(ScaleZoomedDocument);
+        restoreImageSize();
 
         updateStyleAndLayout();
 
         double scale = this->scale();
 
         double scrollX = x / scale - static_cast<double>(frame()->view()->width()) / 2;
         double scrollY = y / scale - static_cast<double>(frame()->view()->height()) / 2;
 
         frame()->view()->setScrollPosition(DoublePoint(scrollX, scrollY), ProgrammaticScroll);
     }
 }
 
 void ImageDocument::imageUpdated()
 {
     DCHECK(m_imageElement);
 
     if (m_imageSizeIsKnown)
         return;
 
     updateStyleAndLayoutTree();
     if (!m_imageElement->cachedImage() || m_imageElement->cachedImage()->imageSize(LayoutObject::shouldRespectImageOrientation(m_imageElement->layoutObject()), pageZoomFactor(this)).isEmpty())
         return;
 
     m_imageSizeIsKnown = true;
 
     if (shouldShrinkToFit()) {
         // Force resizing of the image
-        windowSizeChanged(ScaleOnlyUnzoomedDocument);
+        windowSizeChanged();
     }
 }
 
-void ImageDocument::restoreImageSize(ScaleType type)
+void ImageDocument::restoreImageSize()
 {
     DCHECK_EQ(m_shrinkToFitMode, Desktop);
 
-    if (!m_imageElement || !m_imageSizeIsKnown || m_imageElement->document() != this || (pageZoomFactor(this) < 1 && type == ScaleOnlyUnzoomedDocument))
+    if (!m_imageElement || !m_imageSizeIsKnown || m_imageElement->document() != this)
         return;
 
     DCHECK(m_imageElement->cachedImage());
     LayoutSize imageSize = m_imageElement->cachedImage()->imageSize(LayoutObject::shouldRespectImageOrientation(m_imageElement->layoutObject()), 1.0f);
     m_imageElement->setWidth(imageSize.width().toInt());
     m_imageElement->setHeight(imageSize.height().toInt());
 
     if (imageFitsInWindow())
         m_imageElement->removeInlineStyleProperty(CSSPropertyCursor);
     else
         m_imageElement->setInlineStyleProperty(CSSPropertyCursor, CSSValueZoomOut);
 
     m_didShrinkImage = false;
 }
 
 bool ImageDocument::imageFitsInWindow() const
 {
     DCHECK_EQ(m_shrinkToFitMode, Desktop);
-
-    if (!m_imageElement || m_imageElement->document() != this)
-        return true;
-
-    FrameView* view = frame()->view();
-    if (!view)
-        return true;
-
-    DCHECK(m_imageElement->cachedImage());
-    LayoutSize imageSize = m_imageElement->cachedImage()->imageSize(LayoutObject::shouldRespectImageOrientation(m_imageElement->layoutObject()), pageZoomFactor(this));
-    LayoutSize windowSize = LayoutSize(view->width(), view->height());
-
-    return imageSize.width() <= windowSize.width() && imageSize.height() <= windowSize.height();
+    return this->scale() >= 1;
 }
 
-void ImageDocument::windowSizeChanged(ScaleType type)
+void ImageDocument::windowSizeChanged()
 {
     if (!m_imageElement || !m_imageSizeIsKnown || m_imageElement->document() != this)
         return;
 
     if (m_shrinkToFitMode == Viewport) {
         // For huge images, minimum-scale=0.1 is still too big on small screens.
         // Set max-width so that the image will shrink to fit the width of the screen when
         // the scale is minimum.
         // Don't shrink height to fit because we use width=device-width in viewport meta tag,
         // and expect a full-width reading mode for normal-width-huge-height images.
@@ skipping 11 matching lines @@
             m_imageElement->removeInlineStyleProperty(CSSPropertyCursor);
         else
             m_imageElement->setInlineStyleProperty(CSSPropertyCursor, CSSValueZoomOut);
         return;
     }
 
     if (m_didShrinkImage) {
         // If the window has been resized so that the image fits, restore the image size
         // otherwise update the restored image size.
         if (fitsInWindow)
-            restoreImageSize(type);
+            restoreImageSize();
         else
-            resizeImageToFit(type);
+            resizeImageToFit();
     } else {
         // If the image isn't resized but needs to be, then resize it.
         if (!fitsInWindow) {
-            resizeImageToFit(type);
+            resizeImageToFit();
             m_didShrinkImage = true;
         }
     }
 }
 
 ImageResource* ImageDocument::cachedImage()
 {
     if (!m_imageElement) {
         createDocumentStructure();
         if (isStopped()) {
@@ skipping 14 matching lines @@
 {
     visitor->trace(m_imageElement);
     HTMLDocument::trace(visitor);
 }
 
 // --------
 
 void ImageEventListener::handleEvent(ExecutionContext*, Event* event)
 {
     if (event->type() == EventTypeNames::resize) {
-        m_doc->windowSizeChanged(ImageDocument::ScaleOnlyUnzoomedDocument);
+        m_doc->windowSizeChanged();
     } else if (event->type() == EventTypeNames::click && event->isMouseEvent()) {
         MouseEvent* mouseEvent = toMouseEvent(event);
         m_doc->imageClicked(mouseEvent->x(), mouseEvent->y());
     }
 }
 
 bool ImageEventListener::operator==(const EventListener& listener) const
 {
     if (const ImageEventListener* imageEventListener = ImageEventListener::cast(&listener))
         return m_doc == imageEventListener->m_doc;
     return false;
 }
 
 } // namespace blink