Make canvas filters use the font size in effect when the filter is set

third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2DState.cpp

 // Copyright 2015 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 "modules/canvas2d/CanvasRenderingContext2DState.h"
 
 #include "core/css/CSSFontSelector.h"
 #include "core/css/resolver/FilterOperationResolver.h"
 #include "core/css/resolver/StyleBuilder.h"
 #include "core/css/resolver/StyleResolverState.h"
@@ skipping 69 matching lines @@
     , m_shadowOnlyDrawLooper(other.m_shadowOnlyDrawLooper)
     , m_shadowAndForegroundDrawLooper(other.m_shadowAndForegroundDrawLooper)
     , m_shadowOnlyImageFilter(other.m_shadowOnlyImageFilter)
     , m_shadowAndForegroundImageFilter(other.m_shadowAndForegroundImageFilter)
     , m_globalAlpha(other.m_globalAlpha)
     , m_transform(other.m_transform)
     , m_lineDash(other.m_lineDash)
     , m_lineDashOffset(other.m_lineDashOffset)
     , m_unparsedFont(other.m_unparsedFont)
     , m_font(other.m_font)
+    , m_fontForFilter(other.m_fontForFilter)
     , m_unparsedFilter(other.m_unparsedFilter)
     , m_filterValue(other.m_filterValue)
     , m_resolvedFilter(other.m_resolvedFilter)
     , m_textAlign(other.m_textAlign)
     , m_textBaseline(other.m_textBaseline)
     , m_direction(other.m_direction)
     , m_realizedFont(other.m_realizedFont)
     , m_isTransformInvertible(other.m_isTransformInvertible)
     , m_hasClip(other.m_hasClip)
     , m_hasComplexClip(other.m_hasComplexClip)
@@ skipping 154 matching lines @@
     if (!path.isRect(0))
         m_hasComplexClip = true;
 }
 
 void CanvasRenderingContext2DState::setFont(const Font& font, CSSFontSelector* selector)
 {
     m_font = font;
     m_font.update(selector);
     m_realizedFont = true;
     selector->registerForInvalidationCallbacks(this);
-    // FIXME: We only really need to invalidate the resolved filter if it
-    // uses font-relative units.
-    m_resolvedFilter.clear();
 }
 
 const Font& CanvasRenderingContext2DState::font() const
 {
     ASSERT(m_realizedFont);
     return m_font;
 }
 
 void CanvasRenderingContext2DState::setTransform(const AffineTransform& transform)
 {
     m_isTransformInvertible = transform.isInvertible();
     m_transform = transform;
 }
 
 void CanvasRenderingContext2DState::resetTransform()
 {
     m_transform.makeIdentity();
     m_isTransformInvertible = true;
 }
 
 static void updateFilterReferences(HTMLCanvasElement* canvasElement, CanvasRenderingContext2D* context, const FilterOperations& filters)
 {
     context->clearFilterReferences();
     context->addFilterReferences(filters, canvasElement->document());
 }
 
-SkImageFilter* CanvasRenderingContext2DState::getFilter(Element* styleResolutionHost, const Font& font, IntSize canvasSize, CanvasRenderingContext2D* context) const
+SkImageFilter* CanvasRenderingContext2DState::getFilter(Element* styleResolutionHost, IntSize canvasSize, CanvasRenderingContext2D* context) const
 {
     if (!m_filterValue)
         return nullptr;
 
     if (!m_resolvedFilter) {
         RefPtr<ComputedStyle> filterStyle = ComputedStyle::create();
         // Must set font in case the filter uses any font-relative units (em, ex)
-        filterStyle->setFont(font);
+        filterStyle->setFont(m_fontForFilter);
 
         StyleResolverState resolverState(styleResolutionHost->document(), styleResolutionHost, filterStyle.get());
         resolverState.setStyle(filterStyle);
 
         StyleBuilder::applyProperty(CSSPropertyWebkitFilter, resolverState, m_filterValue.get());
         resolverState.loadPendingResources();
         FilterEffectBuilder* filterEffectBuilder = FilterEffectBuilder::create();
 
         // We can't reuse m_fillPaint and m_strokePaint for the filter, since these incorporate
         // the global alpha, which isn't applicable here.
@@ skipping 13 matching lines @@
         if (m_resolvedFilter) {
             updateFilterReferences(toHTMLCanvasElement(styleResolutionHost), context, filterStyle->filter());
             if (lastEffect->originTainted())
                 context->setOriginTainted();
         }
     }
 
     return m_resolvedFilter.get();
 }
 
-bool CanvasRenderingContext2DState::hasFilter(Element* styleResolutionHost, const Font& font, IntSize canvasSize, CanvasRenderingContext2D* context) const
+bool CanvasRenderingContext2DState::hasFilter(Element* styleResolutionHost, IntSize canvasSize, CanvasRenderingContext2D* context) const
 {
     // Checking for a non-null m_filterValue isn't sufficient, since this value
     // might refer to a non-existent filter.
-    return !!getFilter(styleResolutionHost, font, canvasSize, context);
+    return !!getFilter(styleResolutionHost, canvasSize, context);
 }
 
 void CanvasRenderingContext2DState::clearResolvedFilter() const
 {
     m_resolvedFilter.clear();
 }
 
 SkDrawLooper* CanvasRenderingContext2DState::emptyDrawLooper() const
 {
     if (!m_emptyDrawLooper) {
@@ skipping 207 matching lines @@
         paint->setLooper(0);
         paint->setImageFilter(shadowAndForegroundImageFilter());
         return paint;
     }
     paint->setLooper(sk_ref_sp(shadowAndForegroundDrawLooper()));
     paint->setImageFilter(0);
     return paint;
 }
 
 } // namespace blink