[DevTools] Separate text autosizing from device metrics override.

Source/core/inspector/InspectorPageAgent.cpp

 /*
  * Copyright (C) 2011 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 78 matching lines @@
 static const char pageAgentScriptsToEvaluateOnLoad[] = "pageAgentScriptsToEvaluateOnLoad";
 static const char deviceMetricsOverrideEnabled[] = "deviceMetricsOverrideEnabled";
 static const char pageAgentScreenWidthOverride[] = "pageAgentScreenWidthOverride";
 static const char pageAgentScreenHeightOverride[] = "pageAgentScreenHeightOverride";
 static const char pageAgentDeviceScaleFactorOverride[] = "pageAgentDeviceScaleFactorOverride";
 static const char pageAgentEmulateViewport[] = "pageAgentEmulateViewport";
 static const char pageAgentFitWindow[] = "pageAgentFitWindow";
 static const char deviceScale[] = "deviceScale";
 static const char deviceOffsetX[] = "deviceOffsetX";
 static const char deviceOffsetY[] = "deviceOffsetY";
-static const char fontScaleFactor[] = "fontScaleFactor";
 static const char pageAgentShowFPSCounter[] = "pageAgentShowFPSCounter";
-static const char pageAgentTextAutosizingOverride[] = "pageAgentTextAutosizingOverride";
 static const char pageAgentContinuousPaintingEnabled[] = "pageAgentContinuousPaintingEnabled";
 static const char pageAgentShowPaintRects[] = "pageAgentShowPaintRects";
 static const char pageAgentShowDebugBorders[] = "pageAgentShowDebugBorders";
 static const char pageAgentShowScrollBottleneckRects[] = "pageAgentShowScrollBottleneckRects";
 static const char touchEventEmulationEnabled[] = "touchEventEmulationEnabled";
 static const char pageAgentEmulatedMedia[] = "pageAgentEmulatedMedia";
 static const char showSizeOnResize[] = "showSizeOnResize";
 static const char showGridOnResize[] = "showGridOnResize";
 }
 
 namespace {
 
 KURL urlWithoutFragment(const KURL& url)
 {
     KURL result = url;
     result.removeFragmentIdentifier();
     return result;
 }
 
+static float calculateFontScaleFactor(int width, int height, float deviceScaleFactor)
+{
+    // Chromium on Android uses a device scale adjustment for fonts used in text autosizing for
+    // improved legibility. This function computes this adjusted value for text autosizing.
+    // For a description of the Android device scale adjustment algorithm, see:
+    // chrome/browser/chrome_content_browser_client.cc, GetDeviceScaleAdjustment(...)
+    if (!width || !height || !deviceScaleFactor)
+        return 1;
+
+    static const float kMinFSM = 1.05f;
+    static const int kWidthForMinFSM = 320;
+    static const float kMaxFSM = 1.3f;
+    static const int kWidthForMaxFSM = 800;
+
+    float minWidth = std::min(width, height) / deviceScaleFactor;
+    if (minWidth <= kWidthForMinFSM)
+        return kMinFSM;
+    if (minWidth >= kWidthForMaxFSM)
+        return kMaxFSM;
+
+    // The font scale multiplier varies linearly between kMinFSM and kMaxFSM.
+    float ratio = static_cast<float>(minWidth - kWidthForMinFSM) / (kWidthForMaxFSM - kWidthForMinFSM);
+    return ratio * (kMaxFSM - kMinFSM) + kMinFSM;
+}
+
 }
 
 class InspectorPageAgent::GetResourceContentLoadListener FINAL : public VoidCallback {
 public:
     GetResourceContentLoadListener(InspectorPageAgent*, const String& frameId, const String& url, PassRefPtr<GetResourceContentCallback>);
     virtual void handleEvent() OVERRIDE;
 private:
     InspectorPageAgent* m_pageAgent;
     String m_frameId;
     String m_url;
@@ skipping 253 matching lines @@
     , m_originalDeviceSupportsMouse(false)
     , m_originalDeviceSupportsTouch(false)
     , m_embedderTextAutosizingEnabled(m_page->settings().textAutosizingEnabled())
     , m_embedderFontScaleFactor(m_page->settings().deviceScaleAdjustment())
 {
 }
 
 void InspectorPageAgent::setTextAutosizingEnabled(bool enabled)
 {
     m_embedderTextAutosizingEnabled = enabled;
-    if (!m_deviceMetricsOverridden)
+    bool emulateViewportEnabled = m_enabled && m_deviceMetricsOverridden && m_emulateViewportEnabled;
+    if (!emulateViewportEnabled)
         m_page->settings().setTextAutosizingEnabled(enabled);
 }
 
 void InspectorPageAgent::setDeviceScaleAdjustment(float deviceScaleAdjustment)
 {
     m_embedderFontScaleFactor = deviceScaleAdjustment;
-    if (!m_deviceMetricsOverridden)
+    bool emulateViewportEnabled = m_enabled && m_deviceMetricsOverridden && m_emulateViewportEnabled;
+    if (!emulateViewportEnabled)
         m_page->settings().setDeviceScaleAdjustment(deviceScaleAdjustment);
 }
 
 void InspectorPageAgent::setFrontend(InspectorFrontend* frontend)
 {
     m_frontend = frontend->page();
 }
 
 void InspectorPageAgent::clearFrontend()
 {
@@ skipping 52 matching lines @@
     if (m_state->getBoolean(PageAgentState::pageAgentContinuousPaintingEnabled))
         setContinuousPaintingEnabled(0, false);
     setShowScrollBottleneckRects(0, false);
     setShowViewportSizeOnResize(0, false, 0);
 
     if (m_state->getBoolean(PageAgentState::touchEventEmulationEnabled)) {
         updateTouchEventEmulationInPage(false);
         m_state->setBoolean(PageAgentState::touchEventEmulationEnabled, false);
     }
 
-    if (!deviceMetricsChanged(false, 0, 0, 0, false, false, 1, 0, 0, 1, false))
+    if (!deviceMetricsChanged(false, 0, 0, 0, false, false, 1, 0, 0))
         return;
 
     // When disabling the agent, reset the override values if necessary.
-    updateViewMetrics(false, 0, 0, 0, false, false, 1, 0, 0, m_embedderFontScaleFactor, m_embedderTextAutosizingEnabled);
+    updateViewMetrics(false, 0, 0, 0, false, false, 1, 0, 0);
     m_state->setLong(PageAgentState::pageAgentScreenWidthOverride, 0);
     m_state->setLong(PageAgentState::pageAgentScreenHeightOverride, 0);
     m_state->setDouble(PageAgentState::pageAgentDeviceScaleFactorOverride, 0);
     m_state->setBoolean(PageAgentState::pageAgentEmulateViewport, false);
     m_state->setBoolean(PageAgentState::pageAgentFitWindow, false);
     m_state->setDouble(PageAgentState::deviceScale, 1);
     m_state->setDouble(PageAgentState::deviceOffsetX, 0);
     m_state->setDouble(PageAgentState::deviceOffsetY, 0);
-    m_state->setDouble(PageAgentState::fontScaleFactor, 1);
-    m_state->setBoolean(PageAgentState::pageAgentTextAutosizingOverride, false);
 }
 
 void InspectorPageAgent::addScriptToEvaluateOnLoad(ErrorString*, const String& source, String* identifier)
 {
     RefPtr<JSONObject> scripts = m_state->getObject(PageAgentState::pageAgentScriptsToEvaluateOnLoad);
     if (!scripts) {
         scripts = JSONObject::create();
         m_state->setObject(PageAgentState::pageAgentScriptsToEvaluateOnLoad, scripts);
     }
     // Assure we don't override existing ids -- m_lastScriptIdentifier could get out of sync WRT actual
@@ skipping 244 matching lines @@
         return;
 
     Document* document = frame->document();
     if (!document) {
         *errorString = "No Document instance to set HTML for";
         return;
     }
     DOMPatchSupport::patchDocument(*document, html);
 }
 
-void InspectorPageAgent::setDeviceMetricsOverride(ErrorString* errorString, int width, int height, double deviceScaleFactor, bool emulateViewport, bool fitWindow, const double* optionalScale, const double* optionalOffsetX, const double* optionalOffsetY, const bool* optionalTextAutosizing, const double* optionalFontScaleFactor)
+void InspectorPageAgent::setDeviceMetricsOverride(ErrorString* errorString, int width, int height, double deviceScaleFactor, bool emulateViewport, bool fitWindow, const double* optionalScale, const double* optionalOffsetX, const double* optionalOffsetY)
 {
     const static long maxDimension = 10000000;
     const static double maxScale = 10;
 
     double scale = optionalScale ? *optionalScale : 1;
     double offsetX = optionalOffsetX ? *optionalOffsetX : 0;
     double offsetY = optionalOffsetY ? *optionalOffsetY : 0;
-    bool textAutosizing = optionalTextAutosizing ? *optionalTextAutosizing : false;
-    double fontScaleFactor = optionalFontScaleFactor ? *optionalFontScaleFactor : 1;
 
     if (width < 0 || height < 0 || width > maxDimension || height > maxDimension) {
         *errorString = "Width and height values must be positive, not greater than " + String::number(maxDimension);
         return;
     }
 
     if (deviceScaleFactor < 0) {
         *errorString = "deviceScaleFactor must be non-negative";
         return;
     }
 
     if (scale <= 0 || scale > maxScale) {
         *errorString = "scale must be positive, not greater than " + String::number(maxScale);
         return;
     }
 
-    if (fontScaleFactor <= 0) {
-        *errorString = "fontScaleFactor must be positive";
-        return;
-    }
-
     Settings& settings = m_page->settings();
     if (!settings.acceleratedCompositingEnabled()) {
         if (errorString)
             *errorString = "Compositing mode is not supported";
         return;
     }
 
-    if (!deviceMetricsChanged(true, width, height, deviceScaleFactor, emulateViewport, fitWindow, scale, offsetX, offsetY, fontScaleFactor, textAutosizing))
+    if (!deviceMetricsChanged(true, width, height, deviceScaleFactor, emulateViewport, fitWindow, scale, offsetX, offsetY))
         return;
 
     m_state->setBoolean(PageAgentState::deviceMetricsOverrideEnabled, true);
     m_state->setLong(PageAgentState::pageAgentScreenWidthOverride, width);
     m_state->setLong(PageAgentState::pageAgentScreenHeightOverride, height);
     m_state->setDouble(PageAgentState::pageAgentDeviceScaleFactorOverride, deviceScaleFactor);
     m_state->setBoolean(PageAgentState::pageAgentEmulateViewport, emulateViewport);
     m_state->setBoolean(PageAgentState::pageAgentFitWindow, fitWindow);
     m_state->setDouble(PageAgentState::deviceScale, scale);
     m_state->setDouble(PageAgentState::deviceOffsetX, offsetX);
     m_state->setDouble(PageAgentState::deviceOffsetY, offsetY);
-    m_state->setDouble(PageAgentState::fontScaleFactor, fontScaleFactor);
-    m_state->setBoolean(PageAgentState::pageAgentTextAutosizingOverride, textAutosizing);
     updateViewMetricsFromState();
 }
 
 void InspectorPageAgent::clearDeviceMetricsOverride(ErrorString*)
 {
     if (m_state->getBoolean(PageAgentState::deviceMetricsOverrideEnabled)) {
         m_state->setBoolean(PageAgentState::deviceMetricsOverrideEnabled, false);
         updateViewMetricsFromState();
     }
 }
 
-bool InspectorPageAgent::deviceMetricsChanged(bool enabled, int width, int height, double deviceScaleFactor, bool emulateViewport, bool fitWindow, double scale, double offsetX, double offsetY, double fontScaleFactor, bool textAutosizing)
+bool InspectorPageAgent::deviceMetricsChanged(bool enabled, int width, int height, double deviceScaleFactor, bool emulateViewport, bool fitWindow, double scale, double offsetX, double offsetY)
 {
     bool currentEnabled = m_state->getBoolean(PageAgentState::deviceMetricsOverrideEnabled);
     // These two always fit an int.
     int currentWidth = static_cast<int>(m_state->getLong(PageAgentState::pageAgentScreenWidthOverride));
     int currentHeight = static_cast<int>(m_state->getLong(PageAgentState::pageAgentScreenHeightOverride));
     double currentDeviceScaleFactor = m_state->getDouble(PageAgentState::pageAgentDeviceScaleFactorOverride, 0);
     bool currentEmulateViewport = m_state->getBoolean(PageAgentState::pageAgentEmulateViewport);
     bool currentFitWindow = m_state->getBoolean(PageAgentState::pageAgentFitWindow);
     double currentScale = m_state->getDouble(PageAgentState::deviceScale, 1);
     double currentOffsetX = m_state->getDouble(PageAgentState::deviceOffsetX, 0);
     double currentOffsetY = m_state->getDouble(PageAgentState::deviceOffsetY, 0);
-    double currentFontScaleFactor = m_state->getDouble(PageAgentState::fontScaleFactor, 1);
-    bool currentTextAutosizing = m_state->getBoolean(PageAgentState::pageAgentTextAutosizingOverride);
 
     return enabled != currentEnabled
         || width != currentWidth
         || height != currentHeight
         || deviceScaleFactor != currentDeviceScaleFactor
         || emulateViewport != currentEmulateViewport
         || fitWindow != currentFitWindow
         || scale != currentScale
         || offsetX != currentOffsetX
-        || offsetY != currentOffsetY
-        || fontScaleFactor != currentFontScaleFactor
-        || textAutosizing != currentTextAutosizing;
+        || offsetY != currentOffsetY;
 }
 
 void InspectorPageAgent::setShowPaintRects(ErrorString*, bool show)
 {
     m_state->setBoolean(PageAgentState::pageAgentShowPaintRects, show);
     m_client->setShowPaintRects(show);
 
     if (!show && mainFrame() && mainFrame()->view())
         mainFrame()->view()->invalidate();
 }
@@ skipping 391 matching lines @@
 {
     bool enabled = m_state->getBoolean(PageAgentState::deviceMetricsOverrideEnabled);
     int width = static_cast<int>(m_state->getLong(PageAgentState::pageAgentScreenWidthOverride));
     int height = static_cast<int>(m_state->getLong(PageAgentState::pageAgentScreenHeightOverride));
     bool emulateViewport = m_state->getBoolean(PageAgentState::pageAgentEmulateViewport);
     double deviceScaleFactor = m_state->getDouble(PageAgentState::pageAgentDeviceScaleFactorOverride);
     bool fitWindow = m_state->getBoolean(PageAgentState::pageAgentFitWindow);
     double scale = m_state->getDouble(PageAgentState::deviceScale, 1);
     double offsetX = m_state->getDouble(PageAgentState::deviceOffsetX, 0);
     double offsetY = m_state->getDouble(PageAgentState::deviceOffsetY, 0);
-    double fontScaleFactor = m_state->getDouble(PageAgentState::fontScaleFactor);
-    bool textAutosizingEnabled = m_state->getBoolean(PageAgentState::pageAgentTextAutosizingOverride);
-    updateViewMetrics(enabled, width, height, deviceScaleFactor, emulateViewport, fitWindow, scale, offsetX, offsetY, fontScaleFactor, textAutosizingEnabled);
+    updateViewMetrics(enabled, width, height, deviceScaleFactor, emulateViewport, fitWindow, scale, offsetX, offsetY);
 }
 
-void InspectorPageAgent::updateViewMetrics(bool enabled, int width, int height, double deviceScaleFactor, bool emulateViewport, bool fitWindow, double scale, double offsetX, double offsetY, double fontScaleFactor, bool textAutosizingEnabled)
+void InspectorPageAgent::updateViewMetrics(bool enabled, int width, int height, double deviceScaleFactor, bool emulateViewport, bool fitWindow, double scale, double offsetX, double offsetY)
 {
     if (enabled && !m_page->settings().acceleratedCompositingEnabled())
         return;
 
     m_deviceMetricsOverridden = enabled;
     m_emulateViewportEnabled = emulateViewport;
     if (enabled)
         m_client->setDeviceMetricsOverride(width, height, static_cast<float>(deviceScaleFactor), emulateViewport, fitWindow, static_cast<float>(scale), static_cast<float>(offsetX), static_cast<float>(offsetY));
     else
         m_client->clearDeviceMetricsOverride();
 
     Document* document = mainFrame()->document();
     if (document) {
         document->styleResolverChanged();
         document->mediaQueryAffectingValueChanged();
     }
     InspectorInstrumentation::mediaQueryResultChanged(document);
 
     if (m_deviceMetricsOverridden) {
-        m_page->settings().setTextAutosizingEnabled(textAutosizingEnabled);
-        m_page->settings().setDeviceScaleAdjustment(fontScaleFactor);
+        m_page->settings().setTextAutosizingEnabled(emulateViewport);
+        m_page->settings().setDeviceScaleAdjustment(calculateFontScaleFactor(width, height, static_cast<float>(deviceScaleFactor)));
     } else {
         m_page->settings().setTextAutosizingEnabled(m_embedderTextAutosizingEnabled);
         m_page->settings().setDeviceScaleAdjustment(m_embedderFontScaleFactor);
     }
 
     // FIXME: allow metrics override, fps counter and continuous painting at the same time: crbug.com/299837.
     m_client->setShowFPSCounter(m_state->getBoolean(PageAgentState::pageAgentShowFPSCounter) && !m_deviceMetricsOverridden);
     m_client->setContinuousPaintingEnabled(m_state->getBoolean(PageAgentState::pageAgentContinuousPaintingEnabled) && !m_deviceMetricsOverridden);
 }
 
@@ skipping 100 matching lines @@
 bool InspectorPageAgent::getEditedResourceContent(const String& url, String* content)
 {
     if (!m_editedResourceContent.contains(url))
         return false;
     *content = m_editedResourceContent.get(url);
     return true;
 }
 
 } // namespace WebCore