Add support for touch based zoom gesture on Windows. This change also handles the WM_POINTERDOWN

content/renderer/render_view_impl.cc

 // Copyright (c) 2011 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 "content/renderer/render_view_impl.h"
 
 #include <algorithm>
 #include <cmath>
 #include <string>
 #include <vector>
@@ skipping 254 matching lines @@
 static const int kDelaySecondsForContentStateSyncHidden = 5;
 static const int kDelaySecondsForContentStateSync = 1;
 
 static const size_t kExtraCharsBeforeAndAfterSelection = 100;
 
 // The maximum number of popups that can be spawned from one page.
 static const int kMaximumNumberOfUnacknowledgedPopups = 25;
 
 static const float kScalingIncrement = 0.1f;
 
+static const float kScalingIncrementForGesture = 0.01f;
+
 static void GetRedirectChain(WebDataSource* ds, std::vector<GURL>* result) {
   WebVector<WebURL> urls;
   ds->redirectChain(urls);
   result->reserve(urls.size());
   for (size_t i = 0; i < urls.size(); ++i)
     result->push_back(urls[i]);
 }
 
 // If |data_source| is non-null and has a NavigationState associated with it,
 // the AltErrorPageResourceFetcher is reset.
@@ skipping 307 matching lines @@
     IPC_MESSAGE_HANDLER(ViewMsg_Delete, OnDelete)
     IPC_MESSAGE_HANDLER(ViewMsg_SelectAll, OnSelectAll)
     IPC_MESSAGE_HANDLER(ViewMsg_SelectRange, OnSelectRange)
     IPC_MESSAGE_HANDLER(ViewMsg_CopyImageAt, OnCopyImageAt)
     IPC_MESSAGE_HANDLER(ViewMsg_ExecuteEditCommand, OnExecuteEditCommand)
     IPC_MESSAGE_HANDLER(ViewMsg_Find, OnFind)
     IPC_MESSAGE_HANDLER(ViewMsg_StopFinding, OnStopFinding)
     IPC_MESSAGE_HANDLER(ViewMsg_FindReplyACK, OnFindReplyAck)
     IPC_MESSAGE_HANDLER(ViewMsg_Zoom, OnZoom)
     IPC_MESSAGE_HANDLER(ViewMsg_SetZoomLevel, OnSetZoomLevel)
+    IPC_MESSAGE_HANDLER(ViewMsg_ZoomFactor, OnZoomFactor)
     IPC_MESSAGE_HANDLER(ViewMsg_SetZoomLevelForLoadingURL,
                         OnSetZoomLevelForLoadingURL)
     IPC_MESSAGE_HANDLER(ViewMsg_ExitFullscreen, OnExitFullscreen)
     IPC_MESSAGE_HANDLER(ViewMsg_SetPageEncoding, OnSetPageEncoding)
     IPC_MESSAGE_HANDLER(ViewMsg_ResetPageEncodingToDefault,
                         OnResetPageEncodingToDefault)
     IPC_MESSAGE_HANDLER(ViewMsg_ScriptEvalRequest, OnScriptEvalRequest)
     IPC_MESSAGE_HANDLER(ViewMsg_CSSInsertRequest, OnCSSInsertRequest)
     IPC_MESSAGE_HANDLER(ViewMsg_ReservePageIDRange, OnReservePageIDRange)
     IPC_MESSAGE_HANDLER(DragMsg_TargetDragEnter, OnDragTargetDragEnter)
@@ skipping 2938 matching lines @@
     if ((old_zoom_level > 1 && zoom > 0) ||
         (old_zoom_level < 1 && zoom < 0)) {
       zoom_level = static_cast<int>(old_zoom_level + zoom);
     } else {
       // We're going towards 100%, so first go to the next whole number.
       zoom_level = static_cast<int>(old_zoom_level);
     }
   }
   webview()->setZoomLevel(false, zoom_level);
 #else
+  ZoomFactorHelper(function, 0, 0, kScalingIncrement);
+#endif
+  zoomLevelChanged();
+}
+
+void RenderViewImpl::OnZoomFactor(content::PageZoom zoom,
+                                  int zoom_center_x, int zoom_center_y) {
+  ZoomFactorHelper(zoom, zoom_center_x, zoom_center_y,
+                   kScalingIncrementForGesture);
+}
+
+void RenderViewImpl::ZoomFactorHelper(content::PageZoom zoom,
+                                      int zoom_center_x,
+                                      int zoom_center_y,
+                                      float scaling_increment) {
+  if (!webview())  // Not sure if this can happen, but no harm in being safe.
+    return;
+
   double old_page_scale_factor = webview()->pageScaleFactor();
   double page_scale_factor;
   if (zoom == content::PAGE_ZOOM_RESET) {
     page_scale_factor = 1.0;
   } else {
     page_scale_factor = old_page_scale_factor +
-        (zoom > 0 ? kScalingIncrement : -kScalingIncrement);
+        (zoom > 0 ? scaling_increment : -scaling_increment);
   }
-  webview()->scalePage(page_scale_factor, WebPoint(0, 0));
-#endif
-  zoomLevelChanged();
+  if (page_scale_factor > 0) {
+    webview()->scalePage(page_scale_factor,
+                         WebPoint(zoom_center_x, zoom_center_y));
+  }
 }
 
 void RenderViewImpl::OnSetZoomLevel(double zoom_level) {
   // Don't set zoom level for full-page plugin since they don't use the same
   // zoom settings.
   if (webview()->mainFrame()->document().isPluginDocument())
     return;
 
   webview()->hidePopups();
   webview()->setZoomLevel(false, zoom_level);
@@ skipping 1093 matching lines @@
   return webview()->settings()->useThreadedCompositor();
 }
 
 void RenderViewImpl::OnJavaBridgeInit(
     const IPC::ChannelHandle& channel_handle) {
   DCHECK(!java_bridge_dispatcher_.get());
 #if defined(ENABLE_JAVA_BRIDGE)
   java_bridge_dispatcher_.reset(new JavaBridgeDispatcher(this, channel_handle));
 #endif
 }