Commit f02fcb17 authored by Botond Ballo's avatar Botond Ballo
Browse files

Bug 1556556 - Move GetCallbackTransform() into a new ViewportUtils class. r=kats 

This function (and helper functions that wrap it) will be used extensively
throughout layout code, so keeping it in APZCCallbackHelper seems awkward.

nsLayoutUtils would also be a reasonable place but has the downside that
adding a new function to it triggers recompiling the world.

Differential Revision: https://phabricator.services.mozilla.com/D68296
parent 6a461317

gfx/layers/apz/util/APZCCallbackHelper.cpp

+1 −32
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
#include "mozilla/layers/WebRenderBridgeChild.h"

#include "mozilla/PresShell.h"

#include "mozilla/TouchEvents.h"

#include "mozilla/ViewportUtils.h"

#include "nsContainerFrame.h"

#include "nsContentUtils.h"

#include "nsIContent.h"
@@ -451,38 +452,6 @@ PresShell* APZCCallbackHelper::GetRootContentDocumentPresShellForContent( 
  return context->PresShell();

}



mozilla::CSSToCSSMatrix4x4 APZCCallbackHelper::GetCallbackTransform(

    ScrollableLayerGuid::ViewID aScrollId) {

  if (aScrollId == ScrollableLayerGuid::NULL_SCROLL_ID) {

    return {};

  }

  nsCOMPtr<nsIContent> content = nsLayoutUtils::FindContentFor(aScrollId);

  if (!content) {

    return {};

  }



  // First, scale inversely by the root content document's pres shell

  // resolution to cancel the scale-to-resolution transform that the

  // compositor adds to the layer with the pres shell resolution. The points

  // sent to Gecko by APZ don't have this transform unapplied (unlike other

  // compositor-side transforms) because Gecko needs it applied when hit

  // testing against content that's conceptually outside the resolution,

  // such as scrollbars.

  float resolution = 1.0f;

  if (PresShell* presShell =

          GetRootContentDocumentPresShellForContent(content)) {

    resolution = presShell->GetResolution();

  }



  // Now apply the callback-transform. This is only approximately correct,

  // see the comment on GetCumulativeApzCallbackTransform for details.

  CSSPoint transform = nsLayoutUtils::GetCumulativeApzCallbackTransform(

      content->GetPrimaryFrame());



  return mozilla::CSSToCSSMatrix4x4::Scaling(1 / resolution, 1 / resolution, 1)

      .PostTranslate(transform.x, transform.y, 0);

}



nsEventStatus APZCCallbackHelper::DispatchWidgetEvent(WidgetGUIEvent& aEvent) {

  nsEventStatus status = nsEventStatus_eConsumeNoDefault;

  if (aEvent.mWidget) {

gfx/layers/apz/util/APZCCallbackHelper.h

+0 −17
Original line number Diff line number Diff line
@@ -98,23 +98,6 @@ class APZCCallbackHelper { 
  static PresShell* GetRootContentDocumentPresShellForContent(

      nsIContent* aContent);



  /* Return a "callback transform" to be applied to the coordinates of input

     events targeting content inside the scroll frame identified by |aScrollId|.

     The callback transform has two components:

       1. The pres shell resolution, representing the pinch-zoom scale

          (if the scroll frame |aScrollId| is inside the resolution, which

          is most of the time).

       2. A translation representing async scrolling. This can contain:

           - For any scroll frame, a scroll component resulting from the main

             thread incompletely applying an APZ-requested scroll position.

           - For the RCD-RSF only, a persistent component representing the

             offset of the visual viewport relative to the layout viewport.

         The translation is accumulated for all scroll frames form |aScrollId|

         up to the root, using values populated in UpdateCallbackTransform. See

         that method's documentation for additional details. */

  static CSSToCSSMatrix4x4 GetCallbackTransform(

      ScrollableLayerGuid::ViewID aScrollId);



  /* Dispatch a widget event via the widget stored in the event, if any.

   * In a child process, allows the BrowserParent event-capture mechanism to

   * intercept the event. */

layout/base/ViewportUtils.cpp

0 → 100644
+50 −0
Original line number Diff line number Diff line 
/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */



#include "mozilla/PresShell.h"

#include "mozilla/ViewportUtils.h"

#include "mozilla/layers/APZCCallbackHelper.h"

#include "mozilla/layers/ScrollableLayerGuid.h"

#include "nsIContent.h"

#include "nsLayoutUtils.h"



namespace mozilla {



using layers::APZCCallbackHelper;

using layers::ScrollableLayerGuid;



CSSToCSSMatrix4x4 ViewportUtils::GetCallbackTransform(

    ScrollableLayerGuid::ViewID aScrollId) {

  if (aScrollId == ScrollableLayerGuid::NULL_SCROLL_ID) {

    return {};

  }

  nsCOMPtr<nsIContent> content = nsLayoutUtils::FindContentFor(aScrollId);

  if (!content) {

    return {};

  }



  // First, scale inversely by the root content document's pres shell

  // resolution to cancel the scale-to-resolution transform that the

  // compositor adds to the layer with the pres shell resolution. The points

  // sent to Gecko by APZ don't have this transform unapplied (unlike other

  // compositor-side transforms) because Gecko needs it applied when hit

  // testing against content that's conceptually outside the resolution,

  // such as scrollbars.

  float resolution = 1.0f;

  if (PresShell* presShell =

          APZCCallbackHelper::GetRootContentDocumentPresShellForContent(

              content)) {

    resolution = presShell->GetResolution();

  }



  // Now apply the callback-transform. This is only approximately correct,

  // see the comment on GetCumulativeApzCallbackTransform for details.

  CSSPoint transform = nsLayoutUtils::GetCumulativeApzCallbackTransform(

      content->GetPrimaryFrame());



  return mozilla::CSSToCSSMatrix4x4::Scaling(1 / resolution, 1 / resolution, 1)

      .PostTranslate(transform.x, transform.y, 0);

}



}  // namespace mozilla
 
 No newline at end of file

layout/base/ViewportUtils.h

0 → 100644
+36 −0
Original line number Diff line number Diff line 
/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */



#ifndef mozilla_ViewportUtils_h

#define mozilla_ViewportUtils_h



#include "Units.h"

#include "mozilla/layers/ScrollableLayerGuid.h"



namespace mozilla {



class ViewportUtils {

 public:

  /* Return a "callback transform" to be applied to the coordinates of input

     events targeting content inside the scroll frame identified by |aScrollId|.

     The callback transform has two components:

     1. The pres shell resolution, representing the pinch-zoom scale

        (if the scroll frame |aScrollId| is inside the resolution, which

        is most of the time).

     2. A translation representing async scrolling. This can contain:

         - For any scroll frame, a scroll component resulting from the main

           thread incompletely applying an APZ-requested scroll position.

         - For the RCD-RSF only, a persistent component representing the

           offset of the visual viewport relative to the layout viewport.

       The translation is accumulated for all scroll frames form |aScrollId|

       up to the root, using values populated in

       APZCCallbackHelper::UpdateCallbackTransform. See that method's

       documentation for additional details. */

  static CSSToCSSMatrix4x4 GetCallbackTransform(

      layers::ScrollableLayerGuid::ViewID aScrollId);

};



}  // namespace mozilla



#endif /* mozilla_ViewportUtils_h */

layout/base/moz.build

+2 −0
Original line number Diff line number Diff line
@@ -87,6 +87,7 @@ EXPORTS.mozilla += [ 
    'ScrollTypes.h',

    'ShapeUtils.h',

    'StaticPresData.h',

    'ViewportUtils.h',

]



EXPORTS.mozilla.layout += [
@@ -129,6 +130,7 @@ UNIFIED_SOURCES += [ 
    'StackArena.cpp',

    'StaticPresData.cpp',

    'TouchManager.cpp',

    'ViewportUtils.cpp',

    'ZoomConstraintsClient.cpp',

]