image/OrientedImage.cpp
author Timothy Nikkel <tnikkel@gmail.com>
Sat, 26 Sep 2015 01:26:18 -0500
changeset 264801 d3362879b8b1865812f2ec8c062d7ddd264bf8ac
parent 264264 cdee9be7cdc15a2e1518ca56dd57c812e5cfb107
child 266503 3897da20e42dec0bcf73987af1eaac4f8ce950b8
child 266613 1f51d1614b9a58e41dd3a1bf2dc6aad34dbb2170
permissions -rw-r--r--
Bug 1194837. Don't use the inverse orientation matrix when computing the image space invalidate rect. r=seth The orientation matrix converts from decoded image space to oriented image space. The invalidation rect is in decoded image space. So we need to use the orientation matrix to convert it to oriented image space, not it's inverse.

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 <algorithm>

#include "gfx2DGlue.h"
#include "gfxDrawable.h"
#include "gfxPlatform.h"
#include "gfxUtils.h"
#include "ImageRegion.h"
#include "SVGImageContext.h"

#include "OrientedImage.h"

using std::swap;

namespace mozilla {

using namespace gfx;
using layers::LayerManager;
using layers::ImageContainer;

namespace image {

NS_IMPL_ISUPPORTS_INHERITED0(OrientedImage, ImageWrapper)

NS_IMETHODIMP
OrientedImage::GetWidth(int32_t* aWidth)
{
  if (mOrientation.SwapsWidthAndHeight()) {
    return InnerImage()->GetHeight(aWidth);
  } else {
    return InnerImage()->GetWidth(aWidth);
  }
}

NS_IMETHODIMP
OrientedImage::GetHeight(int32_t* aHeight)
{
  if (mOrientation.SwapsWidthAndHeight()) {
    return InnerImage()->GetWidth(aHeight);
  } else {
    return InnerImage()->GetHeight(aHeight);
  }
}

NS_IMETHODIMP
OrientedImage::GetIntrinsicSize(nsSize* aSize)
{
  nsresult rv = InnerImage()->GetIntrinsicSize(aSize);

  if (mOrientation.SwapsWidthAndHeight()) {
    swap(aSize->width, aSize->height);
  }

  return rv;
}

NS_IMETHODIMP
OrientedImage::GetIntrinsicRatio(nsSize* aRatio)
{
  nsresult rv = InnerImage()->GetIntrinsicRatio(aRatio);

  if (mOrientation.SwapsWidthAndHeight()) {
    swap(aRatio->width, aRatio->height);
  }

  return rv;
}

NS_IMETHODIMP_(already_AddRefed<SourceSurface>)
OrientedImage::GetFrame(uint32_t aWhichFrame,
                        uint32_t aFlags)
{
  nsresult rv;

  if (mOrientation.IsIdentity()) {
    return InnerImage()->GetFrame(aWhichFrame, aFlags);
  }

  // Get the underlying dimensions.
  IntSize size;
  rv = InnerImage()->GetWidth(&size.width);
  NS_ENSURE_SUCCESS(rv, nullptr);
  rv = InnerImage()->GetHeight(&size.height);
  NS_ENSURE_SUCCESS(rv, nullptr);

  // Determine an appropriate format for the surface.
  gfx::SurfaceFormat surfaceFormat;
  if (InnerImage()->IsOpaque()) {
    surfaceFormat = gfx::SurfaceFormat::B8G8R8X8;
  } else {
    surfaceFormat = gfx::SurfaceFormat::B8G8R8A8;
  }

  // Create a surface to draw into.
  RefPtr<DrawTarget> target =
    gfxPlatform::GetPlatform()->
      CreateOffscreenContentDrawTarget(size, surfaceFormat);
  if (!target) {
    NS_ERROR("Could not create a DrawTarget");
    return nullptr;
  }


  // Create our drawable.
  RefPtr<SourceSurface> innerSurface =
    InnerImage()->GetFrame(aWhichFrame, aFlags);
  NS_ENSURE_TRUE(innerSurface, nullptr);
  nsRefPtr<gfxDrawable> drawable =
    new gfxSurfaceDrawable(innerSurface, size);

  // Draw.
  nsRefPtr<gfxContext> ctx = new gfxContext(target);
  ctx->Multiply(OrientationMatrix(size));
  gfxUtils::DrawPixelSnapped(ctx, drawable, size,
                             ImageRegion::Create(size),
                             surfaceFormat, GraphicsFilter::FILTER_FAST);

  return target->Snapshot();
}

NS_IMETHODIMP_(already_AddRefed<SourceSurface>)
OrientedImage::GetFrameAtSize(const IntSize& aSize,
                              uint32_t aWhichFrame,
                              uint32_t aFlags)
{
  // XXX(seth): It'd be nice to support downscale-during-decode for this case,
  // but right now we just fall back to the intrinsic size.
  return GetFrame(aWhichFrame, aFlags);
}

NS_IMETHODIMP_(bool)
OrientedImage::IsImageContainerAvailable(LayerManager* aManager, uint32_t aFlags)
{
  if (mOrientation.IsIdentity()) {
    return InnerImage()->IsImageContainerAvailable(aManager, aFlags);
  }
  return false;
}

NS_IMETHODIMP_(already_AddRefed<ImageContainer>)
OrientedImage::GetImageContainer(LayerManager* aManager, uint32_t aFlags)
{
  // XXX(seth): We currently don't have a way of orienting the result of
  // GetImageContainer. We work around this by always returning null, but if it
  // ever turns out that OrientedImage is widely used on codepaths that can
  // actually benefit from GetImageContainer, it would be a good idea to fix
  // that method for performance reasons.

  if (mOrientation.IsIdentity()) {
    return InnerImage()->GetImageContainer(aManager, aFlags);
  }

  return nullptr;
}

struct MatrixBuilder
{
  explicit MatrixBuilder(bool aInvert) : mInvert(aInvert) { }

  gfxMatrix Build() { return mMatrix; }

  void Scale(gfxFloat aX, gfxFloat aY)
  {
    if (mInvert) {
      mMatrix *= gfxMatrix::Scaling(1.0 / aX, 1.0 / aY);
    } else {
      mMatrix.Scale(aX, aY);
    }
  }

  void Rotate(gfxFloat aPhi)
  {
    if (mInvert) {
      mMatrix *= gfxMatrix::Rotation(-aPhi);
    } else {
      mMatrix.Rotate(aPhi);
    }
  }

  void Translate(gfxPoint aDelta)
  {
    if (mInvert) {
      mMatrix *= gfxMatrix::Translation(-aDelta);
    } else {
      mMatrix.Translate(aDelta);
    }
  }

private:
  gfxMatrix mMatrix;
  bool      mInvert;
};

/*
 * OrientationMatrix() computes a matrix that applies the rotation and
 * reflection specified by mOrientation, or that matrix's inverse if aInvert is
 * true.
 *
 * @param aSize The scaled size of the inner image. (When outside code specifies
 *              the scaled size, as with imgIContainer::Draw and its aSize
 *              parameter, it's necessary to swap the width and height if
 *              mOrientation.SwapsWidthAndHeight() is true.)
 * @param aInvert If true, compute the inverse of the orientation matrix. Prefer
 *                this approach to OrientationMatrix(..).Invert(), because it's
 *                more numerically accurate.
 */
gfxMatrix
OrientedImage::OrientationMatrix(const nsIntSize& aSize,
                                 bool aInvert /* = false */)
{
  MatrixBuilder builder(aInvert);

  // Apply reflection, if present. (This logically happens second, but we
  // apply it first because these transformations are all premultiplied.) A
  // translation is necessary to place the image back in the first quadrant.
  switch (mOrientation.flip) {
    case Flip::Unflipped:
      break;
    case Flip::Horizontal:
      if (mOrientation.SwapsWidthAndHeight()) {
        builder.Translate(gfxPoint(aSize.height, 0));
      } else {
        builder.Translate(gfxPoint(aSize.width, 0));
      }
      builder.Scale(-1.0, 1.0);
      break;
    default:
      MOZ_ASSERT(false, "Invalid flip value");
  }

  // Apply rotation, if present. Again, a translation is used to place the
  // image back in the first quadrant.
  switch (mOrientation.rotation) {
    case Angle::D0:
      break;
    case Angle::D90:
      builder.Translate(gfxPoint(aSize.height, 0));
      builder.Rotate(-1.5 * M_PI);
      break;
    case Angle::D180:
      builder.Translate(gfxPoint(aSize.width, aSize.height));
      builder.Rotate(-1.0 * M_PI);
      break;
    case Angle::D270:
      builder.Translate(gfxPoint(0, aSize.width));
      builder.Rotate(-0.5 * M_PI);
      break;
    default:
      MOZ_ASSERT(false, "Invalid rotation value");
  }

  return builder.Build();
}

static SVGImageContext
OrientViewport(const SVGImageContext& aOldContext,
               const Orientation& aOrientation)
{
  CSSIntSize viewportSize(aOldContext.GetViewportSize());
  if (aOrientation.SwapsWidthAndHeight()) {
    swap(viewportSize.width, viewportSize.height);
  }
  return SVGImageContext(viewportSize,
                         aOldContext.GetPreserveAspectRatio());
}

NS_IMETHODIMP_(DrawResult)
OrientedImage::Draw(gfxContext* aContext,
                    const nsIntSize& aSize,
                    const ImageRegion& aRegion,
                    uint32_t aWhichFrame,
                    GraphicsFilter aFilter,
                    const Maybe<SVGImageContext>& aSVGContext,
                    uint32_t aFlags)
{
  if (mOrientation.IsIdentity()) {
    return InnerImage()->Draw(aContext, aSize, aRegion,
                              aWhichFrame, aFilter, aSVGContext, aFlags);
  }

  // Update the image size to match the image's coordinate system. (This could
  // be done using TransformBounds but since it's only a size a swap is enough.)
  nsIntSize size(aSize);
  if (mOrientation.SwapsWidthAndHeight()) {
    swap(size.width, size.height);
  }

  // Update the matrix so that we transform the image into the orientation
  // expected by the caller before drawing.
  gfxMatrix matrix(OrientationMatrix(size));
  gfxContextMatrixAutoSaveRestore saveMatrix(aContext);
  aContext->Multiply(matrix);

  // The region is already in the orientation expected by the caller, but we
  // need it to be in the image's coordinate system, so we transform it using
  // the inverse of the orientation matrix.
  gfxMatrix inverseMatrix(OrientationMatrix(size, /* aInvert = */ true));
  ImageRegion region(aRegion);
  region.TransformBoundsBy(inverseMatrix);

  return InnerImage()->Draw(aContext, size, region, aWhichFrame, aFilter,
                            aSVGContext.map(OrientViewport, mOrientation),
                            aFlags);
}

nsIntSize
OrientedImage::OptimalImageSizeForDest(const gfxSize& aDest,
                                       uint32_t aWhichFrame,
                                       GraphicsFilter aFilter, uint32_t aFlags)
{
  if (!mOrientation.SwapsWidthAndHeight()) {
    return InnerImage()->OptimalImageSizeForDest(aDest, aWhichFrame, aFilter,
                                                 aFlags);
  }

  // Swap the size for the calculation, then swap it back for the caller.
  gfxSize destSize(aDest.height, aDest.width);
  nsIntSize innerImageSize(InnerImage()->OptimalImageSizeForDest(destSize,
                                                                 aWhichFrame,
                                                                 aFilter,
                                                                 aFlags));
  return nsIntSize(innerImageSize.height, innerImageSize.width);
}

NS_IMETHODIMP_(nsIntRect)
OrientedImage::GetImageSpaceInvalidationRect(const nsIntRect& aRect)
{
  nsIntRect rect(InnerImage()->GetImageSpaceInvalidationRect(aRect));

  if (mOrientation.IsIdentity()) {
    return rect;
  }

  nsIntSize innerSize;
  nsresult rv = InnerImage()->GetWidth(&innerSize.width);
  rv = NS_FAILED(rv) ? rv : InnerImage()->GetHeight(&innerSize.height);
  if (NS_FAILED(rv)) {
    // Fall back to identity if the width and height aren't available.
    return rect;
  }

  // Transform the invalidation rect into the correct orientation.
  gfxMatrix matrix(OrientationMatrix(innerSize));
  gfxRect invalidRect(matrix.TransformBounds(gfxRect(rect.x, rect.y,
                                                     rect.width, rect.height)));
  invalidRect.RoundOut();

  return nsIntRect(invalidRect.x, invalidRect.y,
                   invalidRect.width, invalidRect.height);
}

} // namespace image
} // namespace mozilla