image/OrientedImage.cpp
author Andrew Osmond <aosmond@mozilla.com>
Fri, 17 Nov 2017 06:45:26 -0500
changeset 392470 0cd5200c5f768b8d10ef23ac8986003c0c71375b
parent 374591 d093907b21addffff1273cbc4bae652e6994f2ed
child 392504 54d6ad659f11103861cf2d53259d77764dfd675e
permissions -rw-r--r--
Bug 1368776 - Part 9. Expose getting an image container at a given size. r=tnikkel This adds IsImageContainerAvailableAtSize and GetImageContainerAtSize to the imgIContainer interface, as well as stubbing it for all of the classes which implement it. The real implementations will follow for the more complicated classes (RasterImage, VectorImage).

/* -*- 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 "OrientedImage.h"

#include <algorithm>

#include "gfx2DGlue.h"
#include "gfxDrawable.h"
#include "gfxPlatform.h"
#include "gfxUtils.h"
#include "ImageRegion.h"
#include "SVGImageContext.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);
  }
}

nsresult
OrientedImage::GetNativeSizes(nsTArray<IntSize>& aNativeSizes) const
{
  nsresult rv = InnerImage()->GetNativeSizes(aNativeSizes);

  if (mOrientation.SwapsWidthAndHeight()) {
    auto i = aNativeSizes.Length();
    while (i > 0) {
      --i;
      swap(aNativeSizes[i].width, aNativeSizes[i].height);
    }
  }

  return rv;
}

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()->WillDrawOpaqueNow()) {
    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 || !target->IsValid()) {
    NS_ERROR("Could not create a DrawTarget");
    return nullptr;
  }


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

  // Draw.
  RefPtr<gfxContext> ctx = gfxContext::CreateOrNull(target);
  MOZ_ASSERT(ctx); // already checked the draw target above
  ctx->Multiply(OrientationMatrix(size));
  gfxUtils::DrawPixelSnapped(ctx, drawable, SizeDouble(size), ImageRegion::Create(size),
                             surfaceFormat, SamplingFilter::LINEAR);

  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;
}

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

NS_IMETHODIMP_(already_AddRefed<ImageContainer>)
OrientedImage::GetImageContainerAtSize(LayerManager* aManager,
                                       const IntSize& aSize,
                                       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()->GetImageContainerAtSize(aManager, aSize, 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.PreScale(aX, aY);
    }
  }

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

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

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

  // 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);

  auto orientViewport = [&](const SVGImageContext& aOldContext) {
    SVGImageContext context(aOldContext);
    auto oldViewport = aOldContext.GetViewportSize();
    if (oldViewport && mOrientation.SwapsWidthAndHeight()) {
      // Swap width and height:
      CSSIntSize newViewport(oldViewport->height, oldViewport->width);
      context.SetViewportSize(Some(newViewport));
    }
    return context;
  };

  return InnerImage()->Draw(aContext, size, region, aWhichFrame,
                            aSamplingFilter,
                            aSVGContext.map(orientViewport), aFlags,
                            aOpacity);
}

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

  return IntRect::RoundOut(invalidRect.x, invalidRect.y,
                           invalidRect.Width(), invalidRect.Height());
}

} // namespace image
} // namespace mozilla