image/ClippedImage.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "ClippedImage.h"
   7
   8 #include <algorithm>
   9 #include <cmath>
  10 #include <new>  // Workaround for bug in VS10; see bug 981264.
  11 #include <utility>
  12
  13 #include "ImageRegion.h"
  14 #include "Orientation.h"
  15 #include "gfxContext.h"
  16 #include "gfxDrawable.h"
  17 #include "gfxPlatform.h"
  18 #include "gfxUtils.h"
  19 #include "mozilla/RefPtr.h"
  20 #include "mozilla/SVGImageContext.h"
  21 #include "mozilla/Tuple.h"
  22 #include "mozilla/gfx/2D.h"
  23
  24 namespace mozilla {
  25
  26 using namespace gfx;
  27 using layers::ImageContainer;
  28 using std::make_pair;
  29 using std::max;
  30 using std::modf;
  31 using std::pair;
  32
  33 namespace image {
  34
  35 class ClippedImageCachedSurface {
  36  public:
  37   ClippedImageCachedSurface(already_AddRefed<SourceSurface> aSurface,
  38                             const nsIntSize& aSize,
  39                             const Maybe<SVGImageContext>& aSVGContext,
  40                             float aFrame, uint32_t aFlags,
  41                             ImgDrawResult aDrawResult)
  42       : mSurface(aSurface),
  43         mSize(aSize),
  44         mSVGContext(aSVGContext),
  45         mFrame(aFrame),
  46         mFlags(aFlags),
  47         mDrawResult(aDrawResult) {
  48     MOZ_ASSERT(mSurface, "Must have a valid surface");
  49   }
  50
  51   bool Matches(const nsIntSize& aSize,
  52                const Maybe<SVGImageContext>& aSVGContext, float aFrame,
  53                uint32_t aFlags) const {
  54     return mSize == aSize && mSVGContext == aSVGContext && mFrame == aFrame &&
  55            mFlags == aFlags;
  56   }
  57
  58   already_AddRefed<SourceSurface> Surface() const {
  59     RefPtr<SourceSurface> surf(mSurface);
  60     return surf.forget();
  61   }
  62
  63   ImgDrawResult GetDrawResult() const { return mDrawResult; }
  64
  65   bool NeedsRedraw() const {
  66     return mDrawResult != ImgDrawResult::SUCCESS &&
  67            mDrawResult != ImgDrawResult::BAD_IMAGE;
  68   }
  69
  70  private:
  71   RefPtr<SourceSurface> mSurface;
  72   const nsIntSize mSize;
  73   Maybe<SVGImageContext> mSVGContext;
  74   const float mFrame;
  75   const uint32_t mFlags;
  76   const ImgDrawResult mDrawResult;
  77 };
  78
  79 class DrawSingleTileCallback : public gfxDrawingCallback {
  80  public:
  81   DrawSingleTileCallback(ClippedImage* aImage, const nsIntSize& aSize,
  82                          const Maybe<SVGImageContext>& aSVGContext,
  83                          uint32_t aWhichFrame, uint32_t aFlags, float aOpacity)
  84       : mImage(aImage),
  85         mSize(aSize),
  86         mSVGContext(aSVGContext),
  87         mWhichFrame(aWhichFrame),
  88         mFlags(aFlags),
  89         mDrawResult(ImgDrawResult::NOT_READY),
  90         mOpacity(aOpacity) {
  91     MOZ_ASSERT(mImage, "Must have an image to clip");
  92   }
  93
  94   virtual bool operator()(gfxContext* aContext, const gfxRect& aFillRect,
  95                           const SamplingFilter aSamplingFilter,
  96                           const gfxMatrix& aTransform) override {
  97     MOZ_ASSERT(aTransform.IsIdentity(),
  98                "Caller is probably CreateSamplingRestrictedDrawable, "
  99                "which should not happen");
 100
 101     // Draw the image. |gfxCallbackDrawable| always calls this function with
 102     // arguments that guarantee we never tile.
 103     mDrawResult = mImage->DrawSingleTile(
 104         aContext, mSize, ImageRegion::Create(aFillRect), mWhichFrame,
 105         aSamplingFilter, mSVGContext, mFlags, mOpacity);
 106
 107     return true;
 108   }
 109
 110   ImgDrawResult GetDrawResult() { return mDrawResult; }
 111
 112  private:
 113   RefPtr<ClippedImage> mImage;
 114   const nsIntSize mSize;
 115   const Maybe<SVGImageContext>& mSVGContext;
 116   const uint32_t mWhichFrame;
 117   const uint32_t mFlags;
 118   ImgDrawResult mDrawResult;
 119   float mOpacity;
 120 };
 121
 122 ClippedImage::ClippedImage(Image* aImage, nsIntRect aClip,
 123                            const Maybe<nsSize>& aSVGViewportSize)
 124     : ImageWrapper(aImage), mClip(aClip) {
 125   MOZ_ASSERT(aImage != nullptr, "ClippedImage requires an existing Image");
 126   MOZ_ASSERT_IF(aSVGViewportSize,
 127                 aImage->GetType() == imgIContainer::TYPE_VECTOR);
 128   if (aSVGViewportSize) {
 129     mSVGViewportSize =
 130         Some(aSVGViewportSize->ToNearestPixels(AppUnitsPerCSSPixel()));
 131   }
 132 }
 133
 134 ClippedImage::~ClippedImage() {}
 135
 136 bool ClippedImage::ShouldClip() {
 137   // We need to evaluate the clipping region against the image's width and
 138   // height once they're available to determine if it's valid and whether we
 139   // actually need to do any work. We may fail if the image's width and height
 140   // aren't available yet, in which case we'll try again later.
 141   if (mShouldClip.isNothing()) {
 142     int32_t width, height;
 143     RefPtr<ProgressTracker> progressTracker =
 144         InnerImage()->GetProgressTracker();
 145     if (InnerImage()->HasError()) {
 146       // If there's a problem with the inner image we'll let it handle
 147       // everything.
 148       mShouldClip.emplace(false);
 149     } else if (mSVGViewportSize && !mSVGViewportSize->IsEmpty()) {
 150       // Clamp the clipping region to the size of the SVG viewport.
 151       nsIntRect svgViewportRect(nsIntPoint(0, 0), *mSVGViewportSize);
 152
 153       mClip = mClip.Intersect(svgViewportRect);
 154
 155       // If the clipping region is the same size as the SVG viewport size
 156       // we don't have to do anything.
 157       mShouldClip.emplace(!mClip.IsEqualInterior(svgViewportRect));
 158     } else if (NS_SUCCEEDED(InnerImage()->GetWidth(&width)) && width > 0 &&
 159                NS_SUCCEEDED(InnerImage()->GetHeight(&height)) && height > 0) {
 160       // Clamp the clipping region to the size of the underlying image.
 161       mClip = mClip.Intersect(nsIntRect(0, 0, width, height));
 162
 163       // If the clipping region is the same size as the underlying image we
 164       // don't have to do anything.
 165       mShouldClip.emplace(
 166           !mClip.IsEqualInterior(nsIntRect(0, 0, width, height)));
 167     } else if (progressTracker &&
 168                !(progressTracker->GetProgress() & FLAG_LOAD_COMPLETE)) {
 169       // The image just hasn't finished loading yet. We don't yet know whether
 170       // clipping with be needed or not for now. Just return without memorizing
 171       // anything.
 172       return false;
 173     } else {
 174       // We have a fully loaded image without a clearly defined width and
 175       // height. This can happen with SVG images.
 176       mShouldClip.emplace(false);
 177     }
 178   }
 179
 180   MOZ_ASSERT(mShouldClip.isSome(), "Should have computed a result");
 181   return *mShouldClip;
 182 }
 183
 184 NS_IMETHODIMP
 185 ClippedImage::GetWidth(int32_t* aWidth) {
 186   if (!ShouldClip()) {
 187     return InnerImage()->GetWidth(aWidth);
 188   }
 189
 190   *aWidth = mClip.Width();
 191   return NS_OK;
 192 }
 193
 194 NS_IMETHODIMP
 195 ClippedImage::GetHeight(int32_t* aHeight) {
 196   if (!ShouldClip()) {
 197     return InnerImage()->GetHeight(aHeight);
 198   }
 199
 200   *aHeight = mClip.Height();
 201   return NS_OK;
 202 }
 203
 204 NS_IMETHODIMP
 205 ClippedImage::GetIntrinsicSize(nsSize* aSize) {
 206   if (!ShouldClip()) {
 207     return InnerImage()->GetIntrinsicSize(aSize);
 208   }
 209
 210   *aSize = nsSize(mClip.Width(), mClip.Height());
 211   return NS_OK;
 212 }
 213
 214 Maybe<AspectRatio> ClippedImage::GetIntrinsicRatio() {
 215   if (!ShouldClip()) {
 216     return InnerImage()->GetIntrinsicRatio();
 217   }
 218
 219   return Some(AspectRatio::FromSize(mClip.Width(), mClip.Height()));
 220 }
 221
 222 NS_IMETHODIMP_(already_AddRefed<SourceSurface>)
 223 ClippedImage::GetFrame(uint32_t aWhichFrame, uint32_t aFlags) {
 224   ImgDrawResult result;
 225   RefPtr<SourceSurface> surface;
 226   Tie(result, surface) = GetFrameInternal(mClip.Size(), Nothing(), Nothing(),
 227                                           aWhichFrame, aFlags, 1.0);
 228   return surface.forget();
 229 }
 230
 231 NS_IMETHODIMP_(already_AddRefed<SourceSurface>)
 232 ClippedImage::GetFrameAtSize(const IntSize& aSize, uint32_t aWhichFrame,
 233                              uint32_t aFlags) {
 234   // XXX(seth): It'd be nice to support downscale-during-decode for this case,
 235   // but right now we just fall back to the intrinsic size.
 236   return GetFrame(aWhichFrame, aFlags);
 237 }
 238
 239 std::pair<ImgDrawResult, RefPtr<SourceSurface>> ClippedImage::GetFrameInternal(
 240     const nsIntSize& aSize, const Maybe<SVGImageContext>& aSVGContext,
 241     const Maybe<ImageIntRegion>& aRegion, uint32_t aWhichFrame, uint32_t aFlags,
 242     float aOpacity) {
 243   if (!ShouldClip()) {
 244     RefPtr<SourceSurface> surface = InnerImage()->GetFrame(aWhichFrame, aFlags);
 245     return std::make_pair(
 246         surface ? ImgDrawResult::SUCCESS : ImgDrawResult::NOT_READY,
 247         std::move(surface));
 248   }
 249
 250   float frameToDraw = InnerImage()->GetFrameIndex(aWhichFrame);
 251   if (!mCachedSurface ||
 252       !mCachedSurface->Matches(aSize, aSVGContext, frameToDraw, aFlags) ||
 253       mCachedSurface->NeedsRedraw()) {
 254     // Create a surface to draw into.
 255     RefPtr<DrawTarget> target =
 256         gfxPlatform::GetPlatform()->CreateOffscreenContentDrawTarget(
 257             IntSize(aSize.width, aSize.height), SurfaceFormat::OS_RGBA);
 258     if (!target || !target->IsValid()) {
 259       NS_ERROR("Could not create a DrawTarget");
 260       return std::make_pair(ImgDrawResult::TEMPORARY_ERROR,
 261                             RefPtr<SourceSurface>());
 262     }
 263
 264     RefPtr<gfxContext> ctx = gfxContext::CreateOrNull(target);
 265     MOZ_ASSERT(ctx);  // already checked the draw target above
 266
 267     // Create our callback.
 268     RefPtr<DrawSingleTileCallback> drawTileCallback =
 269         new DrawSingleTileCallback(this, aSize, aSVGContext, aWhichFrame,
 270                                    aFlags, aOpacity);
 271     RefPtr<gfxDrawable> drawable =
 272         new gfxCallbackDrawable(drawTileCallback, aSize);
 273
 274     // Actually draw. The callback will end up invoking DrawSingleTile.
 275     gfxUtils::DrawPixelSnapped(ctx, drawable, SizeDouble(aSize),
 276                                ImageRegion::Create(aSize),
 277                                SurfaceFormat::OS_RGBA, SamplingFilter::LINEAR,
 278                                imgIContainer::FLAG_CLAMP);
 279
 280     // Cache the resulting surface.
 281     mCachedSurface = MakeUnique<ClippedImageCachedSurface>(
 282         target->Snapshot(), aSize, aSVGContext, frameToDraw, aFlags,
 283         drawTileCallback->GetDrawResult());
 284   }
 285
 286   MOZ_ASSERT(mCachedSurface, "Should have a cached surface now");
 287   RefPtr<SourceSurface> surface = mCachedSurface->Surface();
 288   return std::make_pair(mCachedSurface->GetDrawResult(), std::move(surface));
 289 }
 290
 291 NS_IMETHODIMP_(bool)
 292 ClippedImage::IsImageContainerAvailable(WindowRenderer* aRenderer,
 293                                         uint32_t aFlags) {
 294   if (!ShouldClip()) {
 295     return InnerImage()->IsImageContainerAvailable(aRenderer, aFlags);
 296   }
 297   return false;
 298 }
 299
 300 NS_IMETHODIMP_(ImgDrawResult)
 301 ClippedImage::GetImageProvider(WindowRenderer* aRenderer,
 302                                const gfx::IntSize& aSize,
 303                                const Maybe<SVGImageContext>& aSVGContext,
 304                                const Maybe<ImageIntRegion>& aRegion,
 305                                uint32_t aFlags,
 306                                WebRenderImageProvider** aProvider) {
 307   // XXX(seth): We currently don't have a way of clipping the result of
 308   // GetImageContainer. We work around this by always returning null, but if it
 309   // ever turns out that ClippedImage is widely used on codepaths that can
 310   // actually benefit from GetImageContainer, it would be a good idea to fix
 311   // that method for performance reasons.
 312
 313   if (!ShouldClip()) {
 314     return InnerImage()->GetImageProvider(aRenderer, aSize, aSVGContext,
 315                                           aRegion, aFlags, aProvider);
 316   }
 317
 318   return ImgDrawResult::NOT_SUPPORTED;
 319 }
 320
 321 static bool MustCreateSurface(gfxContext* aContext, const nsIntSize& aSize,
 322                               const ImageRegion& aRegion,
 323                               const uint32_t aFlags) {
 324   gfxRect imageRect(0, 0, aSize.width, aSize.height);
 325   bool willTile = !imageRect.Contains(aRegion.Rect()) &&
 326                   !(aFlags & imgIContainer::FLAG_CLAMP);
 327   bool willResample = aContext->CurrentMatrix().HasNonIntegerTranslation() &&
 328                       (willTile || !aRegion.RestrictionContains(imageRect));
 329   return willTile || willResample;
 330 }
 331
 332 NS_IMETHODIMP_(ImgDrawResult)
 333 ClippedImage::Draw(gfxContext* aContext, const nsIntSize& aSize,
 334                    const ImageRegion& aRegion, uint32_t aWhichFrame,
 335                    SamplingFilter aSamplingFilter,
 336                    const Maybe<SVGImageContext>& aSVGContext, uint32_t aFlags,
 337                    float aOpacity) {
 338   if (!ShouldClip()) {
 339     return InnerImage()->Draw(aContext, aSize, aRegion, aWhichFrame,
 340                               aSamplingFilter, aSVGContext, aFlags, aOpacity);
 341   }
 342
 343   // Check for tiling. If we need to tile then we need to create a
 344   // gfxCallbackDrawable to handle drawing for us.
 345   if (MustCreateSurface(aContext, aSize, aRegion, aFlags)) {
 346     // Create a temporary surface containing a single tile of this image.
 347     // GetFrame will call DrawSingleTile internally.
 348     ImgDrawResult result;
 349     RefPtr<SourceSurface> surface;
 350     Tie(result, surface) = GetFrameInternal(aSize, aSVGContext, Nothing(),
 351                                             aWhichFrame, aFlags, aOpacity);
 352     if (!surface) {
 353       MOZ_ASSERT(result != ImgDrawResult::SUCCESS);
 354       return result;
 355     }
 356
 357     // Create a drawable from that surface.
 358     RefPtr<gfxSurfaceDrawable> drawable =
 359         new gfxSurfaceDrawable(surface, aSize);
 360
 361     // Draw.
 362     gfxUtils::DrawPixelSnapped(aContext, drawable, SizeDouble(aSize), aRegion,
 363                                SurfaceFormat::OS_RGBA, aSamplingFilter,
 364                                aOpacity);
 365
 366     return result;
 367   }
 368
 369   return DrawSingleTile(aContext, aSize, aRegion, aWhichFrame, aSamplingFilter,
 370                         aSVGContext, aFlags, aOpacity);
 371 }
 372
 373 ImgDrawResult ClippedImage::DrawSingleTile(
 374     gfxContext* aContext, const nsIntSize& aSize, const ImageRegion& aRegion,
 375     uint32_t aWhichFrame, SamplingFilter aSamplingFilter,
 376     const Maybe<SVGImageContext>& aSVGContext, uint32_t aFlags,
 377     float aOpacity) {
 378   MOZ_ASSERT(!MustCreateSurface(aContext, aSize, aRegion, aFlags),
 379              "Shouldn't need to create a surface");
 380
 381   gfxRect clip(mClip.X(), mClip.Y(), mClip.Width(), mClip.Height());
 382   nsIntSize size(aSize), innerSize(aSize);
 383   bool needScale = false;
 384   if (mSVGViewportSize && !mSVGViewportSize->IsEmpty()) {
 385     innerSize = *mSVGViewportSize;
 386     needScale = true;
 387   } else if (NS_SUCCEEDED(InnerImage()->GetWidth(&innerSize.width)) &&
 388              NS_SUCCEEDED(InnerImage()->GetHeight(&innerSize.height))) {
 389     needScale = true;
 390   } else {
 391     MOZ_ASSERT_UNREACHABLE(
 392         "If ShouldClip() led us to draw then we should never get here");
 393   }
 394
 395   if (needScale) {
 396     double scaleX = aSize.width / clip.Width();
 397     double scaleY = aSize.height / clip.Height();
 398
 399     // Map the clip and size to the scale requested by the caller.
 400     clip.Scale(scaleX, scaleY);
 401     size = innerSize;
 402     size.Scale(scaleX, scaleY);
 403   }
 404
 405   // We restrict our drawing to only the clipping region, and translate so that
 406   // the clipping region is placed at the position the caller expects.
 407   ImageRegion region(aRegion);
 408   region.MoveBy(clip.X(), clip.Y());
 409   region = region.Intersect(clip);
 410
 411   gfxContextMatrixAutoSaveRestore saveMatrix(aContext);
 412   aContext->Multiply(gfxMatrix::Translation(-clip.X(), -clip.Y()));
 413
 414   auto unclipViewport = [&](const SVGImageContext& aOldContext) {
 415     // Map the viewport to the inner image. Note that we don't take the aSize
 416     // parameter of imgIContainer::Draw into account, just the clipping region.
 417     // The size in pixels at which the output will ultimately be drawn is
 418     // irrelevant here since the purpose of the SVG viewport size is to
 419     // determine what *region* of the SVG document will be drawn.
 420     SVGImageContext context(aOldContext);
 421     auto oldViewport = aOldContext.GetViewportSize();
 422     if (oldViewport) {
 423       CSSIntSize newViewport;
 424       newViewport.width =
 425           ceil(oldViewport->width * double(innerSize.width) / mClip.Width());
 426       newViewport.height =
 427           ceil(oldViewport->height * double(innerSize.height) / mClip.Height());
 428       context.SetViewportSize(Some(newViewport));
 429     }
 430     return context;
 431   };
 432
 433   return InnerImage()->Draw(aContext, size, region, aWhichFrame,
 434                             aSamplingFilter, aSVGContext.map(unclipViewport),
 435                             aFlags, aOpacity);
 436 }
 437
 438 NS_IMETHODIMP
 439 ClippedImage::RequestDiscard() {
 440   // We're very aggressive about discarding.
 441   mCachedSurface = nullptr;
 442
 443   return InnerImage()->RequestDiscard();
 444 }
 445
 446 NS_IMETHODIMP_(Orientation)
 447 ClippedImage::GetOrientation() {
 448   // XXX(seth): This should not actually be here; this is just to work around a
 449   // what appears to be a bug in MSVC's linker.
 450   return InnerImage()->GetOrientation();
 451 }
 452
 453 nsIntSize ClippedImage::OptimalImageSizeForDest(const gfxSize& aDest,
 454                                                 uint32_t aWhichFrame,
 455                                                 SamplingFilter aSamplingFilter,
 456                                                 uint32_t aFlags) {
 457   if (!ShouldClip()) {
 458     return InnerImage()->OptimalImageSizeForDest(aDest, aWhichFrame,
 459                                                  aSamplingFilter, aFlags);
 460   }
 461
 462   int32_t imgWidth, imgHeight;
 463   bool needScale = false;
 464   bool forceUniformScaling = false;
 465   if (mSVGViewportSize && !mSVGViewportSize->IsEmpty()) {
 466     imgWidth = mSVGViewportSize->width;
 467     imgHeight = mSVGViewportSize->height;
 468     needScale = true;
 469     forceUniformScaling = (aFlags & imgIContainer::FLAG_FORCE_UNIFORM_SCALING);
 470   } else if (NS_SUCCEEDED(InnerImage()->GetWidth(&imgWidth)) &&
 471              NS_SUCCEEDED(InnerImage()->GetHeight(&imgHeight))) {
 472     needScale = true;
 473   }
 474
 475   if (needScale) {
 476     // To avoid ugly sampling artifacts, ClippedImage needs the image size to
 477     // be chosen such that the clipping region lies on pixel boundaries.
 478
 479     // First, we select a scale that's good for ClippedImage. An integer
 480     // multiple of the size of the clipping region is always fine.
 481     IntSize scale = IntSize::Ceil(aDest.width / mClip.Width(),
 482                                   aDest.height / mClip.Height());
 483
 484     if (forceUniformScaling) {
 485       scale.width = scale.height = max(scale.height, scale.width);
 486     }
 487
 488     // Determine the size we'd prefer to render the inner image at, and ask the
 489     // inner image what size we should actually use.
 490     gfxSize desiredSize(double(imgWidth) * scale.width,
 491                         double(imgHeight) * scale.height);
 492     nsIntSize innerDesiredSize = InnerImage()->OptimalImageSizeForDest(
 493         desiredSize, aWhichFrame, aSamplingFilter, aFlags);
 494
 495     // To get our final result, we take the inner image's desired size and
 496     // determine how large the clipped region would be at that scale. (Again, we
 497     // ensure an integer multiple of the size of the clipping region.)
 498     IntSize finalScale =
 499         IntSize::Ceil(double(innerDesiredSize.width) / imgWidth,
 500                       double(innerDesiredSize.height) / imgHeight);
 501     return mClip.Size() * finalScale;
 502   }
 503
 504   MOZ_ASSERT(false,
 505              "If ShouldClip() led us to draw then we should never get here");
 506   return InnerImage()->OptimalImageSizeForDest(aDest, aWhichFrame,
 507                                                aSamplingFilter, aFlags);
 508 }
 509
 510 NS_IMETHODIMP_(nsIntRect)
 511 ClippedImage::GetImageSpaceInvalidationRect(const nsIntRect& aRect) {
 512   if (!ShouldClip()) {
 513     return InnerImage()->GetImageSpaceInvalidationRect(aRect);
 514   }
 515
 516   nsIntRect rect(InnerImage()->GetImageSpaceInvalidationRect(aRect));
 517   rect = rect.Intersect(mClip);
 518   rect.MoveBy(-mClip.X(), -mClip.Y());
 519   return rect;
 520 }
 521
 522 }  // namespace image
 523 }  // namespace mozilla