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