C++ IntRect::IsEmpty方法代码示例

already_AddRefed<gfx::DrawTarget>
PersistentBufferProviderShared::BorrowDrawTarget(const gfx::IntRect& aPersistedRect)
{
  if (!mFwd->GetTextureForwarder()->IPCOpen()) {
    return nullptr;
  }

  MOZ_ASSERT(!mSnapshot);

  if (IsActivityTracked()) {
    mFwd->GetActiveResourceTracker().MarkUsed(this);
  } else {
    mFwd->GetActiveResourceTracker().AddObject(this);
  }

  if (mDrawTarget) {
    RefPtr<gfx::DrawTarget> dt(mDrawTarget);
    return dt.forget();
  }

  mFront = Nothing();

  auto previousBackBuffer = mBack;

  TextureClient* tex = GetTexture(mBack);

  // First try to reuse the current back buffer. If we can do that it means
  // we can skip copying its content to the new back buffer.
  if (tex && tex->IsReadLocked()) {
    // The back buffer is currently used by the compositor, we can't draw
    // into it.
    tex = nullptr;
  }

  if (!tex) {
    // Try to grab an already allocated texture if any is available.
    for (uint32_t i = 0; i < mTextures.length(); ++i) {
      if (!mTextures[i]->IsReadLocked()) {
        mBack = Some(i);
        tex = mTextures[i];
        break;
      }
    }
  }

  if (!tex) {
    // We have to allocate a new texture.
    if (mTextures.length() >= 4) {
      // We should never need to buffer that many textures, something's wrong.
      MOZ_ASSERT(false);
      // In theory we throttle the main thread when the compositor can't keep up,
      // so we shoud never get in a situation where we sent 4 textures to the
      // compositor and the latter as not released any of them.
      // This seems to happen, however, in some edge cases such as just after a
      // device reset (cf. Bug 1291163).
      // It would be pretty bad to keep piling textures up at this point so we
      // call NotifyInactive to remove some of our textures.
      NotifyInactive();
      // Give up now. The caller can fall-back to a non-shared buffer provider.
      return nullptr;
    }

    RefPtr<TextureClient> newTexture = TextureClient::CreateForDrawing(
      mFwd, mFormat, mSize,
      BackendSelector::Canvas,
      TextureFlags::DEFAULT,
      TextureAllocationFlags::ALLOC_DEFAULT
    );

    MOZ_ASSERT(newTexture);
    if (newTexture) {
      if (mTextures.append(newTexture)) {
        tex = newTexture;
        mBack = Some<uint32_t>(mTextures.length() - 1);
      }
    }
  }

  if (!tex || !tex->Lock(OpenMode::OPEN_READ_WRITE)) {
    return nullptr;
  }

  if (mBack != previousBackBuffer && !aPersistedRect.IsEmpty()) {
    TextureClient* previous = GetTexture(previousBackBuffer);
    if (previous && previous->Lock(OpenMode::OPEN_READ)) {
      DebugOnly<bool> success = previous->CopyToTextureClient(tex, &aPersistedRect, nullptr);
      MOZ_ASSERT(success);

      previous->Unlock();
    }
  }

  mDrawTarget = tex->BorrowDrawTarget();

  RefPtr<gfx::DrawTarget> dt(mDrawTarget);
  return dt.forget();
}

void
GLBlitTextureImageHelper::BlitTextureImage(TextureImage *aSrc, const gfx::IntRect& aSrcRect,
                                           TextureImage *aDst, const gfx::IntRect& aDstRect)
{
    GLContext *gl = mCompositor->gl();

    if (!aSrc || !aDst || aSrcRect.IsEmpty() || aDstRect.IsEmpty())
        return;

    int savedFb = 0;
    gl->fGetIntegerv(LOCAL_GL_FRAMEBUFFER_BINDING, &savedFb);

    ScopedGLState scopedScissorTestState(gl, LOCAL_GL_SCISSOR_TEST, false);
    ScopedGLState scopedBlendState(gl, LOCAL_GL_BLEND, false);

    // 2.0 means scale up by two
    float blitScaleX = float(aDstRect.width) / float(aSrcRect.width);
    float blitScaleY = float(aDstRect.height) / float(aSrcRect.height);

    // We start iterating over all destination tiles
    aDst->BeginBigImageIteration();
    do {
        // calculate portion of the tile that is going to be painted to
        gfx::IntRect dstSubRect;
        gfx::IntRect dstTextureRect = aDst->GetTileRect();
        dstSubRect.IntersectRect(aDstRect, dstTextureRect);

        // this tile is not part of the destination rectangle aDstRect
        if (dstSubRect.IsEmpty())
            continue;

        // (*) transform the rect of this tile into the rectangle defined by aSrcRect...
        gfx::IntRect dstInSrcRect(dstSubRect);
        dstInSrcRect.MoveBy(-aDstRect.TopLeft());
        // ...which might be of different size, hence scale accordingly
        dstInSrcRect.ScaleRoundOut(1.0f / blitScaleX, 1.0f / blitScaleY);
        dstInSrcRect.MoveBy(aSrcRect.TopLeft());

        SetBlitFramebufferForDestTexture(aDst->GetTextureID());
        UseBlitProgram();

        aSrc->BeginBigImageIteration();
        // now iterate over all tiles in the source Image...
        do {
            // calculate portion of the source tile that is in the source rect
            gfx::IntRect srcSubRect;
            gfx::IntRect srcTextureRect = aSrc->GetTileRect();
            srcSubRect.IntersectRect(aSrcRect, srcTextureRect);

            // this tile is not part of the source rect
            if (srcSubRect.IsEmpty()) {
                continue;
            }
            // calculate intersection of source rect with destination rect
            srcSubRect.IntersectRect(srcSubRect, dstInSrcRect);
            // this tile does not overlap the current destination tile
            if (srcSubRect.IsEmpty()) {
                continue;
            }
            // We now have the intersection of
            //     the current source tile
            // and the desired source rectangle
            // and the destination tile
            // and the desired destination rectange
            // in destination space.
            // We need to transform this back into destination space, inverting the transform from (*)
            gfx::IntRect srcSubInDstRect(srcSubRect);
            srcSubInDstRect.MoveBy(-aSrcRect.TopLeft());
            srcSubInDstRect.ScaleRoundOut(blitScaleX, blitScaleY);
            srcSubInDstRect.MoveBy(aDstRect.TopLeft());

            // we transform these rectangles to be relative to the current src and dst tiles, respectively
            gfx::IntSize srcSize = srcTextureRect.Size();
            gfx::IntSize dstSize = dstTextureRect.Size();
            srcSubRect.MoveBy(-srcTextureRect.x, -srcTextureRect.y);
            srcSubInDstRect.MoveBy(-dstTextureRect.x, -dstTextureRect.y);

            float dx0 = 2.0f * float(srcSubInDstRect.x) / float(dstSize.width) - 1.0f;
            float dy0 = 2.0f * float(srcSubInDstRect.y) / float(dstSize.height) - 1.0f;
            float dx1 = 2.0f * float(srcSubInDstRect.x + srcSubInDstRect.width) / float(dstSize.width) - 1.0f;
            float dy1 = 2.0f * float(srcSubInDstRect.y + srcSubInDstRect.height) / float(dstSize.height) - 1.0f;
            ScopedViewportRect autoViewportRect(gl, 0, 0, dstSize.width, dstSize.height);

            RectTriangles rects;

            gfx::IntSize realTexSize = srcSize;
            if (!CanUploadNonPowerOfTwo(gl)) {
                realTexSize = gfx::IntSize(RoundUpPow2(srcSize.width),
                                           RoundUpPow2(srcSize.height));
            }

            if (aSrc->GetWrapMode() == LOCAL_GL_REPEAT) {
                rects.addRect(/* dest rectangle */
                        dx0, dy0, dx1, dy1,
                        /* tex coords */
                        srcSubRect.x / float(realTexSize.width),
                        srcSubRect.y / float(realTexSize.height),
                        srcSubRect.XMost() / float(realTexSize.width),
                        srcSubRect.YMost() / float(realTexSize.height));
            } else {
//.........这里部分代码省略.........