C++ nsIntRegion::Sub方法代码示例

bool
ClientTiledThebesLayer::RenderLowPrecision(nsIntRegion& aInvalidRegion,
                                           const nsIntRegion& aVisibleRegion,
                                           LayerManager::DrawThebesLayerCallback aCallback,
                                           void* aCallbackData)
{
  // Render the low precision buffer, if the visible region is larger than the
  // critical display port.
  if (!nsIntRegion(LayerIntRect::ToUntyped(mPaintData.mCriticalDisplayPort)).Contains(aVisibleRegion)) {
    nsIntRegion oldValidRegion = mContentClient->mLowPrecisionTiledBuffer.GetValidRegion();
    oldValidRegion.And(oldValidRegion, aVisibleRegion);

    bool updatedBuffer = false;

    // If the frame resolution or format have changed, invalidate the buffer
    if (mContentClient->mLowPrecisionTiledBuffer.GetFrameResolution() != mPaintData.mResolution ||
        mContentClient->mLowPrecisionTiledBuffer.HasFormatChanged()) {
      if (!mLowPrecisionValidRegion.IsEmpty()) {
        updatedBuffer = true;
      }
      oldValidRegion.SetEmpty();
      mLowPrecisionValidRegion.SetEmpty();
      mContentClient->mLowPrecisionTiledBuffer.SetFrameResolution(mPaintData.mResolution);
      aInvalidRegion = aVisibleRegion;
    }

    // Invalidate previously valid content that is no longer visible
    if (mPaintData.mLowPrecisionPaintCount == 1) {
      mLowPrecisionValidRegion.And(mLowPrecisionValidRegion, aVisibleRegion);
    }
    mPaintData.mLowPrecisionPaintCount++;

    // Remove the valid high-precision region from the invalid low-precision
    // region. We don't want to spend time drawing things twice.
    aInvalidRegion.Sub(aInvalidRegion, mValidRegion);

    TILING_LOG("TILING %p: Progressive paint: low-precision invalid region is %s\n", this, Stringify(aInvalidRegion).c_str());
    TILING_LOG("TILING %p: Progressive paint: low-precision old valid region is %s\n", this, Stringify(oldValidRegion).c_str());

    if (!aInvalidRegion.IsEmpty()) {
      updatedBuffer = mContentClient->mLowPrecisionTiledBuffer.ProgressiveUpdate(
                            mLowPrecisionValidRegion, aInvalidRegion, oldValidRegion,
                            &mPaintData, aCallback, aCallbackData);
    }

    TILING_LOG("TILING %p: Progressive paint: low-precision new valid region is %s\n", this, Stringify(mLowPrecisionValidRegion).c_str());
    return updatedBuffer;
  }
  if (!mLowPrecisionValidRegion.IsEmpty()) {
    TILING_LOG("TILING %p: Clearing low-precision buffer\n", this);
    // Clear the low precision tiled buffer.
    mLowPrecisionValidRegion.SetEmpty();
    mContentClient->mLowPrecisionTiledBuffer.ResetPaintedAndValidState();
    // Return true here so we send a Painted callback after clearing the valid
    // region of the low precision buffer. This allows the shadow buffer's valid
    // region to be updated and the associated resources to be freed.
    return true;
  }
  return false;
}

bool
ClientTiledLayerBuffer::ProgressiveUpdate(nsIntRegion& aValidRegion,
                                         nsIntRegion& aInvalidRegion,
                                         const nsIntRegion& aOldValidRegion,
                                         BasicTiledLayerPaintData* aPaintData,
                                         LayerManager::DrawThebesLayerCallback aCallback,
                                         void* aCallbackData)
{
  bool repeat = false;
  bool isBufferChanged = false;
  do {
    // Compute the region that should be updated. Repeat as many times as
    // is required.
    nsIntRegion regionToPaint;
    repeat = ComputeProgressiveUpdateRegion(aInvalidRegion,
                                            aOldValidRegion,
                                            regionToPaint,
                                            aPaintData,
                                            repeat);

    // There's no further work to be done.
    if (regionToPaint.IsEmpty()) {
      break;
    }

    isBufferChanged = true;

    // Keep track of what we're about to refresh.
    aValidRegion.Or(aValidRegion, regionToPaint);

    // aValidRegion may have been altered by InvalidateRegion, but we still
    // want to display stale content until it gets progressively updated.
    // Create a region that includes stale content.
    nsIntRegion validOrStale;
    validOrStale.Or(aValidRegion, aOldValidRegion);

    // Paint the computed region and subtract it from the invalid region.
    PaintThebes(validOrStale, regionToPaint, aCallback, aCallbackData);
    aInvalidRegion.Sub(aInvalidRegion, regionToPaint);
  } while (repeat);

  // Return false if nothing has been drawn, or give what has been drawn
  // to the shadow layer to upload.
  return isBufferChanged;
}

static void
SubtractTransformedRegion(nsIntRegion& aRegion,
                          const nsIntRegion& aRegionToSubtract,
                          const Matrix4x4& aTransform)
{
  if (aRegionToSubtract.IsEmpty()) {
    return;
  }

  // For each rect in the region, find out its bounds in screen space and
  // subtract it from the screen region.
  nsIntRegionRectIterator it(aRegionToSubtract);
  while (const IntRect* rect = it.Next()) {
    Rect incompleteRect = aTransform.TransformBounds(ToRect(*rect));
    aRegion.Sub(aRegion, IntRect(incompleteRect.x,
                                   incompleteRect.y,
                                   incompleteRect.width,
                                   incompleteRect.height));
  }
}