gfx::Rect old_tiling_rect_over_tiles =
tiling_.ExpandRectToTileBounds(gfx::Rect(old_tiling_size));
if (min_toss_x < tiling_.num_tiles_x()) {
- int unrecorded_left = std::max(tiling_.TilePositionX(min_toss_x),
- interest_rect_over_tiles.right());
+ // The bounds which we want to invalidate are the tiles along the old
+ // edge of the pile. We'll call this bounding box the OLD EDGE RECT.
+ //
+ // In the picture below, the old edge rect would be the bounding box
+ // of tiles {h,i,j}. |min_toss_x| would be equal to the horizontal index
+ // of the same tiles.
+ //
+ // old pile edge-v new pile edge-v
+ // ---------------+ - - - - - - - -+
+ // mmppssvvyybbeeh|h .
+ // mmppssvvyybbeeh|h .
+ // nnqqttwwzzccffi|i .
+ // nnqqttwwzzccffi|i .
+ // oorruuxxaaddggj|j .
+ // oorruuxxaaddggj|j .
+ // ---------------+ - - - - - - - -+ <- old pile edge
+ // .
+ // - - - - - - - - - - - - - - - -+ <- new pile edge
+ //
+ // If you were to slide a vertical beam from the left edge of the
+ // old edge rect toward the right, it would either hit the right edge
+ // of the old edge rect, or the interest rect (expanded to the bounds
+ // of the tiles it touches). The same is true for a beam parallel to
+ // any of the four edges, sliding accross the old edge rect. We use
+ // the union of these four rectangles generated by these beams to
+ // determine which part of the old edge rect is outside of the expanded
+ // interest rect.
+ //
+ // Case 1: Intersect rect is outside the old edge rect. It can be
+ // either on the left or the right. The |left_rect| and |right_rect|,
+ // cover this case, one will be empty and one will cover the full
+ // old edge rect. In the picture below, |left_rect| would cover the
+ // old edge rect, and |right_rect| would be empty.
+ // +----------------------+ |^^^^^^^^^^^^^^^|
+ // |===> OLD EDGE RECT | | |
+ // |===> | | INTEREST RECT |
+ // |===> | | |
+ // |===> | | |
+ // +----------------------+ |vvvvvvvvvvvvvvv|
+ //
+ // Case 2: Interest rect is inside the old edge rect. It will always
+ // fill the entire old edge rect horizontally since the old edge rect
+ // is a single tile wide, and the interest rect has been expanded to the
+ // bounds of the tiles it touches. In this case the |left_rect| and
+ // |right_rect| will be empty, but the case is handled by the |top_rect|
+ // and |bottom_rect|. In the picture below, neither the |top_rect| nor
+ // |bottom_rect| would empty, they would each cover the area of the old
+ // edge rect outside the expanded interest rect.
+ // +-----------------+
+ // |:::::::::::::::::|
+ // |:::::::::::::::::|
+ // |vvvvvvvvvvvvvvvvv|
+ // | |
+ // +-----------------+
+ // | INTEREST RECT |
+ // | |
+ // +-----------------+
+ // | |
+ // | OLD EDGE RECT |
+ // +-----------------+
+ //
+ // Lastly, we need to consider tiles inside the expanded interest rect.
+ // For those tiles, we want to invalidate exactly the newly exposed
+ // pixels. In the picture below the tiles in the old edge rect have been
+ // resized and the area covered by periods must be invalidated. The
+ // |exposed_rect| will cover exactly that area.
+ // v-old pile edge
+ // +---------+-------+
+ // | ........|
+ // | ........|
+ // | OLD EDGE.RECT..|
+ // | ........|
+ // | ........|
+ // | ........|
+ // | ........|
+ // | ........|
+ // | ........|
+ // +---------+-------+
+
+ int left = tiling_.TilePositionX(min_toss_x);
+ int right = left + tiling_.TileSizeX(min_toss_x);
+ int top = old_tiling_rect_over_tiles.y();
+ int bottom = old_tiling_rect_over_tiles.bottom();
+
+ int left_until = std::min(interest_rect_over_tiles.x(), right);
+ int right_until = std::max(interest_rect_over_tiles.right(), left);
+ int top_until = std::min(interest_rect_over_tiles.y(), bottom);
+ int bottom_until = std::max(interest_rect_over_tiles.bottom(), top);
+
int exposed_left = old_tiling_size.width();
- int left = std::min(unrecorded_left, exposed_left);
- int tile_right =
- tiling_.TilePositionX(min_toss_x) + tiling_.TileSizeX(min_toss_x);
- int exposed_right = tiling_size().width();
- int right = std::min(tile_right, exposed_right);
- gfx::Rect right_side(left,
- old_tiling_rect_over_tiles.y(),
- right - left,
- old_tiling_rect_over_tiles.height());
- resize_invalidation.Union(right_side);
+ int exposed_left_until = tiling_size().width();
+ int exposed_top = top;
+ int exposed_bottom = tiling_size().height();
+ DCHECK_GE(exposed_left, left);
+
+ gfx::Rect left_rect(left, top, left_until - left, bottom - top);
+ gfx::Rect right_rect(right_until, top, right - right_until, bottom - top);
+ gfx::Rect top_rect(left, top, right - left, top_until - top);
+ gfx::Rect bottom_rect(
+ left, bottom_until, right - left, bottom - bottom_until);
+ gfx::Rect exposed_rect(exposed_left,
+ exposed_top,
+ exposed_left_until - exposed_left,
+ exposed_bottom - exposed_top);
+ resize_invalidation.Union(left_rect);
+ resize_invalidation.Union(right_rect);
+ resize_invalidation.Union(top_rect);
+ resize_invalidation.Union(bottom_rect);
+ resize_invalidation.Union(exposed_rect);
}
if (min_toss_y < tiling_.num_tiles_y()) {
- int unrecorded_top = std::max(tiling_.TilePositionY(min_toss_y),
- interest_rect_over_tiles.bottom());
+ // The same thing occurs here as in the case above, but the invalidation
+ // rect is the bounding box around the bottom row of tiles in the old
+ // pile. This would be tiles {o,r,u,x,a,d,g,j} in the above picture.
+
+ int top = tiling_.TilePositionY(min_toss_y);
+ int bottom = top + tiling_.TileSizeY(min_toss_y);
+ int left = old_tiling_rect_over_tiles.x();
+ int right = old_tiling_rect_over_tiles.right();
+
+ int top_until = std::min(interest_rect_over_tiles.y(), bottom);
+ int bottom_until = std::max(interest_rect_over_tiles.bottom(), top);
+ int left_until = std::min(interest_rect_over_tiles.x(), right);
+ int right_until = std::max(interest_rect_over_tiles.right(), left);
+
int exposed_top = old_tiling_size.height();
- int top = std::min(unrecorded_top, exposed_top);
- int tile_bottom =
- tiling_.TilePositionY(min_toss_y) + tiling_.TileSizeY(min_toss_y);
- int exposed_bottom = tiling_size().height();
- int bottom = std::min(tile_bottom, exposed_bottom);
- gfx::Rect bottom_side(old_tiling_rect_over_tiles.x(),
- top,
- old_tiling_rect_over_tiles.width(),
- bottom - top);
- resize_invalidation.Union(bottom_side);
+ int exposed_top_until = tiling_size().height();
+ int exposed_left = left;
+ int exposed_right = tiling_size().width();
+ DCHECK_GE(exposed_top, top);
+
+ gfx::Rect left_rect(left, top, left_until - left, bottom - top);
+ gfx::Rect right_rect(right_until, top, right - right_until, bottom - top);
+ gfx::Rect top_rect(left, top, right - left, top_until - top);
+ gfx::Rect bottom_rect(
+ left, bottom_until, right - left, bottom - bottom_until);
+ gfx::Rect exposed_rect(exposed_left,
+ exposed_top,
+ exposed_right - exposed_left,
+ exposed_top_until - exposed_top);
+ resize_invalidation.Union(left_rect);
+ resize_invalidation.Union(right_rect);
+ resize_invalidation.Union(top_rect);
+ resize_invalidation.Union(bottom_rect);
+ resize_invalidation.Union(exposed_rect);
}
}
projects / platform / framework / web / crosswalk.git / blobdiff