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// Copyright 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CC_TILE_PRIORTY_H_
#define CC_TILE_PRIORTY_H_
#include "base/memory/ref_counted.h"
#include "cc/picture_pile.h"
#include "ui/gfx/rect.h"
#include "ui/gfx/size.h"
namespace cc {
struct TilePriority {
// Set to true for tiles that should be favored during, for example,
// scrolls.
bool on_primary_tree;
// A given layer may have multiple tilings, of differing quality.
// would_be_drawn is set for the tiles that are visible that would be
// drawn if they were chosen.
bool would_be_drawn;
// We expect it to be useful soon.
bool nice_to_have;
// Used to prefer tiles near to the viewport.
float distance_to_viewport;
// TODO(enne): some metric that penalizes blurriness.
};
enum TileMemoryLimitPolicy {
// Nothing.
ALLOW_NOTHING,
// Use as little as possible.
ALLOW_ONLY_REQUIRED, // On primary tree, would be drawn.
// Use as little as possible.
ALLOW_NICE_TO_HAVE, // On either tree, nice to have
// Use as much memory, up to memory size.
ALLOW_ANYTHING,
};
class GlobalStateThatImpactsTilePriority {
public:
GlobalStateThatImpactsTilePriority()
: memory_limit_policy(ALLOW_NOTHING)
, memory_limit_in_bytes(0)
, smoothness_takes_priority(false)
, pending_tree_frame_number(-1)
, active_tree_frame_number(-1) {
}
TileMemoryLimitPolicy memory_limit_policy;
size_t memory_limit_in_bytes;
// Set when scrolling.
bool smoothness_takes_priority;
// Use -1 if no tree.
int pending_tree_frame_number;
int active_tree_frame_number;
};
class TilePriorityComparator {
public:
TilePriorityComparator(GlobalStateThatImpactsTilePriority& global_state)
: global_state_(global_state) {}
int compare(const TilePriority& a, const TilePriority& b) {
// TODO(nduca,enne): Implement a comparator using the attributes here.
return 0;
}
private:
GlobalStateThatImpactsTilePriority global_state_;
};
} // namespace cc
#endif
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